My PhD project focuses on the impact of the controlling factors on the longitudinal phytoplankton succession in the Warnow River, a eutrophic lowland river in north-east Germany. Alternations between free flowing river stretches and fluvial lakes formed by glacial processes are characteristic for this river-lake system. Consequently, the phytoplankton community have to adapt to permanent changes of abiotic, biotic and hydrological parameters to stay alive during downstream transport. These adaptation processes are reflected by changes in species composition and biomass along the river course. To investigate growth and loss effects of phytoplankton, single water parcels are followed downstream by measurements of the actual flow velocity on successive river stations and by tracer experiments.

The study concentrates on:

• analysis of downstream phytoplankton composition and biomass development
• impact of abiotic factors: underwater light, turbidity, nutrient concentrations
• impact of biotic factors: effects of macrophyte cover, grazing by zooplankton and benthic filter feeders
• effects of hydrological parameters: flow velocity, water depth, dead zones

This study has been financially supported by a graduate fellowship of Mecklenburg-West Pomeranian and by the German Research Foundation (Hu 516/2-1).

University of Rostock
Department of Biology, Institute for Biodiversity Research
18051 Rostock
Wismarsche Straße 8
Germany

Phone: +49 (0) 381 498 1984
Fax: +49 (0) 381 498 1980
mandy.bahnwart@stud.uni-rostock.de