Microbial community and geochemical analyses of trans-trench sediments for understanding the roles of hadal environments
Microbial community and geochemical analyses of trans-trench sediments for understanding the roles of hadal environments
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DOI：
10.1038/s41396-019-0564-z
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发表时间：
2020-03-01
期刊：
影响因子：
11
通讯作者：
Nunoura, Takuro
中科院分区：
文献类型：
--
作者：
Hiraoka, Satoshi;Hirai, Miho;Nunoura, Takuro
与邻近的深海平原沉积物相比，深海沟底部（低于海平面6000 m）沉积物具有更高的微生物细胞丰度。这是由沉积有机质（OM）的聚集支持的，并由海沟地形促进。然而，底栖微生物在不同海沟系统中的分布尚未得到很好的探索。在这里，我们对来自西北太平洋三个海沟地区：日本、伊豆小笠原和马里亚纳海沟的7个深海和7个深海沉积物岩心的92个沉积物亚样本进行了小亚基核糖体RNA基因标签测序。标签测序分析显示了与氧和硝酸盐相关的几个门的特定分布模式。根据地理位置和沉积物深度所代表的因素，群落结构在深海和浅海沉积物之间具有明显的差异。共现网络揭示了6个潜在的跨区域共变的原核生物联合体。我们的研究结果进一步支持，除了来自海洋表面的垂直沉积外，OM循环是由海沟底部的潮流和/或快速掩埋形状的微生物群落结构驱动的。我们的跨海沟分析强调了海底表层沉积物中微生物组合和地球化学在海沟内和海沟间的分布，为超深海微生物生态学提供了新的见解，这是我们星球上最后的前沿之一。
Hadal trench bottom (>6000 m below sea level) sediments harbor higher microbial cell abundance compared with adjacent abyssal plain sediments. This is supported by the accumulation of sedimentary organic matter (OM), facilitated by trench topography. However, the distribution of benthic microbes in different trench systems has not been well explored yet. Here, we carried out small subunit ribosomal RNA gene tag sequencing for 92 sediment subsamples of seven abyssal and seven hadal sediment cores collected from three trench regions in the northwest Pacific Ocean: the Japan, Izu-Ogasawara, and Mariana Trenches. Tag-sequencing analyses showed specific distribution patterns of several phyla associated with oxygen and nitrate. The community structure was distinct between abyssal and hadal sediments, following geographic locations and factors represented by sediment depth. Co-occurrence network revealed six potential prokaryotic consortia that covaried across regions. Our results further support that the OM cycle is driven by hadal currents and/or rapid burial shapes microbial community structures at trench bottom sites, in addition to vertical deposition from the surface ocean. Our trans-trench analysis highlights intra- and inter-trench distributions of microbial assemblages and geochemistry in surface seafloor sediments, providing novel insights into ultradeep-sea microbial ecology, one of the last frontiers on our planet.