Coral microbial ecology is a burgeoning field, driven by the urgency of understanding coral health and slowing reef loss due to climate change. Coral resilience depends on its microbiota, and both the tissue and the underlying skeleton are home to a rich biodiversity of eukaryotic, bacterial and archaeal species that form an integral part of the coral holobiont. New techniques now enable detailed studies of the endolithic habitat, and our knowledge of the skeletal microbial community and its eco-physiology is increasing rapidly, with multiple lines of evidence for the importance of the skeletal microbiota in coral health and functioning. Here, we review the roles these organisms play in the holobiont, including nutritional exchanges with the coral host and decalcification of the host skeleton. Microbial metabolism causes steep physico-chemical gradients in the skeleton, creating micro-niches that, along with dispersal limitation and priority effects, define the fine-scale microbial community assembly. Coral bleaching causes drastic changes in the skeletal microbiome, which can mitigate bleaching effects and promote coral survival during stress periods, but may also have detrimental effects. Finally, we discuss the idea that the skeleton may function as a microbial reservoir that can promote recolonization of the tissue microbiome following dysbiosis and help the coral holobiont return to homeostasis.

中文翻译：

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在表面之下：珊瑚骨骼微生物组的群落组装和功能。

珊瑚微生物生态学是一个蓬勃发展的领域，这是由于迫切需要了解珊瑚健康和因气候变化而导致的礁石流失减缓。珊瑚的复原力取决于其微生物群，组织和下面的骨骼都是真核生物，细菌和古细菌物种丰富生物多样性的家园，这些生物多样性构成了珊瑚整体生物的组成部分。现在，新技术可以对石器时代的栖息地进行详细研究，并且我们对骨骼微生物群落及其生态生理学的了解正在迅速增加，有许多证据表明骨骼微生物在珊瑚健康和功能中的重要性。在这里，我们回顾了这些生物在整体生物中的作用，包括与珊瑚宿主的营养交换和宿主骨骼的脱钙。微生物新陈代谢会在骨骼中造成陡峭的理化梯度，从而形成微生态位，再加上扩散限制和优先效应，从而确定了微生物群落的精细组装。珊瑚褪色会导致骨骼微生物组发生剧烈变化，这可以减轻漂白作用并在压力时期促进珊瑚的生存，但也可能具有有害作用。最后，我们讨论了骨骼可能充当微生物贮藏库的想法，该微生物贮藏库可促进生物异位症后组织微生物组的重新定殖，并帮助珊瑚整体生物恢复体内平衡。它可以减轻漂白作用并在压力时期促进珊瑚的生存，但也可能具有有害作用。最后，我们讨论了骨骼可能充当微生物贮藏库的想法，该微生物贮藏库可促进生物异位症后组织微生物组的重新定殖，并帮助珊瑚整体生物恢复体内平衡。它可以减轻漂白作用并在压力时期促进珊瑚的生存，但也可能具有有害作用。最后，我们讨论了骨骼可能充当微生物贮藏库的想法，该微生物贮藏库可促进生物异位症后组织微生物组的重新定殖，并帮助珊瑚整体生物恢复体内平衡。