Periodic Reporting for period 2 - SEACHANGE (Quantifying the impact of major cultural transitions on marine ecosystem functioning and biodiversity)
Période du rapport: 2022-04-01 au 2023-09-30
Marine conservation seeks to protect valuable habitats but the pristine state of marine ecosystem functioning and biodiversity is conjectural. Conservation management strategies are often based on highly altered ecosystems where the degree of human-induced change is unknown. In SEACHANGE, we propose a structured approach to the reconstruction of marine ecosystem baselines in order to quantify the impact of human cultural transitions on marine biodiversity and ecosystem functioning. SEACHANGE addresses two key questions: 1) What was the nature of long-term changes in marine biodiversity and ecosystem functioning associated with major socioeconomic changes across the Mesolithic-Neolithic boundary over a 3000-year period in NW Europe? 2) What has been the scale and rate of marine biodiversity loss and changes to ecosystem functioning as a result of fishing intensity and marine habitat loss during the last 2000 years in the North Sea and around Iceland, eastern Australia and the west Antarctic Peninsula?
To address these questions we are analysing: 1) absolutely-dated annually-resolved bivalve shell series; 2) marine sediment cores; 3) archaeological midden materials including shells and bones. We are dating these samples precisely and undertaking zooarchaeological and palaeoecological, stable isotope geochemical and environmental DNA/DNA analyses. We are comparing the data with historical and archival sources, and later in the project we will generate numerical ecosystem simulations. We will identify how the current marine environment differs from that before large scale human impact and what measures are needed, and how long will it take, for marine biodiversity to recover.
We are investigating five key cultural transitions which frame the proposed work packages (WP):
1. The European transition to farming (Mesolithic to Neolithic, 8K to 5K yrs BP; WP1)
2. The European pre-industrial to modern (last 2K yrs; WP2)
3. The Australian hunter-gatherer (aboriginal) to colonial (last 6K yrs; WP3)
4. The Viking age settlement of Iceland (WP4)
5. The advent of intensive whaling in Antarctica (WP5).
WPs 4 and 5 capture transitions from “fully pristine” to impacted ecosystems, in Iceland from before human settlement in AD 874 to the present day, and in Antarctica from before the start of intensive whaling in the 20th century.
WP6 addresses data management.
To address these questions we are analysing: 1) absolutely-dated annually-resolved bivalve shell series; 2) marine sediment cores; 3) archaeological midden materials including shells and bones. We are dating these samples precisely and undertaking zooarchaeological and palaeoecological, stable isotope geochemical and environmental DNA/DNA analyses. We are comparing the data with historical and archival sources, and later in the project we will generate numerical ecosystem simulations. We will identify how the current marine environment differs from that before large scale human impact and what measures are needed, and how long will it take, for marine biodiversity to recover.
We are investigating five key cultural transitions which frame the proposed work packages (WP):
1. The European transition to farming (Mesolithic to Neolithic, 8K to 5K yrs BP; WP1)
2. The European pre-industrial to modern (last 2K yrs; WP2)
3. The Australian hunter-gatherer (aboriginal) to colonial (last 6K yrs; WP3)
4. The Viking age settlement of Iceland (WP4)
5. The advent of intensive whaling in Antarctica (WP5).
WPs 4 and 5 capture transitions from “fully pristine” to impacted ecosystems, in Iceland from before human settlement in AD 874 to the present day, and in Antarctica from before the start of intensive whaling in the 20th century.
WP6 addresses data management.
The A islandica shells collected during the North Atlantic cruise have been measured and triaged. Shells were selected for their potential for crossdating and the shell chronologies from the North Sea and North Icelandic Shelf have been extended to the present day.
127m of piston and gravity core and 49 megacores were collected on the cruise. Mega cores and water samples were sampled onboard for eDNA as soon as they were collected.
Initial compound specific isotope analysis (CSIA) has been carried out using the organic fraction of A. islandica shells from Iceland and the northern North Sea.
The Mainz group conducted δ15N (CSIA) analyses on the organic fraction of bivalve (A islandica) shells from the Fladen Ground and Orkney to identify shifts in the trophic position of the bivalves that could be indicative of changes in food web complexity through time.
The sclerochronology of gastropods from Orkney shell middens was analysed to determine changes of temperature, seasonality and the season of shellfish collection since medieval times.
A fieldtrip to the Skaill Farm archaeological site on Rousay, Orkney took place. The University of Copenhagen team collected eDNA samples from the site.
The ability of Amino Acid Racemisation (AAR) dating to distinguish between Early Holocene and last millennium shell samples has been demonstrated. This provides a relatively fast and cheap “range-finder” alternative to radiocarbon dating.
The Copenhagen team subsampled material from three long sediment cores collected during the North Atlantic cruise from around the Northern Isles, Scotland. A total of 46 ancient eDNA samples across the cores have been extracted from these subsamples and metagenomic libraries prepared for sequencing. These data will provide insight into changing marine biodiversity across the entire length of the cores.
Samples have been collected for eDNA analysis from 22 archaeological contexts in Orkney and Shetland.
The Australian project partners have met with Darumbal elders (Traditional Owners) to negotiate permissions for Australian fieldwork.
Material has been collected from a series of midden sites across Northern Iceland for eDNA analyses. Alongside the midden work, DNA extraction, PCR inhibition screening and metabarcoding of 18S eukaryote PCR amplicons are being carried out for two marine sediment cores.
