CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
J Environ Manage. 2023 Dec 15;348:119240. doi: 10.1016/j.jenvman.2023.119240. Epub 2023 Oct 12.
Methane leakage from deep-sea cold seeps has a major impact on marine ecosystems. Microbes sequester methane in the water column of cold seeps and can be divided into abundant and rare groups. Both abundant and rare groups play an important role in cold seep ecosystems, and the environmental heterogeneity in cold seeps may enhance conversion between taxa with different abundances. Yet, the environmental stratification and assembly mechanisms of these microbial sub-communities remain unclear. We investigated the diversities and assembly mechanisms in microbial sub-communities with distinct abundance in the deep-sea cold seep water column, from 400 m to 1400 m. We found that bacterial β-diversity, as measured by Sørensen dissimilarities, exhibited a significant species turnover pattern that was influenced by several environmental factors including depth, temperature, SiO, and salinity. In contrast, archaeal β-diversity showed a relatively high percentage of nestedness pattern, which was driven by the levels of soluble reactive phosphate and SiO. During the abundance dependency test, abundant taxa of both bacteria and archaea showed a significant species turnover, while the rare taxa possessed a higher percentage of nestedness. Stochastic processes were prominent in shaping the prokaryotic community, but deterministic processes were more pronounced for the abundant taxa than rare ones. Furthermore, the metagenomics results revealed that the abundances of methane oxidation, sulfur oxidation, and nitrogen fixation-related genes and related microbial groups were significantly higher in the bottom water. Our results implied that the carbon, sulfur, and nitrogen cycles were potentially strongly coupled in the bottom water. Overall, the results obtained in this study highlight taxonomic and abundance-dependent microbial community diversity patterns and assembly mechanisms in the water column of cold seeps, which will help understand the impacts of fluid seepage from the sea floor on the microbial community in the water column and further provide guidance for the management of cold seep ecosystem under future environmental pressures.
深海冷泉渗漏的甲烷泄漏对海洋生态系统有重大影响。微生物在冷泉水柱中隔离甲烷，可以分为丰富和稀有两个组。丰富和稀有组在冷泉生态系统中都发挥着重要作用，冷泉环境中的异质性可能增强了不同丰度类群之间的转化。然而，这些微生物亚群落的环境分层和组装机制仍不清楚。我们研究了深海冷泉水柱中具有不同丰度的微生物亚群落的多样性和组装机制，水深范围从 400 米到 1400 米。我们发现，细菌 β多样性，用 Sørensen 不相似性衡量，表现出显著的物种更替模式，受包括深度、温度、SiO 和盐度在内的几种环境因素的影响。相比之下，古菌 β多样性显示出相对较高的嵌套模式，这是由可溶反应性磷酸盐和 SiO 的水平驱动的。在丰度依赖测试中，细菌和古菌的丰富类群都表现出显著的物种更替，而稀有类群则具有更高的嵌套比例。随机过程在塑造原核生物群落方面很突出，但对丰富类群的确定性过程比稀有类群更为明显。此外，宏基因组学的结果表明，甲烷氧化、硫氧化和固氮相关基因以及相关微生物类群的丰度在底层水中显著较高。我们的结果表明，碳、硫和氮循环在底层水中可能存在强烈的耦合。总的来说，本研究的结果突出了冷泉水柱中分类和丰度依赖的微生物群落多样性模式和组装机制，这将有助于理解海底流体渗漏对水柱中微生物群落的影响，并为未来环境压力下冷泉生态系统的管理提供指导。
