Spatial Variability of Abyssal Nitrifying Microbes in the North-Eastern Clarion-Clipperton Zone
Spatial Variability of Abyssal Nitrifying Microbes in the North-Eastern Clarion-Clipperton Zone
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DOI：
10.3389/fmars.2021.663420
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发表时间：
2021-07-26
影响因子：
3.7
通讯作者：
Young, Robert
中科院分区：
文献类型：
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作者：
Hollingsworth, Anita L.;Jones, Daniel O. B.;Young, Robert
深海微生物驱动生物地球化学循环，调节能量通量并有助于有机碳的产生和再矿化。因此，表征底栖微生物的空间变异性对于了解它们在底栖环境中的作用以及对可能成为商业采矿活动目标的海底区域进行基线评估非常重要。然而，对这些地区底栖微生物群落空间分布的详细评估仍然不完整，并且这些努力尚未考虑海底地形和异质性对不同尺度微生物分布的影响。在这项研究中，我们研究了从赤道太平洋克拉里昂克利珀顿区（CCZ）（水深 4000-4300 米）收集的沉积物和多金属结核中发现的底栖微生物组合的组成和空间变异性。我们使用 16S rRNA 基因序列来表征这些群落。深海沉积物上部 20 厘米处的沉积物及其相关多金属结核中蕴藏着多样化且独特的微生物群落，海底地形区域具有高度相似性。组合组成在沉积物、栖息地以及小到中尺度上存在垂直差异。潜在的固碳微生物形成了沉积物组合相对丰度的 25% 以上，其中以氨氧化古菌 Nitrosopumilus 为主。非光合作用的蓝藻在较深的沉积层和结核中更为常见。沉积物群落中参与氮循环的类群较多，如 Nitrosopumilus、Nitrospina、Nitrospira、AqS1（Nitrosococcaceae）和产甲烷菌 wb1-A12（NC10 门）。相比之下，结节中α变形菌门、γ变形菌门、浮霉菌门、酸杆菌门、拟杆菌门、纳米古菌门和热毛菌门更富集。与潜在金属循环（Magnetospiraceae 和 Kiloniellaceae）、有机碳再矿化（Woeseia）和硫氧化硫卤杆菌科（Thiohalorhabdaceae）相关的微生物在结核中也更加富集。我们的结果表明，底栖微生物群落组成是由沉积物剖面深度和海底小尺度和中尺度异质性驱动的。沉积物中最丰富的微生物类群是硝化微生物和假定的固碳微生物，可能在调节该栖息地的生物地球化学循环中发挥关键的生态作用。
Abyssal microbes drive biogeochemical cycles, regulate fluxes of energy and contribute to organic carbon production and remineralization. Therefore, characterizing the spatial variability of benthic microbes is important for understanding their roles in benthic environments and for conducting baseline assessments of areas of the seabed that might be targeted by commercial mining activities. Yet, detailed assessments of the spatial distributions of benthic microbial communities in these regions are still incomplete, and these efforts have not yet considered the influence of seafloor topography and heterogeneity on microbial distributions across a range of scales. In this study, we investigated the composition and spatial variability of benthic microbial assemblages found in sediments and polymetallic nodules collected from the Clarion Clipperton Zone (CCZ) in the equatorial Pacific (4000-4300 m water depth). We used 16S rRNA gene sequences to characterize these communities. The upper 20 cm of abyssal sediments harbored diverse and distinctive microbial communities in both sediments and their associated polymetallic nodules, with high similarity across topographical areas of the seabed. Assemblage composition differed vertically through the sediment, by habitat and across small to mesoscales. Potential carbon-fixing microbes formed more than 25% relative abundance of sediment assemblages, which were dominated by ammonia-oxidizing Archaea Nitrosopumilus. Non-photosynthetic Cyanobacteria were more frequent in the deeper sediment layers and nodules. Sediment communities had a higher abundance of taxa involved in nitrogen cycling, such as Nitrosopumilus, Nitrospina, Nitrospira, AqS1 (Nitrosococcaceae), and methanogens wb1-A12 (NC10 phylum). In contrast, nodules were more enriched in Alphaproteobacteria, Gammaproteobacteria, Planctomycetes, Acidobacteria, Bacteroidetes, Nanoarchaeaeota, and Calditrichaeota. Microbes related to potential metal-cycling (Magnetospiraceae and Kiloniellaceae), organic carbon remineralization (Woeseia), and sulfur-oxidizing Thiohalorhabdaceae were also more enriched in nodules. Our results indicate that benthic microbial community composition is driven by sediment profile depth and seafloor heterogeneity at small and mesoscales. The most abundant microbial taxa within the sediments were nitrifying and putative carbon-fixing microbes, and may have key ecological roles in mediating biogeochemical cycles in this habitat.