Sea ice algae are speculated to be considerably vulnerable to the effects of enhanced UV from the ozone hole during the Antarctic spring. The amount of UV and visible radiation falling onto the sea ice (the spectrum, intensity and where it comes from in the sky and the polariation of the radiation) was characterised using two instruments at Tent Island and near Scott Base. Measurements include ... total radiation falling onto a flat surface in three bands (UV, Violet and Blue), UVA, UVB, the variation of radiation over 24 hours, maximum intensity at noon, the sun's spectrum (with resolution of 1nm) and the intensity and polarisation of skylight around the sky. The effects of enhanced UV radiation on sea ice algae under radiation levels both visible and ultraviolet which are typical of those encountered in situ was examined. Samples of sea ice algae were collected from under Arrival Heights and near Tent Island. The core was shaded during removal and samples of algae taken. The effect of UVB on growth of algae was determined by estimating the growth rates of algae in culture by measuring the uptake of 14C over time.