Features of summer ice-edge bloom in the Barents sea

Abstract

The paper is devoted to the study of hydrochemical complex and pelagic phytocene in the ice-edge area of the Barents sea during summer. The peak of ice-edge area phytoplankton bloom with a characteristic set of biomass values and complex of dominant species was recorded in the course of the study in the surface layer zone of drifting ice. At the same time in sub-surface horizons diatom transition to the stage of sporulation and mass development of nanoalgae, which is characteristic of seasonal oligotrophy was observed. Based on these data, quite a relevant supposition concerning the intensive development of ice-edge blooming under the solid ice cover off the north of the area studied could be made. To the south of the ice edge area the dominance in the phytoplankton community is shifted: nanoforms occupy a leading position in the community in numbers and biomass compared to microalgae, the composition of the lattest is completely replaced by the summer forms of dinoflagellates. The distribution of silicon and nitrogen consumed in euphotic layer, is fully consistent with the biomass and the number of microphytoplankton – a decrease of these parameters off the north, from the station located in the ice edge towards the south is observed. The maximum depletion of phosphates corresponds well with the area of active proliferation of nanophytoplankton in the southern part of the study area.