Microbial communities thriving in hypersaline brines of solar salterns are highly resistant and resilient to environmental changes, and salinity is a major factor that deterministically influences community structure. Here, we demonstrate that this resilience occurs even after rapid osmotic shocks caused by a threefold change in salinity (a reduction from 34 to 12% salts) leading to massive amounts of archaeal cell lysis. Specifically, our temporal metagenomic datasets identified two co-occurring ecotypes within the most dominant archaeal population of the brines Haloquadratum walsbyi that exhibited different salt concentration preferences. The dominant ecotype was generally more abundant and occurred in high-salt conditions (34%); the low abundance ecotype always co-occurred but was enriched at salinities around 20% or lower and carried unique gene content related to solute transport and gene regulation. Despite their apparent distinct ecological preferences, the ecotypes did not outcompete each other presumably due to weak functional differentiation between them. Further, the osmotic shock selected for a temporal increase in taxonomic and functional diversity at both the Hqr. walsbyi population and whole-community levels supporting the specialization-disturbance hypothesis, that is, the expectation that disturbance favors generalists. Altogether, our results provide new insights into how intraspecies diversity is maintained in light of substantial gene-content differences and major environmental perturbations.

在日光盐田的高盐盐水中茁壮成长的微生物群落对环境变化具有高度抵抗力和弹性，而盐度是决定性影响群落结构的主要因素。在这里，我们证明即使在由盐度三倍变化（从 34% 减少到 12% 盐）导致大量古细菌细胞裂解引起的快速渗透冲击之后，这种弹性也会发生。具体来说，我们的时间宏基因组数据集在卤水Haloquadratum walsbyi最主要的古菌种群中确定了两种同时发生的生态型表现出不同的盐浓度偏好。优势生态型通常更丰富，发生在高盐条件下（34%）；低丰度生态型总是同时出现，但在盐度约为 20% 或更低时富集，并携带与溶质运输和基因调控相关的独特基因含量。尽管它们明显不同的生态偏好，但生态型并没有相互竞争，这可能是由于它们之间的功能差异较弱。此外，渗透休克选择用于Hqr 的分类学和功能多样性的时间增加。walsbyi支持专业化干扰假设的人口和整个社区水平，即干扰有利于通才的期望。总而言之，我们的结果提供了关于如何根据大量基因含量差异和主要环境扰动维持种内多样性的新见解。