In situ monitoring of oxygen depletion in hypoxic ecosystems of coastal and open seas, and land-locked water bodies

Project Information

HYPOX

Grant agreement ID: 226213

Project closed

Start date 1 April 2009

End date 31 March 2012

Funded under

• Specific Programme "Cooperation": Environment (including Climate Change)

Total cost € 4 665 281,20

EU contribution € 3 499 710,90

Coordinated by

MAX-PLANCK-GESELLSCHAFT ZUR FORDERUNG DER WISSENSCHAFTEN EV
Germany

Final Report Summary - HYPOX (In situ monitoring of oxygen depletion in hypoxic ecosystems of coastal and open seas, and land-locked water bodies)

Executive Summary:
4.1.1 Executive Summary

HYPOX carried out pioneering work to build capacities for state of the art oxygen monitoring. The adopted monitoring strategies take relevant temporal and spatial scales of oxygen depletion into account that are inadequately addressed by previous oxygen observation approaches. To achieve this HYPOX deployed stand-alone or cabled observatories that are able to perform long-term continuous measurements of oxygen and associated parameters. At several sites, profiling observatories as well as drifting or towed instruments were used to investigate spatial patterns of hypoxia. The sites were carefully selected to cover a large range of contrasting ‘hypoxia characteristics’ with respect to hydrographical setting, man made pressures, and vulnerability to climate change. Supported by modeling studies that were carried out as part of HYPOX, this facilitates the extrapolation of the knowledge obtained – both with respect to hypoxia characteristics and appropriate monitoring strategies – to a large variety of ecosystems. In order to comprehensively address hypoxia, ecosystem responses (with a strong focus on hypoxia impact on biogeochemical processes and element cycling) have been included as well as the investigation of past hypoxic conditions based on faunal patterns and organic and inorganic proxies from the sediment record. Adopted monitoring strategies and technologies were carefully selected according to identified gaps in knowledge and existing information on the characteristics of the respective target sites. Based on generalized findings achieved by careful analysis of the data from observatories and field campaigns as well as application of data assimilation and modeling techniques, hypoxia ecosystems were classified and recommendations for future oxygen monitoring defined.
Supporting GEO tasks within the running GEO Workplan (2009-12) has been one of the major goals of the project. The results obtained in HYPOX are highly relevant to GEOSS objectives from ecosystem, water management, and climate points of view. Four HYPOX services, each representing a metadata or data delivery service capable to comply with a GEOSS accepted standard, have been registered at the GEOSS registry. Substantial progress was made concerning the interoperability of observation systems for oxygen depletion in different systems. A standardized and GEOSS compliant data flow from the observatories to the end users was established. The achievements of the HYPOX project substantially improved capacities for oxygen monitoring as well as for the prediction of oxygen depletion and evaluation of existing and future impacts on ecosystems. An increased demand for ocean observation and in particular for oxygen observations in the next decades is foreseen in the context of the Marine Strategy Framework Directive and in response to the expected increase in the exploration of marine Resources. HYPOX knowledge provides essential pieces to a conclusive observing strategy to ensure sustainability of the envisaged activities through baseline studies as well as by the observation of changes. This represents a major potential impact generated by the project that will extend into the future.
Observations and measurements obtained by the observatories and during the targeted field campaigns represent one of the most important project results. The data are archived in the long term data repository and publishing network PANGAEA (http://www.pangaea.de) and accessible through the HYPOX data portal (http://dataportals.pangaea.de/hypox). The portal additionally contains information on the sites and descriptions of the observatories. The data sets are also listed in table 4.2.A2 in this report. Peer reviewed publications as well as dissemination activities (e.g. scientific conferences, workshops, TV-, and radio shows, newspapers) represent other important outcomes of the project and are listed in tables 4.2.A1 and A2 of this report. Several reports have been produced to distribute the knowledge obtained in HYPOX. The reports as well as scientific presentations held at the project meetings are available at the information section of the project web site (http://www.hypox.net/front_content.php?idcat=399). The information section further includes more general and intelligible information on HYPOX and on hypoxia in the form of brochures, policy briefs, posters, and presentations. Some of the project outreach material is also included in section 4.1.6. Images and video clips providing further information on project activities and target sites are found in the media section of the project web site (http://www.hypox.net/front_content.php?idcat=528).
Project Context and Objectives:
4.1.2 Summary description of project context and objectives

The occurrence of hypoxic (low oxygen) conditions is increasing in water bodies worldwide. This is mainly a consequence of anthropogenic nutrient input (‘eutrophication’) and global warming. Eutrophication mainly involves fertilizer runoff from agriculture and input of domestic and industrial waste waters and stimulates excessive growth of microalgae (algal blooms) just like crop growing in fertilized farmlands. The biomass produced in excess sinks to the seafloor where it is being utilized by animals and micro-organisms. The oxygen that is consumed by these organisms reduces the oxygen content of bottom waters. If bottom water oxygen declines significantly, ecosystems undergo successive deterioration. If the oxygen drops to very low levels, mass mortality of higher organisms sets in (e.g. Fish kills). Eventually, ecosystems turn into permanently oxygen free (anoxic) ‘dead zones’ where micro-organisms replace all higher life. The collapse of animal communities leads to a dramatic decline in ecosystem functions and services such as biodiversity, fisheries, and tourism. Once the oxygen is depleted a vicious cycle sets in that adds to ecosystem decline and impedes recovery. Nutrients, locked in the sediments in the presence of oxygen are returned to the water column where they stimulate further algal growth. The combination of microbial and chemical processes at oxygen poor conditions further results in the release of toxic substances and greenhouse gases from the seafloor. Global warming is expected to add to oxygen depletion: warming of water will lead to degassing of oxygen, and an enhanced microbial activity. Together with changes in wind and precipitation patterns, higher temperatures will potentially increase stratification at many sites and reduce vertical oxygen transport to deeper waters. The situation is not expected to improve: Global warming is predicted to decrease oceanic oxygen concentrations by several percent over the next century and ever-growing human populations are likely to increase nutrient runoff and the formation of ‘dead zones’.
Irrespective of the substantial threats of hypoxia for aquatic ecosystems, oxygen monitoring is still limited to relatively few sites that are typically visited monthly or even at longer time intervals. To get alarmed before ecosystems lose functions that may take several decades to restore, oxygen monitoring capacities have to be improved. The response of individual organisms and ecosystems as a whole depends on frequency, duration, spatial extent and severity of hypoxia events. Hence, state of the art monitoring efforts need to consider the appropriate temporal and spatial scales in order to address the complexity of hypoxia related effects and to be able to assess the status of an ecosystem. In order to maximize the gained knowledge, HYPOX monitoring of oxygen and related parameters were carried out in a variety of aquatic systems that differ in oxygen status or sensitivity towards change. HYPOX target sites in coastal and open seas include the North Atlantic - Arctic Ocean transition, three contrasting sites in the Black Sea, the world’s largest anoxic basin (Bosporus outlet area, Romanian Shelf, Crimean Shelf) as well as Baltic Sea sites (Gotland Basin, shallow western Baltic). Selected land-locked water bodies include Swiss lakes as freshwater systems, the Swedish Koljoe fjord and the Scottish marine Loch Etive as humid fjord systems as well as several lagoons and embayments in the subtropical Greek Ionian Sea.
Continuous measurements of oxygen and associated parameters and dedicated field campaigns represent the core part of the HYPOX project. The field work focused on the physical and biological processes that contribute to oxygen depletion and on the effects of oxygen conditions on animal communities and biogeochemical processes. Compared to standard oxygen monitoring that simply follows temporal changes in oxygen concentrations this approach allows to assess the causes of hypoxia formation as well as the consequences for ecosystems. Investigations of actual oxygen conditions are accompanied by studies of past hypoxia to improve our understanding of long term trends of hypoxia and the effect of changing climate on oxygen conditions. These studies include analyses of existing long term data series, indicator species, benthic communities, and organic and inorganic proxies for past oxygen conditions that are preserved in the sediment record. These combined investigations allow a holistic perspective on hypoxia causes and consequences and demonstrate how an integrated observation of oxygen depletion may look. In order to extend the gained knowledge in space (i.e. generalization of the findings) as well as in time (i.e. extrapolation of current observations into the future) hypoxia modeling represented another intrinsic part of the project. The obtained generalizations and forecasting capabilities facilitate an examination of the effects of future climate and eutrophication scenarios on oxygen availability and ecosystem functioning. If ecosystems are deteriorating, modeling capabilities will also provide means to decide on adequate countermeasures to be taken. Combining observations and predictions of oxygen availability with existing knowledge about the effects of hypoxia on animal communities and ecosystems improves our understanding of the potential loss of ecosystem functions and services as a consequence of global warming and eutrophication.
One central HYPOX objective was to contribute to the actions towards the implementation of a Global Earth Observation System of Systems (GEOSS) that are coordinated by the Group on Earth Observations (GEO) and laid out in the GEO Workplan (2009-2012). HYPOX adopted GEOSS principles of data sharing and standardization and registered services at the GEOSS registry. By filling gaps in oxygen depletion measurement capabilities and in standardization and sharing of data relevant to understanding present and future impacts of oxygen depletion, HYPOX added to the societal benefits addressed by GEOSS. Project partners took part in selected task groups and actively contributed to GEO activities (plenaries, summits, work group meetings, workshops, GEO Workplan preparation). Workshops carried out at project meetings and conferences served to increase awareness for GEOSS within and outside of the consortium.
Seven work packages (WPs) and a coordination and outreach work package closely collaborate to achieve the objectives and disseminate the obtained data and knowledge concerning in situ monitoring, field work, data sharing, data assimilation, modeling, and the assessment of future hypoxia formation and its impacts on ecosystems. An overview of the work package structure including the interconnections is provided in the supplementary material (part 4.1.6 of this report). The observational work in (1) coastal and open seas and (2) land-locked water bodies is carried out in WP6 and 7, respectively. WP6 and 7 are closely connected to WP1 that is set up to decide on the appropriate observatory technologies and monitoring strategies for the different sites and to collect the knowledge obtained on these issues upon observatory implementation and operation. WP4 adds the historic perspective to oxygen observations looking into long term monitoring data sets, recent and fossil animal communities, and the sedimentary record. WP5 takes care of the collection and archiving of existing data from the different target sites as well as of the huge amount of data obtained in HYPOX in compliance with common standards in ocean observation. WP2 directly uses the data to improve and validate models of hypoxia formation and the effect of oxygen depletion on biogeochemical processes in order to generalize findings and build forecasting capabilities. The knowledge obtained from measuring and modeling efforts is collected and synthesized by WP3. Finally, WP8 takes care of dissemination and outreach activities as well as project coordination. In the following the main tasks of the different WPs are highlighted.
WP1 (‘Improving and integrating in situ observation capacities of oxygen depletion’) provided the platform to discuss and optimize design and operation of in situ observatories at the selected project sites in coastal and open seas, and land-locked water bodies. Additionally, WP1 defined the parameters that, together with oxygen, are required to allow for an unambiguous interpretation of the acquired data. To facilitate data archiving and data sharing, WP1 was – in close collaboration with WP5 – responsible for standardization of metadata and products for data sharing. Another important WP1 task was the collection of information on the characteristics of the respective observatory sites, the site specific scientific requirements, and the instrumentation to be used. WP1 also focused on the definition of recommendations for observatory operation, for a harmonization of metadata descriptions, and for feasible ways to assure and control data quality. Towards the end of the project, WP1 developed recommendations and strategies for future monitoring activities in hypoxic sites according to the data collected in the HYPOX project. Furthermore the design and architecture of an interoperable data system and appropriate quality assurance procedures were defined based on the information collected from the different partners and sites.
WP2 (‘Modeling and prediction of short and long term factors affecting oxygen depletion in different systems’) improved the prediction of oxygen depletion in aquatic ecosystems by developing and using numerical tools to assimilate oxygen sensor data, by integrating the various observations made at different spatial and temporal scales. A further important task was the provision of feedback to observational scientists regarding optimal sampling and observation strategies. The performance of physical and biogeochemical models was tested against the observations from the different HYPOX target sites. Then the models were used to assess the sensitivity of oxygen depletion to variations of physical and biogeochemical parameters on different temporal and spatial scales. This represented a first step to test different scenarios of climate change, eutrophication, natural variability for different open and land-locked systems and their effects on oxygen depletion. Furthermore, WP2 was set up to advance our understanding of the relative importance of oxygen supply and oxygen use in governing oxygen depletion, providing essential knowledge to distinguish natural variability from manageable, anthropogenic effects. Based on the findings obtained in HYPOX, WP2 finally synthesized the knowledge on the factors governing hypoxia formation and on the prediction of hypoxia in the different systems as obtained from the modeling and data assimilation approaches applied.
WP3 (‘Existing and future impacts of hypoxia on ecosystems’) was dedicated to the evaluation of existing and potential future impacts of hypoxia and anoxia on aquatic ecosystems. An important task of WP3 was to gain understanding of the physical processes behind the formation of hypoxia at the different target sits in parallel to the study of biological processes, nutrient cycling, and dissolved oxygen dynamics. This combined effort was crucial for a proper identification of drivers of oxygen deficiency. Based on the knowledge of the drivers, WP3 focused on the impact of hypoxia on ecosystems including spatial as well as temporal aspects to understanding the temporal evolution of hypoxia effects and for the classification of ecosystems with respect to drivers, pressures, impacts, and responses. By analyzing existing knowledge and integrating new findings from the field observatories and by numerical modeling, an interdisciplinary understanding of the drivers of oxygen depletion, pathways of ecosystem decline due to hypoxia, pathways of recovery, and impacts of hypoxia on ecosystem goods and services was developed. In the context of WP3, ecosystem function describes also changes in the biogeochemical environment and redox changes due to changes in oxygen availability. WP3 represented the knowledge platform to provide a synthetic, interdisciplinary understanding to support the prediction of oxygen depletion using modeling (via WP2), and to derive important strategies and tools for decision making related to nutrient and water management scenarios. WP3 also provides feedback to WPs 1, 6, and 7 to adjust monitoring to the specific requirements of the respective ecosystem.
WP4 (‘Indicators of past hypoxia dynamics: improving long term records by abiotic and biotic proxies’) used different proxies for past events of oxygen depletion or anoxia in aquatic ecosystems in order to understand past oxygen concentration changes and to explore their applicability for investigations of recent hypoxic conditions. WP4 contributed to an understanding of the history of aquatic ecosystems with regard to variation in oxygen depletion. This was crucial in order to develop and compare scenarios of global change and their effects on oxygen depletion and the ecosystem. Proxies applied include the benthic community composition as well as inorganic and organic constituents in the sediment record. Methods used in WP4 include high resolution seismic profiling as well as sediment core analysis using a range of inorganic and organic substances that provide information on past conditions. To determine how oxygen availability changes benthic community structure and ecosystems in general, biodiversity (macrobenthic, meiobenthic, microbial) was investigated in sediment samples from different water depths.
WP5 (‘Knowledge base on oxygen depletion: Data sharing, standardization and interoperability according to GEOSS’) was dedicated to enable a regular and reliable flow of data from the observatories and other data acquired within HYPOX or available from other sources to the data archive and the data portal. In cooperation with WP 1, 6, & 7 comprehensive descriptions of the data going back to the individual sensor, data quality descriptors, and instrument standards on calibration and methodology were provided. All that information was collected and added as metadata to the individual sensor data. WP5 data management task encompassed the complete observation data life cycle, from data capture, processing, quality assessment and quality control, archiving and dissemination, compilation and publication of regular and reliable data products. WP5 also assured that HYPOX data management and corresponding infrastructures are compliant with ISO / OGC standards and with the principles of GEOSS to facilitate access by potential users.
WP6 and WP7 (WP6: ‘Assessing in situ oxygen depletion in shelf and open seas’; WP7: ‘Assessing in situ oxygen depletion in land-locked water bodies’) carried out investigations in (1) open and coastal seas and (2) land-locked water bodies, respectively. In situ observatories / monitoring platforms were set up and targeted field campaigns were performed at the different target sites. For WP6 this included sites in the Black Sea (Bosporus outlet are, several sites at the Northwestern shelf off Romania and the Crimean shelf), the Baltic Sea (Gotland Basin, Eckernfoerde Bay), and the HAUSGARTEN area in the Fram Strait at the North-Atlantic / Arctic transition. Target sites in WP7 included Swedish and Scottish fjords (Koljoe Fjord, Loch Etive), Ionian Sea lagoons and embayments (Amvrakikos Gulf, Aetoliko Lagoon, Katakolo Bay) and Swiss Lakes (Lake Zurich, Lake Zug, Lake Lugano, and Lake Rotsee). High temporal resolution continous and – as far as possible – long term monitoring observations and results of targeted field campaigns were used for assessing characteristics, drivers, and consequences of oxygen depletion. As a first step the work in WP6 and 7 also included the collection of existing relevant oceanographic data of the target sites as well as knowledge on ecosystem, water management, and climate. As far as possible this knowledge was delivered or linked to the HYPOX data base and used to characterize the present status as well as history of the respective open sea areas. This information served to decide on appropriate monitoring strategies and contributed to the identification of gaps in current observation capabilities for the respective areas. In WP6, relevant physical (salinity, temperature, currents and freshwater input) and biogeochemical (oxygen, nutrients, turbidity) parameters were measured in the most severe hypoxic / anoxic open European seas (i.e. Baltic Sea, Black Sea) and in the Arctic where previous work indicates rapid decrease in bottom water oxygen concentrations due to alteration of transport processes related to global change. WP7 sites were selected to cover a broad range of settings with respect to anthropogenic impact, hydrographic conditions (e.g. frequency and mechanism of bottom water renewal / overturning events) and sensitivity towards climate change. In collaboration with WP1 and WP5, WP6 and 7 were also responsible for continuous assessment and quality control of collected data. Feedback from other WPs for refinement of technology (WP1), identification of key parameters (WP3), and temporal scales for assessing oxygen depletion in the respective systems was used to adjust observation strategies. Data bases for the respective observatories were established and quality control routines defined together with WP5.
WP8 (‘Coordination, dissemination and outreach’) was dedicated to the management of the project, the dissemination of the project findings, and outreach towards the scientific community, the GEO community, as well as towards potential end users of the data acquired in HYPOX. Management issues included internal communication and integration of all partners as well as monitoring of the overall progress towards project objectives. WP8 supported and guided the project partners with respect to scientific and administrative obligations including deliverables as well as reporting on scientific progress and finances towards the EC. Outreach tasks in WP8 included networking with other scientific bodies and initiatives including members of the GEO community and potential end users of the knowledge produced in HYPOX. WP8 efforts to improve the visibility of HYPOX included the production and distribution of outreach material (project web site, brochures, films...). Furthermore WP8 was responsible for the organization of annual meetings and workshops. In cooperation with WP5, WP8 was responsible for the maintenance and continuous improvement of the project web site.
Project Results:
4.1.3 Description of main S & T results / foregrounds

4.1.3.1 OVERVIEW
HYPOX carried out pioneering work to build capacities for state of the art oxygen monitoring. The adopted monitoring strategies take relevant temporal and spatial scales of oxygen depletion into account that are inadequately addressed by previous oxygen observation approaches. The results obtained in HYPOX largely improve our understanding of the fate of oxygen in aquatic systems. To achieve this HYPOX deployed stand-alone or cabled observatories that are able to perform long-term continuous measurements of oxygen and associated parameters. At several sites, profiling observatories as well as drifting or towed instruments were used to investigate spatial patterns of hypoxia. The sites were carefully selected to cover a large range of contrasting ‘hypoxia characteristics’. Supported by modeling studies that were carried out as part of HYPOX, this facilitates the extrapolation of the knowledge obtained – both with respect to hypoxia characteristics and appropriate monitoring strategies – to a large variety of ecosystems. In order to comprehensively address hypoxia, ecosystem responses (with a strong focus on hypoxia impact on biogeochemical processes and element cycling) have been included as well as the investigation of past hypoxic conditions based on faunal patterns and organic and inorganic proxies from the sediment record. Adopted monitoring strategies and technologies were carefully selected according to identified gaps in knowledge and existing information on the characteristics of the respective target sites. Based on generalized findings achieved by careful analysis of the data from observatories and field campaigns as well as application of data assimilation and modeling techniques, hypoxia ecosystems were classified and recommendations for future oxygen monitoring defined. The results obtained in HYPOX are highly relevant to GEOSS objectives from ecosystem, water management, and climate points of view. The achievements of the HYPOX project substantially improved capacities for oxygen monitoring as well as for the prediction of oxygen depletion and evaluation of existing and future impacts on ecosystems.
Observations and measurements obtained by the observatories and during the targeted field campaigns represent one of the most important project results. The data are archived in the long term data repository and publishing network PANGAEA (http://www.pangaea.de) and accessible through the HYPOX data portal (http://dataportals.pangaea.de/hypox). The portal additionally contains information on the sites and descriptions of the observatories. The data sets are also listed in table 4.2.A2 in this report. Peer reviewed publications as well as dissemination activities (e.g. scientific conferences, workshops, TV-, and radio shows, newspapers) represent other important outcomes of the project and are listed in tables 4.2.A1 and A2 of this report. Several reports have been produced to distribute the knowledge obtained in HYPOX. The reports as well as scientific presentations held at the project meetings are available at the information section of the project web site (http://www.hypox.net/front_content.php?idcat=399). The information section further includes more general and intelligible information on HYPOX and on hypoxia in the form of brochures, policy briefs, posters, and presentations. Some of the project outreach material is also included in section 4.1.6. Images and video clips providing further information on project activities and target sites are found in the media section of the project web site (http://www.hypox.net/front_content.php?idcat=528).

