HR: 0800h
AN: PP31B-1523    [Abstracts]
TI: Geochemical Ecology of a High Latitude Coral: Plesiastrea versipora a new Paleo-Environmental Archive
AU: * Burgess, S N
EM: sam.burgess@anu.edu.au
AF: Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 Australia
AU: * Burgess, S N
EM: sam.burgess@anu.edu.au
AF: South Australian Research and Development Institute: Aquatic Sciences, 2 Hamra Ave, West Beach, SA 6022 Australia
AU: McCulloch, M M
EM: malcolm.mcculloch@anu.edu.au
AF: Research School of Earth Sciences, Australian National University, Canberra, ACT 0200 Australia
AU: Ward, T
EM: ward.tim@saugov.sa.gov.au
AF: South Australian Research and Development Institute: Aquatic Sciences, 2 Hamra Ave, West Beach, SA 6022 Australia
AB: Corals growing in high latitude waters in Southern Australia are considered to be sensitive to changes in climate, including seasonal fluctuations in sea surface temperature. The annual nature of density bands of Plesiastrea versipora were verified using U/Th ages derived from multi-collector ICP-MS analyses and the resulting extension rates varied from an average of 1.2 mm yr ^-1 to 9 mm yr ^-1 for different colonies ranging in age from 120 - 300 years, located within the same reef. High resolution laser-ablation ICP-MS analyses of established paleo-temperature proxies including B/Ca, Mg/Ca, Sr/Ca and U/Ca were obtained from several cores of P. versipora from Gulf St Vincent (34.5°S) and Spencer Gulf (35°S), South Australia. Elemental compositions were compared to in situ sea surface temperature (SST) and satellite (IGOSS) records, and demonstrate significant covariance between Ba/Ca and temperature. Barium may not have been recognised as a temperature proxy in previous studies due to the smaller temperature range for lower latitude environments (~ 5°C versus 12°C for this study) and other factors contributing to the Ba signal such as terrestrially-derived or upwelled sources. Other trace elements analysed gave an indication of both the nutrient availability (P and Mn) and terrestrially derived pollutants (V, Y, Mo, Sn and Pb) correlating strongly with luminescent bands. Several of the stronger luminescent bands coincide temporally with known oil spills at a nearby port refinery and research is ongoing to determine if this is the point source of pollution. These data taken together suggest that P. versipora can provide valuable paleoclimate information in high-latitude environments, recording large seasonal variation in both temperature and productivity regimes with high fidelity and may also be employed to reconstruct anthropogenic activity.
DE: 0438 Diel, seasonal, and annual cycles (4227)
DE: 4902 Anthropogenic effects (1803, 4802)
DE: 4916 Corals (4220)
DE: 4924 Geochemical tracers
DE: 4954 Sea surface temperature
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005