Development and application of stable isotope techniques to understand biogeochemical processes in the hydrosphere

Determination of stable isotopes in nutrients enables to gain information on its source(s) and behaviour in ecosystems. Within this project, we develop, validate and and apply innovative isotope tools to gain insight into carbon, nitrogen, sulfur and phosphorus turnover in the hydrosphere. This includes measurements of 13C of organic matter (13C-OM), dissolved inorganic carbon (13C-DIC) and fatty acids of total lipids (13C-FA), 18O of phosphate (18O-PO4), 34S and 18O of sulphate (34S-SO4, 18O-SO4) and 15N and 18O of nitrate (15N-NO3, 18O-NO3). While these parameters are applied to identify the nutrient sources and to explore and quantify their biogeochemical turnover, the 13C fatty acid approach additionally contribues in understanding food webs.