4.1.3.2 IMPROVING AND INTEGRATION OF OXYGEN OBSERVATION CAPACITIES
As a first step to discuss and optimize design and operation of in situ observatories information available from the HYPOX target sites were collected by the different partners. This included available data sets that were put together and linked to the HYPOX data portal were possible. Separate reports were prepared summarizing the available information for open and coastal sea sites and land locked water bodies: Report D6.2 ‘Report on linking of existing data bases with relevance to oxygen depletion to HYPOX data base’ (http://metaworks.pangaea.de/download.php?fileid=149) and D7.2 ‘Compilation report on existing information and data bases relevant for the project’ (http://metaworks.pangaea.de/download.php?fileid=357). This information as well as additional information compiled by the different partners from the literature and knowledge existing at the respective institutions was summarized in report D1.2 ‘Report on scientific requirements and technical specification of a multiparameter and long-term oxygen depletion observation system’ (http://metaworks.pangaea.de/download.php?fileid=144). The report contains all main pieces of information related to the selected sites where HYPOX monitoring activities were carried out and provides information on the different monitoring systems. For the Crimean shelf (Black Sea) scientific and technical requirements to investigate oscillations of the pycnocline (the layer of the water column with strongest density gradients that separate the upper oxic layer from anoxic waters below) were identified. Several specific sites in the region were selected as HYPOX target sites (Dnepr Canyon, Tarkhankut region, Omega Bay, inner and outer Sevastopol Bay). For the Northwestern Black Sea shelf the bottom water oxygenation and its temporal variability after thirty years of reduced nutrient input as well as its influence on nutrient release from the seafloor was identified as the main gap in knowledge. For the Bosporus outlet area the oxygen injection into the deep water column by the inflow of saline waters from the Marmara Sea was selected as the main focus. Plans included investigations of the areal distribution and intensity of the inflow as well as the fate of the oxygen and the impact on biogeochemical processes of the water column. For all Black Sea sites investigations of benthic assemblages including meio- and macrofauna and in some cases microorganisms were included. The naturally existing across shelf oxygen gradients provide ideal condition to study the impact of bottom water oxygenation and its fluctuations on the composition of benthic communities. For the Baltic Sea it was decided to focus HYPOX activities on the Gotland Basin. Planned investigations again focused on the pycnocline and included the water column as well as the seafloor and the processes occurring there. In the case of the Fram Strait the primary focus was on long term oxygen monitoring in the bottom water to indentify gradual changes that may occur in response to climate change at this particularly vulnerable area. For the land-locked water bodies a large portion of the gaps in knowledge related to frequency, intensity, and mechanisms on bottom water oxygenation in silled and stratified water bodies with restricted exchange. This concerned the target sites Koljoe Fjord (Sweden), Loch Etive (Scotland) and some sites in Greece adjacent to the Ionian Sea. In addition, the potential role of gas seepage from the seafloor as a geogenic driver of oxygen depletion was identified as a scientific task for the Greek lagoons and embayments. Somewhat connected to the work carried out in the pycnocline of the Black and Baltic Sea the focus for the investigations of the Swiss lakes was put on the layer of the strongest gradient in density and oxygen with special emphasis on the lowest concentrations and smallest spatial scales that can be addressed with the technology currently available.
Already at an early stage of the project, roles and responsibilities of HYPOX stakeholders covering the complete work flow from the data production of scientists to long term data archiving and publication were defined and compiled as Report D1.1 ‘Report on recommendations for the operation of the individual observatory systems and how the data should be made available’ (http://metaworks.pangaea.de/download.php?fileid=351). These issues were also promoted during a data management / data sharing session at the first annual meeting (http://metaworks.pangaea.de/download.php?fileid=279). Technical specifications on how a distributed HYPOX data system shall be designed and how metadata should be provided were established. Furthermore, appropriate data format and protocol standards were identified (e.g. OGC CSW, SOS, O&M) as well as the steps necessary to contribute data to the HYPOX data portal and to the relevant GEOSS portals.
Special emphasis was on the selection of appropriate methods to address the scientific questions. As HYPOX was no technology-driven project this mainly involved the selection of appropriate measuring platforms and sensors from what was available at the market or already developed by the different partner institutions. However, in some cases existing technologies and instruments had to be modified, improved, combined, or developed from scratch to meet the scientific requirements. One example is the Multifiber Optode MuFO that was constructed to monitor high frequency oscillations of oxygen concentrations in Crimean shelf bottom waters as they may result from internal waves. MuFO allows to simultaneously measure oxygen concentrations at 100 points in the lowermost meters of the water column (Fischer and Koop-Jacobsen, submitted). In order to resolve oxygen oscillations at the level of the pycnocline in space as well as in time a profiling observatory was set up. This cutting edge technology uses an underwater winch to autonomously record consecutive profiles of oxygen and associated parameters. The in-situ Profiling Analyzer (PIA) was constructed to resolve trace levels of oxygen in the water column of the Swiss lakes. The instrument combines state of the art optical sensors for low oxygen concentrations (trace optodes) with microscale Clark electrodes that were operated by custom-built electronics to improve the performance in the lower concentration range. A lot of effort was also put into the improvement, validation and modification of the so-called eddy correlation technique (Berg et al. 2003). This non-invasive method to quantify benthic oxygen fluxes is ideal for the assessment of the role of benthic oxygen demand for hypoxia development. Within HYPOX workshops were carried out and intensive field testing as well as experimental and modeling studies (e.g. Holtappels et al., in prep.) were performed to better understand strengths and limitations of the method. New developments included programming of the software package ‘ECDiagnostics’ for the analysis of eddy correlation measurements (open access freeware that will be released soon) as well as the modification of the method for the determination of sulfide fluxes. Other technical and methodological developments focused on the optimization of existing sensor technologies. A novel procedure for the calibration of optical oxygen sensors (optodes) was established in cooperation with the manufacturer (AADI, Bergen, Norway) and disseminated to scientists and representatives of companies in the field of sensor production at workshops and conferences as well as via publications (e.g. http://www.earthzine.org/2010/05/26/oxygen-monitoring-in-aquatic-ecosystems-eu-project-hypox/; http://meetingorganizer.copernicus.org/EGU2012/EGU2012-9242-1.pdf). Further investigations focused on the long term stability of oxygen optodes and included careful analysis of long term recordings as well as thorough testing under laboratory conditions (Lo Bue et al 2011; http://archimer.ifremer.fr/doc/00045/15584/14489.pdf). To allow for reliable long term monitoring in highly productive coastal environments the effect of biofouling on sensor readings was investigated as well as the feasibility of different antifouling strategies under in situ conditions.
At a later stage of the project, knowledge obtained from observation activities at the different was summarized and used to identify recommendations for future monitoring attempts. The information was compiled into report D1.3 ‘Report on first data quality checks and recommendations for future observation system’ (http://metaworks.pangaea.de/download.php?fileid=362). In addition to descriptions of the monitoring activities based on examples from the different sites and monitoring recommendations the report also addresses issues of data quality control.

4.1.3.3 ASSESSING OXYGEN DEPLETION IN SHELF AND OPEN SEAS AND LAND LOCKED WATER BODIES
Within HYPOX investigations were carried out in open and coastal seas and land-locked water bodies. In situ observatories were set up and targeted field campaigns were performed at the different target sites. High temporal resolution continuous and – as far as possible – long term monitoring observations and results of targeted field campaigns were used for assessing characteristics, drivers, and consequences of oxygen depletion. Target sites in open and costal seas included the most severe hypoxic / anoxic open European seas (i.e. Baltic Sea, Black Sea) as well as the Arctic where previous work indicated rapid decrease in bottom water oxygen concentrations possibly due to alteration of transport processes related to global change. The target sites in land-locked water bodies covered a broad range of settings with respect to anthropogenic impact, hydrographic conditions (e.g. frequency and mechanism of bottom water renewal / overturning events) and sensitivity towards climate change. Sites were geographically separated from each other and ranged from lagoons and embayments in the Ionian Sea (Aetoliko Lagoon, Amvrakikos Gulf, Katakolo Bay) to fjords in northern Europe (e.g. Koljoe Fjord).
In the beginning of the project existing knowledge on hypoxia occurrence was selected for the respective target sites in order to facilitate planning of field campaigns and observatory deployments. This included review and compilation of all historical and present data sets and literature relevant to the project. Where possible, legacy data were provided to the HYPOX data portal. The information represented a starting point of the observational work and was summarized in separate reports focusing on open and coastal seas (D6.2 ‘Report on linking of existing data bases with relevance to oxygen depletion to HYPOX data base’; http://metaworks.pangaea.de/download.php?fileid=149) and land locked water bodies (D7.2 ‘Compilation report on existing information and data bases relevant for the project’; http://metaworks.pangaea.de/download.php?fileid=357). A third report includes information on the legacy data that have been provided to the portal: D 5.1 ‘HYPOX data management plan and policy and catalogue of relevant legacy data sets’ (http://metaworks.pangaea.de/download.php?fileid=148).
Based on the collected information gaps in knowledge were identified as a basis for the selection of appropriate locations and planning of surveys and observatory deployments. To overcome inadequacies of current observation capabilities, a strong focus was on the identification of parameters to be monitored as well as the selection and set up of appropriate sensors and monitoring platforms. Information about the respective observatories and monitoring strategies that were selected for the different sites were collected into the report D1.2 ‘Report on scientific requirements and technical specification of a multiparameter and long-term oxygen depletion observation system’ (http://metaworks.pangaea.de/download.php?fileid=144). Deployments of observatories in the following implementation phase were highly successful and have been realized at all proposed target sites. The observation instruments and approaches included cabled and stand-alone static and profiling oceanographic moorings, benthic observatories, and drifting profilers, as well as ship based instruments that were deployed from ships for areal surveys or vertical profiling at high resolution. Numerous other sampling and measuring methods and technologies were used during the accompanying field campaigns that were carried out to comprehensively address characteristics, drivers as well as the consequences of hypoxia at the respective sites. Thanks to the dedication of project members and allocation of additional funding sources from other projects and partner institutes funds, initial plans could be substantially extended in several respects. Eckernfoerde Bay was included as an additional site in the western Baltic. The Gotland basin observatory that was projected as a standard static oceanographic mooring could be upgraded and turned into a profiling observatory that was capable to monitor the temporal evolution of water column oxygenation throughout the oxic-anoxic transition zone. The stand-alone observatory in the Koljoe Fjord was additionally provided with a cable to the shore providing power supply for continuous operation and broadband communication for near real time data access. The original plans included only one observatory of this kind to be installed in the Scottish fjord Loch Etive. In addition a sea ice observatory in the Arctic was installed towards the end of the project that included sensors to investigate oxygen concentrations in the ice itself as well as in the upper water column.
The description on observatories and achievements is provided by report D6.1 ‘Installation and operation of in situ observatories for monitoring oxygen depletion and associated parameters in shelf and open seas (Black Sea, Baltic Sea, Fram Strait) and collection of data into the HYPOX web portal’ (http://metaworks.pangaea.de/download.php?fileid=355) and D7.1 ‘Set-up and implementation of in situ observatories for monitoring oxygen depletion and associated parameters in land-locked water bodies (Swiss Lakes, Koljoe Fjord, Loch Etive, Ionian Sea lagoon) and data collection into the HYPOX web portal’ (http://metaworks.pangaea.de/download.php?fileid=356). A lot of the findings from the different sites have been presented at international conferences (table 4.2.A2 and ‘conferences, meetings and workshops’ table in section 4.1.6) and already resulted in a number of peer reviewed publications (table 4.2.A1 and ‘publications published and in press’ table in section 4.1.6). Table ‘submitted and planned publications’ in section 4.1.6 lists some of the publications that will be published in the future based on the work carried out. Some more scientific results have been compiled in the form of reports in the end of the project, again separately for open and coastal sea sites and land locked water bodies: D6.3 ‘Report (if possible in the form of publications) on critical parameters for prediction of oxygen depletion in coastal and open sea systems’ (http://metaworks.pangaea.de/download.php?fileid=398) and D7.3 ‘Report (where possible as publications) and assessment of the key physical and biogeochemical processes affecting oxygen depletion in the respective aquatic systems’; (will be available soon at http://www.hypox.net/front_content.php?idcat=399&idlang=19 section ‘documents’).
Data generated by the observatories and by means of accompanying field campaigns were added to the HYPOX web portal / PANGAEA data repository at minimum delay (http://dataportals.pangaea.de/hypox/). Provision of data to the repository took place either semi-automatically or as discrete submissions uploaded by the responsible scientists. At the end of the project the vast majority of the data from the different sites are uploaded and online data continue to stream in. Following GEOSS data sharing policy data are generally open access. For data sets that are currently protected by a moratorium to provide project partners with the time necessary to finalize validation and preparation of scientific publications unrestricted data download will be granted at the latest three years after submission of the data to the archive. However, all data sets are already listed in the portal and metadata as well as contact information of the PI is provided. The data sets contribute directly to the project target to build a knowledge base on oxygen depletion based on GEOSS data sharing, standardization and interoperability principles.
HYPOX monitoring activities were highly successful and a lot of the efforts will hopefully be continued in future projects or on national funds (see section ‘Involvement of HYPOX partners in future hypoxia monitoring and continuation of monitoring efforts started in HYPOX’)
.
4.1.3.3.1 Black Sea
HYPOX observation efforts focused on three target areas in the Black Sea. Conditions at the Bosporus outlet area and the Crimean shelf area are characterized by the natural oxygen gradient of the Black sea ranging from oxic conditions within surface waters to anoxic conditions below the permanent oxycline at approximately 150m water depth. The sites served as ‘hypoxia model systems’ to investigate potential spatio-temporal dynamics of oxygen depletion and the impact of these conditions on different compartments of ecosystems including faunal patterns and biogeochemical processes. The northwestern shelf off Romania represented the third target site. Situated above the permanent oxycline the Romanian shelf still suffered substantially from oxygen depletion and used to harbor vast ‘dead zones’ in the second half of the 20th century. Only after eutrophication (nutrient input from anthropogenic sources) started to be substantially reduced in the1990s conditions improved. Consequently, HYPOX investigations at the northwestern shelf focused on the recovery of a previously hypoxic ecosystem.

4.1.3.3.1.1 Bosporus area
Observational work in the Bosporus outlet area was carried out during two field campaigns in 2009 (R/V ARAR) and 2010 (R/V MARIA S. MERIAN, leg MSM15/1). Water column work focused on the oxygenation of the anoxic water columns by intrusions of warm, saline, and oxygen-rich water from the Marmara Sea that enter the Black Sea through the Bosporus. Additionally sediment investigations were carried out along depth transects spanning from oxygenated to anoxic conditions to study (1) the influence of bottom water oxygenation on benthic meio- and macrofauna communities and (2) indications of past oxygen / redox conditions of the Black Sea based that are preserved in the sedimentary record.
Extensive CTD surveys were carried out to locate the Marmara sea water plume. In 2009, strong oxygen and temperature signatures of the Bosporus plume were found at the mouth of the Bosporus and at stations further to the East. Investigations revealed, however, that oxygen intrusions by Bosporus waters change over time. During the 2010 cruise no oxygen intrusions could be detected below the permanent oxycline and only at one station an aged plume could be identified based on a weak temperature anomaly. CTD survey data have been submitted to the portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.
In order to investigate the influence of oxygen on biogeochemical processes in the water column (especially the nitrogen and manganese cycle), standard and free-falling pump-CTDs were used for high resolution sampling of the deep water column, especially at the depths of the oxygen intrusions. The water samples were analyzed for nutrients and redox-sensitive species including ammonium, nitrate, nitrite, sulfide, phosphate, silicate and manganese. At specific depths, water was sampled to perform experiments with labeled substrates. 15N-labeled ammonium and nitrate were used to detect potential rates of nitrification, denitrification, and anammox. The study indicated a huge impact of oxygen intrusions on biogeochemical conversions in the water column. To quantify the significance of these processes for the nitrogen cycle of the Black Sea as a whole and to understand the factors governing the inflow of Marmara Sea water into the Black sea investigations with modeling tools have been started. These will continue after the end of the project.
In order to investigate intrusions of Marmara Sea water on larger temporal scales a oxygen sensor equipped ARGO type profiling float ‘PROVOR-DO’ was deployed in the area. In contrast to standard ARGO floats the float was programmed to sink to the seafloor after profiling to avoid drifting of the float with the currents during the resting time between profiles in order to maximize the presence within the target area. Unfortunately the float stopped operation already after a couple of profiles. The data obtained, however, provided valuable information on the behavior of the float and was directly used to improve the design. Specifically the communication was upgraded from Argos to Iridium telemetry to reduce the time needed for data transmission and hence the drift during surfacing of the float. An improved float was already constructed within the lifetime of the project and is expected to be launched soon. Data from the first float are available at float reference 5902291.
Sediments were sampled in the Bosporus outlet area along a depth (and, hence, oxygen) gradient to investigate the influence of bottom water oxygen concentrations on benthic assemblages (meio- and macrofauna). The results have important implications for the assessment of hypoxia impacts on benthic communities for areas that are that are threatened with oxygen depletion. Strong changes in faunal communities with changing oxygen availability were observed and indicator species for hypoxic conditions were successfully identified. As far as they are analyzed, fauna data have been uploaded to the data portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6. The work already resulted in several scientific publications (see table 4.2.A1 and the ‘publications published and in press’ table in section 4.1.6 as well as the report D6.3 at http://metaworks.pangaea.de/download.php?fileid=398). An overview about the fauna work in the Bosporus outlet area is also found in presentations held at the project meetings (http://metaworks.pangaea.de/download.php?fileid=321 and http://metaworks.pangaea.de/download.php?fileid=401).

