三亚湾海水中Sr/Ca、Mg/Ca变化及对珊瑚微量元素温度计的响应

Variations of Sr/Ca, Mg/Ca ratios in seawater of the Sanya Bay and response of coral trace element thermometer

对海南岛南岸三亚湾海水2008~2009年周间隔取样,用全谱直读等离子体原子发射光谱（ICP-AES）分析方法对其Sr、Mg、Ca的含量m（Sr）、m（Mg）、m（Ca）进行了测定。结果显示,m（Sr）/m（Ca）=8.558×10-3~9.227×10-3、m（Mg）/m（Ca）=4.924~5.403,与全球各大洋和主要珊瑚礁区有明显的高异常偏差,而且在春末夏初和秋末冬初两个过渡期,三亚湾海水m（Sr）/m（Ca）波动幅度比m（Mg）/m（Ca）相对较大,且体现了一定的差异性。在此基础上,结合海水的m（Sr）/m（Ca）、m（Mg）/m（Ca）在时间和地域空间上的变化对珊瑚温度计标定的影响,对不同站点建立的珊瑚m（Sr）/m（Ca）温度计进行了重新校正,并与分配系数法对比分析,我们认为利用珊瑚的m（Sr）/m（Ca）、m（Mg）/m（Ca）重建古海水表面温度（SST）记录时必须综合考虑包括海水微量元素比值变化在内的各种影响因素对温度计标定的干扰,为进一步了解气候环境演变具有重要意义。

The contents of trace elements（Sr, Mg, Ca） in seawater obtained weekly, 2008 to 2009 from the Sanya Bay, the South Hainan Island were examined using, inductively coupled plasma atomic emission spectrometry（ICP-AES）. The results showed that the variation range of seawater Sr/Ca, Mg/Ca ratios were 8.558×10-3~ 9.227×10-3, and 4.924~5.403, respectively, which had an obviously high abnormal deviation compared with the global oceans and the main coral reef. Moreover, during the late spring, early summer and late autumn and early winter, the fluctuation amplitude of the seawater Sr/Ca ratios was relatively bigger than Mg/Ca ratios, and both showed some differences. At the same time, influence of variations of Sr/Ca, Mg/Ca ratios on the coral thermometer calibration, in time and regional space was analyzed. Based on this, the coral Sr/Ca thermometer established in different site was re-corrected and it was also compared with the distribution coefficient method. We believe that all kinds of factors including the seawater trace element ratio changes could cause interference to the thermometer calibrations and should be comprehensively considered when reconstructing the SST records by using the Porites corals Sr/Ca, Mg/Ca ratios, which has great significance for further understanding of the climate changes.