Bontemps Zélia, Moënne-Loccoz Yvan, Hugoni Mylène
UMR 5557 Ecologie Microbienne, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, Villeurbanne, France.
Department of Medical Biochemistry and Microbiology, Science for Life Laboratories, Uppsala University, Uppsala, Sweden.
mSystems. 2024 Feb 20;9(2):e0123323. doi: 10.1128/msystems.01233-23. Epub 2024 Jan 30.
Community assembly processes are complex and understanding them represents a challenge in microbial ecology. Here, we used Lascaux Cave as a stable, confined environment to quantify the importance of stochastic vs deterministic processes during microbial community dynamics across the three domains of life in relation to an anthropogenic disturbance that had resulted in the side-by-side occurrence of a resistant community (unstained limestone), an impacted community (present in black stains), and a resilient community (attenuated stains). Metabarcoding data showed that the microbial communities of attenuated stains, black stains, and unstained surfaces differed, with attenuated stains being in an intermediate position. We found four scenarios to explain community response to disturbance in stable conditions for the three domains of life. Specifically, we proposed the existence of a fourth, not-documented yet scenario that concerns the always-rare microbial taxa, where stochastic processes predominate even after disturbance but are replaced by deterministic processes during post-disturbance recovery. This suggests a major role of always-rare taxa in resilience, perhaps because they might provide key functions required for ecosystem recovery.IMPORTANCEThe importance of stochastic vs deterministic processes in cave microbial ecology has been a neglected topic so far, and this work provided an opportunity to do so in a context related to the dynamics of black-stain alterations in Lascaux, a UNESCO Paleolithic cave. Of particular significance was the discovery of a novel scenario for always-rare microbial taxa in relation to disturbance, in which stochastic processes are replaced later by deterministic processes during post-disturbance recovery, i.e., during attenuation of black stains.
群落组装过程十分复杂，理解这些过程是微生物生态学面临的一项挑战。在此，我们以拉斯科洞穴作为一个稳定、封闭的环境，来量化随机过程与确定性过程在横跨生命三域的微生物群落动态变化期间的重要性，这与一种人为干扰有关，该干扰导致了抗性群落（未染色的石灰岩）、受影响群落（存在于黑色污渍中）和恢复力强的群落（变淡的污渍）并排出现。宏条形码数据显示，变淡的污渍、黑色污渍和未染色表面的微生物群落存在差异，变淡的污渍处于中间位置。我们发现了四种情形来解释在稳定条件下生命三域对干扰的群落响应。具体而言，我们提出存在第四种尚未记录的情形，该情形涉及一直稀少的微生物分类群，在这种情形下，即使在干扰后随机过程仍占主导，但在干扰后的恢复过程中会被确定性过程取代。这表明一直稀少的分类群在恢复力方面发挥着重要作用，或许是因为它们可能提供生态系统恢复所需的关键功能。重要性随机过程与确定性过程在洞穴微生物生态学中的重要性是一个迄今被忽视的话题，这项研究在与联合国教科文组织认定的旧石器时代洞穴拉斯科洞穴中黑色污渍变化动态相关的背景下提供了这样一个研究机会。特别重要的是发现了一种关于一直稀少的微生物分类群与干扰相关的新情形，即在干扰后的恢复过程中，也就是在黑色污渍变淡的过程中，随机过程随后会被确定性过程取代。
