Meiobenthos of some Estonian coastal lakes

Abstract

Corer samples of zoobenthos were collected in 20 coastal water bodies of western Estonia including 2 inner parts of bays of the Baltic Sea, 5 lagoons weakly connected with the sea, and 13 freshwater lakes in August 2004. Reigi laht, an open bay, was the only site where brackishwater taxa dominated; in the same bay, eumeiobenthic small Nematoda were very abundant. At all other sites, the bulk of meiobenthos was formed of small, pseudomeiobenthic individuals of Chironomidae and Oligochaeta, while eumeiobenthos, consisting here mainly of Nematoda and Ostracoda, was outnumbered by the former. The near-bottom planktic Cladocera and Copepoda were also common. Freshwater taxa dominated in all lagoons and lakes, with scarce brackish-water species accompanying them in the lagoons as well as in some lakes. The abundance and biomass of pseudoand eumeiobenthos, as well as of planktic crustaceans, were higher in the lagoons than in the freshwater lakes.