工业革命以来南海珊瑚钙化生长对海洋升温的响应  

Coral calcification history in the South China Sea since the Industrial Era and its response to ocean warming

作　　者：陈雪霏[1,2] 邓文峰[1,2] 韦刚健 CHEN Xuefei;DENG Wenfeng;WEI Gangjian(State Key Laboratory of Isotope Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong;CAS Center for Excellence in Deep Earth Science,Guangzhou 510640,Guangdong)

机构地区：[1]中国科学院广州地球化学研究所同位素地球化学国家重点实验室,广东广州510640 [2]中国科学院深地科学卓越创新中心,广东广州510640

出　　处：《第四纪研究》2023年第2期448-457,共10页Quaternary Sciences

基　　金：中国科学院(B类)战略性先导科技专项项目(批准号:XDB40010300);国家自然科学基金项目(批准号:42273009);中国科学院青年创新促进会(批准号:2021352)共同资助。

摘　　要：珊瑚礁不仅滋养着近1/3的海洋生物,同时也贡献了近一半的浅海碳酸盐沉积,在海洋碳循环中扮演重要角色。然而,在"CO_(2)问题"的影响下,珊瑚钙化受到来自海洋升温和酸化的双重胁迫,致使珊瑚礁生态系统遭受到严重的扰动。我国南海由北至南分布有大量的珊瑚礁,在近几十年来活珊瑚覆盖率和生物多样性都呈现退化的趋势,但尚不清楚珊瑚钙化是否也同样受到气候变化的干扰而处于退化状态。本研究汇集了目前已报道的南海滨珊瑚钙化生长的重建记录,分别对海南岛、西沙和南沙典型珊瑚礁区的滨珊瑚钙化生长演变特征进行了对比分析,探讨了工业革命以来南海珊瑚钙化对海水温度变化的响应情况。研究结果表明,南海近岸和离岸的滨珊瑚骨骼密度均呈现长期下降的趋势;而骨骼生长速率呈现多年代际的波动变化,近50年以来仅在西沙显示出下降趋势,这使得珊瑚综合的钙化速率在西沙和南沙均出现明显退化。进一步分析表明,海水温度对南海滨珊瑚钙化生长有显著影响,并且不同海域的背景温度决定着珊瑚骨骼生长对海表温度变化的响应情况。具体来说,西沙和南沙的滨珊瑚骨骼密度受温度影响显著,随着海温升高而逐渐降低,而骨骼生长速率和钙化速率对温度变化并无明显响应。与前两者不同,海南东部滨珊瑚的骨骼密度与温度变化关系并不显著,而其骨骼生长速率和钙化速率受升温影响而有升高的趋势。这些差异可能反映了海南岛较低的冬季温度限制了珊瑚骨骼的钙化生长,因此升温对珊瑚生长有促进作用;而西沙和南沙海域的冬季温度均保持在适宜珊瑚生长的温度范围,且夏季温度较高,因此温度的升高可能限制了珊瑚钙化生长。Coral reefs are home to ca.25%of all marine organisms and produce most of the carbonate in shallow marine environments.This has huge effects on the ocean's biology and chemistry.However,the well-known CO_(2) problem places reef-building corals under a great deal of stress by making the oceans warmer and acidifying,causing significant losses in biodiversity,coral cover,and calcification.Coral reefs are widely distributed in the South China Sea(SCS)and are undergoing severe perturbations owing to environmental changes and human activity,resulting in significant declines in coral cover and biodiversity.However,it is unknown if the calcification of corals in the SCS has been disturbed in recent decades and what mechanisms are responsible for these alterations.In this study,we compile previously reported coral calcification records of Porites from Hainan,Xisha,and Nansha Islands along a latitudinal gradient of the South China Sea(SCS),in order to gain a more comprehensive understanding of how coral calcification has changed since the Industrial Era and how it has responded to the ocean warming in this marginal sea.We demonstrate that the density of coral skeletons in the three reefs studied has been decreasing steadily over the past century,whereas the linear extension rates have showed multi-decadal fluctuation since the late 1800s.In recent decades,only the linear extension rates of Xisha Porites have declined significantly.These variations in coral skeleton growth collectively contribute to a considerable decline in coral calcification rates in Xisha and Nansha.We further show that sea surface temperature(SST)plays an important role in driving the variation in coral skeleton growth in the SCS,and the background SST determines how coral calcification responds to ocean warming.The skeletal density of Porites corals in Xisha and Nansha,where the coral growth is not limited by winter SST,are negatively influenced by increased SST,while the coral linear extension and calcification rates do not respond to the warming.In

关 键 词：南海 造礁珊瑚 钙化生长 海洋升温 

分 类 号：P722.7[天文地球—海洋科学] P731.11