Anaerobic ammonium oxidizers contribute to the removal of fixed nitrogen in oxygen‐deficient marine ecosystems such as oxygen minimum zones (OMZ). Here we surveyed for the first time the occurrence and diversity of anammox bacteria in the Colombian Pacific, a transition area between the prominent South and North Pacific OMZs. Anammox bacteria were detected in the coastal and oceanic areas of the Colombian Pacific in low oxygen (< 22 μM), high nitrate (25–35 μM) and low nitrite (< 0.07 μM), and ammonium (< 1 μM) waters. In these waters, anammox bacteria were rich [∼ 7 operational taxonomic units (OTUs), 98% cut‐off) and microdiverse (Shannon index H′ < 1.24), in comparison with the observed at the prominent OMZ of the Eastern Tropical South Pacific, Arabian Sea and Black Sea. Anammox bacteria‐like sequences from the Colombian Pacific were grouped together with sequences retrieved from the distinct OMZ's marine subclusters (Peru, Northern Chile and Arabian Sea) within Candidatus ‘Scalindua spp’. Moreover, some anammox bacteria OTUs shared a low similarity with environmental phylotypes (86–94%). Our results indicated that a microdiverse anammox community inhabits the Colombian Pacific, generating new questions about the ecological and biogeochemical differences influencing its community structure.

中文翻译：

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哥伦比亚太平洋水域中一个微分形的厌氧菌群落的首次报道，哥伦比亚太平洋水域是热带东部太平洋突出的最低氧气含量区域之间的过渡区域。

厌氧铵氧化剂有助于去除缺氧海洋生态系统中的固定氮，例如最低氧区域（OMZ）。在这里，我们首次调查了哥伦比亚太平洋地区，即南太平洋和北太平洋OMZ之间的过渡区域，厌氧菌的发生和多样性。在低氧（<22μM），高硝酸盐（25-35μM）和低亚硝酸盐（<0.07μM）和铵水（<1μM）水中的哥伦比亚太平洋沿海和海洋地区检测到了厌氧细菌。与在东部热带南太平洋的OMZ上观察到的相比，在这些水域中，厌氧氨氧化细菌丰富[〜7个操作生物分类单位（OTU），截留率达98％）和微生物多样性（香农指数H'<1.24）。 ，阿拉伯海和黑海。Ç andidatus “小号calindua属”。此外，一些厌氧菌OTU与环境系统型的相似性较低（86-94％）。我们的结果表明，一个微小的厌氧菌群落居住在哥伦比亚太平洋，对影响其群落结构的生态和生物地球化学差异提出了新的问题。