AG Geobotany, Faculty of Biology and Biotechnology, Ruhr Universität Bochum, Universitätsstr. 150, 44801, Bochum, Germany.
Department of Biodiversity, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, 45141, Essen, Germany.
Microb Ecol. 2018 May;75(4):875-887. doi: 10.1007/s00248-017-1085-9. Epub 2017 Oct 12.
The increasing number and duration of inundations is reported to be a consequence of climate change and may severely compromise non-adapted macroorganisms. The effect of flooding events on terrestrial and aquatic microbial communities is, however, less well understood. They may respond to the changed abiotic properties of their native habitat, and the native community may change due to the introduction of alien species. We designed an experiment to investigate the effect of five different flooding durations on the terrestrial and aquatic communities of eukaryotic microorganism, using the AquaFlow mesocosms. With amplicon sequencing of the small subunit (SSU) and internal transcribed spacer (ITS) rRNA gene regions, we analyzed community compositions directly before and after flooding. Subsequently, they were monitored for another 28 days, to determine the sustainability of community changes. Our results revealed a temporary increase in similarity between terrestrial and aquatic communities according to OTU composition (operational taxonomic unit, serves as a proxy for species). Increased similarity was mainly caused by the transmission of OTUs from water to soil. A minority of these were able to persist in soil until the end of the experiment. By contrast, the vast majority of soil OTUs was not transmitted to water. Flooding duration affected the community structure (abundance) more than composition (occurrence). Terrestrial communities responded immediately to flooding and the flooding duration influenced the community changes. Independent from flooding duration, all terrestrial communities recovered largely after flooding, indicating a remarkable resilience to the applied disturbances. Aquatic communities responded immediately to the applied inundations too. At the end of the experiment, they grouped according to the applied flooding duration and the amount of ammonium and chloride that leached from the soil. This indicates a sustained long-term response of the aquatic communities to flooding events.
据报道，洪水的次数和持续时间增加是气候变化的结果，这可能严重危及非适应性的大型生物。然而，洪水事件对陆地和水生微生物群落的影响还不太清楚。它们可能对其原生栖息地的非生物特性发生变化做出反应，并且由于引入了外来物种，原生群落可能会发生变化。我们设计了一项实验，使用 AquaFlow 中观模型，研究了五种不同洪水持续时间对真核微生物陆地和水生群落的影响。通过小亚基（SSU）和内部转录间隔区（ITS）rRNA 基因区域的扩增子测序，我们在洪水前后直接分析了群落组成。随后，它们又被监测了 28 天，以确定群落变化的可持续性。我们的结果表明，根据 OTU 组成（分类操作单元，用作物种的替代物），陆地和水生群落之间的相似性暂时增加。相似性的增加主要是由于 OTU 从水到土壤的传播。其中少数能够在土壤中持续存在到实验结束。相比之下，绝大多数土壤 OTU 没有传播到水中。洪水持续时间对群落结构（丰度）的影响大于组成（发生）。陆地群落对洪水立即做出反应，洪水持续时间影响群落变化。独立于洪水持续时间，所有陆地群落在洪水后都基本恢复，表明对应用干扰具有显著的恢复力。水生群落也立即对应用的洪水做出反应。在实验结束时，它们根据应用的洪水持续时间以及从土壤中浸出的铵和氯的量进行分组。这表明水生群落对洪水事件有持续的长期响应。
