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G-Cubed: Geochemistry, Geophysics, Geosystems

 

Keywords

  • coral skeleton
  • oxygen isotope
  • SST and SSS
  • growth rate

Index Terms

  • Biogeosciences: Diel, seasonal, and annual cycles
  • Biogeosciences: Biomineralization
  • Biogeosciences: Paleoclimatology and paleoceanography
Abstract
Cited By (4)
 

Abstract

GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, VOL. 6, Q09017, 16 PP., 2005
doi:10.1029/2005GC000966 [Citation]

Fidelity of δ18O as a proxy for sea surface temperature: Influence of variable coral growth rates on the coral Porites lutea from Hainan Island, China

Michiyo Shimamura

Graduate School of Environmental Earth Science, Hokkaido University, N10W5, Sapporo, Hokkaido, 060-0810, Japan

Tadamichi Oba

Graduate School of Environmental Earth Science, Hokkaido University, N10W5, Sapporo, Hokkaido, 060-0810, Japan

Guoqiang Xu

Department of Marine Geology and Geophysics, Tongji University, 1239 Siping Road, Shanghai, 200092, P. R. China

Bingquan Lu

Department of Marine Geology and Geophysics, Tongji University, 1239 Siping Road, Shanghai, 200092, P. R. China

Luejiang Wang

Graduate School of Environmental Earth Science, Hokkaido University, N10W5, Sapporo, Hokkaido, 060-0810, Japan

Masafumi Murayama

Center for Advanced Marine Core Research, Kochi University, B200, Monobe, Nankoku, 783-8502, Japan

Kazuhiro Toyoda

Graduate School of Environmental Earth Science, Hokkaido University, N10W5, Sapporo, Hokkaido, 060-0810, Japan

Amos Winter

Department of Marine Sciences, University of Puerto Rico, Mayagüez, PR 00681-9013, Puerto Rico

The extremely high temporal resolution (nearly daily interval) measurement was conducted on the coral (Porites lutea) oxygen isotope compositions (δ18Oc) to examine the detailed relationship between δ18Oc and sea surface temperature (SST) and seawater oxygen isotope composition (δ18Ow) from Hainan Island, China. Although SST and sea surface salinity (SSS) or δ18Ow varied in a wide range at the studied site, the dynamic range of δ18Oc recorded in coral was much smaller than expected from SST and SSS (δ18Ow) changes. The extremely high (>30°C) and low (<22°C) SST and low (<27) SSS are not suitable for coral calcification, and coral could not record the information as their skeletal δ18O. Estimated coral extension rates (the overall rate is 15 mm/year) varied by a factor of about 18 within one year, from very slow in winter to very fast in spring. Light availability could affect the extension rate of coral skeleton through the activity of photosynthesis of symbiont algae. Such cessation and acceleration of calcification cause a serious distortion of the δ18O profile, which makes it difficult to make a correlation between δ18O and SST. Because high and low extension rates correspond to low- and high-density bands, respectively, a detailed examination of the density structure may assist the correction for distortion of the δ18O profile.

Received 9 March 2005; accepted 27 July 2005; published 27 September 2005.

Citation: Shimamura, M., T. Oba, G. Xu, B. Lu, L. Wang, M. Murayama, K. Toyoda, and A. Winter (2005), Fidelity of δ18O as a proxy for sea surface temperature: Influence of variable coral growth rates on the coral Porites lutea from Hainan Island, China, Geochem. Geophys. Geosyst., 6, Q09017, doi:10.1029/2005GC000966.

Cited By

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