The oceanic components of the global cycles of Carbon, Oxygen, Nitrogen and other macro/micronutrients are still not well constrained while they are undergoing unprecedented changes as a result of anthropogenic pressures. Studies of past and present observations as well as of future projections reveal biogeochemical perturbations at all spatio-temporal scales and emphasize complex interactions between ocean physics and biology, all of which are crucial to understand in order to anticipate their implications and future changes for biogeochemical cycling and ocean sustainability. Such knowledge is essential to the development of solutions for the monitoring of the ocean biogeochemical state, for the management of marine living resources and for various research as well as operational applications. This session will bring together researchers that use a range of novel techniques, including observations (e.g. in-situ measurements, remote sensing, global syntheses), experiments (e.g. laboratory and mesocosms), and modeling approaches (e.g. Earth System models, coupled biogeochemical-circulation models, theoretical models) to further improve our understanding of the biological carbon-pump, the biogeochemical cycles in the ocean and their connections to climate, as well as to increase the potential for operational applications.

We welcome contributions (1) dealing with the cycling of Carbon, Oxygen, and Nitrogen in the ocean, dissolved and particulate stoichiometry and elemental ratios, oceanic primary production, ocean acidification, exchange processes at the air-sea interface, role of sea-ice in global biogeochemical cycles and synthesis studies using global compiled data sets; (2) exploring innovative approaches to model-data fusion (e.g. novel methods in data assimilation, assimilation of data from novel in-situ or remote platforms, assimilation of up- or downstream products of ocean color remote sensing), model skill assessment, downscaling from large to regional domains, and case studies of research and operational applications (e.g. HAB prediction, episodic hypoxia, etc…); (3) focusing on a range of spatial scales (regional to global).

Deoxygenation in the marine environment is a critical global issue. Dissolved oxygen concentrations are indicators of ecosystem health as measures of biological productivity, remineralisation, and global climate trends. Oxygen deficient regions are present around the world, as persistent open ocean oxygen minimum zones or seasonal features in shelf seas.

Despite significant uncertainty under future climate scenarios, Earth system models predict deoxygenation across many ocean basins and shelf seas. This deoxygenation has a compound effect on oxygen deficient environments, causing shoaling, expansion, intensification and critical shifts in biogeochemical cycling pathways.

We must develop a better understanding of how physical, chemical and biological processes interact to impact low oxygen regions under changing oxygen conditions and climates. What are the interactions and feedbacks with biological communities and biochemical processes? How will these changes impact the marine environment at regional and global scales?

We invite contributions that investigate ocean deoxygenation and its physical, chemical and/or biological drivers, using observational or model-based approaches at regional or global scales.

Due to the growing pressures on marine natural resources and the ecosystem services demand, the interest of scientific and politic world is moving to ensure the conservation of marine ecosystems and environmental sustainable development of anthropogenic activities. Recently the principal European policies meet these issues, focusing on maintaining/ reaching the good environmental status (GES) of water bodies (WFD/MSFD) and solving the conflicts between anthropogenic pressures and marine ecosystems (MSP).
Some of the anthropogenic activities could have a potential impact on marine environment altering the marine ecosystems equilibrium. Since the dynamical processes influence the pollutants dispersion, it is compelling to analyse the ecosystems status through the study of abiotic variables distribution at proper spatial and temporal resolution.
From this perspective a large amount of data obtained by global observation systems (e.g. GOOS, EMODNET…) is needed to properly analyse the environmental quality both in the coastal and open ocean areas.
The session focuses on marine ecosystems, abiotic and biotic factors affecting their dynamics, highlighting the effects of anthropogenic impacts.
The following topics will be discussed: quantitative analysis of the effects of pollution on biota considering their natural and anthropogenic sources; benthic and pelagic community dynamics; economic evaluation of natural capital.
In this session multidisciplinary approaches using data coming from multiple sources (mathematical model, in-situ and remote observations) are encouraged.
Studies regarding the marine strategy descriptors, with the aim to develop methods, technologies and best practices to maintain/restore biodiversity and to guarantee a sustainable marine resources use, are also welcome.

Oceanographic modelling and monitoring are both widely used to study the pathways and fate of marine pollutants such as hydrocarbons, plastic litter, suspended sediments, radionuclides, etc. In this session, advanced models, operational applications and techniques related to tracing pollutants on local, regional and global scales, as well as the coupling with met-oceanographic transport fields from operational oceanography products such as Copernicus Marine Monitoring Environment Service will be discussed.
Parcel trajectory numerical schemes, ensemble and multi-model methods, uncertainties estimation, risk algorithms, monitoring techniques and decision support systems are solicited topics. Integration of modelling and observing systems for both data assimilation and model validation are also very welcome.
Key questions of the session are identified as follows.
Which factors affect the dispersion of the oil, floating debris and other pollutants?
What happens to the contaminants on the ocean’s surface and in the water column?
How do oil, marine litter and other pollutants interact with water and sediments?
Impacts of pollutants on the marine ecosystems and resilience to pollution events are also important subjects for discussion: What are the oil’s, plastics’, and sediments’s behavior in the water column, on various beach sediments, rocks and seabed? 
E.g., what is the biodegradation rate of oil droplets remaining in the water column and what are the controlling factors? What is the rate of aggregation, biofouling, degradation and fragmentation of plastics?
What is the rate of beaching and sedimentation of marine pollutants and what are the ways of entering the marine food chains (including human consumption)?

The coastal ocean has been increasingly recognized as a dynamic component of the global carbon budget. This session aims at fostering our understanding of the roles of coastal environments and of exchange processes, both natural or perturbed, along the terrestrial / coastal sea / open ocean continuum in global biogeochemical cycles. During the session recent advancements in the field of coastal and shelf biogeochemistry will be discussed. Contributions focusing on carbon and nutrient and all other element's cycles in coastal, shelf and shelf break environments, both pelagic and sedimentary, are invited.

This session is multidisciplinary and is open to observational, modelling and theoretical studies in order to promote the dialogue. The session will comprise subsections on coastal carbon storage, and on benthic biogeochemical processes.

This session is open to all contributions in biogeochemistry and ecology where stable isotope techniques are used as analytical tools, with a focus on stable isotopes of light elements (C, H, O, N, S, ...). We welcome studies from both terrestrial and aquatic (including marine) environments as well as methodological and experimental, theoretical and modeling studies that introduce new approaches or techniques (including natural abundance work, labeling studies, multi-isotope approaches, clumped and metal isotopes).