UV Photobiology of Planktonic Development Stages of Antarctic Benthic Invertebrates

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9528241 Karentz Recently documented global decreases in stratospheric ozone have brought attention to the potential ecological consequences of increased ultraviolet-B (UVB) radiation in marine communities. Even without ozone depletion, UVB radiation penetrating into surface waters of the ocean represents a biological hazard to many marine organisms. The most extensive destruction of ozone has been occurring over the Antarctic continent and Southern Ocean, where over 50% depletion is recorded each spring. A major obstacle in assessing UV effects is that very little is known about the UV photobiology of individual species. In the Antarctic, some of the more ecologically dominant benthic invertebrate species occupy intertidal and shallow subtidal depths where biological effects of UVB have already been documented. Many of these species have planktonic development and their spawning season coincides with the period when ozone depletion is occurring; thus their microscopic embryos and larvae are exposed to increasingly higher levels of UVB. At present there is no information on the potential short- or long-term effects of increased UVB levels on populations of Antarctic benthic invertebrates. The research proposed here will focus on the UV photobiology of three important Antarctic invertebrate species that inhabit intertidal and subtidal areas in the region of Palmer Station, Anvers Island, Antarctic Peninsula. These species are the limpet Nacella concinna, the sea urchin Sterechinus neumayeri and the sea star Odontaster validus. The adults of these species are dominant members of Antarctic intertidal and shallow subtidal benthic communities, and their embryos and larvae develop for months in surface waters from late austral winter through summer. This study will evaluate the impact of ambient UVB on early stages (gametes, embryos and larvae) of the life histories of these species by 1) examining potential UV exposure levels, 2) assessing differential sensiti vities, 3) identifying molecular, chromosomal and morphological UVB induced damage, and 4) evaluating potential protection and recovery from UVB exposure. Since these species have taxonomic equivalents at both temperate and tropical latitudes, this work will provide important biological parameters for increasing our knowledge about UV effects on both local and global scales.