Trutschel Leah R, Kruger Brittany R, Sackett Joshua D, Chadwick Grayson L, Rowe Annette R
Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States.
Division of Hydrologic Sciences, Desert Research Institute, Las Vegas, Las Vegas, NV, United States.
Front Microbiol. 2023 Jun 15;14:1182497. doi: 10.3389/fmicb.2023.1182497. eCollection 2023.
Terrestrial serpentinizing systems allow us insight into the realm of alkaliphilic microbial communities driven by geology in a way that is frequently more accessible than their deep subsurface or marine counterparts. However, these systems are also marked by geochemical and microbial community variation due to the interactions of serpentinized fluids with host geology and the surface environment. To separate the transient from the endemic microbes in a hyperalkaline environment, we assessed the Ney Springs terrestrial serpentinizing system microbial community and geochemistry at six time points over the span of a year. Using 16S rRNA gene surveys we observed 93 amplicon sequence variants (ASVs) that were found at every sampling event. This is compared to ~17,000 transient ASVs that were detected only once across the six sampling events. Of the resident community members, 16 of these ASVs were regularly greater than 1% of the community during every sampling period. Additionally, many of these core taxa experienced statistically significant changes in relative abundance with time. Variation in the abundance of some core populations correlated with geochemical variation. For example, members of the group, showed a positive correlation with variation in levels of ammonia at the spring. Investigating the metagenome assembled genomes of these microbes revealed evidence of the potential for ammonia generation via Stickland reactions within . This observation offers new insight into the origin of high ammonia concentrations (>70 mg/L) seen at this site. Similarly, the abundance of putative sulfur-oxidizing microbes like , , and a species could be linked to changes observed in sulfur-oxidation intermediates like tetrathionate and thiosulfate. While these data supports the influence of core microbial community members on a hyperalkaline spring's geochemistry, there is also evidence that subsurface processes affect geochemistry and may impact community dynamics as well. Though the physiology and ecology of these astrobiologically relevant ecosystems are still being uncovered, this work helps identify a stable microbial community that impacts spring geochemistry in ways not previously observed in serpentinizing ecosystems.
陆地蛇纹石化系统使我们能够深入了解由地质作用驱动的嗜碱微生物群落领域，这种方式通常比其深部地下或海洋对应系统更容易研究。然而，由于蛇纹石化流体与宿主地质和地表环境的相互作用，这些系统也存在地球化学和微生物群落的变化。为了在高碱性环境中区分短暂性微生物和地方性微生物，我们在一年的时间跨度内的六个时间点评估了内伊泉陆地蛇纹石化系统的微生物群落和地球化学。通过16S rRNA基因调查，我们观察到在每个采样事件中都发现的93个扩增子序列变体（ASV）。与之相比，在六个采样事件中仅被检测到一次的约17000个短暂性ASV。在常驻群落成员中，其中16个ASV在每个采样期内的群落中经常占比超过1%。此外，这些核心分类群中的许多在相对丰度上随时间发生了具有统计学意义的变化。一些核心种群丰度的变化与地球化学变化相关。例如，某组的成员与泉水中氨含量的变化呈正相关。对这些微生物的宏基因组组装基因组进行研究，揭示了通过该组内的斯特克兰德反应产生氨的潜力的证据。这一观察结果为该地点所见的高氨浓度（>70mg/L）的来源提供了新的见解。同样，像某几种假定的硫氧化微生物的丰度可能与硫代硫酸盐和连四硫酸盐等硫氧化中间体的变化有关。虽然这些数据支持核心微生物群落成员对高碱性泉水地球化学的影响，但也有证据表明地下过程会影响地球化学，并且可能也会影响群落动态。尽管这些与天体生物学相关的生态系统的生理学和生态学仍在被揭示，但这项工作有助于识别一个稳定的微生物群落，它以蛇纹石化生态系统中以前未观察到的方式影响泉水地球化学。
