加速器质谱中心知识库

To be used as proxies of seawater surface temperature (SST), the delta O-18(c) values and Sr/Ca and Mg/Ca ratios of scleractinian coral skeletons must be verified by coral culture experiments in the laboratory. This paper describes a coral culture experiment that was conducted at several seawater temperatures T (21-28A degrees C) using a tandem aquarium system and the new method for depositing coral skeletons grown under controlled conditions. The delta O-18(c) values and the Sr/Ca and Mg/Ca ratios of the cultured coral were measured. We concluded that the delta O-18(c) values and Sr/Ca and Mg/Ca ratios of the cultured coral are clearly correlated with T. The linear regression curve is delta O-18(c)(aEuro degrees)=-0.1427xT(A degrees C)-0.1495 (n=18, r=0.955, p < 0.0001), and the slope of -0.1427aEuro degrees/A degrees C is at the low end of the range of published values (-0.13- -0.29aEuro degrees/A degrees C). The Sr/Ca ratio decreases with increasing T, whereas the Mg/Ca ratio increases with increasing T, indicating a negative correlation between Sr/Ca and Mg/Ca. Their linear regression curves are Sr/Ca(mmol/mol)=-0.04156xT+10.59 (n=15, r=0.789, p < 0.005) and Mg/Ca (mmol/mol)=0.04974xT+2.339 (n=17, r=0.457, p < 0.05), respectively, which demonstrate that when Mg/Ca and Sr/Ca are increased by one unit, T increases by 5.19A degrees C and decreases by 15.62A degrees C, respectively. These variations are significantly lower than published values.