Wter masses, bottom sediments, and zoobenthos in the area of the Novosibirsk Polynya in September 2008

Eight bottom biocenoses were observed in the Novosibirsk Polynya region. Species composition of these communities was common for areas of dominating surface arctic water masses. The biocenoses were characterized by high population density (up to 3200 ind./m**2) and elevated biomass (up to 233.5 g/m**2). The number of species increased seaward and according to bottom depth. Patterns of spatial distribution of macrobenthos biomass were closely related to bottom sediment types and salinity patterns. Macrobenthos biomass was significantly higher in areas where surface arctic water masses dominated relative to arctic estuary water mass. Areas of convergence of these two water masses were characterized by significantly lower biomass values. The maximal macrobenthos biomass was observed in cores of water mass areas.