ABSTRACT: Seawater microorganisms play an important role in coral reef ecosystem functioning and can be influenced by biological, chemical, and physical features of reefs. As coral reefs continue to respond to environmental changes, the reef seawater microbiome has been proposed as a conservation tool for monitoring perturbations. However, the spatial variability of reef seawater microbial communities is not well studied, limiting our ability to make generalizable inferences across reefs. In order to better understand how microorganisms are distributed at multiple spatial scales, we examined seawater microbial communities in Florida Reef Tract and US Virgin Islands reef systems using a nested sampling design. On 3 reefs per reef system, we sampled seawater at regular spatial intervals close to the benthos. We assessed the microbial community composition of these waters using ribosomal RNA gene amplicon sequencing. Our analysis revealed that reef water microbial communities varied as a function of reef system and individual reefs, but communities did not differ within reefs and were not significantly influenced by benthic composition. For the reef system and inter-reef differences, abundant microbial taxa were found to be potentially useful indicators of environmental difference due to their high prevalence and variance. We further examined reef water microbial biogeography on a global scale using a secondary analysis of 5 studies, which revealed that microbial communities were more distinct with increasing geographic distance. These results suggest that biogeography is a distinguishing feature for reef water microbiomes, and that development of monitoring criteria may necessitate regionally specific sampling and analyses.

中文翻译：

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从珊瑚礁内到全球尺度的珊瑚礁水微生物的生物地理学

摘要：海水微生物在珊瑚礁生态系统功能中发挥着重要作用，并受到珊瑚礁生物、化学和物理特征的影响。随着珊瑚礁继续对环境变化做出反应，珊瑚礁海水微生物组已被提议作为监测扰动的保护工具。然而，珊瑚礁海水微生物群落的空间变异性并没有得到很好的研究，这限制了我们对珊瑚礁进行普遍推断的能力。为了更好地了解微生物如何在多个空间尺度上分布，我们使用嵌套采样设计检查了佛罗里达珊瑚礁和美属维尔京群岛珊瑚礁系统中的海水微生物群落。在每个珊瑚礁系统的 3 个珊瑚礁上，我们在靠近底栖生物的规则空间间隔对海水进行采样。我们使用核糖体 RNA 基因扩增子测序评估了这些水域的微生物群落组成。我们的分析表明，珊瑚礁水微生物群落随着珊瑚礁系统和单个珊瑚礁的变化而变化，但珊瑚礁内的群落没有差异，并且不受底栖生物组成的显着影响。对于珊瑚礁系统和珊瑚礁间的差异，发现丰富的微生物类群是环境差异的潜在有用指标，因为它们的普遍性和变异性很高。我们使用对 5 项研究的二次分析进一步研究了全球范围内的珊瑚礁水微生物生物地理学，结果表明微生物群落随着地理距离的增加而更加明显。这些结果表明，生物地理学是珊瑚礁水微生物群落的一个显着特征，