全球变暖和海洋酸化背景下珊瑚礁生态响应的研究进展

生物礁是由珊瑚虫、藻类等造礁生物组成、具有抗浪结构的海相碳酸盐岩,是全球主要碳库之一,也是观察热带海洋影响中-高纬度环境过程的重要窗口。近二、三十年以来,伴随着海洋水体的显著酸化和增温,全球热带海洋生物礁的主体——珊瑚礁系统遭受了不同程度的影响。其中,对于高温强迫而言,海水温度上升诱发珊瑚白化、抑制珊瑚的自我修复;海洋酸化可以显著改变珊瑚钙化率、抑制珊瑚幼虫发育、引发珊瑚礁的溶解;两大因素均可改变珊瑚礁的群落结构。针对这些环境要素的改变,珊瑚自身可以通过共生藻的种类转换以及调控基因表达等手段在一定程度上抵抗高温胁迫;但若温室气体的排放不受控制,绝大多数珊瑚礁到21世纪末都将遭受灾难性打击。为应对未来不同场景下的珊瑚礁变化,还需要对高温、酸化等关键因子响应特征进行更深入的研究;珊瑚礁长序列研究有可能为珊瑚的长周期演化特征提供关键认识,也为现代观测提供有益补充。

A review on ecological response of coral reefs to global warming and oceanic acidification

Tropical reefs are anti-wave structures composed of corals,algae and other reef-building organisms.They are one of the world's major carbon banks and an important window to observe the linkages and interactions between the mid-to high-latitude environmental processes and tropical oceans.In the past decades,with the significant acidification and warming of global oceans,the tropical coral reefs are seriously under threat.Ocean acidification is a factor which may significantly affect coral calcification rates,inhibit the development of coral larvae,and trigger the dissolution of coral reefs.And high temperature may cause the rising of sea temperature,coral bleaching and inhibit the self-repair of coral reefs.In addition,both of the two factors may induce changes in the community structure of coral reefs.In response to the changes in these environmental factors,corals can resist heat stress to a certain extent by changing the types of symbiotic algae and regulating gene expression.However,if the emission of greenhouse gases is not properly controlled in the near future,most coral reefs on the Earth may face complete elimination by the end of this century.A more comprehensive understanding of coral reefs’response to the key factors in the climate system change,including higher temperature and acidification,is required to cope better with changes of coral reefs in different possible scenarios in the future.The study of reef depositional sequences may provide key insights into the long-term evolving patterns of coral reefs,and serve as a valuable supplement for modern observations.