Catalan Institute for Water Research, (ICRA-CERCA), Carrer Emili Grahit 101, 17003 Girona, Spain.
Facultad de Ciencias, Departamento de Biología, Universidad Nacional de Colombia, Cra 30 45 02, Ciudad universitaria, Bogotá 111321, Colombia.
FEMS Microbiol Ecol. 2024 Sep 14;100(10). doi: 10.1093/femsec/fiae126.
Bacterial communities in river sediments are shaped by a trade-off between dispersal from upstream or nearby land and selection by the local environmental conditions. In temporary rivers (i.e. those characterized by long drying periods and subsequent rewetting) seasonal hydrological dynamics shape bacterial communities by connecting or disconnecting different river habitats. In this study, we tracked and compared the temporal and spatial changes in the composition of bacterial communities in streambed sediments and floodplain habitats across both permanent and intermittent river segments. Our findings revealed that environmental selection played a key role in assembling bacterial communities in both segments. We argue that distinct environmental features act as filters at the local scale, favoring specific bacterial taxa in isolated pools and promoting some typically terrestrial taxa in dry areas. Considering the prospective extension of drying intervals due to climate change, our results suggest an emerging trend wherein bacterial assemblages in temporary streams progressively incorporate microorganisms of terrestrial origin, well-adapted to tolerate desiccation phases. This phenomenon may constitute an integral facet of the broader adaptive dynamics of temporary river ecosystems in response to the impacts of climate change.
河流沉积物中的细菌群落是由来自上游或附近陆地的扩散和当地环境条件选择之间的权衡塑造的。在季节性河流（即具有长时间干燥期和随后再湿润的河流）中，季节性水力学动态通过连接或断开不同的河流栖息地来塑造细菌群落。在这项研究中，我们跟踪和比较了永久性和间歇性河流段的河床沉积物和洪泛区栖息地中细菌群落组成的时间和空间变化。我们的研究结果表明，环境选择在两个河段的细菌群落组装中都起着关键作用。我们认为，不同的环境特征在局部尺度上起着过滤作用，有利于孤立池塘中的特定细菌类群，并促进干旱地区中一些典型的陆地类群。考虑到气候变化导致干燥期的预期延长，我们的研究结果表明，临时溪流中的细菌组合逐渐纳入了适应干燥阶段的陆地来源的微生物，这是一个新兴趋势。这种现象可能构成临时河流生态系统对气候变化影响的更广泛适应动态的一个组成部分。
