Microbiota inhabiting the intermittent streambeds mediates several in-stream processes that are essential for ecosystem function. Reduced stream discharge caused by the strengthened intermittency and increased duration of the dry phase is a spreading global response to changes in climate. Here, the impacts of a 5-month desiccation, one-week rewetting and punctual storms, which interrupted the dry period, were examined. The genomic composition of total (DNA) and active (RNA) diversity, and the community level physiological profiles (CLPP) were considered as proxies for functional diversity to describe both prokaryotes and eukaryotes inhabiting the surface and hyporheic streambeds. Comparisons between the genomic and potential functional responses helped to understand how and whether the microbial diversity was sensitive to the environmental conditions and resource acquisition, such as water stress and extracellular enzyme activities, respectively. RNA expression showed the strongest relationship with the environmental conditions and resource acquisition, being more responsive to changing conditions compared to DNA diversity, especially in the case of prokaryotes. The DNA results presumably reflected the legacy of the treatments because inactive, dormant, or dead cells were included, suggesting a slow microbial biomass turnover or responses of the microbial communities to changes mainly through physiological acclimation. On the other hand, microbial functional diversity was largely explained by resources acquisition, such as metrics of extracellular enzymes, and appeared vulnerable to the hydrological changes and duration of desiccation. The data highlight the need to improve the functional assessment of stream ecosystems with the application of complementary metrics to better describe the streambed microbial dynamics under dry-rewet stress.

中文翻译：

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水文变化影响流化微生物的多样性和功能响应。

居住在间歇性河床中的微生物群介导了对生态系统功能至关重要的几个流中过程。由于间歇性的增强和干旱阶段持续时间的增加而导致的溪流排放量减少，这是全球对气候变化的反应正在蔓延。在这里，研究了中断干燥期的5个月的干燥，一周的重新润湿和准时暴风雨的影响。总的（DNA）和活性的（RNA）多样性的基因组组成，以及群落水平的生理概况（CLPP）被认为是功能多样性的代表，可以描述居住在地表和流变河床中的原核生物和真核生物。基因组和潜在功能响应之间的比较有助于了解微生物多样性如何以及是否分别对环境条件和资源获取（例如水分胁迫和细胞外酶活性）敏感。RNA表达与环境条件和资源获取之间关系最密切，与DNA多样性相比，对变化的条件更敏感，特别是在原核生物的情况下。DNA的结果大概反映了治疗的传统，因为其中包括无活性的，休眠的或死细胞，这表明微生物的生物量转换缓慢或微生物群落对变化的反应主要是通过生理适应。另一方面，微生物功能的多样性很大程度上可以通过资源获取来解释，例如细胞外酶的指标，并且似乎容易受到水文变化和干​​燥持续时间的影响。数据强调需要通过补充指标的应用来改善河流生态系统的功能评估，以更好地描述干重湿应力下的河流微生物动态。