Plankton Structure of Shallow Coastal Zone at Admiralty Bay, King George Island, West Antarctic Peninsula (Wap) During Early Summer/2010: Pico, Ultra and Microplankton and Chlorophyll Biomass

e phytoplankton composition and biomass are being monitored in Admiralty Bay, Antarctic Peninsula since 2002 to detect possible interannual changes on a long-term monitoring perspective. In this report, we present the results of the December 2010 survey regarding the phytoplankton size-structure and biomass. Microplankton densities were higher than those observed during the survey 2009/2010, and a dominance of diatoms, especially the centric alassiosira spp, over dino agellates was registered. Pico and ultraplankton densities (~106 cells L–1) were similar to those registered in previous studies, and results showed that phytoplankton were dominated in density by cells <10 μm. e shi in phytoplankton structure pointed out by the dominance of picoand ultra-size cells in phytoplankton density and dominance of microphytoplankton in biomass must be con rmed by continuing the long-term monitoring program and the implementation of microvariation sampling e ort to identify the factors that are actually in uencing phytoplankton populations in this environment.