4.1.3.3.1.2 Crimean Shelf area
The observational work focused on two areas at the western Crimean shelf (Dnepr Canyon Paleo-Delta). Investigations were carried out during cruise leg MSM 15/1 of R/V MARIA S. MERIAN. To get a first overview of the position of the oxycline CTD surveys were carried out. Data have been uploaded to the portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6. Oxygen conditions in the bottom waters and visual inspection of the benthic habitats was done by spatial surveys with the towed observatory MEDUSA and the manned submersible JAGO. Track data as well as oxygen and additional data and videos recorded by MEDUSA are available at the data portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.
To investigate temporal dynamics in bottom water oxygen concentrations an array of three moorings were deployed for the duration of the cruise in two areas at different depths around the position of the oxycline. Parameters measured included oxygen, temperature, salinity, and water currents. Some details of the observatory setup and deployment and an example plot are found at http://dataportals.pangaea.de/hypox/index.php?ptype=map&detail&id=112. Indeed, bottom water oxygen showed large fluctuations on time scales of hours to days indicating that hypoxia is not a static phenomenon. Hence benthic communities – potentially also in other areas – have to cope with a much higher variability than previously imagined. Data from the moorings are uploaded to the portal. Direct links are found in table ‘data generated in HYPOX’ in section 4.1.6. Oxygen profiles recorded in the lower meters of the water column at high temporal resolution with the MuFO system showed that fluctuations in bottom water oxygen concentrations even involved lower time scales down to the range of minutes. Detailed investigations of bottom water properties and benthic oxygen demand with short term benthic observatories (BBL-profiler, Eddy Correlation System, micro profiler, benthic chambers) showed that the observed strong temporal variations in oxygen concentration were strongly coupled to physical displacement of the oxycline while the effect of biological processes (benthic oxygen uptake) was minor. To further investigate the oceanographic drivers of the observed oscillations modeling studies are started that will continue after the project ended.
Extensive investigations were carried out to study the influence of oxygen availability on biogeochemical cycling of elements at the Crimean shelf. Main focus of the investigations was on rates and pathways of organic matter mineralization. Studies included in situ investigations with short term benthic observatories (micro profiler, benthic chambers) as well as incubation experiments and geochemical investigations on retrieved sediment cores. Rates of oxygen uptake and total mineralization rates proved to be low. Only a minor fraction of the oxygen is used for the oxidation of reduced substances that are produced during anaerobic carbon degradation in the sediment. Iron and manganese driven early diagenetic processes are restricted to the oxic part of the shelf while significant sulfate reduction is only found in the sediments underlying anoxic waters. Interestingly, sediments subject to hypoxic conditions and strong temporal changes in bottom water oxygen concentrations showed reduced rates of biogeochemical processes, although organic carbon, carbon and nitrogen isotopic composition, as well as C/N ratios were present in similar amounts in all stations. In situ microprofiles of oxygen and geochemical parameters of retrieved cores were uploaded to the portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.
Visual inspections carried out during the MEDUSA and JAGO surveys and close up photography of the seafloor by a high resolution still camera attached to the benthic crawler C MOVE already indicated that benthic live was hardly able to colonize hypoxic zones and zones of strong oscillations in bottom water oxygenation. This was confirmed by sediment samples taken along depth gradients at the Crimean shelf. Rich benthic macrofauna live was restricted to the shallowest depth (100m) where oxygen is presumed to be always available. Further down the shelf where oxygen is found only in limited amounts or only at certain periods in time diversity, abundance, and biomass of macrofauna organisms strongly decreased. In contrast, meiofauna organisms were found at all depths where oxygen was at least occasionally available. Also at low oxygen conditions meiofauna sometimes appeared in large numbers and show complex patterns of species richness and abundances across the oxic and hypoxic shelf. Careful studies of life organisms in freshly retrieved samples indicated that some meiofauna organisms were able to thrive even at anoxic depths. The physiological principle allowing for life without oxygen as well as the question if the organisms are able to complete their life cycle in anoxic habitats are yet to be investigated. Macro and meiofauna data have been uploaded to the portal. Direct links are found in table ‘data generated in HYPOX’ in section 4.1.6. Microorganisms appeared at all depths in relatively uniform numbers. Studies of microbial diversity clearly indicated a strong effect on bottom water oxygenation and its dynamics on benthic bacterial community structure. This work will strongly increase our understanding of hypoxia effects at the microbial scale. Microbial abundances were uploaded to the data portal (Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.). At circular organic matter rich spots of unknown origin that were abundant at the hypoxic parts of the shelf, mats of filamentous sulfide oxidizing bacteria of the genus Beggiatoa were found. To our knowledge this is the first record of the occurrence of mat-forming sulfide reducers in this area.
In order to extend investigations of Black Sea water column properties two ARGO type oxygen sensor equipped floating profilers (‘NEMO floats’) were deployed in the western Black Sea. Within the lifetime of the project they recorded as many as 260 oxygen profiles - equivalent to 8% of all deep Black Sea oxygen profiles collected since measurements started in 1923. They show important oceanographic features of the Black sea with high significance for the oxygenation of the water column and the seafloor (e.g. effect of the shelf topography on diapycnal mixing, cold intermediate water formation in winter). Data analysis requires extensive application of modeling tools and is currently underway. Some first results are found in report D2.5 ‘Report on assimilation of HYPOX observatory oxygen data and model results on factors governing oxygen dynamics in the Black Sea’ (http://metaworks.pangaea.de/download.php?fileid=353)
Further project work was carried out at several other Crimean shelf sites (inner and outer Sevastopol Bay, Omega Bay, Tarkhankut area). Work at these sites did not involve in situ oxygen monitoring. Instead water column and sediments were characterized based on retrieved samples by means of traditional techniques and voltammetry. Again, investigations included extensive studies of benthic fauna. The data are uploaded to the portal (direct links are found in table ‘data generated in HYPOX’ in section 4.1.6).

4.1.3.3.1.3 Northwestern shelf off Romania
Several surveys investigating oxygen distribution, water column characteristics, and benthic fauna assemblages were carried out along established depth transects off the coast of Romania. Oxygen distribution and fauna surveys (macro and meiobenthos) were carried out. In agreement with studies carried out in earlier years oxygen was found to generally decrease with depths. Oceanographic data from the surveys were uploaded to the portal (direct links are found in table ‘data generated in HYPOX’ in section 4.1.6).
Studies of fauna showed a similar pattern as found on the Crimean shelf with biodiversity, abundances, and biomass strongly decreasing with depth. This pattern is indicative of the loss in benthic ecosystem function and services to be expected when systems turn hypoxic. However, compared to conditions in the second half of the last century the ecosystem of the northwestern Black Sea shelf clearly recovered as the former dead zones are largely recolonized. On the other hand, fast growing, opportunistic and sometimes invasive species still occupy ecological niches where long-lived and slow-growing species were found beforehand. Characteristic habitats like mussel beds and fields of the red algae Phyllophora still did hardly reestablish.
The observatory was installed in the sheltered ‘Portita area’ at 28m water depth to monitor the seasonal evolution of bottom water oxygenation on the shelf. The observatory consisted of a static mooring with sensors for oxygen, oceanographic parameters, and currents installed close to the seafloor and an additional oxygen sensor attached further up in the bottom water layer. The obtained data provided the first long-term (3-month) in-situ time-series of oxygen and additional parameters at the seafloor of the north-western shelf. The time series data were uploaded to the data portal (Direct links are found in table ‘data generated in HYPOX’, section 4.1.6.). The observatory data are complemented by benthic nutrient fluxes measurements performed in core incubations and by in situ chamber deployments in May and Sep.. Based on the data it was possible to identify biological and hydrophysical controls on oxygen. In spring at low biological activity and before the evolution of the seasonal thermocline (temperature driven density gradient) bottom water oxygen remained constant. In early summer oxygen decreased probably due to restricted bottom water ventilation as a consequence of thermal stratification. Later in July a sudden drop coincided with increased turbidity indicative of settling organic matter from a sinking senescent phytoplankton bloom. In combination with reduced oxygen solubility and restricted vertical transport bottom water oxygen levels reach hypoxic levels. A few weeks before minimum oxygen concentrations were met at the Portita site a significant fish kill was recorded by project members in a nearby area. The observatory data as well as the fish kill event in Jul. 2010 clearly demonstrate that even after three decades of reduced nutrient input oxygen conditions at the Romanian shelf still didn’t recover completely and may still drop to critical levels in warm summers. When bottom water oxygen concentrations are low, reduced forms of nutrient effluxes (ammonium, phosphate) from the sediment internally fuel productivity, even decades after the peak of eutrophication relaxed.

4.1.3.3.2 Baltic Sea
HYPOX investigations in the Baltic Sea were originally restricted to the eastern Gotland basin where they covered both studies of the water column and the bottom water and seafloor. As in the Black Sea the deep basins of the Baltic Sea are characterized by oxygenated surface waters that are separated by a strong density gradient form the underlying, dense, and anoxic deep waters. Investigations in the Gotland basin again made use the natural ‘hypoxia laboratory’ created by these conditions. Following a project expedition to the Gotland Basin that partially failed due to bad weather conditions, Eckernfoerde Bay in the western Baltic was included as additional project site. This was possible through a close collaboration with the long term monitoring site ‘Boknis Eck’ where regular ship based observations are regularly carried out since decades. The addition of this site broadened the focus of the project considerably and provided strong support to modeling activities.

4.1.3.3.2.1 Eastern Gotland basin
The Gotland basin water column was investigated by means of the stand-alone profiling mooring GODESS (GOtland Deep Environmental Sampling Station; http://www.io-warnemuende.de/GODESS.html). The GODESS observatory consists of a profiling body that contains a multiparameter CTD and a fast optical oxygen sensor that is connected to an underwater winch sitting in the deep anoxic water column. At predefined times the winch is released and the profiling body ascends through the upper part of the water column while recording oxygen, salinity, temperature and additional oceanographic parameters. Three successful deployments were carried out at different seasons within the lifetime of the project. The data have been uploaded to the portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6. Further information as well as an example plot is found in the HYPOX web portal at http://dataportals.pangaea.de/hypox/index.php?ptype=map&detail&id=121.
Although the deep Baltic Sea is one of the most stable stratified water bodies on earth it turned out that conditions at the transition between the oxic and anoxic water part of the water column strongly fluctuate on a time scale of hours to days. The position of the oxic-anoxic interface oscillates most likely due to a combination of vertical movements of the pycnocline (the layer of the steepest gradient in density) and due to water masses with different pycnocline properties passing along the location of the mooring. Fluctuations were most prominent in the stormy season where even injections of oxygen into the anoxic water column below the pycnocline were observed. The observed temporal dynamics in oxygen and, hence, in redox conditions have significant implications for biogeochemical processes and element fluxes between the lower and the upper compartment of the water column (i.e. diapycnal transport). The latter is of high significance for the Baltic Sea ecosystem as nutrients (esp. phosphate) released from the anoxic sediments can be provided to the sunlit top water layer if they cross the pycnocline. In the top layer the nutrients fuel productivity of microalgae including harmful cyanobacteria that are observed to bloom in summer at increasing frequency.
Benthic observatories were deployed in the Gotland Basin in different seasons to investigate areal distribution and temporal dynamics of bottom water oxygenation. Special focus was on the depth where the dynamic oxycline described above hits the seafloor. Bottom water hypoxia monitoring was accompanied by short term incubations of additional instruments to investigate the impact of different oxygen conditions on benthic processes and fluxes. These instruments included benthic chambers, micro profilers, an eddy correlation device and planar optodes for snapshots of vertical oxygen distributions in the sediments. The focus of these studies was on organic matter mineralization and fluxes of nutrients (nitrogen species and phosphate) across the sediment-water interface. Furthermore investigations included water column and sediment sampling for chemical and geochemical analyses and mapping of habitats across the oxygen and depth gradient by means of a towed camera system. Data available at the data portal include water chemistry, sediment geochemical data, as well as interfacial fluxes of oxygen and DIC. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.
Several month long time series of bottom water oxygen concentrations were successfully recorded at the position of the oxycline. In agreement with GODESS observations, measurements depict oxygen fluctuations in the hypoxic zone with periodicities in the range of hours to weeks. Fluctuations were strongest in the stormy season when bottom water oxygenation oscillated between deep hypoxia and concentrations close to air saturation. Correlation with wind data showed that strongest injections of oxygen into bottom waters coincided with strong southwesterly winds. Such major bottom water oxygenation events will strongly affect the redox-sensitive N and P cycling and associated nutrient release from the underlying sediments.
Nutrient release showed strong correlations with the bottom water oxygenation and the prevailing pathway of organic matter mineralization. Ammonium efflux from the sediment peaked under anoxic conditions where also strong fluxes of sulfide were measured. Habitat mapping revealed the pronounced occurrence of microbial mats around the oxycline. Their presence has distinct implications for the benthic nitrogen cycle as these organisms are able to store high amounts of nitrate that is turned into ammonium upon the oxidation of sulfide. Indeed, a strong release of ammonium was found to be associated with the occurrence of microbial mats. This contributes to enhanced primary production potentially leading to eutrophication and promoting fast oxygen depletion. More information on the studies carried out at the Gotland basin seafloor are found in presentations held at the HYPOX project meetings (http://metaworks.pangaea.de/download.php?fileid=331; ...fileid=373; ... fileid=374)

4.1.3.3.2.2 Eckernfoerde Bay / western Baltic
The focus of the investigations at the long term monitoring site Boknis Eck in Eckernfoerde Bay was on nutrient recycling under a regime of seasonal hypoxia. The site was visited monthly over a period of one year and water column characteristics were studied by standard CTD casts. Investigations were mostly based on geochemical analyses of sediment cores as well as core incubations and involved a strong modeling component. Geochemical data obtained from the sediment cores are uploaded to the portal (direct links in table ‘data generated in HYPOX’ in section 4.1.6.). Data on oxygen and many other parameters are available through the Boknis Eck monitoring time series (http://www.loicz.org/projects/documents/010412/index_0010412.html.en)
High nutrient concentrations in the western Baltic lead to an intense productivity in surface waters. Microalgae that sink out of the sunlit top layer settle on the seafloor where they are mineralized. Nutrients, especially ammonium are released from the algal biomass upon microbial degradation and efficiently pumped back to the water column by sediment dwelling worms keeping rates of nutrient recycling high. At warm and stagnant summer conditions severe hypoxia was found to develop in the bottom water. Consequently, seafloor worm populations were wiped out. Nutrient effluxes from the seafloor stay high also without the worms’ pumping activity. Measurements, experiments and numerical simulations revealed that methane produced by microorganisms under hypoxic conditions seeped from the seafloor and carried nutrient-rich pore water to the water column in summer. Nutrient recycling even got more efficient under these conditions as in addition to ammonium also phosphates escaped from the anoxic sediments. Seasonal hypoxia thus acts in support of even more hypoxia by fertilizing algal growth that further reduces bottom water oxygen upon decay. As a side effect hypoxia also adds to global warming if methane – a strong greenhouse gas – escapes to the atmosphere. It can be expected that similar feedback loops exist also in other areas that similarly suffer from summer hypoxia.

4.1.3.3.3 HAUSGARTEN / Fram Strait
In order to understand the impact of large-scale environmental changes on the Arctic marine ecosystem, the deep-sea observatory HAUSGARTEN in Fram Strait west of Svalbard was established. Multidisciplinary research activities at HAUSGARTEN cover almost all compartments of the marine ecosystem from the pelagic zone to the benthic realm. Repeated water and sediment sampling and the deployment of moorings and free-falling systems have taken place since the observatory was established in summer 1999. Previous investigations indicated a decrease in bottom water oxygen concentrations that may be due to alteration of transport processes related to global change. Within HYPOX observational work was continued and long term oxygen measurements were extended. More information on the benthic observatory that was equipped with additional oxygen sensors and deployed in HYPOX is found at http://dataportals.pangaea.de/hypox/index.php?ptype=map&detail&id=13. Oxygen data from the HAUSGARTEN observatory including long term time series recorded before and during HYPOX (> 2000 days of recording in total) and discrete bottom water oxygen values determined in samples were uploaded to the data portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.
The data obtained by the replicate sensors were used to investigate the long term stability and reliability of optode readings. The findings were included into a publication (Lo Bue et al. 2011). Based on the current knowledge it has to be concluded that despite the good performance of the optodes in short-term and shallow-water applications, this sensor type is probably not entirely suited for long-term measurements in deep, polar waters, and in low-current environments in general. The attempt to continuously study the temporal development of dissolved oxygen concentrations in the deep Arctic Ocean remains to be a big challenge, and apparently needs new, improved sensors.
The monitoring of bottom water oxygenation was complemented with microprofiler measurements of sediment oxygenation. Transecting microprofilers were used to investigate benthic oxygen distribution / aerobic mineralization on a microscale. A long term micro profiler device with long-lived optical microsensors was deployed in summer 2011. Data from the instrument that will be retrieved in summer 2012 will show for the first time seasonal changes and the effect of ice cover on sediment oxygen distributions and uptake rates. Finally, sediment sampling for geochemical analyses has been carried out in HYPOX.
Connected to HYPOX objectives and partly based on knowledge obtained within the project an autonomous monitoring system was built in cooperation with OPTIMARE (Bremerhaven, Germany) and successfully deployed during in the Arctic in 2011. The system monitors chemical, oceanographic and optical parameters in and under the Arctic sea ice (oxygen, temperature, salinity, photosynthetically active radiation and chlorophyll fluorescence) and allows to extend investigations of oxygen levels and climate change effects to the Arctic. The system consists of a surface unit standing on the ice and three sensor modules, one located within the ice and two below the ice at different water depths. In addition, a temperature string with 24 thermistors is connected to the surface unit to measure temperature profiles within the ice and in the upper water column. Data are sent via Iridium satellite network in near real time.

4.1.3.3.4 Loch Etive
Investigations in the fjord-like Loch Etive in Scotland, UK started with surveys on properties of the seafloor (including investigations of benthic fauna and biogeochemical conditions) and the water column in the two contrasting basins (upper and lower Loch Etive). These provided baseline data and served to identify suitable observatory locations.
Subsequently, two permanent in situ observatories, one cabled online observatory in the upper hypoxic basin and one autonomous mooring in the lower well mixed basin in Loch Etive, have been deployed in autumn 2009. The new and innovative Loch Etive Cabled Observatory (LECO) has been designed and constructed for long term monitoring of oxygen concentrations and other physical parameters (salinity, temperature, current speed and direction) at two different depths at high temporal resolution. A base station to which the observatory is connected was established on the shores of upper Loch Etive. The cable and base station enables real-time data transfer (via broadband) and continuous power supply for the instruments which in turn provide the possibility for long term monitoring of oxygen, salinity, temperature and currents at high temporal resolution (every 10min). Additional information on the observatory is found at http://dataportals.pangaea.de/hypox/index.php?ptype=map&detail&id=21. From the beginning on the collected data are stored on a local database at SAMS and displayed in real-time on a dedicated webpage since spring 2010. Since summer 2011 the data stream has been hooked via SOS server to the data repository PANGAEA and the HYPOX data portal. The observatory generated high quality data until it was struck by lightning in winter 2011. Repair is underway and a redeployment of the observatory is planned for the near future. Data of the LECO observatory were automatically uploaded to the data portal and will continue to be archived after redeployment. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6. Plotting functionalities to display the most recent data are implemented in the portal and will be automatically updated once data start again streaming in (http://dataportals.pangaea.de/hypox/sosclient/chart.php?id=21&client=lochetive_seaguard&cy=1).
Continuous recordings proved highly suitable to monitor rare and episodic events of bottom water oxygenation by dense and saline waters overflowing the shallow Bonawe Sill. These events are easily overlooked with classical monitoring approaches. The combination of observatories in the upper and lower basin allowed an in depth analysis of the bottom water renewal events as the potential to overcome the sill is a combination of conditions at both sides of the sill. It turned out that these events require very specific oceanographic and meteorological conditions including spring tides, cold temperatures, easterly winds, and weak freshwater input. Besides the long term monitoring capacity, the data collected by the observatory provide important input for the SAMS modeling work in Loch Etive. Online data access further allowed to continuously compare model results with the data streaming in which substantially increased the efficiency of modeling studies. Last not least real time data provided the opportunity for targeted sampling campaigns when changing conditions were recorded by the observatory and can serve as the basis for future early warning services in cases where conditions in the deep Loch Etive get unfavorable for benthic life.

