| Popis: |
In January 2004 the microplankton community from the coastal waters of Terre Adelie and Georges V Land (139 degrees E-145 degrees E) was studied. Results showed a diatom-dominated bloom with chlorophyll a levels averaging 0.64 mu g l(-1) at 5 m depth (range 0.21-1.57 mu g l(-1)). Three geographic assemblages of diatoms were identified, based on principal diatom taxa abundances. The stratified waters near the Mertz Glacier presented highest phytoplankton biomasses (0.28-1.57 mu g Chl a l(-1) at 5 m) and diatom abundances (6,507-70,274 cells l(-1) at 5 m), but low diversity, dominated by Fragilariopsis spp. Lower biomasses (0.38-0.94 mu g Chl a l(-1) at 5 m) and abundances (394-9,058 cells l(-1) stop at 5 m) were observed in the mixed waters around the Astrolabe Glacier with a diverse diatom community characterised by larger species Corethron pennatum and Rhizosolenia spp. Finally an intermediate zone between them over the shallower shelf waters of the Adelie Bank represented by Chaetoceros criophilus, where biomasses (0.21-0.35 mu g Chl a l(-1) at 5 m) and abundances (1,190-5,431 cells l(-1) at 5 m) were lowest, coinciding with the presence of abundant herbivorous zooplankton. |
