The objective is to assess how the peatland’s water balance, the current dynamics and hydraulic properties of the marine sediments and the subsoil influence sea water intrusions into the peatland and/or submarine groundwater discharge into the Baltic Sea. The underlying hypotheses are: Sea level dynamics and sea water intrusions modify the flow and transport processes in the peatland and the underlying aquifer. Flow and transport processes within the peat are governed by transfer processes between differently mobile water regions. The variability of the hydraulic conductivity of the sediment and its surface structure generate a characteristic small-scale turbulence field in the shallow water, controlling the matter distribution in the water layers next to the sea floor. The small-scale matter distribution in shallow coastal waters influences large-scale transport processes in the Baltic Sea.

The objective is to evaluate how (bio)geochemical transformation processes both in the marine and the terrestrial part of the coast are influenced by water and matter inputs from the respective other coastal domain. The underlying hypotheses are: Terrestrial compounds govern the release of trace gases and the matter transformation in the coastal waters of the Baltic Sea. Fluctuations in brackishness of waters in the peatland (i.e. concentrations of chloride, sulphate, and the like) influence the quantity and quality of dissolved organic matter (DOM) originating from both the rhizosphere and the peat. Methane exchange can be used as a proxy for the influence of the vegetation on these aforementioned interactions. Intrusions of brackish sea water into the peatland causes an enhanced release of DOM with a feedback on the transport of DOM, C, N and P to the nearshore coastal waters.

The objective is to reveal how the primary production and the composition of the micro- and macro-phytobenthos in the shallow Baltic Sea influence matter transformation processes. The underlying hypotheses are: Activity and productivity of the microphytobenthos and macrophyte communities in the shallow coastal waters of the Baltic Sea are governed by terrestrial matter inputs. The microbial transformation of P in the sandy sediments strongly depends on wave movements and the activity of benthos organisms. Availability and mixing of organic substrate and disposable oxidants strongly enhances remineralisation in marine sediments.