Marine oxygen minimum zones play a crucial role in the global oceanic carbon, nitrogen, and sulfur cycles as they harbor microbial communities that are adapted to the water column chemistry and redox zonation, and in turn control the water column chemistry and greenhouse gas release. These micro-organisms have metabolisms that rely on terminal electron acceptors other than O₂ and often benefit from syntrophic relationships (metabolic coupling). Here, we study chemo(auto)trophy along the redoxcline in two stratified fjords on Vancouver Island (Canada) using bacterial bacteriohopanepolyols and archaeal ether lipids. We analyze the distribution of these lipid classes in suspended particulate matter (SPM) to trace ammonia oxidation, anaerobic ammonium oxidation (anammox), sulfate reduction/sulfur oxidation, methanogenesis, and methane oxidation, and investigate ecological niches to evaluate potential links between their respective bacterial and archaeal sources. Our results show an unparalleled BHP and ether lipid structural diversity that allows tracing the major redox-driven metabolic processes at the time of sampling: Both fjords are dominated by archaeal ammonia oxidation and anammox; sulfate-reducing bacteria may be present in Deer Bay, but absent from Effingham Inlet; methanogenic Euryarchaeota and archaeal and bacterial methanotrophs are detectable at low abundance. Correlation analysis reveals distinct biomarker clusters that provide constraints on the biogeochemical niches of some orphan BHP and ether lipids such as in situ-produced adenosyl-BHPs or unsaturated archaeols.

中文翻译：

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沿着温哥华岛峡湾氧化还原线的细菌和古菌脂质追踪化学（自体）营养

海洋最低氧区在全球海洋碳、氮和硫循环中起着至关重要的作用，因为它们拥有适应水柱化学和氧化还原带的微生物群落，进而控制水柱化学和温室气体释放。这些微生物的新陈代谢依赖于 O ₂以外的末端电子受体并且经常受益于共养关系（代谢耦合）。在这里，我们使用细菌 bacteriohopanepolyols 和古菌醚脂质研究了温哥华岛（加拿大）两个分层峡湾中沿氧化还原线的化学（自）营养。我们分析这些脂质类别在悬浮颗粒物 (SPM) 中的分布以追踪氨氧化、厌氧氨氧化 (anammox)、硫酸盐还原/硫氧化、产甲烷和甲烷氧化，并调查生态位以评估它们各自之间的潜在联系细菌和古菌来源。我们的结果显示了无与伦比的 BHP 和醚脂质结构多样性，可以在采样时追踪主要的氧化还原驱动的代谢过程：两个峡湾都以古菌氨氧化和厌氧氨氧化为主；鹿湾可能存在硫酸盐还原菌，但埃芬汉湾不存在；产甲烷的 Euryarchaeota 和古细菌和细菌甲烷氧化菌在低丰度下是可检测到的。相关性分析揭示了不同的生物标志物簇，这些簇对一些孤儿 BHP 和醚脂质（如原位产生的腺苷 BHP 或不饱和古菌）的生物地球化学生态位提供了限制。