Structure of mesozooplankton community in the Barents Sea and adjacent waters in August 2009

Strong climatic fluctuations have been documented in the Arctic in recent years. To detect possible impacts of the climatic variability on the pelagic ecosystem we investigated mesozooplankton communities collected in the summer of 2009. Oithona similis dominated in terms of total abundance while Calanus species contributed a major part of the total biomass. The total mesozooplankton abundance ranged from 143 to 6145 individuals m(-3). The highest average mesozooplankton biomasses were found in the frontal zone of Atlantic waters (AW) located south of the Svalbard archipelago and in Arctic waters (ArW), while the minimum was registered in Murmansk coastal waters (MCW). The spatial distributions of the mesozooplankton communities were strongly related to latitude and hydrological conditions. A possible impact of the recent cooling registered in the Barents Sea since 2007 was detected as a decrease in the total mesozooplankton biomass within MCW in the summer of 2009.