UV radiation penetration into the marine ecosystem of McMurdo Sound

UV radiation transmission measurements on sea ice surface and through the annual sea ice into the underlying water column were made during Antarctic spring months (October - November) in conjunction with the spring-time ozone hole, over several seasons (2002-2006) to characterise the underwater light field of McMurdo Sound. Measuring ambient UV-R, the penetration of UV-R through the annual ice and water column and inherent optical properties of the water column will allow modelling of the UV-R environment of the inner McMurdo Sound and to increase our knowledge of the effects, if any, of increased UV-R on shallow water communities or their larval stages. Spectroradiometers (LiCor Li-1800UW) were deployed simultaneously to measure UV-B (300-320 nm), UV-A (320-400 nm) and PAR - Photosynthetically Active Radiation (400-750 nm). The spectroradiometers measured irradiance as downwelling, reflected (from which sea ice albedo could be calculated), sub-sea ice and through the underlying water column. During spectroradiometer deployments, the Inherent Optical Properties of the water column (backscatter coefficient, diffuse attenuation, absorption and fluorescence) were measured using optical instrumentations. Sample sites include Cape Armitage, Pram Point, Cinder Cone, Cape Evans and the sea ice edge.