大气中的高CO2降低了淡水湖中的甲基产量
Pei Lei1,2,3, Jin Zhang1,2, Ri-Qing Yu4
1School of Environment, Nanjing Normal University, Nanjing, China.
Nature communications
|December 26, 2025
概括
升高的二氧化碳 (CO2) 水平通过改变微生物群落来减少湖泊中的甲基 (MeHg) 生产. 这一发现影响了气候变化下的未来污染预测.
科学领域:
- 环境科学 环境科学
- 微生物学 微生物学
- 环境化学环境化学
背景情况:
- 大气中二氧化碳 (CO2) 的升高会改变微生物群落,但其对水生生态系统中甲基 (MeHg) 生产的影响尚不清楚.
- 甲是一种强大的神经毒素,了解影响其产生因素对于环境风险评估至关重要.
研究的目的:
- 调查二氧化碳水平升高对淡水湖中的MeHg净产量的影响.
- 确定微生物机制,特别是甲素社区转移,负责观察到的MeHg生产变化.
主要方法:
- 在环境和高二氧化碳条件 (650和1000 ppm) 下,在广泛的度范围内研究了45个淡水湖.
- 分析了微生物群落的组成,重点关注甲基生物和甲基化基因 (hgcA) 的存在.
- 测量净MeHg产量和甲 (CH4) 产量速度.
- 利用模型模拟来预测未来二氧化碳场景下的全球MeHg产量.
主要成果:
- 在所有研究的湖泊中,二氧化碳的升高始终降低了净MeHg产量,而在环氧化条件下 (54-96%的减少) 效果更为明显.
- 由二氧化碳驱动的转变有利于缺乏hgcA基因的性甲生物,而不是拥有hgcA基因的乙类甲生物.
- 甲素丰度 (hgcA副本) 降低了18-98%,其活性 (CH4产生) 降低了13-53%,导致抑制了Hg甲基化.
- 模型模拟预测,在未来的二氧化碳情景下,湖泊MeHg产量将在全球范围内下降33%-74%.
结论:
- 大气中高水平的二氧化碳作为淡水湖中的甲基化显著抑制剂.
- 碳代谢的转变有利于缺乏hgcA基因的特定甲基组,这是减少MeHg生产背后的主要机制.
- 未来的气候变化缓解策略包括减少二氧化碳,可以降低MeHg风险,部分抵消气候变暖引起的增加.
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