4.1.3.3.5 Koljoe Fjord
Two field campaigns represented the first steps towards monitoring of the Koljoe Fjord / the Orust-Tjörn fjord system in Sweden. Based on knowledge obtained during these campaigns a design for a stand alone moored observatory was developed. The mooring consisted of a string of sensors and a current meter and monitors salinity, temperature, and oxygen at four different depths in the water column as well as bottom water current speeds and sea level variations. A first short term test deployment was carried out in autumn 2009. Subsequently a long-term deployment took place in Havstens Fjord in the same ford system. In extension of original plans the stand-alone observatory was turned into a cabled observatory with online data access and deployed in Koljoe Fjord in Apr. 2011. Additional information on the Koljoe fjord observatory is found at http://dataportals.pangaea.de/hypox/index.php?ptype=map&detail&id=22. Since the deployments the observatory has continuously provided real-time data. Using the same technology as in case of Loch Etive data sets are automatically transferred to the data repository PANGAEA and the HYPOX data portal. The measurements are available in near real time and the latest data that are streaming in are displayed with an online plotting tool at the HYPOX data portal as well as through a web display run by Gothenburg University (http://dataportals.pangaea.de/hypox/sosclient/chart.php?id=22&client=koljoefjord_seaguard; http://dataportals.pangaea.de/hypox/sosclient/chart.php?id=22&client=koljoefjord_rdcp; http://mkononets.dyndns-home.com:8080). In order to include also conditions in the surface waters an additional mooring was deployed in the Koljoe Fjord in September 2011 that measures oxygen, salinity and temperature at 3m water depth. Data sets available at the portal include measurements from the stand-alone observatory deployments as well as data from the cabled observatory that are periodically added as they stream in. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.
As in Loch Etive, deep water renewal events were found to happen rarely and episodically. Again, meteorological and oceanographic conditions have to act together to allow for deep water overcoming the sills. Hydrographic conditions in the Orust-Tjörn fjord system that opens to the Baltic Sea on both ends are rather complex. Depending on water levels at the entrances circulation through the fjord system can happen clockwise or counterclockwise. Deep water renewal may both increase or decrease oxygen concentrations in the deep Koljoe Fjord depending on the origin of the water and deep water conditions in the neighboring fjords. Online access to the data proved favorable for quality control and modeling activities performed in parallel. In order to understand the functioning of the system, effects of vertical mixing, water exchange, tides, and wind forcing on the oxygen distribution and variability in the fjord were assessed with modeling tools. Quality control of the obtained data has been undertaken through comparisons with reference data collected by the Swedish Meteorological and Hydrological Institute on a monthly basis.
Accompanying field campaigns were carried out in Koljoe Fjord to investigate drivers of hypoxia and to assess the impact of oxygen conditions on biogeochemical processes. Sediment-water exchange rates of oxygen, dissolved inorganic carbon and nutrients in the Koljoe Fjord were measured by means of in situ in chambers and benthic landers. The results are used to constrain the role of sediments in oxygen depletion in the Koljoe Fjord. Data from the accompanying field campaigns were uploaded to the portal (direct links in table ‘data generated in HYPOX’ in section 4.1.6.).

4.1.3.3.6 Ionian Sea lagoons and embayments
Investigations were carried out in two semienclosed systems (Amvrakikos Gulf and Aetoliko Lagoon) and an open embayment (Katakolo Bay). The main objective of the work was to investigate characteristics and temporal evolution of hypoxia occurrence and the role of the respective drivers of oxygen depletion (geographic and oceanographic conditions, anthropogenic forcing, and gas seepage). The majority of observations were carried out during repeated field campaigns with small local vessels. Methods used included CTD casts, coring for geochemical analyses, acoustic surveys as well as ROVs and the towed multiparameter observatory MEDUSA. Measurements of temperature, salinity, oxygen, pH, currents, ORP, turbidity, dissolved methane and sulfide were carried out at all three sites. Gas, water, and sediment samples were collected by divers for gas analysis (methane isotopic analysis in Amvrakikos Gulf, methane and sulfide isotopic analysis in Aetoliko Lagoon). In addition, visual inspection of the sea-floor was carried out and seismic data were recorded in order to identify structures (pockmarks) indicative of gas seepage
MEDUSA surveys were carried out in order to monitor variations of oxygen in correspondence with methane and sulfide seepage. To investigate the role of gas seepage as a driver of oxygen depletion in more detail, the benthic observatory GMM (Gas Monitoring Module) was deployed for four months in Katakolo Bay.
Data from the different field campaigns including survey data obtained with the towed observatory MEDUSA as well as time series recorded with the benthic observatory GMM were uploaded to the data portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.
Amvrakikos Gulf was found to be seasonal anoxic. The main drivers of hypoxia / anoxia in Amvrakikos Gulf were confirmed to be oceanographic and anthropogenic (fertilizer runoff, sewage, fish farming). Surveys with the towed observatory MEDUSA in three different sectors of Amvrakikos Gulf did not show significant gas seepage, apart from a pockmark site. Here an enhanced depletion of oxygen was observed but only in close vicinity to the seabed and inside the pockmark itself. In the permanently anoxic Aetoliko Lagoon the vertical distribution of the oxygen in the water column was found to be controlled by density stratification of the water column. The surface layer is well oxygenated throughout the year while in deeper waters oxygen content was found to continuously decrease reaching anoxia at depth. The depth of the oxycline was found to change with season. Stratification in Aetoliko Lagoon is mainly controlled by salinity due to the relatively strong fresh-water input, and the limited connection to the adjacent Messolonghi Lagoon. Hypoxia and anoxia potentially increase microbial production of sulfide and methane in the sediments indicating that gas in Aetoliko Lagoon is rather a product of hypoxia, not a driver.
In Katakolo Bay gas seepage was found to be much more vigorous and of clearly thermogenic origin. Hundreds of bubble plumes were detected over a wide area during MEDUSA surveys and lowered oxygen concentrations were observed around the plumes. Modeling activities are underway to explain the observed oxygen and methane distribution.
The design of the benthic observatory GMM that was deployed in Katakolo Bay detects dissolved gases (oxygen, methane, sulfide) with commercially available sensors and additionally records key physicochemical factors (temperature, pressure, conductivity). The GMM observatory successfully performed a long term (22 Sep. to 31 Dec. 2010) monitoring of oxygen in a methane seepage site. Periods where oxygen decreases down to hypoxic levels often correlated with times of increased methane concentrations. GMM data showed a complex interrelationship between oceanographic parameters (currents, temperature, methane and oxygen) and meteorological factors (wind intensity and direction). Data interpretation was facilitated by the chosen time series approach as the different processes contributing to the observed variations (seepage, currents, meteorological conditions) all operate on different time scales from minutes to days. The hypoxia episodes appeared to be due to a combination of enhanced degassing from the seabed and very low regimes of currents and wind (low circulation).

4.1.3.3.7 Swiss lakes
The water columns of Swiss lakes were investigated to study the effect of oxygen on water column biogeochemistry of freshwater systems at the smallest possible scales. Oxic-anoxic interfaces are known to represent biogeochemical hotspots of element cycling in aquatic systems characterized by intense redox-cycling. These investigations called for novel technologies as sensors to trace oxygen down to nanomolar concentrations at high resolution and with fast response times were missing. Such sensors are required for the localization and description of the oxic-anoxic interface at the lower end of the hypoxic zone. The recently introduced amperometric STOX-sensor (Revsbech 2009) provides the necessary lower detection limit but proved too slow for the planned profiling applications in the lake water columns.
Electrochemical and optical oxygen microsensors were successfully used for profiling measurements. This was possible by performing in situ calibrations and by the introduction of custom-built amplification-stages for the amperometric sensors. This innovation resulted in a detection limit below 5nmol / L and a resolution of 0.06 nmol for the amperometric sensor. The sensors were combined with a high resolution online-controlled water sampler to form the profiling observatory PIA (In situ Profiling Analyzer). A photograph of the PIA device as well as additional information is found at http://dataportals.pangaea.de/hypox/index.php?ptype=map&detail&id=24.
PIA was successfully deployed from small research platforms in Lake Rotsee, Lake Zug, and Lake Lugano. Online data analysis and presentation during profiling allowed controlled sampling of the hypoxic zone down to the nanomolar concentration-range. Water samples were analyzed for dissolved nitrogen species, phosphate, manganese, iron, and methane. Data obtained with PIA in Lake Zug and Lake Rotsee were uploaded to the portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.
High-resolution profiles revealed that even the sharp oxyclines in strongly stratified lakes show hypoxic tails on the meter scale with oxygen concentrations still in the nanomolar range. This knowledge is crucial for water column sampling as well as for an understanding of the interconnection of the different redox processes and their relation to oxygen. In Lake Rotsee, analyses of nutrient, metal and methane concentration profiles clearly showed that redox-cycling of nitrogen-species directly below the oxycline was thus spatially separated by the long hypoxic tails from the true oxic-anoxic interface where redox-cycling of methane, manganese and iron species occurred. The depth of the oxic-anoxic interface as well as the spatial distribution of submicromolar oxygen concentrations varied significantly between casts and were closely followed by the respective redox-reactions. This seems to indicate a spatially heterogeneous distribution of submicromolar oxygen-concentrations and an enhanced spatial redox-variability in this biogeochemically active zone.

4.1.3.4 IMPROVING LONG TERM HYPOXIA RECORDS BY ABIOTIC AND BIOTIC PROXIES
Different proxies for past events of oxygen depletion or anoxia in aquatic ecosystems were applied in order to understand past oxygen concentration changes and to explore their applicability for investigations of recent hypoxic conditions. This included organic and inorganic proxies, benthic community structure, and hypoxia indicator species. Studies were focused on Black Sea shelf areas (Bosporus outlet area, Crimean shelf, Sevastopol area, Romanian shelf), Ionian Sea lagoons (Amvrakikos Gulf), Swiss Lakes (Lake Zurich, Lake Rotsee), and Eckernfoerde Bay (western Baltic Sea). In extension of the initial plans additional studies in the northern Baltic (Bottenwiek area) as well as in Lake Alat (Bavaria, Germany) were carried out by the associated HYPOX partner MfN (Museum for Natural History, Berlin, Germany). The main objectives were to reconstruct the recent and past changes in the redox conditions using geochemical proxies and to obtain knowledge on structures of the benthic communities and species that indicate hypoxia in the various basins. Understanding the history of aquatic ecosystems with regard to variation in oxygen depletion is crucial in order to develop and compare scenarios of global change and their effects on oxygen depletion and the ecosystem.
At the beginning of the project available knowledge about long-term and short-term effects of changes in the oxygen regime on biota and communities was compiled for the different target sites. The review of available data indicated the insufficiency of the existing knowledge for an adequate interpretation of observed changes in benthic communities in response to hypoxia. The data on biological characteristics in the Black Sea, Baltic Sea, Swiss lakes and Ionian Sea lagoons were selected to characterize past oxygen regime at the respective target sites. The collected data included information about spatial and temporal variations in oxygen depletion and response of biota to these changes on the levels of individuals, populations, and communities. Available data on macro- and meiobenthic communities at the oxic-anoxic transition of the Crimean shelf and the Bosporus area were reviewed with special focus on the influence of bottom water oxygen on abundances and diversity of the respective groups. For the Romanian shelf existing data on past hypoxia occurrence and eutrophication and its influence on benthic communities were collected. Reports for the Baltic Sea indicated mats of sulfide oxidizing bacteria as obvious indicators of past oxygen conditions. Based on legacy data on sediment geochemistry a strong influence of near-bottom oxygen conditions on the cycling of Nitrogen compounds and redox-sensitive metals can be expected. Existing long term monitoring data from Swiss lakes suggest that thermal stratification and increased algal blooms are the main cause of the hypoxia in the Swiss lakes. Existing knowledge on sedimentation rates, and visual inspections of the sediment characteristics indicate that deep water anoxia in Amvrakikos Gulf evolved in the last 20-30years. The results of the collection of available data has been compiled into report D4.2 ‘Report on available knowledge about past oxygen regimes and benthic indicators species at selected target sites’ (http://metaworks.pangaea.de/download.php?fileid=147).
Several cruises were conducted at an early stage of the project to carry out sediment coring as well as geological and geophysical surveys. Target sites of these investigations were the Bosporus outlet area and the Romanian shelf in the Black Sea as well as Ionian Sea Lagoons and Swiss lakes. The main objective of the work was to reconstruct the basin evolution and past changes in the redox conditions in the various basins. In the Bosporus area geophysical subbottom profiling and sediment sampling was carried out and sediments were collected for geochemical measurements as well as analyses of benthic fauna. At the Romanian shelf analysis of sediment characteristics was performed along a depth gradient with a special focus on signs of past benthic communities and signs of recent biological and geochemical processes (e.g. iron precipitation, sediment layering). Cores were taken in Swiss lakes for later biomarker analysis. In the Greek lagoons sediments were sampled for the analysis of foraminifera indicative for past oxygen conditions. Report D 4.3 ‘Report on coring, marine geological and geophysical surveys’ (http://metaworks.pangaea.de/download.php?fileid=354) compiles information on the investigations carried to identify past oxygen conditions, to characterize the ecosystems and to collect samples for later analyses.
Over the time course of the project, analyses of the samples and data obtained at the different sites during several field campaigns were carried out. In the Bosporus outlet area of the Black Sea, geochemical analyses of cores were done in order to study the hypoxia history and the effects of Mediterranean water in the ventilation of the area. Methods used included XRF core scanning and TOC/TIC analysis. Benthic community and indicator species studies were carried out and compared to information on oxygen distribution obtained in parallel. In Lake Rotsee lipid biomarkers were studied. In Lake Zurich trace metal distributions were carried out as well as an analysis of existing long term monitoring data of oxygen and associated parameters. Lipid biomarker studies were also carried out in Amvrakikos Gulf and complemented by investigations of Foraminifera assemblages. Pore water geochemistry was analyzed for phosphorus-iron dynamics in Eckernfoerde Bay (western Baltic Sea). Nitrogen and carbon isotopes and purple sulfur bacteria were studied in samples from the northern Baltic Sea (Bottenwiek) and Lake Alat, respectively. Finally, benthic population structure and hypoxia indicator species were studied in the Black Sea shelf areas (Istanbul Strait outlet area, Crimean shelf and Sevastopol area, and the Romanian shelf). The findings obtained with the different methodologies at the different sites are compiled in report D4.1 ‘Report on assessment of changes in oxygen availability using organic and inorganic proxies, benthic communities structure, and hypoxia indicator species’ (http://metaworks.pangaea.de/download.php?fileid=364). Several publications and manuscripts showing more about the work carried out by the project partners in relation to past oxygen changes is found in report D4.4 ‘Publications on past variation of oxygen depletion and relation to paleo-environmental changes’ (http://metaworks.pangaea.de/download.php?fileid=396). A lot of the findings from the different sites have been presented at international conferences (table 4.2.A2 and conferences, meetings and workshops table in section 4.1.6) and already resulted in some peer reviewed publications (table 4.2.A1 and ‘publications published and in press’ table in section 4.1.6). Table ‘submitted and planned publications’ in section 4.1.6 lists some of the publications that will be published in the future based on work carried out. A summary of the main achievements is provided below.

4.1.3.4.1 Inorganic geochemical studies in the Bosporus outlet area
The Bosporus is the only connection of the Black Sea to the world’s ocean. The area is characterized by the Mediterranean inflow that is responsible for the ventilation and sluggish deep circulation of the anoxic Black Sea basin. The Mediterranean water enters the Bosporus outlet area through the submarine extension of the Bosporus channel, and then spreads as a uniform 2-3 m thick saline sheet over the shelf. At depths of 50-75 m, it mixes with the Cold Intermediate Water and sinks along the continental slope forming a series of lateral intrusions to depths of 500 m. The Bosporus outlet area is also characterized by a fan-delta complex on the mid and outer shelf areas. Shallow sill depth of the Istanbul Strait together with the oxygen consumption by organic matter mineralization is responsible for the establishment of a permanent oxic-anoxic boundary (chemocline) in the area. The oxic-anoxic boundary is presently at 100-150 m depth, but may have varied in the past as result of the changes in the amounts of the Mediterranean water, of riverine water input and global sea level.
Geophysical subbottom profiling and sediment coring was performed during two cruises along transects ranging from water depths of 75 to 300m. The cores were analyzed for physical properties, elemental analysis, and for total organic carbon (TOC) and inorganic carbon (TIC) and dated by 14C analysis. The core data were uploaded to the data portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.
The Holocene basin evolution was investigated based on high resolution seismic profiling and the obtained cores and showed evidence for two unconformities. The inorganic geochemical studies indicate that the anoxia development started after the latest connection with the Mediterranean. Redox changes and anoxia history in the area have been unraveled using manganese and the iron-carbon-sulfur system. Oxic-anoxic boundaries and changes in the bottom water conditions in the slope area are detectable by manganese, sulfur and iron anomalies in the cores, which show the rise of the redox boundary to water depths between 120 and 150 m around 6800 years before present. As a result of this work, the change in the direction (eastward shift) at 5300 years before present and ventilation effects of the Mediterranean inflow can be observed. In the eastern part of the outlet area down to water depths of at least 300m, ventilation effect of Mediterranean water is indicated by high manganese concentrations that last until today. These manganese anomalies are not associated to contents of iron and sulfide. A recent shoaling of the oxic-anoxic boundary about 250-300 years ago is indicated by manganese anomalies associated with iron and sulfur anomalies in a core collected from western side of the study area where no ventilation effect by Mediterranean water is observed today.

4.1.3.4.2 Inorganic Geochemical Studies Lake Rotsee and Lake Zurich
Lake Rotsee is a small 16m deep, prealpine, monomictic (i.e. water column is completely mixing once per year) and eutrophic lake. The lake has a stable stratified water column and is anoxic at depth throughout most of the year. Eutrophication by untreated sewage impacts the lake since 150 years and led to an elevated productivity. The large mesotrophic Lake Zurich has a maximal depth of 136 meters. Long-term monitoring data (1936 to present) including oxygen concentrations exist for Lake Zurich. The lake is highly sensitive to changes in climate, namely temperature changes. The discrete annually deposited layers (varves) in the sediments were used to obtain an age model.
Cores were taken in both lakes. Inorganic markers, i.e. trace metals, were analyzed in the sediment cores of Lake Zurich. Iron and manganese distributions showed a seasonal pattern in Lake Zurich. Our results suggest that a peak of iron in the winter half year was due to higher terrigenous supply, whereas manganese was sensitive to bottom water oxygenation. The ratio of manganese to iron was correlated with bottom water oxygen concentrations and indicated that manganese traces oxygenation of the bottom water during spring when the lake mixes completely. Data from geochemical analyses were uploaded to the data portal (links are found in table ‘data generated in HYPOX’ in section 4.1.6).

4.1.3.4.3 Long term monitoring data series for Lake Zurich
A several decade long oxygen monitoring program of Swiss authorities in Lake Zurich allowed HYPOX scientists to investigate the impact of climate variability on oxygen conditions. Throughout the 1970ies and 1980ies the 135 m deep water column overturned nearly every winter ventilating the lake down to the bottom. Since then, increasing water temperatures led to a stronger stratification of the lake and winter cooling failed to completely mix lake waters and fully replenish bottom water oxygen sometimes for periods of several years. This resulted in an overall decrease in oxygen availability in the deep lake in the last twenty years that clearly reflects climate forcing. Oxygen loss through biological oxygen demand can be ruled out as phosphorous loading of the lake steadily declined throughout the period due to improved wastewater treatment and banning of phosphates in detergents. Long term monitoring clearly confirmed the potential of global warming to turn ecosystems hypoxic.

4.1.3.4.4 Pore water Phosphorus-Iron Dynamics in Boknis Eck / Eckernfoerde Bay
From mid Mar. until mid Sep., vertical mixing is restricted by density stratification of the water column, which leads to pronounced periods of hypoxia during late summer due to microbial respiration of organic material in the deep layer and sediment. In autumn the stratification breaks up and bottom water oxygen concentrations rise again. The dominant fauna in the sediments in winter / spring are polychaetes that exist in high abundances and irrigate the pore waters. Filamentous sulfide oxidizing bacteria are present below the sediment surface at the redox interface at the top of the sulfide layer and appear at the sediment surface at low oxygen conditions in summer. Between Feb. 2010 and Jan. 2011 sampling of sediment cores was carried out monthly.
Geochemical analysis of the sediments showed that ferrous iron and phosphate concentrations rapidly increased following the onset of anoxia. This is most likely due to reductive dissolution of iron oxide minerals and the release of iron-adsorbed phosphate. Ferrous iron and phosphate fluxes across the sediment water interface increased by a factor 10 from Sep. to Oct., remained fairly high in Nov. and then returned to background levels in Dec. when fully oxic conditions are restored in the bottom water. The results demonstrate the dynamicity of the sediments over the short autumn anoxic period and the potential importance of the benthos in supplying nutrients to the water column for the following spring. Ongoing work will address whether the phosphate and ferrous iron fluxes out of the sediments are determined directly by the onset of anoxia or indirectly by the ceasing bio-irrigation due to animal mortality. Geochemical data from Eckernfoerde Bay cores were uploaded to the data portal (links in table ‘data generated in HYPOX’ in section 4.1.6.).

