Records of southern and central Baltic Sea eutrophication in δ13C and δ15N of sedimentary organic matter

The Baltic Sea catchment area has seen considerable agricultural and industrial development over the last century, but observational evidence of eutrophication is ambiguous. We examined organic carbon accumulation rates and the stable isotope signature of δ13C and δ15N in organic matter in four 210Pb-dated short sediment cores from the southern and central Baltic Sea to search for sedimentary records of increased nutrient input and biological production. Organic carbon accumulation rates vary little through time in the cores from the Oder estuary and the Arkona Basin, but increase significantly in the Bornholm Basin and in the Gotland Deep records over the last 40years.