HR: 15:30h
AN: GC34A-01    [Abstracts]
TI: Micromorphology and Trace Metal Content as Indicators of Bleaching in Skeletons of Modern and Holocene Corals
AU: * Burr, S A
EM: sab45@cornell.edu
AF: Department of Earth and Atmospheric Sciences, Snee Hall Cornell University, Ithaca, NY 14853 United States
AB: Morphology and trace metal content of scleractinian corals have previously been used as proxies for past environmental conditions, but no proxy for the health of ancient corals currently exists. Skeletal material associated with bleached and non-bleached tissue from Recent Porites divaricata and Montastrea franksii were analyzed with SEM and ICPAES. Both morphology and trace metal content differed between skeletal material associated with bleached and non-bleached tissue in P. divaricata. SEM analysis showed skeletal corallites associated with unbleached tissue had well-defined septal and columellar denticles. Skeletal corallites associated with bleached tissue had weakly-defined denticles, many appearing rudimentary. SEM analysis was inconclusive for morphological differences between samples known to have been bleached and non-bleached in M. franksii. Significantly higher trace metal/Ca ratios were found with ICPAES for Ag, As, Cd, and Co between skeletal material associated with bleached than with non-bleached tissue in P. divaricata, and Ag, As, P, and Zn between skeletal material associated with bleached than with non-bleached tissue in M. franksii. The presence of these differences suggested the processes of skeletogenesis and the uptake and deposition of trace metals in the scleractinian skeleton were affected by bleaching. Mid-Holocene (~5,000 ybp) Porites sp. were tested to determine if such indicators of bleaching might be observed in the fossil record. Skeletal morphology and trace metal content differ between Recent bleached and non-bleached Porites divaricata from Punta Cana, Dominican Republic, trace metal content differs between bleached and non-bleached Montastrea franksii from Looe Key, FL. It is possible that these indicators allow the recognition of coral bleaching in the fossil record
DE: 1615 Biogeochemical processes (4805)
DE: 1699 General or miscellaneous
SC: Global Climate Change [GC]
MN: 2005 Joint Assembly