4.1.3.4.5 Studies of inorganic and organic proxies in Baltic Sea, Black Sea and Lake Alat
Sediment cores were studied for the impact of eutrophication in the northern most Baltic Sea (Bottenwiek). The results indicate that during the past hundred years the area of the Bottenwiek was eutrophied only to a small extent. However, sedimentary nitrogen and carbon isotopes show clear trends towards higher values in more recent sediments (the last 2 decades) indicating the increasing bioproductivity and more nutrients in that area. This potentially has strong implications for future oxygen conditions in the area. The physicochemical stratification and stability of the meromictic (permanently stratified) and anoxic Lake Alat was studied with respect to the influence of the dense population of purple sulfur bacteria on the nitrogen cycle. Water samples and surface sediments obtained from short cores are used for the analysis with a sub-decadal resolution. Ages are obtained by the lead 210 dating method. The analyses are ongoing.

4.1.3.4.6 Natural radionuclides and Cesium studies in Amvrakikos Gulf (Greece)
Amvrakikos Gulf is a semi-enclosed embayment with an area of 405 square kilometers. It is connected to the open sea through a narrow and shallow channel. The gulf receives relatively large freshwater inputs by two rivers. As a result, Amvrakikos Gulf is stratified with a surface layer and a bottom layer that are separated by a strong pycnocline (steep density gradient). Amvrakikos Gulf is the only Mediterranean Sea fjord and shows an outflow of brackish water at the surface and an inflow of saline water in the near-bed region. While the surface layer is well oxygenated, oxygen concentrations decline sharply below the pycnocline and reach anoxic conditions in the bottom layer. Natural radionuclides (238U, 232Th, 226Ra, 40K), man-made cesium 137 distributions and total concentrations of iron and manganese were investigated in the sediment cores. Enhanced uranium activity levels and disequilibrium between 238U and 232Th were observed and are attributed to riverine inputs of phosphate fertilizer that hold radioactive materials. Uranium input by input of weathering products of the phosphate rocks via surface and ground waters seemed of lesser importance. Highest concentrations of cesium 137 were found in the deeper sediment layers and suggest high sedimentation rates for the Amvrakikos Gulf. Preliminary sedimentation rate estimates based on lead 210 are in the range of 0.3 to 0.6 cm per year. Higher resolution Cesium data and the final lead 210 data will provide the age model that allows for more detailed reconstructions of past oxygen conditions at the seafloor based on foraminifera analyses. Existing data on sediment radionuclides and metals as well as foraminifera were uploaded to the data portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.

4.1.3.4.7 Noble Gases in the Black Sea
Sediment samples for analyses of noble gas distributions were collected at different water depths at the Crimean shelf and the northwestern shelf off Romania as well as in the Bosporus outlet area. Investigations aim to reconstruct hypoxia through determination of atmospheric noble gases (He, Ne, Ar, Kr and Xe) in the pore waters from three different locations. The core sites in the Bosporus area and at the Crimean shelf were chosen to represent oxic, hypoxic and anoxic zones. The noble gas content in the Bosporus area samples may provide insight into oxygen as well as salinity conditions before and after the Mediterranean-Bosporus connection. It is anticipated that through the diversity of the three sites, the noble gas measurements could provide very interesting insight into past variations in oxygen and salinity along the Black Sea shelf. In order to evaluate the potential of noble gases as a record of oxygen abundance, analyses will focus on periods in the sediment record where the Black Sea evolved from a rather oxic, limnic basin into a brackish, hypoxic, anoxic and euxinic (no oxygen, free sulfide) state. Furthermore, noble gases may be used as a tracer for past methane production in the sediments. Analysis of the collected sediment samples is ongoing and results should become available in the coming months.

4.1.3.4.8 Biomarkers studies in Lake Rotsee and Lake Zurich, Amvrakikos Gulf, and the Northwestern Black Sea shelf off Romania
The high-resolution Lake Rotsee biomarker study revealed a complete eutrophication history of the last 150 years. We observed times of higher primary productivity especially around 1920 and in the 1960s that can be explained by high nutrient input from the catchment through agriculture and untreated sewage. Periods of higher productivity resulted in enhanced stratification, as indicated by higher Tetrahymanol concentrations beginning in the 1920s. The coincidence of high TOC values with higher concentrations of C16:1?7 fatty acid indicates higher biomass of iron-, manganese and sulfate-reducing bacteria and times of more intense or longer hypoxia in the lake. High concentrations of delta 13C non-depleted glycerol dialkyl glycerol tetraether concentrations indicated periods with high methanogen biomass in the sediment and increased emissions of methane into the water column. The onset of higher methane production is characterized by higher concentrations of strongly delta 13C depleted 17beta-21beta-bishomohopanoic acid and diploptene indicating radiation of aerobic methane oxidizing bacteria. Later, anaerobic methanotrophic Archaea increased in abundance, which was traced by higher sn2- and sn3-hydroxyarchaeol concentrations in the sediment. The Chromatiaceae derived pigment okenone and the pigment isorenierantene which is derived from Chlorobiaceae, could be detected in Lake Rotsee and suggested that anoxic conditions reached into the photic zone in the past.
For the Amvrakikos Gulf two biomarkers (isorenieratene and chlorobactene) were found, indicating at least seasonal photic zone anoxia. Biomarkers and benthic fauna were analysed in a combined study in order to reconstruct eutrophication and hypoxia in this embayment, with high similarities to developments of hypoxia in the Black Sea. Data on geochemical properties of Amvrakikos gulf sediments were uploaded to the data portal (links in table ‘data generated in HYPOX’ in section 4.1.6.)

4.1.3.4.9 Benthic community structure and hypoxia indicator species at the Crimean shelf and the Bosporus outlet area
An extensive study of the benthic community structure and hypoxia indicator species was carried in the Crimean shelf and Bosporus outlet area of the Black Sea. Oceanographic and benthic environmental conditions were studied during two cruises (R/V ARAR and R/V MARIA S. MERIAN) in Nov. 2009 and Apr. / May 2010. In the coastal zone of Crimea, sampling was carried out every 45 days throughout the year. The analyses involved oxygen concentrations in the water column and oxygen and sulfide in sediment pore waters. Sediment sampling for the biological studies were carried out using multi-corer, push-corer and box corers.

4.1.3.4.9.1 Crimean shelf
Studies were carried out in five areas (1) Tarkhankut, (2) Omega Bay, (3) inner Sevastopol Bay, (4) outer Sevastopol Bay, and (5) Dnepr Canyon (Paleo-Delta). The studies focused on the changes in taxonomic structure, quantity and biomass of modern meiobenthos in response to seasonal hypoxia in the environment. Oxygen and sulfide in the pore waters was determined by voltammetry in retrieved cores. Pore water and bottom water chemical data and fauna data are available at the data portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.

4.1.3.4.9.2 Tarkhankut seeps
The cape Tarkhankut at the westernmost part of the Crimean peninsula is characterized by shallow methane seeps. Sulfides in pore waters as well as bacterial mats are typical features of the benthic habitat. The only time of sulfide absence in the bottom sediments was during winter storms, when bacterial mats vanish completely. As soon as sediments are undisturbed for several weeks bacterial mats are again formed. At the end of the summer sulfide concentrations in the pore waters of up to 3 millimol / L were observed. The meiobenthos density in the sediment layer varies widely depending on redox conditions. At a sulfide free reference site, abundance and diversity of meiofauna was highest in the upper sediment and decreased with depth. In sulfidic sediments on the other hand meiofauna abundance was highest in the lower sediment layers where the hydrogen sulfide concentration reaches its maximum. Alive specimens of the harpacticoid copepod (Darcythompsonia fairlensis) were found in the anoxic and sulfidic sediments in high abundances. At the reference site, in normoxia, more species of harpacticoid copepods were observed but D. fairlensis was missing. The studies demonstrate that some benthic metazoans are able to thrive into sulfidic environments. Populations of D. fairlensis may be used as indicators of hypoxic conditions.

4.1.3.4.9.3 Sevastopol Bay
Bottom waters in the inner Sevastopol Bay regularly experience hypoxic conditions as a result of anthropogenic / industrial pollution and restricted water exchange. Sediments in the inner part of the bay are rich in organics and always anoxic / sulfidic. Sulfides are released from the sediments during hypoxic events. The outer part of the Sevastopol Bay is rather pristine and was chosen as reference site. Hypoxic events have never been reported for the outer bay waters.
Omega Bay is located at the shoreline of Sevastopol, but no industrial objects are located around the bay. Anthropogenic pressure is thus restricted to municipal waste waters. The water exchange is restricted by a narrow outlet. Hypoxic conditions in the bottom waters typically evolve in summer and sulfide is present in the pore waters in high concentrations.
Total macrobenthos abundance was found to decrease when sulfide reached the upper sediment layers but the sensitivity towards sulfide was different in different taxonomic groups. Several groups, including gastropods, certain crustaceans, and nematodes, even showed the opposite tendency with highest abundances where sulfide appeared closest to the sediment surface. This is especially true for many nematode species that seem to prefer hypoxic habitats.
Fifteen species of harpacticoid copepods were recorded in the inner part of Sevastopol Bay with Haloschizophera pontarchis dominating the community at strong hypoxic conditions. In Omega Bay species composition of harpacticoid copepods changed in response to oxygen availability. While Darcythompsonia fairliensis dominated in hypoxic conditions individuals of the genus Scotopssyllus dominated under normoxic conditions when D. fairliensis was absent. H. pontarchis and D. fairlensis may thus serve as indicator species of hypoxic conditions in bottom sediments of the Crimean shelf coastal zone.

4.1.3.4.9.4 Dnepr Canyon Paleo-Delta / western Crimean shelf
Sediment samples were collected along two depth transects at the western Crimean shelf. Total benthos abundances were highest at the shallowest station at approx. 100m water depth and generally declined with depth. Nematodes dominated the benthic communities at all depths in terms of abundances. Depending on water depth, harpacticoid copepods, foraminifers, or bivalves represented the second most abundant groups. Again, the polychaete Vigtorniella zaikai showed maximum abundances in the oxygen-sulfide transition zone. This suggests, that this species may be useful as indicator for hypoxia in water column and bottom sediments at all regions of the Black Sea.

4.1.3.4.9.5 Bosporus outlet area
The response of the benthic fauna to oxygen depletion in the Bosporus Strait outlet area was studied along a transect ranging from 100 to 300m water depth. Benthic fauna analyses suggest that the oxic / anoxic transition zone supports a rich protozoan and metazoan community. ‘Live’ organisms were investigated based on Rose-Bengal staining and by means of direct observations using microscopy on board the research vessel. Living specimen of several groups (gromiids, allogromiids, hydrozoans, nematodes, polychaetes) were found under hypoxic as well as anoxic / sulfidic conditions in water depths region of 150 to 300m. These results suggest a successful adaptation of some groups of benthic organisms to hypoxic / anoxic and even sulfidic environments. Main groups of macrobenthos in the sediments of the Bosporus outlet area were crustaceans, annelids, bivalves and echinoderms. Annelids, gastropods and the polychaete Vigtorniella zaikai were found down to water depths of 250m. V. zaikai showed highest abundances at the oxygen / hydrogen sulfide transition at about 160 m water depth and may serve as indicator species for these conditions. Meiobenthos assemblages were dominated by nematodes and harpacticoid crustaceans. Abundances generally decreased with water depth but occurred in greater depths as compared to macrobenthic organisms (i.e. 300m). Fauna data from the Bosporus outlet area were uploaded to the data portal. Direct links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6.

4.1.3.4.10 Benthic community studies at the Romanian Shelf
The Romanian shelf in the NW Black Sea is characterized by the Danube inflow that has a strong influence in terms of salinity, organic load and sediment grain-size. The dominant biocoenoses in the coastal zone are Mya arenaria, Lentidium mediterraneum, Melinna palmata, and Modiolula phaseolina communities. There have been mass mortalities of some marine organisms such as fish, mollusks, crustaceans and other animals in the Romanian littoral zone during summer months due to hypoxia.
Four cruises were performed with the R/V MARE NIGRUM within HYPOX and covered all the Romanian continental shelf at water depths ranging from 10 to 200m. Sf. Gheorghe transect, a south-eastward oriented transect in front of the Danube Delta, as well as a sheltered area (‘Portita’) were chosen to monitor the oxygen regime and the benthic fauna. Supplementary research was conducted at Constanta and Mangalia transects for a comparison of the northern and the southern ecosystems. Bottom water and water column chemical properties were uploaded to the data portal (links to the data are found in table ‘data generated in HYPOX’ in section 4.1.6).
In Sf. Gheorghe and Portita, in front of the Danube Delta benthic macrofauna communities were dominated by worms, mollusks, and crustaceans. The most abundant populations were found in the biocoenoses of hard bottom mussels and muddy-shelly bottom mussels in the deeper areas of Sf. Gheorghe and Mangalia transects. In the Sf. Gheorghe area two species of polychaeta - Melinna palmata and the invasive species Dipolydora quadrilobata, appeared in particularly high numbers. Melinna palmata dominated assemblages represent a new sub-coenosis that is found in areas that were before typically occupied by Mytilus communities. The high abundances of Melinna palmata indicate that the state of the benthic ecosystem in the area is still fragile.
The Macrofauna communities still differ substantially from the situation in the 1960s at the beginning of the highly eutrophic period. While in the 1960s the main benthic communities extended over large areas some of them have now been reduced and fragmented while others while others were completely replaced by invasive species occupying their habitats. In 2010 mass mortalities of some marine organisms such as fish, mollusks, crustaceans and jellyfishes were recorded in shallow waters of the Romanian Black Sea. Mortalities were generally the result of oxygen depletion induced by high temperatures, unusually high fresh water input and calm weather. At the end of Jul. 2010 the lowest oxygen concentration of the last 12 years was recorded in the area.
Several polychaete species were identified as possible indicator species for eutrophication (nutrient rich conditions) and organic pollution. High abundances of Heteromastus filiformis indicate natural or human induced disturbances. Nephtys hombergii is tolerant to organic pollution and the low oxygen concentration. Melinna palmata is a very common species throughout the whole Black Sea basin and indicates natural or anthropogenic disturbances if it appears in high abundance and forms high biomasses. Prionospio cirrifera is resistant to pollution with organic substances or petroleum products and is abundant in areas with moderate pollution and increased eutrophication.
Meiobenthos communities
The Black Sea meiobenthic communities are poorly studied. Nematodes at the Romanian shelf were intensely studied in HYPOX. The highest diversity was found on the profile Sf. Gheorghe in the stations at around 100m water depth. A dominant nematodes community tolerant to eutrophication conditions, organic loading and hypoxic conditions is spread throughout the investigated area, from the shallow waters to the deepest bottoms at the limit of the metazoan life. In 2011 the dominant species were Sabatieria abysalis, S. pulchra, Desmodora pontica, Halanonchus bullatus, Axonolaimus ponticus and Theristus oxycercus. The nematode diversity increases with depth, which may suggest that the nematodes in the Black Sea, under unfavourable conditions, may have an adaptive strategy in response to physiological stress factors like hypoxia. Their occurrence deep in the anoxic part of the sediments suggest that the nematodes may develop different metabolic ways, possibly including chemosynthetic mechanisms to produce energy and obtain food. Nematode communities were well represented when oxygen concentrations were particularly low in some parts of the shelf in 2010.

4.1.3.4.10 Benthic Foraminifera studies in Amvrakikos Gulf (Ionian Sea)
Benthic Foraminifera analyses were carried out in sediment cores from the Amvrakikos Gulf. Preliminary results show that benthic Foraminifera assemblages exhibit changes in relation to the decline of oxygen availability at the bottom of the gulf. The onset of low oxygen availability is marked in the core sediments by a lithological change. At this transition layer, benthic Foraminifera diversity started to decrease. Shallow infauna species dominated together with agglutinated foraminifera. The abundance of epifauna species showed a gradual decrease. When the sea floor is characterized by the minimum oxygen values, the benthic diversity is the lowest and deep infauna species become dominant. The oxygen increase at the sea floor is characterized by an increase in benthic diversity with epifauna and shallow infauna species replacing the microfauna. Many of the benthic species obtained at the onset of the low-oxygen interval were observed also at this stage. Foraminifera data were uploaded to the portal (links in table ‘data generated in HYPOX’ in section 4.1.6.)

4.1.3.5 MODELING AND PREDICTION OF FACTORS AFFECTING OXYGEN DEPLETION
Modeling activities in HYPOX were aimed at: (1) improving our understanding of the hydrologic and biogeochemical processes leading to hypoxia formation, (2) building the model capacity to better predict the future risk of oxygen depletion in aquatic ecosystems, and (3) to be able distinguish natural controls from manageable, anthropogenic effects causing hypoxia. This was done by developing and applying numerical tools to simulate the oxygen dynamics at the HYPOX field sites. A particular point of attention was to assimilate high-resolution oxygen sensor data and integrate various observational data made at different spatial scales and temporal resolutions. Based on model simulation results, feedback was provided to observational scientists regarding optimal sampling and observation strategies.
Two modeling workshops were held during the HYPOX project. The first workshop took place during the kick off meeting and was used to plan and harmonize modeling activities by the different partners. At the same time, this workshop established connections between modelers and observational scientists at the different institutions. The second workshop was carried out during the first annual meeting and consisted of a training workshop on physical-biogeochemical modeling of oxygen depletion. Tutorial lectures were given by HYPOX principal investigators and invited experts.
The modeling work performed in HYPOX was principally focused on the the different HYPOX target sites. Typically, the work was carried out by modeling groups located at the same institutions as the scientists running the HYPOX observatories. This made sure that field observations and model simulations were harmonized. From a model perspective, key efforts in HYPOX related to (1) circulation and biogeochemistry in the Black Sea basin (2) Baltic Sea sediment biogeochemistry (3) water exchange and mixing in fjord systems, and (4) generic modeling tools to advance understanding of reactive transport of oxygen in estuarine and coastal areas. Modeling achievements were strengthened by additional investigations of the affiliated project partners, namely the Norwegian Institute for Water Research (NIVA) and the Interfacultary Center for Marine Research at Liège University (MARE-ULg).
Model-based research in HYPOX was presented at international conferences (table 4.2.A2 and conferences, meetings and workshops table in section 4.1.6) and already resulted in some peer reviewed publications (table 4.2.A1 and ‘publications published and in press’ table in section 4.1.6). Table ‘submitted and planned publications’ in section 4.1.6 lists some publications that will be published in the future based on the work carried out. All project reports on HYPOX modeling work were prepared towards the end of the project and thus provide a good synthesis of the work carried out. Report D2.1 ‘Report on the relative importance of physical processes, sediment biogeochemistry, macrobenthos, and human-impact on hypoxia development in aquatic systems varying in tidal energy, topography and human impact’ (will be available soon at http://www.hypox.net/front_content.php?idcat=399&idlang=19 section ‘documents’) uses a benthic-pelagic ecosystem model to investigate how climate change will increase the risk of hypoxia in coastal seas. Report D2.3 ‘Report on vertical mixing in hypoxic basins and its dependence on atmospheric and marine boundary conditions’ (http://metaworks.pangaea.de/download.php?fileid=390) focuses on the modeling of fjord systems with reference to fjords at the Swedish coast. Report D2.4 ‘Report on oxygen dynamics in silled basins and its dependence on atmospheric, marine, and terrestrial boundary conditions, including land-use and nutrient loading’ (http://metaworks.pangaea.de/download.php?fileid=391) reports on fjord exchange taking Loch Etive as an example. Report D2.5 ‘Report on assimilation of HYPOX observatory oxygen data and model results on factors governing oxygen dynamics in the Black Sea’ (http://metaworks.pangaea.de/download.php?fileid=353) compares observations of the profiling floats obtained in the Black Sea basin in HYPOX to modeling results and investigates the future potential of oxygen sensor equipped floats for data assimilation approaches. The below text describes some of the modeling work carried out in HYPOX and highlights some of the results.

