Johan Eklöf, Department of Ecology, Environment and Plant Sciences Stockholm University
Johan Eklöf, Department of Ecology, Environment and Plant Sciences, Stockholm University

How would you describe your project in a few sentences?

Eutrophication from nutrient-loading is a well-known environmental problem in shallow coastal areas of the Baltic Sea, but recent work suggest that loss of large predatory fish could play an equally important role by reducing trophic control over algal biomass. A poorly studied but potentially important organism group in this context are coastal zooplankton, that i) could control phytoplankton and thereby improve water quality, and ii) constitute an important food source for juvenile fish.

In this project we are analyzing how i) ecosystem productivity, ii) zooplankton-eating fish, and iii) the local habitat complexity (aquatic plants) affect the abundance and composition of zooplankton, using samples collected at ca. 200 stations distributed across 32 shallow bays along the Baltic Sea coastline. Given that zooplankton analyses require expert skills and are very time-consuming, the analyses are still ongoing and the data has yet to be analyzed.

What are your most important results, and for whom are they particularly useful?

We expect the coming results to shed light on zooplankton as a potential key component in shallow coastal areas, and help explain the ecosystem linkages between eutrophication, loss of large predatory fish, and water quality.

How can it assist an ecosystem-based management of the marine environment?

These results will aid managers dealing with ways of combating eutrophication problems, as well as management aimed at halting and reversing the decline in coastal fish stocks.