Investigation of microbial metabolisms in an extremely high pH marine-like terrestrial serpentinizing system: Ney Springs
Investigation of microbial metabolisms in an extremely high pH marine-like terrestrial serpentinizing system: Ney Springs
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在极高 pH 值的类海洋陆地蛇纹石化系统中微生物代谢的研究：Ney Springs
DOI：
10.1016/j.scitotenv.2022.155492
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发表时间：
2022
影响因子：
9.8
通讯作者：
Dart, E
中科院分区：
文献类型：
--
作者：
Trutschel, L;Chadwick, G;Kruger, B;Brazelton, W;Dart, E
内伊斯普林斯是北方加州的一个大陆性蛇泉，据报道，其天然水源的pH值异常高（12.4）。由于具有高导电性的流体，它在地球化学上比其他陆地位置更类似于海洋蛇纹化系统。我们的地球化学分析还显示，相对于其他蛇纹岩系统，硫化物浓度（544 mg/L）和甲烷排放量（83%体积气体含量）较高。热力学计算被用来调查潜在的底物产生的蛇纹石燃料微生物的生命，并被发现支持充满活力的可行性硫酸盐还原，厌氧甲烷氧化，反硝化，和厌氧硫化物氧化在这个系统中。通过16 S rRNA分类基因调查和宏基因组测序的微生物群落的评估揭示了一个社区的组成占主导地位的theIzemoplasmatales和Clostridiales的特征不佳的成员。这些优势类群的基因组指向发酵生活方式，尽管其他高度完整（>90%）的宏基因组组装的基因组支持生物体进行硫酸盐还原、硫还原和/或硫氧化（需氧和厌氧）的潜力。在宏基因组中鉴定出两种化能无机异养菌，a Halomonassp.和杜鹃花科（Rhododopyraceae），分离并显示氧化硫代硫酸盐，并能够在pH 12.4的条件下生长。尽管是蛇纹石化反应的特征产物，但几乎没有证据表明内斯普林斯微生物群落中的氢和甲烷利用。氢不是很丰富，在到达泉水社区之前就可以被消耗掉。其他代谢策略可能会被能量更有利的异养或发酵反应所击败，甚至被春季的其他化合物（如氨）所抑制。内斯普林斯独特的地球化学提供了一个机会，研究当地地质如何与蛇纹化流体相互作用，而其微生物群落可以更好地告知我们在超碱性环境中采用的代谢策略。
Ney Springs, a continental serpentinizing spring in northern California, has an exceptionally high reported pH (12.4) for a naturally occurring water source. With high conductivity fluids, it is geochemically more akin to marine serpentinizing systems than other terrestrial locations. Our geochemical analyses also revealed high sulfide concentrations (544 mg/L) and methane emissions (83% volume gas content) relative to other serpentinizing systems. Thermodynamic calculations were used to investigate the potential for substrates resulting from serpentinization to fuel microbial life, and were found to support the energetic feasibility of sulfate reduction, anaerobic methane oxidation, denitrification, and anaerobic sulfide oxidation within this system. Assessment of the microbial community via 16S rRNA taxonomic gene surveys and metagenome sequencing revealed a community composition dominated by poorly characterized members of theIzemoplasmatalesandClostridiales. The genomes of these dominant taxa point to a fermentative lifestyle, though other highly complete (>90%) metagenome assembled genomes support the potential for organisms to perform sulfate reduction, sulfur disproportionation and/or sulfur oxidation (aerobic and anaerobic). Two chemolithoheterotrophs identified in the metagenome, aHalomonassp. and aRhodobacteraceaesp., were isolated and shown to oxidize thiosulfate and were capable of growth in conditions up to pH 12.4. Despite being characteristic products of serpentinization reactions, little evidence was seen for hydrogen and methane utilization in the Ney Springs microbial community. Hydrogen is not highly abundant and could be consumed prior to reaching the spring community. Other metabolic strategies may be outcompeted by more energetically favorable heterotrophic or fermentation reactions, or even inhibited by other compounds in the spring such as ammonia. The unique geochemistry of Ney Springs provides an opportunity to study how local geology interacts with serpentinized fluids, while its microbial community can better inform us of the metabolic strategies employed in hyperalkaline environments.