4.1.3.5.1 Black Sea hydrophysical and biogeochemical modeling
The suboxic zone in the Black Sea (a layer between oxic surface and anoxic deeper water) is highly variable and depends on climate variability as well as anthropogenic eutrophication. However, it is still uncertain which factor is the more important one governing the low oxygen concentrations. So far numerical models have not been explored in detail to assess the biogeochemical system response to anthropogenic and climate forcing. A coupled 1D hydrophysical-biogeochemical model (GOTM plus ROLM) was set up to study the major elements in the redox transition layer in the Black Sea. The model was able to adequately reproduce the observed data. Furthermore the analysis of the difference between interannual and perpetual-year runs clearly showed a pronounced impact of the North Atlantic Oscillation (NAO) on the oxygen dynamics of the Black Sea. In a second step the Nucleous of European Modeling (NEMO) physical model was coupled to the ROLM model to investigate the performance in simulating the main physical and biogeochemical features in the Black Sea. Finally, the Black Sea simulation work was extended by coupling ROLM with the 3D hydrophysical model GETM. This promising approach will be followed up also after the end of the project. Modeling tools were also used to analyze data from two ARGO type profiling floats that were released in the Black Sea as part of HYPOX. These data shed new light on spatial and temporal dynamics of hypoxia in the Black Sea (e.g. the seasonal variability of the subsurface oxygen maximum, cold water mass formation and diapycnal mixing) and were also used to estimate minimum requirements for future float based studies of Black Sea oxygen conditions.
Other Black sea modeling efforts concerned the investigation of the hydrophysical processes that lead to the temporal dynamics in water column and bottom water oxygenation observed in the Bosporus outlet area as well as at the Crimean Shelf (see above). Modeling studies are ongoing and will serve to better understand Marmara Sea water injections in the Bosporus outlet area and short and medium term oscillations of the oxycline at the Crimean Shelf and in the open Black Sea. The associated HYPOX partner MARE-ULg has performed numerical model simulations of the Black Sea biogeochemistry using a 3D coupled hydrodynamical - biogeochemical model describing the food web from bacteria to gelatinous carnivores and explicitly representing processes in the anoxic layer down to the bottom. The relative importance of the different processes implied in the oxygen budget of the Black Sea, as well as their seasonal / interannual variability has been assessed.

4.1.3.5.2 Fjord exchange modeling
4.1.3.5.2.1 Loch Etive
A physical fjord circulation/mixing model for the HYPOX target site at Loch Etive was constructed and optimized based on the POLCOMS (structured grid) model. In an early phase of the work, legacy data and data obtained by a standard stand-alone mooring in Airds Bay as well from annually repeated CTD surveys were used for model testing and validation. In the following, real time data from the Loch Etive Cabled Observatory (LECO) were additionally used. The model proved feasible to describe how short and long term variations in external forcing (tidal forcing, wind, heat flux and rivers runoff) affect the hydrodynamic structure and thermo-haline fields in the Loch Etive fjord. To improve horizontal resolution and better capture deep water renewal events a higher resolution model (FVCOM) was setup for hydrostatic simulations of the main physical properties of Loch Etive. FVCOM was able to handle complex geometries and topographies and was found to be highly suitable for fjord system studies. Sensitivity model runs were performed based on climatological data from 1999-2001 with realistic atmospheric forcing and tidal data from nearest gauging station (Oban). Validation of FVCOM modeling results based on real-time data sets obtained from the Loch Etive Cabled observatory (LECO) revealed excellent agreement for physical parameters: T, S and tidal oscillations. In collaboration with University of Edinburgh a localized version of FVCOM was run at the National Supercomputer Centre HECToR with improved horizontal resolution. This led to a successfully description of stratification very close to the observed data, especially in the vicinity of the narrow straits with shallow sills. Amendment of the modeling environment with oxygen as a variable and with algebraic expressions for water column and benthic oxygen demand are underway and will be continued in the future.

4.1.3.5.2.2 Koljoe Fjord
A coupled physical-biogeochemical-ecological basin model was set up for the Orust-Tjörn system, which includes three sub-basins Havstens Fjord, By Fjord as well as the HYPOX target site Koljoe Fjord. The physical circulation and mixing model has been originally developed by Anders Stigebrandt and applied to several other fjords earlier with good results. The biogeochemical part, originally developed to study eutrophication of Norwegian fjords, has been updated to include all processes needed for hypoxia simulations in the fjord system. Topographic, meteorological and hydrological forcing data has been collected for the fjord system. The boundary conditions to the open Skagerrak turned out to be crucial and it was found that at least a weekly resolution was needed. Historically there are only monthly observations, so weekly measurements were initiated in HYPOX to obtain the state at the Skagerrak border and the internal states of the fjord basins. Using forcing datasets with different temporal resolution (from monthly to daily forcing obtained from the HYPOX mooring in the Havstens Fjord), the modeling of physical variables characteristic for vertical mixing and stratification such as temperature and salinity, has been tested carefully and proved to give very reliable results with high correlation to observations. Oxygen modeling was successfully added and preliminary model outputs showed good agreement with measurements. A phosphorus submodel is under development and will shortly be implemented. An additional model has been derived that predicts minimum oxygen concentrations in the deep water of fjords and assesses the importance of different physical and biogeochemical parameters for hypoxia. In conclusion the model simulations revealed that the coastal monitoring program at the Swedish west coast are not sampling frequently enough to target hypoxia and deep water exchange events in the fjord and that wind patterns along the coast are very important for in- and outflows over the sills.

4.1.3.5.3 Baltic Sea reactive biogeochemical modeling
Models were developed to investigate benthic cycling of redox sensitive elements in environments subject to hypoxia. The overall goal was to investigate how the pathways of organic matter degradation and biogeochemical fluxes across the sediment-water interface respond to changing oxygen concentrations. Most of the work focused on the seasonally-hypoxic HYPOX target site in the southwestern Baltic, the Boknis Eck site in Eckernfoerde Bay. The observational data were obtained from monthly sampling and additional laboratory experiments were used to constrain the model. The data set included geochemical pore water profiles, sediment- water fluxes (dinitrogen, ammonium, nitrate, nitrite) and bioirrigation data from core incubations. A sensitivity analysis was performed on how the sedimentary nitrogen cycling changes as a function of bottom water oxygen levels. The model results show excellent agreement with observations and provide a general mechanistic framework for interpreting the existing knowledge of nitrogen turnover processes and fluxes in continental margin sediments, as well as for predicting the types of environment where these reactions are expected to occur (Dale et al. 2011).

4.1.3.5.4 Site independent / generalized modeling studies
The mathematical equations for the transport-reaction modeling of 1D, 2D and 3D oxygen fields in sediments as a consequence of bio-irrigation were systematically investigated using the open source software R (Meysman et al. 2010). All modeling tools developed prior and during HYPOX available to consortium members and others (via open access R site; http://cran.r-project.org/). A combined experimental and modeling study of surface-subsurface flow in sand ripples was carried out together with modelers from the University of Austin in Texas, USA. The study has strong implications for fluxes of oxygen and other solutes in permeable sediments exposed to hypoxia (Janssen et al., in press).
A model investigation was carried out to assess the relative importance of climate forcing versus nutrient loadings on the development of hypoxia in temperate coastal systems (contribution to report D2.1; (will be available soon at http://www.hypox.net/front_content.php?idcat=399&idlang=19 section ‘documents’). The role of the different drivers on the evolution of hypoxia was investigated using a 1D coupled physical-biological model (a pelagic 1D turbulence k-epsilon model, a pelagic ecosystem model, and a benthic diagenetic model). The model is calibrated for the Oyster Grounds (North Sea) but the model approach is generic, allowing to assess both the impact of changing climate forcing and nutrient loadings on hypoxia in stratified coastal ecosystems.

4.1.3.5.5 Use of simulations and statistical tools to advance Eddy Correlation measurements
The relatively novel Eddy Correlation (Eddy Covariance) method to quantify benthic fluxes of oxygen and potentially also other solutes (e.g. sulfide) has a strong potential to assess the role of sediment oxygen demand for hypoxia development in bottom waters. However, data analysis and interpretation is still under debate. HYPOX partners took part and were involved in the organization of several workshops on the Eddy Correlation method. The software package ECDiagnostics was developed in HYPOX for the processing of oxygen Eddy Correlation data. The software is written in the open source framework R and produces diagnostic documents providing flux calculations, statistics and quality indicators. The R software has been distributed for beta-testing among HYPOX partners and a publication is in progress. In parallel a 2-D k-epsilon model of the benthic boundary layer was developed within the COMSOL Multiphysics software environment to describe the influence of non steady state conditions in the bottom water (i.e. current velocities and solute concentrations) on bottom water fluxes determined by means of Eddy Correlation measurements. The study revealed that Eddy Covariance measurements of oxygen fluxes can be heavily biased by these transient conditions. Based on the obtained results it is possible to estimate the error that is potentially introduced.

4.1.3.6 EXISTING AND FUTURE IMPACTS OF HYPOXIA ON ECOSYSTEMS
Based on the findings from the observational work, investigations of past hypoxia and modeling efforts that are described above the existing and potential future impacts of hypoxia on aquatic ecosystems were evaluated. To meet this objective an understanding of the physical processes behind the formation of hypoxia at the different target sites had to be gained in parallel to the study of biological processes, nutrient cycling, and oxygen dynamics. This combined effort was crucial for a proper identification of drivers of oxygen deficiency. Based on the knowledge of the drivers, the impact of hypoxia on ecosystems was assessed including spatial as well as temporal aspects. This was a crucial step in order to understand the temporal evolution of hypoxia effects and to be able to classify ecosystems with respect to drivers, pressures, impacts, and responses. Combining existing knowledge and with new findings from investigations at the different sites and numerical studies, an interdisciplinary understanding of the drivers of oxygen depletion, pathways of ecosystem decline and recovery, and impacts of hypoxia on ecosystem goods and services was developed. In this context ecosystem function describes also changes with respect to biogeochemical conditions and redox changes due to changes in oxygen availability. The obtained knowledge on hypoxia drivers and consequences represented an important prerequisite in order to adjust monitoring strategies to the specific requirements of the respective ecosystem – within HYPOX as well as for future monitoring attempts.
A first step towards these objectives was the compilation of existing information on hypoxia characteristics and the impact on ecosystems at the different target sites. The collected information was summarized in report D3.3 ‘Compilation of existing data on effects of hypoxia on ecosystems at target sites’ (http://metaworks.pangaea.de/download.php?fileid=146). At a later state of the project, a similar overview was produced, this time including information obtained during the project. Again, a report was produced (D3.4 ‘Report on ecosystem function decline due to hypoxia and recovery’; http://metaworks.pangaea.de/download.php?fileid=395).

Starting already at the kick off meeting several workshops on impacts of hypoxia on ecosystems were carried out. A main objective of these workshops was the development of conceptual models listing the most important driving forces, pressures, impacts, and ecosystem responses as well as their interdependencies for the respective target sites. Graphical representations of these conceptual models are part of report D3.1 ‘Report on drivers / mechanisms of hypoxia / anoxia and their spatial and temporal occurrence’ (will be available soon at http://www.hypox.net/front_content.php?idcat=399&idlang=19 section ‘documents’).
During a final 4 day workshop, partners from most HYPOX institutions drafted an overview manuscript synthesizing the most important knowledge obtained in the project that will be submitted for publication in Biogeosciences soon after the end of the project (Friedrich et al., in prep.). An overview of the content of that manuscript was already presented at two international conferences (http://meetingorganizer.copernicus.org/EGU2012/EGU2012-9136.pdf; http://www.pices.int/publications/presentations/2012-Climate-Change/Yeosu-2012-presentations.aspx session 8). Another important product is a report on hypoxia impacts on ecosystems with a strong focus on biogeochemistry and large scale element cycling (D3.2 ‘Report on future impacts of hypoxia on ecosystems and their goods and services’; available soon at http://www.hypox.net/front_content.php?idcat=399&idlang=19 section ‘documents’).

4.1.3.7 KNOWLEDGE BASE ON OXYGEN DEPLETION: DATA SHARING, STANDARDIZATION AND INTEROPERABILITY
In order to turn the monitoring results and the other data obtained in HYPOX into useful and accessible information large efforts were undertaken to enable a regular and reliable flow of data to the data archive and the data portal. This included HYPOX data as well as available data from other sources. For the monitoring results, special emphasis was on comprehensive descriptions of the data going back to the individual sensor and the provision of data quality descriptors and instrument standards on calibration and methodology. All that information was collected and added as metadata to the individual sensor data. HYPOX data management tasks encompassed the complete observation data life cycle, including data capture, processing, quality assessment and quality control, archiving and dissemination, compilation and publication of regular and reliable data products. Furthermore a functional sensor registry and interoperable data collection architecture was designed and it was assured that HYPOX data management and corresponding infrastructures were compliant with ISO / OGC standards and with the principles of the Global Earth Observation System of Systems (GEOSS). Conformity with agreed standards and connection to interdisciplinary earth observation initiatives was identified as an important requirement to facilitate access by potential users. To support GEOSS, HYPOX collected a large amount of hypoxia-related data, linked different HYPOX observatories to GEOSS, and pioneered in the testing and definition of common standards and protocols for oxygen observation and sensor calibration. Once GEOSS is fully operational the collected information and description of available services will be made available to the public through the ‘GEOSS common infrastructure’ – a set of services and archives that helps to search for data and results of past and ongoing earth observations.
Before observational work started existing data from HYPOX target sites was compiled by the different partners (see above). The incoming legacy data were used as a first case study to establish the data flow from partners to the data archive and the data portal and to implement data management practices and policies. To facilitate data upload of legacy data an online collaboration tool (panMetaWorks; http://metaworks.pangaea.de/) was adopted for HYPOX
for online submission of data sets. A report on these issues including an inventory of the collected legacy data was prepared already in the first year of the project and presented to the project partners at the first annual meeting (D5.1 ‘HYPOX data management plan and policy and catalogue of relevant legacy data sets’; http://metaworks.pangaea.de/download.php?fileid=148)
Semi-automatized data retrieval from the two cabled observatories (Loch Etive and Koljoe Fjord) to the Pangaea data archive and the HYPOX data portal was established. This included the development of Software components (Sensor Observation Service (SOS) and SOS clients) that implement standards of the Open Geospatial Consortium (OGC) in compliance with GEOSS. The SOS is a web service that offers standardized interfaces to collect information about instruments and to retrieve data produced by those instruments. The data is being offered using the OGC observations and measurement (O&M) protocol. The first SOS client regularly connects to the SOS and request data from it. The client than automatically conducts all work necessary to produce the files required for data import into the data archive PANGAEA. A second SOS client is used to request near-real time data from the SOS and graphically display it on the HYPOX portal page. The cabled observatories were set up to be queried with OGC/SWE compatible SOS standard interfaces which enable these observatories to provide standardized real-time access to their data. All components implement OGC SWE (‘Sensor Web Enablement’) standards and provide a significant contribution to GEOSS. The observatory systems in Loch Etive and Koljoe Fjord served as platforms to test new data access concepts based on OGC SWE. This standard is highly suited for ocean observation applications as it is able to handle the complexity and diversity of ocean data collection systems. This standard is also recommended by GEOSS but has only been implemented in a few cases within ocean sciences so far. HYPOX is providing crucial feedback to allow for a widespread introduction of this class of standards into ocean observation systems. Sensor Observation Services from both cabled observatories were registered at the GEOSS services registry.
More than 250 data sets that have been collected by the different observatories and during HYPOX field campaigns have been curated, archived, and made available through the HYPOX data portal (http://dataportals.pangaea.de/hypox/). An overview of the uploaded data sets is found in table 4.2.A2 as well as in the table ‘data generated in HYPOX’ in section 4.1.6. The data portal was created already in the first year of the project and has been continuously refined and enriched with information on target sites and the monitoring activities carried out. Extended functionalities were implemented and include plotting functionalities as well as the possibility to display near real-time data from the two cabled observatories (e.g. http://dataportals.pangaea.de/hypox/sosclient/chart.php?id=22&client=koljoefjord_seaguard). The data portal further includes a GeoRSS feed that is basically a GML (Geographical Markup Language) enriched news feed, which shows the latest HYPOX datasets and their coordinates. This GeoRSS feed was successfully added as a service to the Compust GEOSS portal (http://geossregistries.info/geosspub/service_details_ns.jsp?serviceId=urn:geoss:csr:service:urn:uuid:5e3ce24e-4434-4781-bd8e-be7a22dfa652).
A workshop on the HYPOX data portal and on HYPOX contributions to GEOSS) was held at the final project meeting. Presentations and discussions held during this workshop were compiled as a report (D5.3 ‘Status report of the HYPOX data inventory, and on HYPOX data management procedures as contribution to the GEO work plan activities (GEO 2007) including concepts, schemes, and established workflows within observatories and archives’; http://metaworks.pangaea.de/download.php?fileid=397).
The efforts towards the implementation of standardized and interoperable data handling and data provision represent a major contribution to promote GEOSS and to strengthen Europe’s visibility in the GEO community. In addition, HYPOX contributed to GEOSS by many other means. These activities are described in the following part (Potential impact of the project).


4.1.3.8 REFERENCES
Berg, P., Røy, H. Janssen, F., Meyer, V., Jørgensen, B.B. Huettel, M., De Beer, D. (2003) Oxygen uptake by aquatic sediments measured with a novel non-invasive eddy-correlation technique. Marine Ecology Progress Series 261: 75-83

Dale, A. W., Sommer, S., Bohlen, L., Treude, T., Bertics, V. J., Bange, H. W., Pfannkuche, O., Schorp, T., Mattsdotter, M., Wallmann, K. (2011) Rates and regulation of nitrogen cycling in seasonally hypoxic sediments during winter (Boknis Eck, SW Baltic Sea): sensitivity to environmental variables. Estuarine, Coastal and Shelf Science 95: 14-28

Fischer, J.P. Koop-Jakobsen, K. (submitted) The Multi Fiber Optode (MuFO): A novel system for simultaneous analysis of multiple fiber optic oxygen sensors. Sensors & Actuators B, Chemical

Friedrich, J., Janssen, F. , Aleynik, D., Boltacheva, N., Dale, A., Etiope, G., Erdem, Z., Geraga, M., Gomoiu, M-T., Hall P., Hanson, D., Holtappel M., Kirf, M., Kononets, M., Konovalov, S., Lichtschlag, A., Livingston, D., Marinaro, G., Mazlumyan, S., Näher, S., North, R., Papatheodoru, G., Pfannkuche, O., Prien, R., Rehder, G., Schubert, C., Soltwedel, Th., Sommer, St., Stahl, H., Teaca, A., Tengberg, A., Waldmann, Ch., Wehrli, B., Wenzhöfer, F. (in prep.) Investigating hypoxia: diverse approaches to addressing a complex phenomenon. To be submitted to Biogeosciences.

Holtappels, M., Khalili, A., Donis, D., Wenzhöfer, F., Glud, R., Kuypers, M. (in prep.) Effects of non steady state oxygen concentrations on benthic exchange rates as assessed by eddy covariance measurements

Janssen, F., Cardenas, M.B. Sawyer, A.H. Dammrich, T., Krietsch, J., de Beer, D. (in press) A comparative experimental and multiphysics computational fluid dynamics study of coupled surface-subsurface flow in bedforms. Water Resources Research

Lavik, G., Stührmann, T., Brüchert, V., Van der Plas, A., Mohrholz, V., Lam, P., Mußmann, M., Fuchs, B.M. Amann, R., Lass, U., Kuypers, M.M.M. (2009) Detoxification of sulphidic African shelf waters by blooming chemolithotrophs. Nature 457: 581-584.

