Understanding the oceanic carbon cycle
The ocean has a key role in regulating atmospheric CO2 concentrations and currently take up about 25% of annual anthropogenic carbon emissions. The oceanic carbon cycle is composed of processes that exchange carbon between various pools within the ocean, as well as between the atmosphere, Earth interior, and the seafloor. The oceanic carbon cycle is a result of many interacting forces across multiple time and space scales. The oceanic carbon cycle is a central element of the global carbon cycle and contains three main processes (or pumps): the solubility pump, the carbonate pump, and the biological pump. In order to better understand, quantify and predict the ocean’s potential for carbon uptake, actions should further research the oceanic carbon cycle. The deep sea and its water column may be the largest carbon sink on Earth but its large-scale carbon uptake potential and future is still unknown. Ocean carbon sequestration options include the management of natural ocean processes, i.e. actions to maintain the integrity of natural carbon stores and actions that enhance the long-term (century-scale) removal and sequestration of greenhouse gases from the atmosphere by marine systems, primarily by biological means. Actions should aim at developing innovative approaches to understand the complex processes underlying the oceanic carbon cycle, its efficiency, climate sensitivity, and emerging feedbacks. Actions should further the understanding of the resilience to climate change and temporal and regional variability of the natural carbon inventory in the ocean. Actions should further the understanding of how the biological pump and the deep ocean carbon sink will respond to the rapid and ongoing anthropogenic changes to our planet—including warming, acidification, and deoxygenation of ocean waters. Actions should advance the scientific understanding of marine pelagic and benthic invertebrate and vertebrate carbon, the carbon services they provide (i.e. trophic cascade carbon, biomixing carbon, carbon mineralisation, bony fish carbonate, whale pump, twilight zone carbon, biomass carbon, deadfall carbon and marine vertebrate mediated carbon), and the intricate biological pathways involved in carbon cycling and the associated implications for climate regulation. Actions should assess and model the marine vertebrate carbon services and should link them to population dynamics, with a view to gathering enough evidence to enable their inclusion in the models of carbon cycling. Actions should assess and model the as yet poorly quantified carbonate-forming invertebrate species in the deep sea, such as reef-building scleractinians, as well as their resilience to cumulative impacts of global changes. Actions should contribute to ocean observations and the Digital twin of the oceans by providing an ocean carbon-modelling environment. Actions should improve the sampling of regions and metrics for marine organisms and should gather evidence and data to estimate and quantify the global CO2 sequestration potential of protecting and restoring populations of invertebrates and vertebrates to previous levels. Actions should explore the efficiency and global magnitude of the biological pump and how this will be affected by climate change. Actions should deliver quantification and predictability of the ocean carbon sink and in so doing, should contribute to resolving the uncertainty in the magnitude and sign of projections of future global ocean primary production. The regional variability in the amplification or reduction of the efficiency of the ocean carbon sink is an important element that actions should take into consideration, as the climate effects on the carbon sink (both on the physical and biological drivers) will have a strong regional correlation. The importance of polar regions in the carbon cycle needs to be kept in mind. Actions should further the regional predictive skill beyond five years.
Actions should further investigate tipping points and irreversibility in the ocean carbon cycle (both for the upper ocean and the intermediary & deep ocean), the biogeochemical feedbacks, the changes that will occur in the 21st century, both globally and regionally, and how the multiple stressors will affect the primary production (monitoring strategies to have access to all the compartments - upper, intermediary and deep ocean). Among the stressors, the effects of trawling, drilling, overfishing, deep-sea mining and dredging on carbon cycling and sediment dynamics should be included and investigated using marine monitoring techniques. Actions should look into the policy implications of the findings of this research.
For this action, the multifaceted nature of the ocean carbon cycle necessitates collaboration across disciplines, taking an ecosystem approach. At a minimum, actions should link science on the changing ocean physics and chemistry, and more generally on climate, with the study of the marine biota and their evolution. International cooperation is strongly encouraged. Actions under this topic should plan on a close collaboration among each other and should build upon and link with Horizon 2020 projects and other European and international ocean observing initiatives, including the Integrated Ocean Carbon Research, IOC-R. All in-situ data collected through actions funded from this call should follow INSPIRE principles and be available through open access repositories supported by the European Commission (Copernicus, GEOSS, and EMODnet). Where relevant, creating links to and using the information and data of the European Earth observation programme Copernicus, the Group on Earth Observations (GEO) and the Global Earth Observation System of Systems (GEOSS) is expected.
This topic links with research conducted under Cluster 5 (‘Climate, Energy and Mobility’) Destination ‘Climate sciences and responses’; Cluster 6 (‘Food, Bioeconomy, Natural Resources, Agriculture and Environment’) Horizon Europe Mission Ocean, seas and waters, Destination ‘Biodiversity and ecosystem services’, Destination ‘Clean environment and zero pollution’, Destination ‘Land, ocean and water for climate action’, Destination ‘Resilient, inclusive, healthy and green rural, coastal and urban communities’ and Destination ‘Innovative governance, environmental observations and digital solutions in support of the European Green Deal’; Horizon Europe Mission Ocean, seas and waters.