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Archaeal lipid diversity, alteration, and preservation at the Cathedral Hill deep sea hydrothermal vent, Guaymas Basin, Gulf of California, and its implications regarding the deep time preservation paradox
Organic Geochemistry ( IF 3 ) Pub Date : 2021-08-30 , DOI: 10.1016/j.orggeochem.2021.104302
Jeremy N. Bentley 1 , G. Todd Ventura 1 , Connor J. Dalzell 1 , Clifford C. Walters 2 , Carl A. Peters 3 , Anthony S. Mennito 2 , Robert K. Nelson 4 , Christopher M. Reddy 4 , Jeffrey S. Seewald 4 , Stefan M. Sievert 5
Affiliation  

Archaea are among the earliest evolved organisms. Today, they exist in nearly every habitable environment and their highly recalcitrant membrane lipids are both abundant and easily detected in modern sediments. Yet, unlike bacteria and eukaryotes, the lipid biomarker signatures of archaea are almost entirely absent in the ancient rock record (>145 Ma). We present a comprehensive study of archaeal lipids from the Cathedral Hill hydrothermal vent complex in Guaymas Basin, Gulf of California. Here, porewaters reach 155 °C by 21 cm below the sea floor (cmbsf), which enables the near-complete tracking of sedimentary organic matter (SOM) accumulation, diagenetic alteration and thermochemical transformation into petroleum-like hydrocarbons within and beyond the habitable zone of life. Identified intact polar lipids (IPLs) of living archaea included mono- and di-glycosidic archaeols (1G-AR, 2G-AR) and glycerol dialkyl glycerol tetraethers (1G- and 2G-GDGTs). The 1G- and 2G-ARs, potentially derive from methane-oxidizing archaeal groups ANME-1 and ANME-2 and anaerobic thermophilic methanogens, reach sediment depths of ∼ 135 cm and 50 °C temperatures. The 1G-and 2G-GDGT lipids reach a depth of ~180 cm where vent fluid temperatures are ~145 ± 15 °C. Core lipids (CLs) include archaeols (AR) and isoprenoidal and branched GDGTs (iGDGTs, brGDGTs). The core GDGTs (cGDGTs) closest to the vent center have high rates of lipid loss. Up to 95% of all identified archaeal biomarkers, including lipids supplied from the upper water column, are degraded or recycled in the surface sediments and do not reach conditions of late diagenesis and catagenesis. Only ∼ 0.11%, proportional to the lipid bound component in the protokerogen, marks thermochemically cracked biphytane – a prominent archaeal hydrocarbon biomarker. This extreme reduction indicates archaeal lipids do not necessarily become incorporated into kerogen thereby helping to explain the deep time archaeal lipid preservation paradox.



中文翻译:

加利福尼亚湾瓜伊马斯盆地大教堂山深海热液喷口的古菌脂质多样性、改变和保存,及其对深时保存悖论的影响

古细菌是最早进化的生物之一。今天,它们几乎存在于所有宜居环境中,它们高度顽固的膜脂在现代沉积物中既丰富又容易检测到。然而,与细菌和真核生物不同,古细菌的脂质生物标志物特征在古代岩石记录(>145 Ma)中几乎完全不存在。我们对加利福尼亚湾瓜伊马斯盆地的大教堂山热液喷口复合体的古菌脂质进行了全面研究。在这里,孔隙水在海底以下 21 厘米处达到 155°C (cmbsf),这使得可以近乎完整地追踪可居住区内外的沉积有机质 (SOM) 积累、成岩作用和热化学转化为类石油的碳氢化合物的生活。已鉴定的活古菌的完整极性脂质 (IPL) 包括单糖苷和双糖苷古菌(1G-AR、2G-AR)和甘油二烷基甘油四醚(1G-和 2G-GDGT)。1G- 和 2G-ARs 可能来自甲烷氧化古菌群 ANME-1 和 ANME-2 以及厌氧嗜热产甲烷菌,达到约 135 cm 的沉积深度和 50 °C 的温度。1G 和 2G-GDGT 脂质达到 ~180 厘米的深度,其中排放流体温度为 ~145 ± 15 °C。核心脂质 (CL) 包括古细菌 (AR) 和类异戊二烯和支链 GDGT。1G 和 2G-GDGT 脂质达到 ~180 厘米的深度,其中排放流体温度为 ~145 ± 15 °C。核心脂质 (CL) 包括古细菌 (AR) 和类异戊二烯和支链 GDGT。1G 和 2G-GDGT 脂质达到 ~180 厘米的深度,其中排放流体温度为 ~145 ± 15 °C。核心脂质 (CL) 包括古细菌 (AR) 和类异戊二烯和支链 GDGT。i GDGT,br GDGT)。最靠近排气口中心的核心 GDGT ( c GDGT) 具有较高的脂质损失率。高达 95% 的所有已鉴定古菌生物标志物,包括从上部水柱提供的脂质,在表层沉积物中降解或回收,并且没有达到晚期成岩作用和退化作用的条件。只有约 0.11%,与原干酪根中的脂质结合成分成正比,标志着热化学裂解的联植烷 - 一种重要的古菌烃生物标志物。这种极端减少表明古菌脂质不一定会被纳入干酪根,从而有助于解释深时古菌脂质保存悖论。

更新日期:2021-08-30
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