Lo Bue, N., Vangriesheim, A., Khripounoff, A., Soltwedel, T. (2011) Anomalies of oxygen measurements performed with Aanderaa optodes. Journal of Operational Oceanography 4(2): 29-39

Meysman, F.J.R. Galaktionov, O., Glud, R.N. Middelburg, J. J. (2010) Oxygen penetration around burrows and roots in aquatic sediments. Journal of Marine Research 68: 309-336

Revsbech, N. P., Larsen L. H., Gundersen, J., Dalsgaard, T., Ulloa, O., Thamdrup, B. (2009) Determination of ultra-low oxygen concentrations in oxygen minimum zones by the STOX sensor. Limnology and Oceanography Methods 7: 371-381
Potential Impact:
4.1.4 Potential impact and main dissemination activities and exploitation results

4.1.4.1 POTENTIAL IMPACT AND WIDER SOCIETAL IMPLICATIONS
One of the major findings during the lifetime of HYPOX was that the general public as well as decision makers have been highly interested in the findings of the HYPOX project. In particular residents who learned about monitoring activities in close by waters were very positive about the established facilities and even offered their support to ensure continuous operation. There is a natural curiosity to learn about the environmental issues and to ensure the conservation of the ecosystem. Within HYPOX public outreach activities have been playing a significant role and as the focus of research is immediately recognized as of high importance for judging the environmental conditions HYPOX has been successful in producing an impact with wider societal implications.
With the foreseeable growth in offshore activities in the next decades there will be a strong demand in carrying out baseline studies and in monitoring of any changes of the affected freshwater and marine environments. Currently a strong interest in exploring natural resources in the Arctic has developed and some countries and non- governmental organizations are concerned about letting these activities evolve without proper environmental monitoring. Projects like HYPOX are able to provide essential pieces to a conclusive observing strategy to ensure sustainability of the envisaged activities. Within HYPOX a number of observing strategies have been explored and therefore an expertise has been built up that can be used for any oxygen observing system either in closed waters or the open sea. Through the continuation of observatory sites as for instance Loch Etive and Koljoe Fjord Points of Contact for consultation will endure well beyond the lifetime of the project.

Strongest societal relevance and impact was immanent to the project through contribution to earth observation and to the societal benefit areas of the Global Earth Observation System of Systems (GEOSS). The impacts achieved are in line with the main targets of FP7 activity 6.4 (‘Earth observation and assessment tools for sustainable development’), and, more specifically in Activity 6.4.1.2 ‘Cross-cutting research activities relevant to GEO’. HYPOX supported GEOSS through contributing to individual GEOSS tasks and help in further fostering the GEOSS Common Infrastructure. Therefore the vision for GEOSS was fully embraced by HYPOX in particular to support the establishment of an infrastructure for a comprehensive and sustained Earth observations and information system.
HYPOX activities have been aligned to address some of the strategic targets of GEOSS i.e. to assist in the provision of timely, quality long-term global information as a basis for sound decision making. This will enhance the delivery of benefits to society in the following initial areas [GEOSS Strategic Targets Document 12 (Rev1), as accepted at GEO-VI, Nov 2009]:
- Understanding environmental factors affecting human health and well-being
- Understanding, assessing, predicting, mitigating, and adapting to climate variability and change
- Improving the management and protection of terrestrial, coastal, and marine ecosystems
- Understanding, monitoring, and conserving biodiversity
Data acquisition, processing, and dissemination in HYPOX were following the principles and recommendations of the GEOSS initiative. The applicability of proposed common standards for data formats and handling has been excessively tested and fed back to GEOSS and best practices in the field of oxygen observation (e.g. with respect to sensor calibration) have been developed and proposed to the ocean observation community. HYPOX also strongly engaged in initiatives to promote visibility and acceptance for GEOSS. On the long run, HYPOX impact will be strongly related to future GEOSS achievements. Through the continuation of the work started within HYPOX in other project like for instance the proposed project COOPEUS (lead by MARUM at Uni-HB and currently under negotiation with the EC) and similar national and European initiatives where HYPOX partners are strongly involved in an enduring impact on future observing programs can be foreseen.
HYPOX strongly improved capacities for monitoring and predicting oxygen depletion by carrying out oxygen observations at sites which are threatened by oxygen stress and / or global change, but were so far lacking adequate monitoring capacities. HYPOX efforts resulted in knowledge for the prediction of future conditions of water bodies. This is essential in order to propose measures for the prevention of further oxygen depletion at sites were drivers are identified as manageable. Reliability of the predictions was improved by investigating the role of the sediments and benthic fauna in addition to water column monitoring. HYPOX helped to constrain uncertainties on the influence of climate change and eutrophication on the oxygen content of a wide range of aqueous environments. Hypoxia monitoring - until now largely neglected in the observing and monitoring programs - was implemented and promoted as an essential element in ocean observation. Improved monitoring strategies have been developed and applied to target ecosystems. The appropriate technologies and sensors have been selected and efforts were made to assess and improve their performance and reliability (e.g. by development of calibration procedures and addressing issues of biofouling). Depending on hypoxia characteristics, a large variety of different platforms were used and quality control measures as well as a reliable and standardized flow of data were established. Observations were transformed into scientific results and knowledge with strong support from numerical modeling and data assimilation efforts that represented a key component of the project. The impact obtained by HYPOX will exceed the lifetime of the project as the obtained knowledge will provide a strong and valuable input for future oxygen observation attempts.
In situ oxygen monitoring was carried out at all proposed target sites in Europe’s open and coastal seas, in land locked marine systems (including fjords, lochs, lagoons) as well as freshwater systems (lakes). Additional observations were obtained from the open Black Sea Basin as well as from Eckernfoerde Bay in the shallow western Baltic. HYPOX addressed interactions with all earth system components and as well as their contributions to oxygen depletion in water bodies. Quantification of oxygen uptake and consumption rates in HYPOX links the aquatic realm with the connected solid and gaseous earth system components. Investigations carried out in land locked water bodies directly connected to the impact of terrestrial processes on hypoxia at these sites. Legacy data from all sites including long term data series were evaluated to identify the key parameters driving oxygen depletion in the different ecosystem and to decide on appropriate monitoring strategies. Data obtained from observatories and dedicated field campaigns during the project were used to assess drivers of oxygen depletion as well as consequences for the ecosystems. A key component of this analysis was the employment of modeling tools that were developed and tested and that took the role of biogeochemical processes as well as atmospheric and terrestrial components acting on the ecosystems into account. Furthermore the models added predictive capacities to the investigations that allowed to test hypotheses on the impact of global change and pollution on oxygen depletion. This interdisciplinary approach strongly improved current observation capabilities for the target ecosystems and will provide a large impetus and provide invaluable know-how for future oxygen monitoring in European waters.
By quantifying the oxygen content in aqueous environments and its temporal changes, HYPOX directly contributed to the prediction of the resulting impact on marine ecosystems, biodiversity and hypoxia-related biogeochemical processes. HYPOX observations provide quantitative inputs for predicting the external forcing processes today and in future. This knowledge as well as the modeling expertise gained in HYPOX will continue to serve as a basis for correct oxygen depletion forecasts. This in turn contributes to the planning of appropriately tailored adaptation measures to climatic change. HYPOX activities, especially investigations at previously eutrophied systems at the northwestern shelf and in Swiss lakes, provide valuable information concerning the extent to which a reduction of anthropogenic nutrient input leads to an alleviation of the oxygen depletion problem. This knowledge is strongly needed for cost benefit analyses in order to optimize mitigation measures. By investigating hypoxia in aqueous environments in conjunction with hypoxia impacts on animal communities and biogeochemical processes HYPOX helped to predict the future impacts on marine ecosystems, including biodiversity and related biogeochemical feedbacks. The work carried out in HYPOX represents a milestone towards a knowledge base on oxygen depletion that provides European policy and decision makers with the necessary information to optimally guide the overall strategies for sustainable development and the successful planning and negotiation of internationally binding treaties.
Substantial progress was made concerning the interoperability of observation systems for oxygen depletion in different systems. A standardized data flow to a permanent data repository and the web-based HYPOX data portal was established and open access is provided to all metadata and numerous data sets already now and will include all HYPOX data sets at the latest three years after upload. This includes the semi-automatized handling of the observation from the cabled observatories as well as a standardized web-based upload procedure to collect data and metadata from the large variety of moored and ship based observatories as well as the data collected during targeted field campaigns carried out in HYPOX. Managing and merging the huge range of observations of different origin was successfully carried out by the World data center WDC-Mare in conjunction with the data repository and data publishing network PANGAEA which also services a wide range of other interdisciplinary EU projects. The solid data base and knowledge platform created by HYPOX contributes information needed to evaluate the status of hypoxia at the target ecosystems and its potential future impact on the ecosystems. The HYPOX web site not only supplies the measured data through its data portal but also includes the full suite of knowledge and higher level information on hypoxia causes and consequences gained during the project (e.g. reports and presentations). Dedicated dissemination activities and strong links with GEOSS assure the visibility of HYPOX in the field of earth system observation and raise the chance that future hypoxia monitoring will add to the obtained knowledge base. This will further increase its value for decision making processes that are needed in order to keep ecosystems in healthy conditions, to allow for their recovery, and to avert catastrophic events like fish mass mortalities.

4.1.4.2 EXPLOITATION OF THE RESULTS
4.1.4.2.1 Improvements of hypoxia monitoring capacities accomplished within HYPOX and benefit for future monitoring efforts
The projected increase in oxygen depletion will increase the demand for state of the art oxygen monitoring in the future. Oxygen conditions represent a key parameter for the assessment of the environmental status of ecosystems. More observations of oxygen and other environmental parameters in coastal and continental shelf areas will be soon needed in the scope of the European Marine Strategy Framework Directive. This will enlarge the impact of HYPOX results and the need for the knowledge on appropriate monitoring strategies obtained in HYPOX.
HYPOX represents a pilot mission towards the implementation of a hypoxia observation network in European waters. A significant part of the HYPOX monitoring capacities will be sustained also after the lifetime of the project. Examples are the cabled observatories deployed in Koljoe Fjord and Loch Etive which will continue operation and data provision to the archive and the data portal (in case of the Loch Etive Cabled Observatory LECO that suffered from a lightning stroke a redeployment will take place after repair). Likewise, deployments of the profiling mooring GODESS (Gotland Deep Environmental Sampling Station in the Baltic Sea) will most likely continue in the future. Apart from the different HYPOX products / reports that are all made available through the HYPOX web page, maintained monitoring activities will assure that Points of Contact for consultation will endure well beyond the lifetime of the project.
The main contribution to future hypoxia monitoring, however, is represented by the knowledge obtained on appropriate monitoring strategies for different ecosystems. This includes the identified scientific requirements and knowledge gaps as well as technological aspects that have to be addressed in the future in order to successfully describe hypoxia causes, characteristics, and consequences at a given site. HYPOX investigations clearly showed that standard monitoring approaches (infrequent water column sampling at fixed stations) are inadequate to tackle the crucial aspects of hypoxia in a comprehensive way. Aspects missed by standard approaches include resolving of (1) temporal and (2) spatial scales of hypoxia, (3) addressing specific hypoxia thresholds of different ecosystem components (e.g. benthic fauna vs. microbial conversion pathways), (4) addressing hypoxia drivers, and (5) addressing hypoxia consequences:
Prerequisite of appropriate monitoring is the availability of adequate technologies and technological expertise. In HYPOX, substantial progress was achieved concerning the development of new technologies and the adaptation of existing technologies to specific monitoring requirements. Examples are found in sections 4.1.3.2 ‘Improving and integration of oxygen observation capacities’ and 4.1.3.3 ‘Assessing oxygen depletion in shelf and open seas and land locked water bodies’.
In addition to knowledge obtained concerning monitoring strategies and technologies HYPOX also demonstrated the benefit of combining observations and simulations. This contributed to a better understanding of the processes underlying hypoxia development, to distinguishing natural variability from manageable, anthropogenic effects, to the generalization of findings and gaining of predictive capacities, and to the optimization observational strategies. Another substantial improvement of monitoring capacities achieved in HYPOX concerns the implementation of a regular and reliable flow of data from observatories to the data archive and the data portal. Furthermore, HYPOX ensured compliance with the Global Earth Observation System of Systems (GEOSS) and common ocean observation standards and established links to GEOSS. Operational data flows as well as connection to global earth observation initiatives will be a crucial step for any future monitoring activities and will again invoke a demand for knowledge obtained in HYPOX.

4.1.4.2.2 Use of HYPOX results and knowledge by HYPOX partners
The primary use of the results obtained in HYPOX will be to add to the scientific output of the respective partners in the form of peer reviewed publications and contributions to international conferences. Already within the lifetime of HYPOX numerous talks and publications were provided to the scientific community and many more will follow soon (table 4.2.A1 and 4.2.A2 as well as tables ‘publications published and in press’ and ‘submitted and planned publications’ in section 4.1.6). By mentioning of the funding sources in the presentations and publications this likewise advertises the engagement of the European Union in the field of ocean observation. Publications and contributions to conferences will improve the scientific profile of the project partners and improve prospects of success for future project applications.
The huge amount of data collected in HYPOX calls for a continuation of analysis efforts which will also result in further cooperation, project applications, publications, and will continuously add to the visibility of HYPOX in the scientific community. Some examples:
1) The time-series data obtained at the northwestern Black Sea shelf off Romania will be assimilated into the Black Sea model that is run by ISMAR-CNR. Modeling of the oxygen dynamics on the shelf floor is envisaged with Eawag, Department of Surface Waters.
(2) Based on oxygen observations obtained in the Bosporus outlet area and at the Crimean shelf further modeling work will be carried out at HZG / GKSS. Main objectives will be a better understanding of the hydrophysical mechanisms of the observed oxygen oscillations and the contribution of biogeochemical processes in Bosporus plume waters to the Black Sea nitrogen cycle.
(3) The data collected in Eckernfoerde Bay are used at IFM-GEOMAR to predict the effect of seasonal hypoxia on benthic nutrient fluxes. This will help interpret water column data (e.g. oxygen and nutrients) measured at ‘Boknis Eck’ in Eckernfoerde Bay but also in other areas.
(4) Sediments, collected in the Gotland Basin will be used by IFM-GEOMAR to investigate the redox-sensitive cycling of Uranium and Molybdenum as a proxy of paleo oxygen variability.
(5) Knowledge on fjord exchange processes obtained by SAMS will be expanded to the entire western Scottish coast. Modeling of local hydrodynamics at the entrance of Loch Etive was already used for the design of the monitoring component in the international sea-bed carbon dioxide release project. In addition to physical processes the model will also be used to investigate biological and environmental issues (e.g. prediction of harmful algal blooms and dispersal of fish parasites).
(6) Hypoxia expertise at NIOO-KNAW / NIOZ is applied to North Sea ecosystems that were not covered by HYPOX. This takes place in a recently started project on coastal hypoxia in the North Sea area (funded by the Darwin Center for Biogeociences / Dutch Science foundation).

4.1.4.2.3 Potential use and users of the data and knowledge results outside the HYPOX consortium
Oxygen represents a key variable for many ecosystems. Oxygen availability governs the suitability of a given ecosystem as habitat for any higher live from the tiniest work to the largest fish. As an example, effects on benthic fauna have been demonstrated by investigations carried out along oxygen gradients at the HYPOX target sites in the Black Sea. Likewise, the presence or absence of oxygen has a vast influence on pathways and rates of biogeochemical processes with prominent implications for large scale element cycling including the possible release of nutrients, toxic substances, and greenhouse gases to the environment. Effects on sediment and water column biogeochemistry have been clearly shown by HYPOX investigations at several sites (e.g. Bosporus and Swiss Lakes water column, Gotland Basin, Eckernfoerde Bay and Crimean Shelf sediments). On the other hand, oxygen conditions and oxygen uptake integrate a large variety of biological as well as physical processes and may used as a general indicator for status and trends of aquatic systems. Data on oxygen depletion in European waters are thus highly significant for a large variety of applications including the assessment of Ecosystem status in connection to the European Marine Strategy Framework Directive. Possible applications that could benefit from HYPOX results and future monitoring that is based on HYPOX knowledge (1) assessment of ecosystem status (identification of baseline, observation of trends, comparison with past conditions), (2) identification of relevant sites and proper strategies and technologies for hypoxia monitoring (3) identification of risks for ecosystems (e.g. deteoriation, development of dead zones, loss of biodiversity or fishery yield, biogeochemical processes releasing toxic substances, e.g. sulfide), (4) identification of the need for mitigation and restoration measures (5) identification of appropriate mitigation and restoration measures and evaluation of their effectiveness, (6) assessment of the vulnerability of ecosystems to anthropogenic activities (e.g. nutrient release (eutrophication), exploratory activities) and climate change.
Over the time course of the project a list of possible users has been compiled, including projects and initiatives dealing with environmental issues, stakeholders, governmental bodies, and non-governmental agencies. The list is included in part 4.1.6 of the report. Some specific benefits and users of HYPOX data and knowledge are listed below as examples of the broad applicability.
(1) Data obtained at the deep-sea observatory HAUSGARTEN will feed into decision-making processes of the Arctic Monitoring and Assessment Programme (AMAP), the Arctic Ocean Sciences Board (AOSB), the International Arctic Science Committee (IASC), the European Polar Board (EPB) and other, related international organizations.
(2) Time series of oxygen and associated oceanographic parameters recorded at the North-western shelf will help to identify hypoxia drivers (currents, temperature, oxygen utilization during decomposition of organic matter, stratification, climate variability) and to assess the ecosystem’s recovery from past eutrophication, the potential for recolonization of former ‘dead zones’, the state of the habitat for bottom-dwelling fish, and the impact of hydrocarbon exploitation on the northwestern shelf.
(3) Observational data obtained in HYPOX have already been incorporated in a GIS data base for the Bay of Sevastopol and other costal areas of Crimea. The results have already been delivered to the local community, used and endorsed by local stakeholders (http://wiki.iczm.org.ua/en/index.php/Dissemination). The received biological data have been used in other EU projects (CoCoNet, PERSEUS), National programs of the Ukrainian National Academy of Sciences and other scientists outside the HYPOX consortium (e.g. Marine Biology and Ecology Department at the Fisheries Faculty at Sinop University, Turkey, Shirshov Institute of Oceanology (RAS), Moscow, Russia).
(4) Results obtained in Eckernfoerde Bay at station Boknis Eck provide important insights into the contribution of sediments to bottom water hypoxia (directly and via feed back loops). Boknis Eck should be considered as a natural laboratory for studying hypoxia and the potential impact on benthic biota and foodwebs. This type of information would be invaluable for marine authorities, ecosystem modelers and NGOs.
(5) Data from the profiling mooring will complement IOW’s long term monitoring program data. In the future the data are expected to be incorporated into the HELCOM database to which all IOW monitoring data are contributing. This will fosters the use of the data by researchers interested in the Gotland Basin region.
(6) The identified combination of natural and man made conditions that results in inflow events and deep water renewal of Loch Etive provides the means to regulate oxygen conditions at depth to some extent. Specifically, short term reduction of freshwater inflow through the River Awe hydro-electric system would be needed in times of spring tides and favorable winds. This would be possible by joint efforts of local authorities and energy suppliers (Scottish and Southern Energy) based on on-line monitoring data flow from equipment deployed in the deep-basin and at the entrance of Loch Etive, similar to one deployed within the HYPOX project.
(7) The BOX project in By Fjord in the Koljoe Fjord / Orust-Tjörn fjord system shows that active oxygenation of the deepwater in anoxic fjords decreases the leakage of phosphorus from the sediments. If these efforts are continued and extended into other fjords the expertise gained in HYPOX would be valuable to identify appropriate strategies for monitoring of the efficiency of the oxygenation measures.
(8) The Koljoe Fjord observatory leaders have been approached by a state organization to find out about the possibility to monitor the impact of dumping of excavated sediment into the fjord. In this case a continuous, online access to relevant parameters is of great importance to have control over the dumping process and the parameters that characterize the status of the fjord water.