Lead isotope dating of multicores from three sites in Antarctica indicates that the cores cover the last 60 to 120 years. The record therefore does not extend back unequivocally to the period prior to intensive whaling. Bone material was sampled from typical Antarctic seal and whale species collected between the 1850s and 1950s and stored at the Natural History Museum. These samples will be subject to stable isotope analysis to determine the background trophic positions of these species before and during the start of extensive whaling. The Copenhagen team have continued working on multicore seabed eDNA samples from Antarctica. These have now been sequenced at three different metabarcoding markers. In addition, material from two cores has been made available by a new collaborator (AWI, Germany). This new material has been subsampled and is awaiting eDNA extraction and sequencing. Collectively the material now under analysis now provides good spatial coverage across the Western Antarctic Peninsula, offering a broad picture of marine biodiversity changes across the target period and location.
127m of piston and gravity core and 49 megacores were collected on the cruise. Mega cores and water samples were sampled onboard for eDNA as soon as they were collected.
Initial compound specific isotope analysis (CSIA) has been carried out using the organic fraction of A. islandica shells from Iceland and the northern North Sea.
The Mainz group conducted δ15N (CSIA) analyses on the organic fraction of bivalve (A islandica) shells from the Fladen Ground and Orkney to identify shifts in the trophic position of the bivalves that could be indicative of changes in food web complexity through time.
The sclerochronology of gastropods from Orkney shell middens was analysed to determine changes of temperature, seasonality and the season of shellfish collection since medieval times.
A fieldtrip to the Skaill Farm archaeological site on Rousay, Orkney took place. The University of Copenhagen team collected eDNA samples from the site.
The ability of Amino Acid Racemisation (AAR) dating to distinguish between Early Holocene and last millennium shell samples has been demonstrated. This provides a relatively fast and cheap “range-finder” alternative to radiocarbon dating.
The Copenhagen team subsampled material from three long sediment cores collected during the North Atlantic cruise from around the Northern Isles, Scotland. A total of 46 ancient eDNA samples across the cores have been extracted from these subsamples and metagenomic libraries prepared for sequencing. These data will provide insight into changing marine biodiversity across the entire length of the cores.
Samples have been collected for eDNA analysis from 22 archaeological contexts in Orkney and Shetland.
The Australian project partners have met with Darumbal elders (Traditional Owners) to negotiate permissions for Australian fieldwork.
Material has been collected from a series of midden sites across Northern Iceland for eDNA analyses. Alongside the midden work, DNA extraction, PCR inhibition screening and metabarcoding of 18S eukaryote PCR amplicons are being carried out for two marine sediment cores.
Lead isotope dating of multicores from three sites in Antarctica indicates that the cores cover the last 60 to 120 years. The record therefore does not extend back unequivocally to the period prior to intensive whaling. Bone material was sampled from typical Antarctic seal and whale species collected between the 1850s and 1950s and stored at the Natural History Museum. These samples will be subject to stable isotope analysis to determine the background trophic positions of these species before and during the start of extensive whaling. The Copenhagen team have continued working on multicore seabed eDNA samples from Antarctica. These have now been sequenced at three different metabarcoding markers. In addition, material from two cores has been made available by a new collaborator (AWI, Germany). This new material has been subsampled and is awaiting eDNA extraction and sequencing. Collectively the material now under analysis now provides good spatial coverage across the Western Antarctic Peninsula, offering a broad picture of marine biodiversity changes across the target period and location.
A methodology has been developed for compound-specific nitrogen isotopic analysis of amino acids (CSIA-AA) in the shell organic matrix of the bivalve A. islandica. Using this methodology the first annually resolved AA-specific δ15N chronology from bivalves has been generated, covering ca. 150 years. It provides details of the changing trophic position (TP) of the studied specimens as well as the nitrogen isotope baseline of the environment. The δ15N values may reflect the use of fertilisers as well as decadal ocean variability.
This CSIA-AA methodology has demonstrated the potential of combining amino acid-specific nitrogen isotope analysis with bivalve sclerochronology. This is a very powerful tool for the reconstruction of temporal changes of the ecosystem nitrogen isotope baseline, allowing the quantification of anthropogenic influences and the ability to track changing water masses and changes in the integrated food web complexity.
A novel qPCR method has been developed for the detection of PCR inhibition in eDNA samples. This method successfully demonstrated undetectable levels of PCR inhibitors in eDNA extracted across the work packages.
It has been shown that airborne eDNA is a source of vertebrate DNA, enabling the establishment of a baseline for conservation of marine ecosystems.
Work is continuing on the application of machine learning (AI) to the reading and interpretation of shell growth increments. This development will significantly improve and expedite our ability to construct long growth increment series from bivalve molluscs.
This CSIA-AA methodology has demonstrated the potential of combining amino acid-specific nitrogen isotope analysis with bivalve sclerochronology. This is a very powerful tool for the reconstruction of temporal changes of the ecosystem nitrogen isotope baseline, allowing the quantification of anthropogenic influences and the ability to track changing water masses and changes in the integrated food web complexity.
A novel qPCR method has been developed for the detection of PCR inhibition in eDNA samples. This method successfully demonstrated undetectable levels of PCR inhibitors in eDNA extracted across the work packages.
It has been shown that airborne eDNA is a source of vertebrate DNA, enabling the establishment of a baseline for conservation of marine ecosystems.
Work is continuing on the application of machine learning (AI) to the reading and interpretation of shell growth increments. This development will significantly improve and expedite our ability to construct long growth increment series from bivalve molluscs.