The structure and dynamics of zooplankton communities in shallow bays in the northern Baltic Sea during a single growing season

The littoral zone forms a large proportion of the northern Baltic Sea and creates diverse and prolific habitats with high regional importance. However, our understanding of the structure and functioning of littoral food webs is constricted, because their zooplankton communities remain virtually unstudied. We investigated variability in the structure and dynamics of littoral zooplankton communities, in relation to landscape-level gradients in environmental conditions, in four shallow bays in the Aland archipelago during one growing season. The variability was best explained by the productivity potential, i.e. the concurrent effects of temperature, trophic state, and phytoplankton biomass, of the environment. Zooplankton abundance and biomass showed a significant, positive correlation with these factors. Also the structure of zooplankton communities and their seasonal succession patterns were strongly associated with productivity potential. In general, the littoral zooplankton communities were characterized by higher diversity and abundance, and earlier succession patterns than previously reported for the northern Baltic pelagial.