Climate change and ecosystem function(ing)
Microbial plankton holds a key position for the function(ing) of oceanic and freshwater ecosystems: (i) autotrophic microbes belongs to major light harvesters driving open ocean primary productivity; (ii) bacteria and fungi are mostly responsible for biogeochemical cycles; (iii) through selective grazing phagotrophic eukaryotic microbes contribute to the control of prokaryote dynamics and indirectly influence global biogeochemical cycles (top-down control); and (iv) microbial plankton is of critical importance to support higher life in the oceans by transferring energy and carbon to higher trophic levels (bottom-up control). Therefore, a better understanding of the response of microbial plankton communities (structure and function) to a changing environment is mandatory to predict the effects of global change on ecosystem processes. In this context, we study the structures and functions of microbial plankton communities in oceanic systems (mainly Eastern North-Atlantic, but also the global ocean) and diverse freshwater bodies including (high-)mountain lakes. Therefore, we use state-of-the-art molecular tools such as eDNA metabarcoding, biocomputational tools (high-performance computing), biostatistical approaches (modeling, networking), cultivation techniques and diverse experimental approaches to quantify the flux of organic matter as a marker for ecosystem function(ing).