4.1.4.2.4 Interactions with companies
Close contacts were established to professional suppliers of instruments and services in the field of oxygen and ocean observation throughout the lifetime of the project. The strong interest in ocean observation efforts in European waters of the companies working in this field is obvious from the letter of recommendation that was provided in the preparatory phase by the Norwegian company Aaderaa Data Instruments (AADI) and the commitments specified therein. Another clear indication of the relevance of the project work to companies was the positive response of companies to the invitation for an oxygen sensing workshop held at the second annual meeting in Horw, Switzerland. Representatives of several international companies from Germany, Switzerland, Denmark, Norway, and Japan participated in the workshop and several others sent posters and printed information material. Companies did profit from close contacts to HYPOX scientists not only through the revenue of products supplied to the project members but also with respect to knowledge transfer and the identification of innovation potential and future markets in the field of ocean observation. Some specific examples of fruitful interactions of HYPOX with SMEs are described below.
(1) Anderaa Data Instruments (AADI, Bergen, Norway) used the Koljoe Fjord observatory as test bed for the recently developed sensor strings as well as for the novel optical carbon dioxide sensor. AADI further actively took part in the development of the closed vessel calibration procedure within HYPOX. A similar system was already installed at AADI and will serve for the calibration of optical sensors for oxygen and carbon dioxide.
(2) Develogic (Hamburg, Germany) was involved in the setup of HYPOX cabled observatories. Thanks to this involvement Develogic is now able to deliver electronic components to provide real-time data access to observatory data based on cellphone services. An important argument for customers is the fact that the system is field proven.
(3) Institute for Marine Resources GmbH (IMARE Bremerhaven, Germany) was subcontracted by AWI to design a mooring for long-term observation of oxygen in shallow waters based on off the shelf underwater equipment and to provide quality control of the time series data obtained at the northwestern Black Sea shelf. The obtained technical solution proved successful and could potentially be established and marketed as low-cost standard solution for oxygen monitoring, e.g. in mussel farms.
(4) NKE electronics (Hennebont, France) will benefit from the knowledge obtained within HYPOX on float operation in ‘seafloor resting mode’. This will help NKE to keep its position in the world market of Argo floats.
(5) Antifouling experiments on oxygen optodes by means of automated chlorination continued at Ifremer within HYPOX. These technologies have a substantial marketing potential. Strong sensor biofouling observed in HYPOX cabled observatories demonstrated the need for antifouling measures for successful oxygen monitoring in coastal areas. Discussions were started about a transfer of technologies between Ifremer and AADI.
(6) Tecnomare-ENI has been collaborating with INGV for many years to develop systems for long term monitoring of near seafloor processes. An example of such instruments is the Gas Monitoring Module (GMM) that was deployed in HYPOX to monitor oxygen and methane variations in Katakolo Bay. A similar platform could serve as a standard instrument for the monitoring of many different kinds of seafloor phenomena. Similar cooperations were established in HYPOX with the sensor manufactures FRANATECH (Lueneburg, Germany) and CONTROS (Kiel Germany) that provided methane sensors for investigations in HYPOX.

4.1.4.2.5 Involvement of HYPOX partners in future hypoxia monitoring and continuation of monitoring efforts started in HYPOX
As mentioned above, several of the oxygen monitoring activities started in HYPOX (cabled observatories in Koljoe Fjord and Loch Etive, profiling observatory in the Gotland Basin) will be followed up also in the future. In addition, continuous oxygen measurements at the HAUSGARTEN observatory will be continued for an indefinite period on national as well as international funding (if available). Initiatives integrating physical oceanographic work across Fram Strait and the LTER (Long-Term Ecological Research) site HAUSGARTEN in a larger, preferably cabled, submarine infrastructure are currently under evaluation by the HGF (Helmholtz Association of German Research Centres) and the German BMBF (Federal Ministry of Education and Research). Monthly water column monitoring in Eckernfoerde Bay by the Boknis Eck Time Series project is established and will be ongoing. As a follow up of biogeochemical investigations carried out in HYPOX the addition of a benthic monitoring program is currently under discussion. INGV and UGOT will continue joint efforts to investigate the significance of gas seepage as geogenic driver of oxygen depletion at the Ionian sea target sites.
Several of the HYPOX partners (e.g. AWI, Ifremer, IOW, INGV) were already strongly engaged in ocean observation activities before the start of the project. These institutions strengthened their profile with respect to hypoxia monitoring and will of course continue activities in this field.
The core expertise of most of the consortium was primarily centered around basic research in marine and freshwater environments. The experience obtained within HYPOX therefore opens an additional field of research for many of the groups involved. Several partners are planning to make use of these new opportunities. As a basis for future activities in this field all observatory leaders compiled funds needed for observations of oxygen and associated parameters as they were carried out at the different target sites. The figures are summarized in a table in section 4.1.6 and include the costs for the purchasing / constructing the observatories as well as funds needed for five years of sustained observations. Below some specific examples of planned future ocean observation activities are provided.
(1) IFM GEOMAR and several other HYPOX partners seek to continue their research in the Baltic Sea within the EU BONUS program. Consortia are currently formed and more detailed planning is underway. Within the recently approved ROBOX project (HGF, National funding) the Baltic Sea will serve as a test site for sensors and platforms for the long-term in situ measurements of gases by in situ mass-spectrometry. Monitoring of bottom water oxygen dynamics is central to these activities. A cruise with R/V ALKOR to the Gotland Basin will be carried out in 2013 as a follow up of HYPOX to continue investigations of nutrient fluxes in response to bottom water oxygenation in the hypoxic transition zone.
(2) IBSS is aiming to extend the focus of its investigations of black sea fauna to ecosystem monitoring with special focus on the response of the benthic communities to anthropogenic pressures and climate change. Oxygen monitoring is identified as an essential component in local programs for investigation and protection of coastal environments and will be carried out by MHI in Sevastopol – a cooperation that proved extremely fruitful already in HYPOX studies at the Crimean shelf.
(3) ITU EMCOL and INGV are involved in EMSO and ESONET activities to establish a permanent cabled observatory for earthquake and environmental monitoring in the Sea of Marmara. Recently, ITU-EMCOL has submitted a proposal (MARDEP) to the Turkish authorities to apply for two fixed point observatories to monitor Mediterranean Sea water intrusions and the oxycline at the HYPOX target site in the Bosporus outlet area.
(4) UGOT will apply for funding to sustain the cabled observatory in Koljoe Fjord for a elongated period of time. Participation in HYPOX also facilitated the participation in upcoming proposals to the EU in the field of ocean observation and sensor development.
GeoEcoMar will purchase an oxygen- and possibly chlorophyll sensor equipped ARGO type float in the framework of the FP7 PERSEUS project to be used for Black Sea monitoring. Furthermore, the implementation of an early warning system for marine geohazards is planned which will include 5 buoys that will be equipped with oxygen sensors.

4.1.4.3 MAIN DISSEMINATION ACTIVITIES
A major component of the work carried out in HYPOX was dedicated to the transfer of the knowledge to audiences within and outside the scientific community. In agreement with the strong implications of hypoxia and hypoxia research for ecosystem goods and services and, hence, for society, activities were not restricted to dissemination of scientific results. Additionally, endeavors have been made to increase the awareness for the issue of oxygen depletion in aquatic systems also outside the scientific community. The main activities concerning the dissemination of the obtained results and the increase of awareness for hypoxia included (1) scientific publication and contributions to conferences and workshops, (2) contacts to media and other dissemination activities including the preparation of outreach products, (3) provision and maintenance of the project web site, and (4) networking with projects, initiatives, and knowledge platforms. An overview about these activities is given below.

4.1.4.3.1 Publications, conferences, and workshops
Numerous hypoxia-related studies were already published by project partners during the project lifetime, most of them in peer-reviewed journals (see table 4.2.A1 and the ‘publications published and in press’ table in section 4.1.6). A lot more publications are expected for the future (table ‘submitted and planned publications’ in section 4.1.6 lists some of them. A central project publication that is expected to foster the visibility of HYPOX in the scientific community is the planned project overview article to be published in Biogeosciences. The article will provide an overview of the HYPOX findings with respect to hypoxia characteristics at the different target sites, appropriate monitoring strategies as well as impacts and consequences of hypoxia for ecosystems (see above). HYPOX was well represented in international conferences and workshops. Contributions included presentations and posters as well as invited talks and organization and chairing of topical sessions. An overview about the contributions of all partners is found in table 4.2.A2 as well as in table ‘conferences, meetings, and workshops’ in section 4.1.6. Several workshops that were open to non-project members were organized during the annual meetings. This included the modeling workshop and the Data portal / GEOSS workshop described above as well as an oxygen sensing workshop that took place during the second annual meeting. The sensing workshop focused on oxygen sensor technology and applications and brought scientists in contact with invited representatives from leading manufacturers of oxygen sensing devices. Most of the presentations held during that workshop as well as posters from manufacturers that couldn’t join the workshop are found at http://www.hypox.net/front_content.php?idcat=399 in section ‘Annual meeting 2011: Oxygen Sensor Workshop’.

4.1.4.3.2 Media contact and public outreach activities
HYPOX engaged in a lot of public outreach activities (see table table 4.2.A2 and table ‘media contact and public outreach activities’ in section 4.1.6). Categories of activities included informative meetings with policy makers, stakeholders, and civil society, public lectures for the interested public as well as school children, press releases, weblogs, podcasts, publication of popular science articles, interviews in newspapers, radio and TV programs including talk shows, science programs as well as TV shows for children. A lot of the outreach activities were centered around general information on hypoxia with a special focus on project activities (annual meetings, upcoming cruises, observatory deployments). A good example for the information of the public about project activities and their relevance for society are the efforts undertaken to inform the County Board, the regional community and school children about the services provided by the Koljoe Fjord cabled observatory.
In order to make policy makers, stakeholders, and the general public aware of the threats of hypoxia and the need for improved oxygen monitoring a project brochure as well as four two-page policy briefs (‘Hypoxia briefs’) were produced. The brochure provides information on the general issue of hypoxia and its link to global change and eutrophication, as well as on project focus and scientific approaches, and the members of the HYPOX consortium. The brochure is available online since spring 2010 (http://www.hypox.net/upload/infomaterial/brochure_hypox100114_Online.pdf). The policy briefs merge general information on different aspects of hypoxia with findings from the HYPOX project. The ‘Hypoxia Briefs’ are available online since Jul. 2012 and distributed through the project web page (section ‘Policy briefs’ at http://www.hypox.net/front_content.php?idcat=399). 150 hardcopies of the brochure as well as of the four ‘Hypoxia Briefs’ were distributed to partners, related projects, potential end users, and GEO task representatives. Brochure mailing took place in early summer 2010 while the policy briefs were sent around at the end of the project.
In early summer 2010 the Coordination Team launched an information article on HYPOX in “International Innovation”, an annual produced by Research Media (www.research-europe.com). In addition to recipients specified by the HYPOX coordination team (partners, related projects, potential end users, and GEO task representatives), Research Media distributed the magazine to numerous people in science, industry, governmental as well as non-governmental institutions. An online version of the article is also available through the HYPOX web page (www.hypox.net/upload/infomaterial/hypox_international_innovation.pdf)
The HYPOX web site (www.hypox.net) was launched right away at the start of the project and updated and improved throughout the project. Project relevant images and films, news and project information and products (outreach material as well as deliverables / reports) were added to the media, news and information section, respectively. The media section is based on implemented Web 2.0 Services Picasa and YouTube. The HYPOX Picasa web album contains several hundred photographs from HYPOX activities. Video footage available in the media section includes videos showing deployment of HYPOX observatories as well as other oceanographic instruments. Furthermore it includes underwater footage obtained with the manned submersible JAGO in the Black Sea during the HYPOX cruise with R/V MARIA S. MERIAN as well as short interviews with the HYPOX observatory leaders that introduce to the different target sites. The data portal described above is directly linked to the HYPOX web site and includes not only the links to the data sets but also description of sites (including links to the observatory leader’s site introductions mentioned above), descriptions and images of observatories, as well as example plots of monitoring data and modeling results.

4.1.4.3.3 Linkages with projects and initiatives
Apart from scientific publications and contributions to conferences and workshops, networking with other projects and initiatives was carried out as more direct means to inform about HYPOX and to strengthen awareness for hypoxia and oxygen monitoring in the scientific community and connected domains. The main contacts established are mentioned below.
Contact to the ARGO float community was made by presenting an optode calibration procedure developed in HYPOX at the ARGO-oxygen meeting. Strong links to ESONET-EMSO-VISO and other projects and initiatives aiming to improve hypoxia monitoring in European waters were maintained and several project representatives joined the 2011 general assembly of the ESONET NoE. HYPOX partners further contributed to meetings of additional ocean observation and biodiversity initiatives, including Lifewatch, LTER, and ASPERA. Overview talks on HYPOX observatory activities were held at the final meeting of the FP7 project EuroSITES. Additional contacts made by HYPOX representatives included several other institutions and projects, e.g. the ‘SCOR working group 128 on hypoxia’, the ‘Benguela Current Commission’, the ‘Ocean Obs’ initiative, the ‘Collaborative Research Centre on subsurface dissolved oxygen in the tropical ocean (SFB 754)’. HYPOX further interfaced with the EU project CLAMER (www.clamer.eu) and contributed to several CLAMER public outreach activities. A text on ocean deoxygenation and coastal hypoxia was provided as a contribution for the CLAMER synthesis report. Further linkages were built with other projects and initiatives to disseminate scientific as well as technological aspects of HYPOX. These included affiliations and contributions to EURO-ARGO (www.euro-argo.eu) the CORDIS Technology Marketplace (http://cordis.europa.eu/marketplace) LOICZ (http://www.loicz.org) Marine TT (www.marinett.eu) innovation seeds (www.innovationseeds.eu) WaterDISS (www.waterdiss.eu) and the Science for Environment Policy News Alert Service (http://ec.europa.eu/environment/integration/research/newsalert/index_en.htm).
Striking evidence for a successful project networking was the recruitment of four additional partner institutions towards the end of the first year of the project: (1) Laboratoire des Sciences du Climat et de l’Environnment at the Commissariat à l’Energie Atomique et aux Energies Alternatives, France, (2) Museum of Natural History / Leibniz Institute for Research on Evolution and Biodiversity at the Humboldt University Berlin, Germany, (3) MARE Interfacultary Research Centre, University of Liege, Belgium, and (4) Norwegian Institute for Water Research, Norway. Scientists from the affiliated partner institutions contributed to project meetings and scientific discussions but also to HYPOX studies and hence to the scientific output of the project.
4.1.4.3.4 Promotion of GEOSS and strengthening of Europe’s visibility in the GEO community
Supporting GEO tasks within the running GEO Workplan (2009-12) has been one of the major goals of the HYPOX projects. As described in the DoW of HYPOX a number of GEOSS partners took over responsibilities in selected task groups. One major initiative was related to the GEO task ST-09-02 that deals with the integration of universities and research institutions into GEOSS (Promoting Awareness and Benefits of GEO). As part of this activitiy GEOSS workshops on ocean observation have been organized back to back to the IEEE OCEANS conference (Mai 2009).
The visibility of the HYPOX project in the GEO community was fostered by contributions to and participation in GEO meetings (see table table 4.2.A2 and ‘conferences, meetings and workshops’ table in section 4.1.6). The publication of an article on HYPOX in the GEO related online journal Earthzine (www.earthzine.org/2010/05/26/oxygen-monitoring-in-aquatic-ecosystems-eu-project-hypox/) added to the visibility of HYPOX in the GEO community.
Two GEO workshops have been organized with colleagues in the US to bring different stakeholders in the field together and come up with recommendations on next steps towards establishing GEOSS in ocean science (GEOSS Workshop XXVII ‘Understanding the Integrated Ocean Observation System, including Sub-surface Sensors’), and XXXVIII ‘Evolution of Oceans Observing Systems – Building an Infrastructure for Science’. One of the outcomes has been that agreement on the establishment of a GEO Community of Practice to allow for a better international coordination of existing and to be established observing infrastructures.
Four HYPOX services, each representing a metadata or data delivery service capable to comply with a GEOSS accepted standard, have meanwhile been registered at the GEOSS registry. These standardized services are linked to the HYPOX component.
HYPOX was engaged to introduce new ideas into the formulation of the new GEO Worksplan 2012-15. A new task (SB-01) emphasizing the role of ocean observations was phrased where an active participation of HYPOX partners is documented. A major component of this work will be helping to define best practices and standard processing methods to harmonize the data quality.
A close connection was established to EGIDA a project that is setup to coordinate earth and environmental projects to promote GEOSS (www.egida-project.eu). At the GEOSS workshop during the final HYPOX meeting a close collaboration between HYPOX and EGIDA was established. The brokering approach promoted by EGIDA appears to be the right concept to improve detectability and accessibility of ocean observation data. Agreement has been reached between project partners and representatives of EGIDA to support the demonstration of the EGIDA approach by making HYPOX core observational data available to the EGIDA services.

4.1.4.4 SOCIO ECONOMIC IMPACT
For the case of HYPOX, socio-economic impact is here defined as the benefits and costs that impact welfare and economic growth among the population in the regions where new observation infrastructures are established. The benefits and costs that should be taken into account in a socio-economic analysis are those that are generated directly by the project and relate to the objectives of stakeholders that relate to the project. In case of oxygen observations in HYPOX and in general, stakeholders include research institutions, state operated monitoring agencies like hydrographic offices, fishery organizations, tourism industry and companies involved in offshore operations. A good example relating to benefits and costs is connected to the HYPOX observatory in Koljoe Fjord. The observatory leaders have been approached by a state organization to assess the possible feasibility for the monitoring of the impact of dumping excavated sediment into the fjord. In this case a continuous, online access to oxygen and other relevant parameters would be of great importance to have control over the dumping process and the parameters that characterize the status of the fjord water. This example shows that HYPOX benefits can be directly related to the preservation of the environmental status of the monitored regions by providing the necessary information needed to adjust dumping operations in order to minimize the environmental impact. With respect to costs in that particular example access to online data from an observatory would probably save the customer investments of the order of several hundred thousands Euro for accompanying observations. In many cases, however, quantifications of benefits of observing infrastructures are not that straightforward but may still be highly significant to society. One example would be the increased production of hydrogensulfide in coastal waters under hypoxic conditions. This may lead to a smell nuisance with strong implications for recreational value and potentially harmful consequences to human health. Consequently an impact on tourism and also on the welfare of residents living close by can be expected but is not easily turned into benefits in terms of costs that were saved.
Socio-economic impact can also be measured by quantifying the increase of contractual research revenues based on HYPOX work and findings. This includes European, national, or research projects negotiated with private companies. Within HYPOX several companies were involved in developing and supplying adequate instruments and devices (see above), potentially improving their competitiveness on the marine technology market.
Five areas of socio-economic benefit to which the project significantly contributed are listed below. In brackets some links to other parts of the final report are provided where the HYPOX contributions to the respective areas are addressed in some detail. However, it exceeds the scope of this report to present a comprehensive quantitative analysis. Instead the main categories for assessing the socio-economic impact have been addressed in a more qualitative manner.
KNOWLEDGE. Example benefits: Publication of data sets through the publication network Pangaea, publications of scientific results in scientific journals (see tables 4.2.A1 4.2.A2 and tables ‘data generated in HYPOX’, ‘publications published and in press’ and ‘submitted and planned publications’ in section 4.1.6’), value of the access granted to external researchers through the adopted open access data policy (see section ‘Potential use and users of the data and knowledge results outside the HYPOX consortium’)
DEVELOPMENT. Example Benefits: Technological output represented by the identified monitoring technologies and practices including novel approaches to handle the obtained data sets as well as calibration procedures developed and transferred to the ocean observation community (see section ‘Improvements of hypoxia monitoring capacities accomplished within HYPOX and benefit for future monitoring efforts’)
EDUCATION AND TRAINING. Example benefits: Graduates (masters and PhD level) trained in the observation infrastructure, and students using the infrastructure (see table ‘HYPOX students’ in section 4.1.6)
EMPLOYMENT. Example benefits: newly created jobs (researchers and non-research staff at project partner institutions, potentially employees in manufacturers in the field of ocean observation; see table ‘HYPOX staff’ in section 4.1.6 and section ‘Interactions with companies’)
KNOWLEDGE TRANSFER AND COLLABORATIONS. Example benefits: Collaborative projects building on HYPOX achievements and involving HYPOX partners, competitive national and international funding (see section ‘Involvement of HYPOX partners in future hypoxia monitoring and continuation of monitoring efforts started in HYPOX’)
List of Websites:
www.hypox.net
All relevant contact details are provided on the project web site

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