HA3 Effects of Multiple Stressors on Marine Resources
254 Portland Ballroom
8:00 AM - 12:00 PM, Thursday
() Coral responses to climate and land use changes.
Fisher, W.1, Santavy, D.1, Rogers, J.1, Zepp, R.2, 1 U.S. Environmental Protection Agency, ORD / National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, Gulf Breeze, FL, USA2 U.S. Environmental Protection Agency, ORD / National Exposure Research Laboratory, Ecosystems Research Division, Athens, GA, USA
ABSTRACT- Coral reefs have experienced unprecedented levels of bleaching and disease during the last three decades. Several stressors have been identified, including elevated water temperature, increased exposure to solar radiation, and degraded water quality, each related in some manner to global climate or land use changes. Consequences of bleaching and disease vary; some corals recover, while others lose tissue, die, become diseased or succumb to algal overgrowth. EPAs Global Change Research Program is addressing potential vulnerabilities from different components of global change that may adversely affect coral reef ecosystems: (1) climate variability and change; (2) changes in ultraviolet radiation; and (3) land use change. Worldwide coral bleaching has been linked to El Niño Southern Oscillation phases which can generate warm, stratified water conditions in certain geographic regions. During these doldrum periods, penetration of both PAR (400-700 nm) and UV-R (280-400 nm) wavelengths is increased. Light attenuation over reefs is influenced by the types and amounts of dissolved and particulate matter in the water column; ultraviolet radiation, for example, is attenuated by dissolved organic matter. Sediments, nutrients, contaminants and microorganisms entering the water from land and air are influenced by climate, weather, and land use patterns. Integrated laboratory and field studies are employed to determine which corals, reefs and geographic regions are at greatest risk from bleaching, disease, tissue loss, and skeletal degradation, and which environmental factors are most responsible. Coral reefs in the Florida Keys have been surveyed for occurrence of bleaching and disease, and additional indicators are being applied across the Keys to characterize the status of coral condition. Studies on cultured symbiotic algae have demonstrated combined effects of temperature and UV-R on growth rates and survival. Laboratory studies are designed to compare the effects of temperature, light penetration, and water quality on various coral species from the Florida Keys.
Key words: climate change, coral, land use change, multiple stressors