Marginal sea methane seep sediments sustain highly productive chemosynthetic ecosystems and are hotspots of intense biogeochemical cycling. Rich methane supply stimulates rapid microbial consumption of oxygen; these systems are thus usually hypoxic to anoxic. This and reported evidence for resident nitrogen fixation suggest the presence of an anaerobic ammonium-oxidizing (anammox) bacterial community in methane seep sediments. To test this hypothesis, we employed detection of genes encoding 16S rRNA gene and hydrazine dehydrogenase (hzo) to investigate the structure, abundance and distribution of the anammox bacterial community in the methane seep sediments of the Okhotsk Sea. Diverse complements of Candidatus Scalindua-related 16S rRNA and hzo gene sequences were obtained. Most of the deep-sea sites harbored abundant hzo genes with copy numbers as high as 10(7) g(-1) sediment. In general, anammox bacterial signatures were significantly more abundant in the deep-water sediments. Sediment porewater NO3-, NOx- (i.e. NO3- + NO2-), NOx-/NH4+ and sediment silt content correlated with in situ distribution patterns of anammox bacterial marker genes, likely because they determine anammox substrate availability and sediment geochemistry, respectively. The abundance and distribution of anammox bacterial gene markers indicate a potentially significant contribution of anammox bacteria to the marine N cycle in the deep-sea methane seep sediments.

中文翻译：

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鄂霍次克海的深海甲烷渗透沉积物维持着丰富多样的厌氧氨氧化细菌。

边缘海甲烷渗透物沉积物维持着高产的化学合成生态系统，是激烈的生物地球化学循环的热点。丰富的甲烷供应刺激了微生物对氧气的快速消耗；因此，这些系统通常缺氧至缺氧。居民固氮的这一证据和所报道的证据表明，甲烷渗流沉积物中存在厌氧铵氧化（厌氧氨）细菌群落。为了验证该假设，我们使用了检测16S rRNA基因和肼脱氢酶（hzo）的基因，以研究鄂霍次克海甲烷渗流沉积物中厌氧氨氧化细菌群落的结构，丰度和分布。获得了与假丝酵母相关的16S rRNA和hzo基因序列的不同互补序列。大多数深海站点都藏有丰富的hzo基因，其拷贝数高达10（7）g（-1）沉积物。通常，深水沉积物中的厌氧菌特征明显很多。沉积物孔隙水NO3-，NOx-（即NO3- + NO2-），NOx- / NH4 +和沉积物淤泥含量与厌氧菌标记物基因的原位分布模式相关，可能是因为它们分别决定了厌氧菌基质的可利用性和沉积物的地球化学。厌氧菌细菌基因标记的丰富和分布表明，厌氧菌对深海甲烷渗透沉积物中海洋氮循环的潜在重要贡献。NOx- / NH4 +和沉积物淤泥含量与厌氧菌标记物基因的原位分布模式相关，可能是因为它们分别决定了厌氧菌底物的有效性和沉积物的地球化学。厌氧菌细菌基因标记的丰富和分布表明，厌氧菌对深海甲烷渗透沉积物中海洋氮循环的潜在重要贡献。NOx- / NH4 +和沉积物淤泥含量与厌氧菌标记物基因的原位分布模式相关，可能是因为它们分别决定了厌氧菌底物的有效性和沉积物的地球化学。厌氧菌细菌基因标记的丰富和分布表明，厌氧菌对深海甲烷渗透沉积物中海洋氮循环的潜在重要贡献。