Zooplankton ecology

Research fields

Our research addresses ecological problems related to the effects of short- and long –term variation of pelagic physical-chemical conditions on food web interactions and dynamics of marine zooplankton. We focus particularly but not exclusively on copepods of the Baltic Sea. Using various approaches ranging from small-scale laboratory experiments and field studies to long-term monitoring of zooplankton, we investigate zooplankton life history traits and the interaction of abiotic and biotic factors in controlling the seasonal dynamics and productivity of key species along the salinity gradient of the Baltic Sea. By providing a mechanistic understanding we aim at a better assessment of the effects of climate variation and change on the biodiversity of Baltic zooplankton.

Another focus of the work group are trophic interactions between protists and zooplankton, particularly with regard to nutritional quality and toxicity.

Research topics

Environmental tolerances of key species

The Baltic Sea is characterized by steep seasonal or spatial gradients in environmental factors. Marine species dominate the zooplankton in the major basins and their sensitivity to small changes in the physicochemical settings is key to understand fluctuations and future impacts on biodiversity and population size. We currently conduct experimental studies to investigate the physiological tolerances and limits with regard to salinity and temperature of laboratory reared key species such as Acartia bifilosa and Temora longicornis. The central question whether species are adapted or can adapt to changing environmental conditions is addressed by comparing the phenotypic plasticity and genotypic determination of tolerances of different local populations. This work is connected to the Bonus Project BIO-C3 which focuses on causes, consequences and management implications of biodiversity change in the Baltic Sea.

Monitoring mesozooplankton in the western Baltic Sea

The work group conducts long-term monitoring of zooplankton in the Baltic Sea on behalf of the German ‘Bundesamt für Seeschifffahrt und Hydrographie’. Sampling is conducted on seven stations covering offshore waters from the Bay of Kiel to the Bornholm Basin. The monitoring is an integral part of our research aiming at identifying causes and mechanisms for long-term changes in the abundance of key species of copepods and in biodiversity in general. We currently seek to understand how the interplay of physical factors and food availability determines the population dynamics and phenology of copepods. The implications of this temporal variability for assessing the applicability of HELCOM zooplankton core indicators for the description of the good environmental status of the western Baltic Sea are currently evaluated in an UBA project.

Trophic interactions

The working group has diverse interests in the interactions of phyto- and zooplankton with particular focus in the role of harmful algal species. In the past, we have experimentally evaluated the potential disruption of grazer-algae interactions by biochemical or physical defense mechanisms and its consequences for the productivity of zooplankton. Currently, we are interested to investigate how these impacts change under diverse climate change scenarios, in particular ocean acidification.