The ocean and coastal ecosystems and habitats play a significant role in the global carbon cycle, representing the largest long-term carbon sink.  here are remaining research gaps for advancing opportunities to incorporate potential ocean and blue carbon ecosystems into climate frameworks.

Option A: European and polar blue carbon hotspots and priority areas for climate policy frameworks and effective management
The action should also gather information on organic carbon stocks and accumulation, their characteristics (source, lability, dissolved particulate, living, non-living), and their potential change under pressures from human activities. The action should identify the key characteristics that make the selected ecosystem and habitat a hotspot for blue carbon (i.e. geomorphology, physical-chemical characteristics, anthropogenic manipulation, sea level rise effects, etc.). The action should enable a better understanding of the dynamics of carbon between these reservoirs and the associated timescales involved. A quantification of the approximate amount of carbon (and preferably nutrients) fixed annually by those natural ecosystems in Europe, as well as a quantification of the annual degradation rates of the ecosystems and consequent reduction in carbon sequestration should also be carried out. This knowledge should then be consolidated into a framework for predictive tools to investigate climate-smart management scenarios at appropriate scales, as well as methodologies, methods, and guidance tailored to the specific EU maritime region. The research action will identify and recommend best suited, fit-for-purpose, climate smart and resilient initiatives and activities that are relevant to local communities in order to protect, sustainably manage, restore, and enhance blue carbon habitats. Particular attention should be given to win-win-win solutions and strategies that have multiple benefits for climate mitigation and adaptation, biodiversity gains and benefit to people, including nature-based solutions, ecosystem-based approaches and technological-ecological synergies (TES) (combining technological and nature-based solutions).

Option B: Uncover mitigation opportunities of newly emerging European and polar blue carbon habitats
Blue carbon gains from glacier retreat along fjords (fjordic blue carbon, i.e. seabed biological carbon gains as a result of recent rapid glacier retreat along fjords); blue carbon gains from ice shelf losses through opening up of productive new habitat and leaving nutrient-fertilized wakes of enhanced productivity; slight increases in sea temperature may also increase polar blue carbon; blue carbon around Antarctica is increasing with climate change, and the productivity within emerging fjords is likely to further increase with age and seasonal sea ice loss; snow and ice retreat in the subarctic and subantarctic; marine ice losses that create new polar continental shelf habitat across millions of km2 and doubling seabed carbon stocks in 25 years; fjords that have become exposed by glacier retreat (fjords are hotspots for the burial and storage of organic carbon and for their potential to provide an important long-term global climate regulation service); massive coastal embayment emerging as a result of giant iceberg breakout from ice shelves; new and intense phytoplankton blooms around the Southern Ocean which have doubled carbon storage by seafloor organisms in the last 25 years; marine ice loss in the Arctic; macroalgal particulate organic carbon sinks; changes in primary production in open Arctic waters; loss of pagophilic (ice-dependent) species and lower albedo, macroalgae, bivalves; species yet to be discovered in polar and deep-ocean ecosystems; relatively inaccessible habitats; novel approaches to secure carbon stocks in the face of fishing disruption (e.g., through changes in target species, gear, target areas).The action should build on existing and novel datasets (in-situ and satellite) to gather carbon information on stocks and accumulation, carbon characteristics (source, lability), change under pressures from human activities if not protected, the potential for carbon sequestration and associated timescales, understanding of carbon dynamics, framework and criteria to integrate these considerations and predictive tools to investigate management scenarios at appropriate scales, including displacement and trade-offs.