Species-specific productivity of phytoplankton in an ice-edge bloom in the Ross Sea

During January and February, 1983 studies were conducted in a phytoplankton bloom associated with a receding ice-edge in the Ross Sea. Physical and biological data indicated that the bloom was characterized by elevated biomass and primary productivity; which were tightly coupled with a surface lens of reduced salinity and density. Taxanomic and autoradiographic analysis of the phytoplankton population revealed that the bloom was dominated by a single diatom species of Nitzschia curta (section Fragilariopsis). N. curta accounted for greater than 80% of the total primary productivity and greater than 65% of the total standing stock (cells m"^) at stations tested. Statistical analysis of the regression of relative productivity versus station (as distance from shore) indicated that the importance of N. curta decreased seaward. Further, taxanomic analysis of the epontic community revealed a considerable overlap of taxa with the bloom community. These data suggest that N. curta was released from the ice and that this process may have been important in providing a viable seed stock for the bloom.