Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA.
Department of Marine Biology, The Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel.
Glob Chang Biol. 2020 Jan;26(1):31-53. doi: 10.1111/gcb.14912. Epub 2019 Dec 14.
Hard, or stony, corals make rocks that can, on geological time scales, lead to the formation of massive reefs in shallow tropical and subtropical seas. In both historical and contemporary oceans, reef-building corals retain information about the marine environment in their skeletons, which is an organic-inorganic composite material. The elemental and isotopic composition of their skeletons is frequently used to reconstruct the environmental history of Earth's oceans over time, including temperature, pH, and salinity. Interpretation of this information requires knowledge of how the organisms formed their skeletons. The basic mechanism of formation of calcium carbonate skeleton in stony corals has been studied for decades. While some researchers consider coral skeletons as mainly passive recorders of ocean conditions, it has become increasingly clear that biological processes play key roles in the biomineralization mechanism. Understanding the role of the animal in living stony coral biomineralization and how it evolved has profound implications for interpreting environmental signatures in fossil corals to understand past ocean conditions. Here we review historical hypotheses and discuss the present understanding of how corals evolved and how their skeletons changed over geological time. We specifically explain how biological processes, particularly those occurring at the subcellular level, critically control the formation of calcium carbonate structures. We examine the different models that address the current debate including the tissue-skeleton interface, skeletal organic matrix, and biomineralization pathways. Finally, we consider how understanding the biological control of coral biomineralization is critical to informing future models of coral vulnerability to inevitable global change, particularly increasing ocean acidification.
硬珊瑚或石珊瑚形成的岩石，在地质时间尺度上，会导致在热带和亚热带浅海形成大规模的珊瑚礁。在历史和现代海洋中，造礁珊瑚的骨骼保留了有关海洋环境的信息，这是一种有机-无机复合材料。它们骨骼的元素和同位素组成经常被用来重建地球海洋的环境历史，包括温度、pH 值和盐度。解释这些信息需要了解生物是如何形成它们的骨骼的。几十年来，人们一直在研究硬珊瑚碳酸钙骨骼形成的基本机制。虽然一些研究人员认为珊瑚骨骼主要是海洋条件的被动记录者，但越来越明显的是，生物过程在生物矿化机制中起着关键作用。了解动物在活石珊瑚生物矿化中的作用以及它是如何进化的，对于解释化石珊瑚中的环境特征以了解过去的海洋条件具有深远的意义。在这里，我们回顾了历史假说，并讨论了目前对珊瑚如何进化以及它们的骨骼如何随地质时间变化的理解。我们特别解释了生物过程，特别是那些发生在亚细胞水平的生物过程，如何对碳酸钙结构的形成起到关键的控制作用。我们研究了不同的模型，以解决当前的争论，包括组织-骨骼界面、骨骼有机基质和生物矿化途径。最后，我们考虑了理解珊瑚生物矿化的生物学控制对告知未来珊瑚对不可避免的全球变化，特别是海洋酸化的脆弱性模型的重要性。
