Isotope hydrobiogeochemical composition of a managed river entering the southern Baltic Sea: A seasonal perspective
2 Geochemistry & Isotope Biogeochemistry, Marine Geology, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany/ Marine Geochemistry, University of Greifswald, Germany/ Interdisciplinary Faculty, University of Rostock, Germany
3 Geochemistry & Isotope Biogeochemistry, Marine Geology, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany/ present address: Umweltplan, Greifswald, Germany
4 Geochemistry & Isotope Biogeochemistry, Marine Geology, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany/ present address: National Agency of Agriculture and the Environment of Mecklenburg-Western Pomerania (Stalu-MM), Rostock, Germany
5 Geochemistry & Isotope Biogeochemistry, Marine Geology, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany/ present address: Bioplan, Institute of Applied Biology and Landscape Management, Nienhagen, Germany
6 Geochemistry & Isotope Biogeochemistry, Marine Geology, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany/ present address: Biota, Institut für ökologische Forschung und Planung, Bützow, Germany
P 3.1 in Earth System Science and Reconstruction
The composition of a river, the Warnow River (WR), flowing into the Baltic Sea off Warnemünde (Germany), was investigated. A spatial study was carried out to follow the variations from the origin to the estuary. A temporal study was conducted at one site just before WR meets the estuary. Surface water was sampled to analyze nutrients, major and trace elements, stable (H, C, O ,S), and Ra isotopes. The composition was controlled by its tributaries, in situ processes, exchange with the atmosphere, and diffuse groundwater. The WR is like a lake system, leading to high evaporation and interaction with sediments/soils. The WR was a source of dissolved inorganic carbon to the estuary, which may further impact the Baltic coastal waters. The calculated CO2 partial pressure was higher than the modern atmospheric value, indicating that WR is a source of CO2 to the atmosphere. Due to CO2 degassing and photosynthetic activity, calcium carbonate may be formed, which causes a decrease in dissolved Ca. In spring, pelagic primary production strongly impacts pH and redox-sensitive elements. In summer and autumn, influences occurred by benthic microbial activity, diffusive release from soils/sediments and tributaries. The results highlight the need to investigate surface water systems discharging into coastal areas to better understand the coastal carbon cycle.
The study was supported by BALTIC TRANSCOAST (DFG), DAAD, CARBOSTORE/COOLSTYLE (BMBF), and Leibniz IOW.