Aquatic Sciences Meeting, Albuquerque 2001

SS21 Ultraviolet Radiation and the Aquatic Biota (Disciplinary Connections)

Date: Wednesday, February 14, 2001, Time: 4:00:00 PM

Location: Galisteo

Anderson, S, , U.C. Davis Bodega Marine Laboratory, Bodega Bay, USA, susanderson@ucdavis.edu

Zepp, R, , USEPA National Exposure Research Laboratory , Athens, USA, zepp.richard@epamail.epa.gov

Machula , J, , U.C. Davis Bodega Marine Laboratory, Bodega Bay, USA, jemachula@ucdavis.edu

Hansen, L, , USEPA National Health and Environmental Effects Research Laboratory, Gulf Breeze, USA, hansen.lara@epamail.epa.gov

Cherr, G, , U.C. Davis Bodega Marine Laboratory, Bodega Bay, USA, gncherr@ucdavis.edu

Mueller , E, , Mote Marine Laboratory Center for Tropical Research, Summerland Key, USA, emueller@mote.org

ASSESSING UV IRRADIANCE OVER FLORIDA KEYS REEFS AND QUANTIFICATION OF UV-SPECIFIC DNA DAMAGE IN CORAL AND ZOOXANTHELLAE

UV penetration into the water near coral reefs may be increasing as a consequence of global climate change. Calm waters associated wtih ENSO conditions can enhance stratification that increases the amount of photobleaching of chromophoric dissolved organic matter (CDOM) in surface waters, causing increased UV penetration. We are examining CDOM spectral and photochemical properties as well as UV penetration at Florida Keys reef sites and in Hawk Channel. Initial characterization of CDOM sources and biological, chemical, and physical processes have shown that CDOM at the reefs photobleaches and that UV penetration above the thermocline is greater than below. Sources of CDOM may include seagrass beds and mangroves. Immunoblotting and immunolocalization procedures have been developed to evaluate UV-specific DNA damage (thymine dimers)in coral and zooxanthellae of Porites porites. Laboratory studies indicate a nearly proportional response to increases in UV radiation. Field studies suggest that diurnal cycles of damage and repair vary among colonies. Damage to DNA is localized in both coral and zooxanthellae. These findings may help to determine whether UV irradiance plays a significant role in coral bleaching.

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Aquatic Sciences Meeting, Albuquerque 2001

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