Background and Aims

EL Nino-Southern Oscillation (ENSO) events exert significant effects on ecosystem carbon (C) cycle. However, how forest Rs in the East Asian monsoon region can respond to ENSO events remains unclear.

Methods

Based on multi-source databases, we conducted a synthesis to analyze the differential responses of forest Rs in different climatic zones of East Asia to ENSO events. The response differences between Rs components and the time lag effects were then further investigated.

Results

We found that Rs in tropical-subtropical zones (TSZ) was positively correlated with ENSO, while in warm temperate zones (WTZ) it was negatively correlated, and there was no significant relationship in cold-middle temperate zones (CMTZ). Heterotrophic respiration and soil moisture also had significant linear correlation with ENSO. In TSZ, Rs lagged behind ENSO events by 9 months, while in WTZ, it led ENSO events by 4 months, and in CMTZ, Rs lagged behind ENSO events by 5 months.

Conclusion

The response of Rs to ENSO events was strongest in WTZ while weakest in CMTZ. Meanwhile, the response patterns in TSZ and WTZ were opposite. These abovementioned different responses were controlled by the precipitation anomaly arising from the variation of summer monsoon. Heterotrophic respiration was more sensitive to ENSO events than autotrophic respiration. The times lags of response of Rs to ENSO events in different climate zones were different. Our results have important implications for better understanding forest soil C emission processes under ENSO events and developing corresponding ecosystem C accumulation strategies.

中文翻译：

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东亚季风区森林土壤呼吸对 ENSO 事件的响应

 背景和目标

EL Nino-Southern Oscillation （ENSO） 事件对生态系统碳 （C） 循环产生重大影响。然而，东亚季风地区的森林 Rs 如何响应 ENSO 事件仍不清楚。

 方法

基于多源数据库，我们进行了综合分析东亚不同气候区森林 Rs 对 ENSO 事件的不同响应。然后进一步研究了 Rs 分量之间的响应差异和时间滞后效应。

 结果

我们发现热带-亚热带区 （TSZ） 的 Rs 与 ENSO 呈正相关，而在暖温带 （WTZ） 中呈负相关，在寒冷-中温带 （CMTZ） 中没有显着关系。异养呼吸和土壤水分也与 ENSO 呈显著线性相关。在 TSZ 中，Rs 落后于 ENSO 事件 9 个月，而在 WTZ 中，它领先 ENSO 事件 4 个月，在 CMTZ 中，Rs 落后于 ENSO 事件 5 个月。

 结论

Rs 对 ENSO 事件的响应在 WTZ 中最强，而在 CMTZ 中最弱。同时，TSZ 和 WTZ 的反应模式相反。上述不同的响应受到夏季季风变化引起的降水异常的控制。异养呼吸比自养呼吸对 ENSO 事件更敏感。不同气候区 Rs 对 ENSO 事件的响应时间滞后不同。我们的结果对于更好地了解 ENSO 事件下森林土壤 C 排放过程和制定相应的生态系统 C 积累策略具有重要意义。