Seasonal development of meso-zooplankton biomass and production on the sw coast of Finland

Abstract

Abstract Seasonal development of mesozooplankton abundance, biomass and production were studied on the SW coast of Finland in three hydrographically distinct areas with different phytoplankton dynamics. In addition, the present species composition was compared to that at the beginning of the century, using a multidimensional scaling analysis. Mesozooplankton biomass and production were dominated by only a few species: the largest part of the production in the archipelago and open sea areas (11.3 g C m-2 year-1 and 28.1 g C m-2 year-1, respectively) consisted of that by raptorial and suspension-feeding calanoid copepods (Acartia bifilosa and Eurytemora affinis) and of that by rotifers (Synchaeta baltica), while annual mesozooplankton production in the bay area (10.5 g C m-2 year-1) was mainly due to production of filter-feeding cladocerans (Daphnia cucullata and Bosmina longispina) and predatory cyclopoid copepods (Thermocyclops oithonoides). The food chain in the bay area seemed to be based on heterotroph...