Algal biomass in the East Antarctic pack ice

Sea ice algal biomass in the eastern Antarctic zone was assessed using measurements and observations. This assessment was entered into a simple model, using remote sensing data to estimate habitat extent, to make an estimate of total sea ice algal biomass in the region. The late spring (2000) algal biomass and species composition in the bottom and surface communities in pack ice floes in East Antarctica (105-115°E) is described. Ice cores and surface ice samples were taken, and a simple ship based observation technique to estimate algal biomass is evaluated and assessed. Measured values of biomass compared well with observed values. The bottom algal biomass was between 0.66 to 28.05 mg Chl a m\\(^{-2}\\) , and highly variable across the bottom of ice floes. Surface ice algal biomass was less than the bottom and was heavily influenced by floe edge effects. Remote sensing data, viewed in GIS software, was used to calculate the ice thickness distribution and the habitat extent of each ice type across the entire study area (30-150°E). This information was used, together with measurements of the distribution of algal biomass within the ice column, to estimate total algal biomass. The total sea ice algal biomass in this region was estimated to be 7.81 Tg C on 20 November 2000, 80% of which was in the bottom community. Extrapolating this result to December based on a conservative ice algal growth rate resulted in a maximum standing algal crop of 8.51 Tg C, 95% of which was in pack ice, and 80% was in the pack ice bottom community. This is ~14% of the Antarctic ice algal biomass. These results suggest that bottom communities are far more important in the East Antarctic region than they have previously been assessed to be.