| 滨珊瑚Sr/Ca的种间和种内差异性* |
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| 引用本文： | 胡敏航,陈天然,张文静.滨珊瑚Sr/Ca的种间和种内差异性*[J].热带海洋学报,2018,37(6):74-84. |
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| 作者姓名： | 胡敏航 陈天然 张文静 |
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| 作者单位： | 1. 中国科学院边缘海与大洋地质重点实验室(南海海洋研究所), 广东 广州 5103012. 中国科学院大学, 北京 100049; |
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| 基金项目： | 国家自然科学基金(41476038、41676049);中国科学院青年创新促进会基金(2015284) |
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| 摘 要： | 滨珊瑚骨骼的锶和钙元素的比值(Sr/Ca)是重建热带海区海水表面温度(sea surface temperature, SST)变化最常用的地球化学代用指标之一。但是, 珊瑚作为生物体, 其生理活动会对骨骼内的Sr/Ca产生干扰从而影响重建的准确度。文章采用全谱直读等离子体原子发射光谱(Inductively Coupled Plasma Optical Emission Spectrometer, ICP-OES)技术对南海北部涠洲岛两块滨珊瑚的Sr/Ca比值进行测量, 并结合卫星观测的SST值分别建立各个珊瑚个体的Sr/Ca-SST温度计方程。结果显示: 1) 该研究采集的两种滨珊瑚(澄黄滨珊瑚和普哥滨珊瑚)的Sr/Ca值和温度计具有显著的种间差异。因此在古气候重建时, 建议古珊瑚和现代珊瑚严格使用同一种滨珊瑚; 2) 同种滨珊瑚不同个体之间的Sr/Ca也存在差异性, 一方面是由于冬、夏季的极端低、高温对珊瑚生理产生胁迫, 从而造成Sr/Ca出现异常值; 另一方面则是取样误差导致, 尤其是夏季高温和冬季低温时期; 3) 同一珊瑚个体内的不同生长轴的生长率存在显著差异, 然而Sr/Ca却没有显著的差异性, 说明不同生长轴的取样对骨骼Sr/Ca没有显著影响。最后, 文章用多样品的平均值建立Sr/Ca温度计方程, 用于减小个体之间的差异性带来的误差, 得到Sr/Ca(mmol·mol-1)= -0.04027×SST(℃)+9.623的方程。用该温度计对涠洲岛海域的SST后报的误差为±0.6℃(1σ), 达到了古海温重建的精度需求。
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| 关 键 词： | 滨珊瑚 Sr/Ca 种间差异 种内差异 生长率 海表温度 |
| 收稿时间： | 2018-01-11 |
Inter-species and inter-colony differences of Sr/Ca-SST calibration in Porites |
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| Minhang HU,Tianran CHEN,Wenjing ZHANG.Inter-species and inter-colony differences of Sr/Ca-SST calibration in Porites[J].Journal of Tropical Oceanography,2018,37(6):74-84. |
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| Authors: | Minhang HU Tianran CHEN Wenjing ZHANG |
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| Institution: | 1. Key laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China2. University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | Strontium-to-calcium (Sr/Ca) ratio in Porites corals is widely used as sea surface temperature (SST) proxy in tropical oceans. However, growth-related kinetic/metabolic effects in Porites may influence skeletal Sr/Ca and ultimately affect the accuracy of SST reconstruction. Here, Sr/Ca ratios in multiple Porites from Weizhou Island were measured using an Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), to estimate the inter-species and inter-colony differences of Sr/Ca and the Sr/Ca-SST calibration with instrumental SST records. The results are as follows. (1) In this study, two species of Porites corals, Porites pukoensis and Porites lutea, were collected. Significant differences of Sr/Ca and Sr/Ca-SST equation were found between the two species. We suggest using the same species in coral-based paleo-climate reconstructions. (2) Inter-colony Sr/Ca differences were found in Porites pukoensis and Porites lutea, resulting from extreme warm and cold temperatures, which disturbed coral physiologies and caused anomalously Sr/Ca ratios, as well as sampling errors, especially in warm and cold periods. (3) No significant differences of Sr/Ca were found in different axes in a Porites colony. We established a Sr/Ca-SST thermometer as Sr/Ca (mmol/mol) = -0.04027×SST(℃)+9.623 based on multi-colony calibrations. The multi-colony approach can minimize individual biases or noise referred to growth related “vital effects” or other kinetic/metabolic effects, and eventually increase the accuracy of SST reconstruction. The error of the Sr/Ca-derived SST was ±0.6℃(1σ). |
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| Keywords: | Porites Sr/Ca inter-species offset inter-conoly offset growth rate SST |
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