Liu Ying, Chen Songze, Xie Zhe, Zhang Li, Wang Jiahua, Fang Jiasong
Shanghai Engineering Research Center of Hadal Science and Technology, Shanghai Ocean University, Shanghai 200120, China.
Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen 518000, China.
Microorganisms. 2023 Mar 1;11(3):630. doi: 10.3390/microorganisms11030630.
Recent studies reported that highly abundant alkane content exists in the ~11,000 m sediment of the Mariana Trench, and a few key alkane-degrading bacteria were identified in the Mariana Trench. At present, most of the studies on microbes for degrading hydrocarbons were performed mainly at atmospheric pressure (0.1 MPa) and room temperature; little is known about which microbes could be enriched with the addition of -alkanes under in-situ environmental pressure and temperature conditions in the hadal zone. In this study, we conducted microbial enrichments of sediment from the Mariana Trench with short-chain (SCAs, C-C) or long-chain (LCAs, C-C) -alkanes and incubated them at 0.1 MPa/100 MPa and 4 °C under aerobic or anaerobic conditions for 150 days. Microbial diversity analysis showed that a higher microbial diversity was observed at 100 MPa than at 0.1 MPa, irrespective of whether SCAs or LCAs were added. Non-metric multidimensional scaling (nMDS) and hierarchical cluster analysis revealed that different microbial clusters were formed according to hydrostatic pressure and oxygen. Significantly different microbial communities were formed according to pressure or oxygen ( < 0.05). For example, Gammaproteobacteria () were the most abundant anaerobic -alkanes-enriched microbes at 0.1 MPa, whereas the microbial communities shifted to dominance by Gammaproteobacteria (, , and ) and Bacteroidetes () at 100 MPa. Compared to the anaerobic treatments, Actinobacteria () and Alphaproteobacteria ( and ) were the most abundant groups with the addition of hydrocarbon under aerobic conditions at 100 MPa. Our results revealed that unique -alkane-enriched microorganisms were present in the deepest sediment of the Mariana Trench, which may imply that extremely high hydrostatic pressure (100 MPa) and oxygen dramatically affected the processes of microbial-mediated alkane utilization.
最近的研究报道，在马里亚纳海沟约11000米深处的沉积物中存在高丰度的烷烃，并且在马里亚纳海沟中鉴定出了一些关键的烷烃降解细菌。目前，大多数关于微生物降解烃类的研究主要是在大气压（0.1MPa）和室温下进行的；对于在深渊带原位环境压力和温度条件下添加正构烷烃后哪些微生物能够富集，人们了解甚少。在本研究中，我们用短链（SCAs，C-C）或长链（LCAs，C-C）正构烷烃对马里亚纳海沟的沉积物进行了微生物富集，并在0.1MPa/100MPa和4℃的有氧或厌氧条件下将它们培养150天。微生物多样性分析表明，无论添加的是SCAs还是LCAs，在100MPa下观察到的微生物多样性都高于0.1MPa。非度量多维尺度分析（nMDS）和层次聚类分析表明，根据静水压力和氧气形成了不同的微生物簇。根据压力或氧气形成了显著不同的微生物群落（<0.05）。例如，γ-变形菌纲（）是0.1MPa下最丰富的厌氧正构烷烃富集微生物，而在100MPa下微生物群落转变为以γ-变形菌纲（、和）和拟杆菌纲（）为主导。与厌氧处理相比，放线菌纲（）和α-变形菌纲（和）是100MPa有氧条件下添加烃类时最丰富的类群。我们的结果表明，在马里亚纳海沟最深的沉积物中存在独特的正构烷烃富集微生物，这可能意味着极高的静水压力（100MPa）和氧气显著影响了微生物介导的烷烃利用过程。
