Response of the zooplankton community to improving water quality in the Scheldt estuary.

The evolution of the water quality and ecological functioning of the Scheldt estuary are monitored since 1996 in the frame of the OMES project, coordinated by P. Meire, ECOBE, UAntwerp. This monitoring has shown a considerable improvement of water quality, leading to a shift from a hypereutrophic to a eutrophic system (Van Damme et al., 1995; Cox et al., 2009). The stimulated primary production, mostly of diatoms, improved the water oxygen concentration but also leads to silica – limitation. This could favor development of other primary producers, such as green algae and cyanobacteria. The zooplankton community, which is studied by EcoLab in the frame of OMES, has shown clear changes in parallel with water quality improvement. The zone of maximal abundance of calanoid copepods has changed from the brackish water area towards the freshwater area where a decrease in cyclopoids and cladocerans abundance has been observed (Mialet et al., 2010; 2011). The thesis of S. Chambord examines to which physico-chemical factors these changes are related. As zooplankton assures the transfer of primary production to higher trophic levels, grazing experiments are performed to evaluate in how far the 'new' zooplankton community is able to control potential phytoplankton blooms and could play a role in silica regeneration.

Keywords:SCHELDT ESTUARY, TROPHIC ADAPTATIONS, MANAGEMENT

Disciplines:Geology, Animal biology, Aquatic sciences, challenges and pollution

Project type:Collaboration project