SIGNIFICANCE OF SEDIMENTATION FOR THE TERMINATION OF PHAEOCYSTIS BLOOMS

The role of sedimentation for the termination of Phaeocystis blooms is exemplified through case studies from the literature as well as from anecdotal evidence. Scenarios of high and low sedimentation following Phaeocystis blooms exist. Mass sedimentation was found in the Barents Sea and the Ross Sea, but vertical flux below the euphotic zone was in significant in a north Norwegian fjord and the Weddell Sea. In general , no regular and recurring pattern of sedimentation events can be expe cted during Phaeocystis blooms. Factors influencing the fate of senesc ent Phaeocystis blooms are probably water depth, turbulent energy supp ly, aggregate formation, release of flagellated cells from colonies, m icrobial degradation, zooplankton grazing as well as lysis of colonies and cells. The role sedimentation plays for the termination of Phaeoc ystis blooms seems to be determined by the physical and biological cha racteristics of the specific ecosystem where the bloom occurs. In gene ral, Phaeocystis-dominated ecosystems tend to endorse pelagic rather t han benthic mineralization.