Purpose

Wetland soils may face more severe water stress under future climate change. Our aim was to assess the change characteristics of wetland soil bacterial community and metabolic potentials under drought and flood conditions.

Methods

Wetland soil was incubated under five different water environments (including constant moisture at 30%, natural air-dried, and 3 types of flooding depths) by conducting experimental microcosms. After 1, 21, and 132 days of incubation, the soil bacterial community structure and metabolic potential were examined by the 16S rRNA gene sequencing and Biolog-Ecoplates method, respectively.

Results

The results showed that Actinobacteria and Firmicutes were significantly enriched under drought and flooding treatments, respectively. Compared to flooding, drought decreased soil microbial biomass and carbon metabolism more severely. However, the depth of flooding did not significantly change bacterial community composition and carbon metabolism. In addition, the responses of soil metabolic functions to drought were more sensitive than the change of bacterial community composition. When the wetland soil faced water stress (drought and flooding), its metabolic functions showed close correlations with bacterial community composition and were negatively affected by most of environmental factors (such as pH, NO₃-N, and NH₄-N).

Conclusions

The results indicate that the drying condition is more severe and rapid than flooding in threatening soil microbial metabolic activity. In addition, the depth of flooding does not significantly change bacterial community composition and carbon metabolism.

中文翻译：

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在实验微观环境中跟踪干旱和洪水条件下湿地土壤细菌群落的变化和代谢潜能

目的

在未来的气候变化下，湿地土壤可能面临更严重的水分胁迫。我们的目的是评估干旱和洪水条件下湿地土壤细菌群落的变化特征和代谢潜能。

方法

通过进行实验缩影，在五种不同的水环境（包括30％的恒定湿度，自然风干和3种浸水深度）下孵育湿地土壤。培养1、21和132天后，分别通过16S rRNA基因测序和Biolog-Ecoplates方法检查土壤细菌群落结构和代谢潜能。

结果

结果表明，在干旱和水淹处理下，放线菌和硬顶菌分别显着富集。与洪水相比，干旱更严重地降低了土壤微生物的生物量和碳代谢。但是，淹没深度并没有显着改变细菌群落组成和碳代谢。此外，土壤代谢功能对干旱的响应比细菌群落组成的变化更为敏感。当湿地土壤面临水分胁迫（干旱和洪水）时，其代谢功能与细菌群落组成密切相关，并受到大多数环境因素（例如pH，NO ₃ -N和NH ₄ -N）的负面影响。

结论

结果表明，在威胁土壤微生物新陈代谢的活动中，干燥条件比洪水更严重，更迅速。此外，淹没深度不会显着改变细菌群落组成和碳代谢。