Aims

Soil organic carbon (SOC) stability greatly affects soil carbon sequestration capacity and carbon emissions, is related to soil bacterial communities, but it remains unclear whether such relationships exist in alpine wetland biogeomorphic succession.

Methods

Here, we used a space-for-time approach across hydrological gradients, and alpine wetland succession can be divided into three types: “Swamp” (S), “Swamp Meadow” (SM), and “Meadow” (M) to examine the dynamics change of SOC fractions and bacterial communities.

Results

The succession from S-SM-M resulted in decreased SOC stability (SM and M decreased by 18.65% and 31.88% compared to S). Furthermore, the decrease in SOC stability was primarily due to the decrease in soil moisture during succession and moisture-induced changes in bacterial community structure. e.g., the relative abundance of Proteobacteria decreased significantly by 40.99% and 52.87% in SM and M, while the relative abundance of Acidobacteria increased by 43.49% and 185.04% in SM and M compared to S. Co-occurrence network and random forest analyses further identified that changes in keystone taxa of bacteria, including Deltaproteobacteria, Acidimicrobiia, Bacteroidia and Gammaproteobacteria, were associated with SOC stability.

Conclusions

In conclusion, bacteria shifted their community composition to reduce SOC stability in response to soil moisture variations during succession, and underscores the importance of identifying keystone taxa that are crucial for maintaining SOC stability.

中文翻译：

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中亚干旱地区高山湿地生物地貌演替过程中土壤细菌介导有机碳稳定性

目标

土壤有机碳（SOC）稳定性极大地影响土壤固碳能力和碳排放，与土壤细菌群落相关，但高寒湿地生物地貌演替中是否存在这种关系尚不清楚。

方法

这里，我们采用跨水文梯度的时空方法，将高山湿地演替分为“沼泽”（S）、“沼泽草甸”（SM）和“草甸”（M）三种类型来考察SOC 分数和细菌群落的动态变化。

结果

S-SM-M 的继承导致 SOC 稳定性下降（与 S 相比，SM 和 M 分别下降了 18.65% 和 31.88%）。此外，SOC稳定性的下降主要是由于演替过程中土壤水分的减少以及水分引起的细菌群落结构的变化所致。例如，与S相比，SM和M中Proteobacteria的相对丰度显着下降了40.99％和52.87％，而SM和M中Acidobacteria的相对丰度则增加了43.49％和185.04％。共现网络和随机森林进一步分析发现细菌关键类群（包括 Deltaproteobacteria、Acidimicrobiia、Bacteroidia 和 Gammaproteobacteria）的变化与 SOC 稳定性相关。

结论

总之，细菌改变了群落组成，以降低演替过程中土壤湿度变化的 SOC 稳定性，并强调了识别对维持 SOC 稳定性至关重要的关键类群的重要性。