热带草原中的气候驱动的动态:吸收率低,脉冲排放和弱封存
Ge Zhang1, Wei Yuan2, Longyu Jia2
1College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
Journal of hazardous materials
|July 19, 2025
概括
由于独特的气候和土壤因素,萨凡纳是动态交换区,而不是水槽. 这项研究揭示了脉冲排放和低封存,影响了全球模型.
科学领域:
- 环境科学 环境科学
- 生物地质化学生物地质化学
- 生态系统生态学生态学
背景情况:
- 草原生态系统覆盖了广的全球区域,对 (Hg) 循环至关重要.
- 独特的草原特征,如开放的树冠,季节性干旱和高温,可能会显著地影响Hg动态.
- 之前的研究已经研究了草原环境中的循环.
研究的目的:
- 进行首次对中国大草原生态系统中动态的全面评估.
- 研究草原特有的气候和结构特征如何影响循环模式.
- 评估草原作为全球预算中的汇或源的作用.
主要方法:
- 测量了大气中的 (Hg0) 度.
- 分析了通过落下的沉积,区分颗粒和溶解的形式.
- 监测了土壤中的排放量,特别是在干旱季节.
- 评估了植物的吸收率.
- 测定了表面土壤中的度.
主要成果:
- 大气中的Hg0平均为2.29±0.46 ng/m3.
- 透Hg沉积主要由颗粒Hg (50-80%),与森林中占主导地位的溶解形式不同.
- 干旱季节强烈的太阳辐射和温度导致脉冲土壤Hg排放,创造了一个"漏"的动态.
- 生态系统的净沉积点很弱 (6.9 ± 17.2 μg/m2 yr−1).
- 由于干旱压力,植物Hg吸收比热带森林要低 (3-4倍) 显著.
- 表面土壤Hg度很低 (22.7 ± 6.1 ng/g).
结论:
- 萨凡纳作为动态交换区,而不是长期储存水库.
- 草原中独特的Hg循环过程挑战了陆地捕获的传统假设.
- 这些发现需要将草原生物地质化学过程纳入全球模型和政策框架.
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