Understanding the ecocline at shallow coasts of the Baltic Sea

We report on results of the Research Training Group Baltic TRANSCOAST. The overall aim of Baltic TRANSCOAST is to enhance our knowledge of the shallow coast ecocline. How is the marine coastal zone influenced by terrestrial processes? How is the terrestrial coastal zone influenced by marine processes? These questions lead our research within the three research fields covering hydro-dynamic, (bio)geochemical and biological processes. Regarding the hydro-dynamics we 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. With respect to (bio)geochemical processes we address 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. Finally, reagrding the biological processes, we are interested in revealing how the primary production and the composition of the micro- and macro-phytobenthos in the shallow Baltic Sea influence matter transformation processes. The integrative approach of Baltic TRANSCOAST allows us to get to grips with questions that are otherwise hard to tackle. For instance, we address how the pore water constituents drive microbial processes and the deposition of nutrients and and how they are impacted by sediment resuspension and translocation. We investigate how the hydrology of the peat layers interferes with the generation of trace gases and investigate the role of the nearby Warnow river and its plume and how this changes under the impact of wind direction and wind strength. For the latter we rely on data and models. Further, as a common basis for all topics addressed in Baltic TRANSCOAST we established the geology of the study area and learned that regional variability may play a major role in shaping the processes under study.