N-Amazon: Forschungsfahrt METEOR M174 (GPF 19-1-13)
The Amazon River is the largest river on earth and delivers 20% of global. Despite large seasonal variations in the outflow and inorganic nutrient concentrations, these impact the productivity along the northward spreading river plume and shape the phyto- and zooplankton communities. Higher tropic level organisms have to adapt to the varying food sources.
During the field program we will link direct measurements of hydrographic properties with focused experimental studies of nutrient supply and nutrient limitation of phytoplankton, as well as the transfer of phytoplankton nitrogen to the zooplankton food web. Species ecology will be evaluated by colleagues from Brazil. Isotopic evidence from particles and dissolved substances will be used to understand the processes and transport of material. Together the experimental and field data will allow delineating how heterotrophy and autotrophy can orchestrate the cycling of essential micro- and macronutrients in aquatic food webs.