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Background and aims <p>How SOC decomposition and their <i>Q</i><sub><i>10</i></sub> of labile and recalcitrant C respond to warming and drying in wetlands remains unclear under climate change, especially in subtropical seasonally flooded Poyang Lake wetlands.</p> Methods <p>We conducted a long-term (742&#xa0;days) soil incubation to examine the dynamics of depth-associated SOC mineralization, <i>Q</i><sub><i>10</i></sub>-labile, and <i>Q</i><sub><i>10</i></sub>-recalcitrant with warming and moisture changes.</p> Results <p>Topsoil generates more than three times CO<sub>2</sub> emissions than subsoil in response to warming. Compared with flooding, the drying (50% WHC and 80% WHC) treatments sharply increased CO<sub>2</sub> emission in the topsoil, but slightly decreased in the subsoil. SOC decomposition rates declined dramatically by day 153, then gradually reduced with more labile C decomposed, as cumulative SOC decomposition amounts were negatively correlated with DOC content, and the abundances of Actinobacteria and Firmicute increased after incubation in the topsoil. The <i>Q</i><sub><i>10</i></sub>-labile was significantly lower than the&#xa0;<i>Q</i><sub><i>10</i></sub>-recalcitrant in both soil depths. When converted from flooding to drying, subsoil <i>Q</i><sub>10</sub> values increased and continued to increase during the incubation, but topsoil <i>Q</i><sub>10</sub> was decreased before 5% of total SOC was depleted, then increased and was higher than the flooding treatments finally.</p> Conclusion <p>Our findings showed that a combination of warming and drying would exacerbate SOC decomposition in the topsoil, but have a minor impact on the subsoil carbon pool of the Poyang Lake wetland.&#xa0;</p>

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Temperature and moisture changes altered soil organic carbon decomposition and its temperature sensitivity in Poyang Lake wetland

  • 期刊论文

  • 发表日期：

    2025年6月19日

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  • Jinfeng Liang,
  • Qiong Ren,
  • Bo Yao,
  • Qin Wu,
  • Wenjing Yang,
  • Jian Xu,
  • Qiwu Hu

摘要

Background and aims

How SOC decomposition and their Q10 of labile and recalcitrant C respond to warming and drying in wetlands remains unclear under climate change, especially in subtropical seasonally flooded Poyang Lake wetlands.

Methods

We conducted a long-term (742 days) soil incubation to examine the dynamics of depth-associated SOC mineralization, Q10-labile, and Q10-recalcitrant with warming and moisture changes.

Results

Topsoil generates more than three times CO2 emissions than subsoil in response to warming. Compared with flooding, the drying (50% WHC and 80% WHC) treatments sharply increased CO2 emission in the topsoil, but slightly decreased in the subsoil. SOC decomposition rates declined dramatically by day 153, then gradually reduced with more labile C decomposed, as cumulative SOC decomposition amounts were negatively correlated with DOC content, and the abundances of Actinobacteria and Firmicute increased after incubation in the topsoil. The Q10-labile was significantly lower than the Q10-recalcitrant in both soil depths. When converted from flooding to drying, subsoil Q10 values increased and continued to increase during the incubation, but topsoil Q10 was decreased before 5% of total SOC was depleted, then increased and was higher than the flooding treatments finally.

Conclusion

Our findings showed that a combination of warming and drying would exacerbate SOC decomposition in the topsoil, but have a minor impact on the subsoil carbon pool of the Poyang Lake wetland.