Phosphatases – Development of new quantitative assays along terrestrial-aquatic gradients

Phosphatase aktivity measurments in soil with p-Nitrophenolphosphate as substrate
Visualization (Fluorescence signal) of the phosphatase activity using Elf97-P substrate

Phosphatases are key enzymes of bacteria, fungi and algae in the mobilization of organic bound P in the aquatic and terrestrial environment. In addition, plant roots secrete these enzymes into the soil matrix. Phosphatases are controlled by the inorganic bioavailable P pool, i.e. the lower this source the higher the phosphatase activity. However, knowledge on the in-situ enzyme activity, their impact by environmental factors and consequently on the quantitative turnover in terrestrial and aquatic biogeochemical cycles is only fragmentary. This gap will be closed by a methodological approach consisting of comparison, validation and intercalibration of all available phosphatase assays utilized in terrestrial and aquatic research, as well as by the development of new reliable, sensitive and quantitative assays based on new model substrates and radio tracers in combination with alternative detection systems such as, for example, nanoSIMS. The outcome of this project is most essential for quantification of the P fluxes in agricultural production systems, soils and the aquatic environment.