The Baltic Sea is one of the world’s largest brackish inland seas and its coastal ecosystems display large salinity gradients. Temperature and ice conditions change markedly with latitudes. Geology and land use vary substantially in the drainage area with significant impact on material fluxes from land to sea. These settings allow for a diverse range of biological communities and ecosystem configurations.

The theme focuses on understanding processes and functioning of the Baltic Sea watershed, coastal zone and open waters, including all aspects of eutrophication, acidification and food-web alteration. This includes studies of hydrodynamics, biogeochemistry, geology, and biology that aim to improve our understanding of the complex interplay of different drivers and processes shaping these ecosystems. Interdisciplinary studies are particularly welcome. The sessions under this theme will address key questions such as:

• How do saltwater inflows, upwelling and mixing control the stratification and circulation patterns in the  Baltic Sea?
• What is the role of sub-mesoscale eddies for the transport of energy in the Baltic Sea?
• How will changes in hydrodynamics affect the marine ecosystem?
• What is the ecological and biogeochemical role of the submarine groundwater discharge?
• Do multiple pressures have synergistic, antagonistic or additive effects on organisms, communities and  ecosystems?
• How is benthic-pelagic coupling varying along the environmental gradients and affecting                    biogeochemical processes?
• How is biodiversity linked to ecosystem functioning and sustainability?
• Are the Baltic Sea and its coastal systems sources or sinks for greenhouse gases?
• What are the important processes regulating land-sea interaction?
• Are there ecological “hotspots” for biological communities and biogeochemical cycles?
• What is the role of bottom-up versus top-down control of food webs in the Baltic region?
• Are there significant feedback mechanisms between biogeochemical processes and organization of    biological communities?
• How does the functioning of the Baltic Sea compare with other similar ecosystems?