Working Group Food Web

The Food Web Group focusses on complex interactions between planktonic organisms concentrating on primary producers at the base of the food web (phytoplankton) and their primary and secondary consumers (e.g. micro- and mesozooplankton). Planktonic food webs are considered as highly complex with a plethora of different feeding interactions, spatio-temporal dynamics and functions in the plankton. The characterization of Shelf Sea food webs is our central aim. By using field and experimental approaches,  we address the effects of external (e.g. nutrients, temperature, light, hydrodynamics, CO2, O2) and internal drivers (intra- and inter-specific interactions) on food web structure and dynamics as well as bottom-up and top-down control mechanisms that either limit organisms by resource availability or include predation and herbivory at each trophic level.

Micrograzers play a prominent role as trophic link between microbial and classical food webs. As a result, we specifically consider small-sized protozoa (e.g. heterotrophic dinoflagellates, ciliates) and metazoa (e.g. meroplanktonic larvae, nauplii) in the plankton. Especially the ability of micrograzers to (1) buffer nutritional imbalances at the base of the food web, (2) suppress and modulate phytoplankton blooms and (3) improve the food quality for secondary consumers are central aspects of our research. By using multi-trophic approaches, we further aim to assess the impact of food quantity and quality aspects on the transfer of limitation signals and on energy transfer efficiencies onto higher trophic levels.