The effects of UV-B on the growth and productivity of sea ice algae was investigated with two experiments. The growth of sea ice algae was investigated in situ under four different light treatments including a) control; under normal snow cover (10cm) with UV-B and PAR radiation, b) normal snow cover, natural PAR but no UV-B radiation, c) no snow, natural UV-B and PAR radiation and d) no snow, ... natural PAR radiation but no UV-B. Sea ice algal biomass was measured over a 15 day period. The second experiment was undertaken in the on site lab at Cape Evans. Cores of sea ice algae were subjected to a range of UV-B and PAR irradiances to simulate the effects of the depleted ozone layer to determine the effects of UV-B on sea ice algal productivity. A heliostat was trialled to obtain a natural solar spectrum.