Tutolo Benjamin M, Perrin Robert, Lauer Rachel, Bossaer Shane, Tosca Nicholas J, Hutchings Alec, Sevgen Serhat, Nightingale Michael, Ilg Daniel, Mott Eric B, Wilson Thomas
Department of Earth, Energy, and Environment, University of Calgary, Calgary, AB T2N 1N4, Canada.
Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK.
Life (Basel). 2024 Dec 7;14(12):1624. doi: 10.3390/life14121624.
Alkaline lakes are thought to have facilitated prebiotic synthesis reactions on the early Earth because their modern analogs accumulate vital chemical feedstocks such as phosphate through the evaporation of dilute groundwaters. Yet, the conditions required for some building block synthesis reactions are distinct from others, and these conditions are generally incompatible with those permissible for nascent cellular function. However, because current scenarios for prebiotic synthesis have not taken account of the physical processes that drive the chemical evolution of alkaline lakes, the potential for the co-occurrence of both prebiotic synthesis and the origins and early evolution of life in prebiotic alkaline lake environments remains poorly constrained. Here, we investigate the dynamics of active, prebiotically relevant alkaline lakes using near-surface geophysics, aqueous geochemistry, and hydrogeologic modeling. Due to their small size, representative range of chemistry, and contrasting evaporation behavior, the investigated, neighboring Last Chance and Goodenough Lakes in British Columbia, Canada offer a uniquely tractable environment for investigating the dynamics of alkaline lake behavior. The results show that the required, extreme phosphate enrichments in alkaline lake waters demand geomorphologically-driven vulnerability to evaporation, while the resultant contrast between evaporated brines and inflowing groundwaters yields Rayleigh-Taylor instabilities and vigorous surface-subsurface cycling and mixing of lake and groundwaters. These results provide a quantitative basis to reconcile conflicting prebiotic requirements of UV light, salinity, metal concentration, and pH in alkaline lake environments. The complex physical and chemical processing inherent to prebiotic alkaline lake environments thus may have not only facilitated prebiotic reaction networks, but also provided habitable environments for the earliest evolution of life.
碱性湖泊被认为在早期地球上促进了益生元合成反应，因为它们现代的类似物通过稀释的地下水蒸发积累了重要的化学原料，如磷酸盐。然而，一些构建模块合成反应所需的条件与其他条件不同，而且这些条件通常与新生细胞功能所允许的条件不相容。然而，由于目前的益生元合成设想没有考虑到驱动碱性湖泊化学演化的物理过程，益生元碱性湖泊环境中益生元合成与生命起源和早期演化同时出现的可能性仍然受到很大限制。在这里，我们使用近地表地球物理学、水地球化学和水文地质建模来研究活跃的、与益生元相关的碱性湖泊的动态。由于其规模小、具有代表性的化学范围以及不同的蒸发行为，加拿大不列颠哥伦比亚省相邻的、被研究的最后机会湖和古德诺夫湖提供了一个独特的易于处理的环境，用于研究碱性湖泊行为的动态。结果表明，碱性湖水中所需的极端磷酸盐富集需要地貌驱动的蒸发脆弱性，而蒸发盐水与流入的地下水之间的反差会产生瑞利 - 泰勒不稳定性以及湖泊和地下水的强烈地表 - 地下循环和混合。这些结果提供了一个定量基础，以协调碱性湖泊环境中紫外线、盐度、金属浓度和pH值等相互冲突的益生元需求。因此，益生元碱性湖泊环境中固有的复杂物理和化学过程不仅可能促进了益生元反应网络，而且还为生命的最早演化提供了宜居环境。
