普遍低估了全球干旱地区雨水引起的土壤碳排放
Ngoc B Nguyen1, Mirco Migliavacca2, Maoya Bassiouni1
1Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA USA.
概括
降雨事件对干旱地区的碳循环产生重大影响,导致大量的碳排放. 这些雨引起的碳脉冲对于了解全球干旱地区碳平衡和生态系统呼吸至关重要.
科学领域:
- 地球和环境科学 地球和环境科学
- 生态生态学 生态生态学
- 生物地质化学生物地质化学
背景情况:
- 干旱地区的生态系统对水的可用性非常敏感,雨水脉冲显著影响碳流.
- 雨引起的碳排放对干旱地区全球碳平衡的确切贡献仍然不太清楚.
- 现有的方法可能低估了生态系统呼吸和光合作用在这些关键的潮湿时期的作用.
研究的目的:
- 量化雨脉冲事件对全球干旱地区碳平衡的影响.
- 描述控制这些雨引起的碳排放的时空控制.
- 开发和验证一种方法,用于准确估计雨季期间的碳流.
主要方法:
- 利用来自全球34个干旱地区的-共变观测,收集碳,水和能源流量的数据.
- 编制了一份1800多个手动识别的雨引起的二氧化碳 (CO2) 脉冲事件的清单.
- 开发了一种机器学习算法,用于自动检测二氧化碳脉冲事件,并与手动识别进行验证.
主要成果:
- 雨脉冲事件对年度碳流量有重大贡献,占生态系统呼吸量的16.9% ± 2.8%和生态系统净生产力的9.6% ± 2.2%.
- 低估了生态系统的呼吸和光合作用高达30%发生在雨脉冲期间当前的分区方法.
- 在这些事件期间的碳损失强度与年度生产力,干旱度和土壤pH强烈相关.
结论:
- 雨水引起的碳排放是全球干旱地区碳循环的关键,经常被低估的组成部分.
- 确定了雨水诱导的二氧化碳脉冲的普遍衰变率,使呼吸估计的偏差修正成为可能.
- 生态系统模型可能需要修订,以更好地纳入雨水脉冲对干旱土地碳动态的重大影响.
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