Bessette Sandrine, Moalic Yann, Gautey Sébastien, Lesongeur Françoise, Godfroy Anne, Toffin Laurent
Institut Carnot Ifremer EDROME, Centre de Bretagne, REM/EEP, Laboratoire de Microbiologie des Environnements Extrêmes, UMR 6197Plouzané, France.
Laboratoire de Microbiologie des Environnements Extrêmes, Institut Universitaire Européen de la Mer, UMR 6197, Université de Bretagne OccidentalePlouzané, France.
Front Microbiol. 2017 Apr 25;8:715. doi: 10.3389/fmicb.2017.00715. eCollection 2017.
Sitting at ∼5,000 m water depth on the Congo-Angola margin and ∼760 km offshore of the West African coast, the recent lobe complex of the Congo deep-sea fan receives large amounts of fluvial sediments (3-5% organic carbon). This organic-rich sedimentation area harbors habitats with chemosynthetic communities similar to those of cold seeps. In this study, we investigated relative abundance, diversity and distribution of aerobic methane-oxidizing bacteria (MOB) communities at the oxic-anoxic interface of sedimentary habitats by using fluorescence hybridization and comparative sequence analysis of particulate mono-oxygenase () genes. Our findings revealed that sedimentary habitats of the recent lobe complex hosted type I and type II MOB cells and comparisons of community compositions showed variations among the different organic-rich habitats. Furthermore, the lineages were taxonomically more diverse compared to methane seep environments and were related to those found at cold seeps. Surprisingly, MOB phylogenetic lineages typical of terrestrial environments were observed at such water depth. In contrast, MOB cells or sequences were not detected at the previous lobe complex that is disconnected from the Congo River inputs.
刚果深海扇最近的叶状体复合体位于刚果-安哥拉边缘约5000米水深处，距西非海岸约760公里，接收大量河流沉积物（有机碳含量为3-5%）。这个富含有机物的沉积区域拥有与冷泉类似的化学合成群落栖息地。在本研究中，我们通过使用荧光原位杂交和颗粒单加氧酶（pmo）基因的比较序列分析，研究了沉积栖息地有氧甲烷氧化细菌（MOB）群落的相对丰度、多样性和分布。我们的研究结果表明，最近叶状体复合体的沉积栖息地含有I型和II型MOB细胞，群落组成比较显示不同富含有机物的栖息地之间存在差异。此外，与甲烷冷泉环境相比，pmo谱系在分类学上更加多样化，并且与在冷泉中发现的谱系相关。令人惊讶的是，在如此水深下观察到了典型的陆地环境中的MOB系统发育谱系。相比之下，在与刚果河输入隔绝的先前叶状体复合体中未检测到MOB细胞或pmo序列。
