Lithium in the aragonite skeletons of massive Porites corals: A new tool to reconstruct tropical sea surface temperatures
Lithium in the aragonite skeletons of massive Porites corals: A new tool to reconstruct tropical sea surface temperatures
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DOI：
10.1029/2012pa002311
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发表时间：
2013-03
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影响因子：
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通讯作者：
E. Hathorne;T. Felis;A. Suzuki;H. Kawahata;G. Cabioch
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作者：
E. Hathorne;T. Felis;A. Suzuki;H. Kawahata;G. Cabioch
以前的研究已经证明了珊瑚文石中锂含量记录环境条件信息的潜力，但没有对热带珊瑚的详细研究。在这里，我们提出了锂和镁钙比在两个现代滨珊瑚，属最常用于古气候重建在热带印度-太平洋地区的每两个月到每月的决议超过25年。珊瑚Li/Ca与当地实测SST之间存在较强的相关性，表明珊瑚Li/Ca可用于重建热带SST变化。然而，1979-1980年期间沉积的骨架的Li/Ca比值并没有很好地跟踪当地SST，并且在某些地方非常高。这段时间的Mg/Ca比值也非常高，我们建议只有当Mg/Ca数据用于仔细筛选相对罕见的生物效应时，Li/Ca才能用于重建热带SST。Mg/Li或Li/Mg比率提供比Li/Ca比率小的优势，除了Li/Mg温度关系的斜率在两种珊瑚之间更相似之外。镁/锂温度关系的珊瑚，经历了一个大的温度范围是相似的冷水珊瑚和文石底栖有孔虫在以前的研究中发现。与其他生物成因文石的数据比较表明，Li/Mg与水温的关系可以用一个单一的指数关系来描述。尽管这暗示了总体控制，但很明显，生物过程强烈影响珊瑚Li/Ca，在广泛应用代理之前需要进行更多的校准工作
Previous studies have demonstrated the potential for the Li content of coral aragonite to record information about environmental conditions, but no detailed study of tropical corals exists. Here we present the Li and Mg to Ca ratios at a bimonthly to monthly resolution over 25 years in two modern Porites corals, the genus most often used for paleoclimate reconstructions in the tropical Indo-Pacific. A strong relationship exists between coral Li/Ca and locally measured SST, indicating that coral Li/Ca can be used to reconstruct tropical SST variations. However, Li/Ca ratios of the skeleton deposited during 1979-1980 do not track local SST well and are anomalously high in places. The Mg/Ca ratios of this interval are also anomalously high, and we suggest Li/Ca can be used to reconstruct tropical SST only when Mg/Ca data are used to carefully screen for relatively rare biological effects. Mg/Li or Li/Mg ratios provide little advantage over Li/Ca ratios, except that the slope of the Li/Mg temperature relationship is more similar between the two corals. The Mg/Li temperature relationship for the coral that experienced a large temperature range is similar to that found for cold water corals and aragonitic benthic foraminifera in previous studies. The comparison with data from other biogenic aragonites suggests the relationship between Li/Mg and water temperature can be described by a single exponential relationship. Despite this hint at an overarching control, it is clear that biological processes strongly influence coral Li/Ca, and more calibration work is required before widely applying the proxy