PP53C-2355
Can Diploastrea heliopora be an Alternate Coral Climate Archive in the Indo-Pacific?
Friday, 18 December 2015
Poster Hall (Moscone South)
Riovie Dela Pena Ramos, Earth Observatory of Singapore, Nanyang Technological University, Singapore, Singapore, Nathalie Goodkin, Nanyang Technological University, Earth Observatory of Singapore, Singapore, Singapore, Fernando Pascual Siringan, Marine Science Institute, University of the Philippines, Metro Manila, Philippines and Konrad A Hughen, Woods Hole Oceanographic Institution, Department of Marine Chemistry and Geochemistry, Woods Hole, MA, United States
Abstract:
While climate events in the climatically important Indo-Pacific have been captured in Porites geochemical proxies, very few of these records extend more than 100 years, thus preventing reconstruction of multi-centennial climate variability. Century scale paleoclimate records may be stored in Diploastrea heliopora, a massive slow-growing long-lived coral prevalent in the region. Thus far, Diploastrea’s δ18O has revealed multi-decadal to multi-century long records in the region. However, since δ18O is a combined proxy for sea surface temperature (SST) and salinity, an independent SST proxy would be more advantageous. To evaluate the geochemistry of Diploastrea, adjacent Porites and Diploastrea cores were collected from Palaui Island, Philippines, and analyzed for Sr/Ca. An offset of about 0.20 mmol/mol is observed between the colonies, likely due to the greater Sr uptake of the slow-growing coral. Least-squares linear regressions of monthly Diploastrea and Porites Sr/Ca to SST reveal significant correlations (p-values < 0.0001). The Pacific Decadal Oscillation (PDO) is one of the climatically important processes impacting SST in the region. Winter Sr/Ca for both corals significantly correlates with PDO (p-values = 0.02) indicating promise for Diploastrea as a climate archive, particularly in the absence of multi-century long records from Porites.
