Environmental Geochemistry

Catchment phosphorus discharge from agricultural areas in Sweden

Dr. Heinrich Taubald, MSc Daniel Schöckle, Prof. Karin Tonderski (Univ. Linköping, Sweden) and Prof. Lotta Andersson (SMHI, Norrköping, Sweden)

Strong efforts are necessary to decrease the phosphorus load to the Baltic Sea in order to reduce eutrophication. The greatest uncertainty in catchment P flow predictions is associated with the partitioning of riverine load between various sources. The relative importance of different P sources is usually assessed from annual flux budgets that are often dominated by diffuse P inputs from agricultural land. Dissolved inorganic phosphate (DIP, PO43-) can be analysed for O isotope composition. The P-O bond in phosphate is resistant to inorganic hydrolysis, and does not exchange O with water without biological mediation. We measure oxygen isotope ratios on DIP from stream water (outflow of catchment), field drains and rural sewage-/wastewater to trace and quantify the contribution of different sources of P to the total P discharge from a catchment in South Sweden.

Identifying Phosphate Sources and anthropogenic impact in river water near Tübingen

Dr. Heinrich Taubald, MSc Daniel Schöckle

The “Ammertal” valley area west of Tübingen represents an agriculturally highly influenced region, typical for Middle Europe, and is drained mostly by the river “Ammer”. The “Schönbuch” aera, located north of Tübingen is a nature park and thus provides an almost perfect catchment area without anthropogenic impact. We use oxygen isotope measurements in riverine dissolved inorganic phosphate (DIP) to constrain the individual contribution of natural and anthropogenic sources (e.g. waste water treatment plant, fertilizers).

Hydrological Model for the Schönbuch Aera, constrained by HO-isotope measurements on water

Dr. Heinrich Taubald and BSc and MSc Students from Tübingen University

In Student Lab-Practicals and BSc/MSc theses we analyse the Hydrogen, Oxygen and Carbon isotope ratios of rain, surface water (rivers, lakes) and groundwater (wells). At least four samplings are performed per year to see seasonal effects. The overall aim of the study is to build a hydrological model of the Schönbuch area and gain insight in relevant sources for Carbon in DIC.

  • BSc projects Luca Rößler, Valentin Grau, Bernd Rieger, Johannes Dettweiler, Felix Hüttemann, Lukas Büttner & Alexander Mast