滨珊瑚Sr/Ca的种间和种内差异性  

Inter-species and inter-colony differences of Sr/Ca-SST calibration in Porites

作　　者：胡敏航 陈天然 张文静[1,2] HU Minhang;CHEN Tianran;ZHANG Wenjing(Key laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences,Guangzhou 510301, China;University of Chinese Academy of Sciences, Beijing 100049, China)

机构地区：[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510301 [2]中国科学院大学,北京100049

出　　处：《热带海洋学报》2018年第6期74-84,共11页Journal of Tropical Oceanography

基　　金：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)~~

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。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(℃)+9.623based 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).

关 键 词：滨珊瑚 Sr/Ca 种间差异 种内差异 生长率 海表温度 

分 类 号：Q958.112.4[生物学—动物学] P736.4[天文地球—海洋地质]