“…15 Coastal zones are among the most productive marine regions characterised by high, organic matter accumulation and decomposition (e.g. Hjalmarsson et al, 2010). The Skagerrak, located between the North Sea and the Baltic Sea and in the close proximity to land, has many potential nutrient sources, such as the North Atlantic, Baltic Sea, North Sea, as well as continental discharge and river runoff (Aure and Dahl, 1994;Andersson, 1996;Gustafsson and Stigebrandt, 1996).…”