由于北半球微生物来源减少,甲增长率降低
Fuu Ming Kai1, Stanley C Tyler, James T Randerson
1Department of Earth System Science, University of California, Irvine, California 92697, USA. fmkai@smart.mit.edu
Nature
|August 12, 2011
概括
大气甲 (CH4) 的增长放缓,原因是北半球微生物来源减少,特别是来自亚洲大米农业的微生物来源减少. 这一发现澄清了大气中的甲难题. 关键词:大气中的甲,微生物来源,大米农业.
科学领域:
- 大气化学和气候科学.
- 生物地质化学循环和温室气体排放.
背景情况:
- 大气中的甲 (CH4) 水平在20世纪上升,然后放缓,然后再次增加.
- 之前的研究指出,化石燃料,湿地,农业和氧化 (OH) 沉是减速的潜在原因.
研究的目的:
- 调查20世纪末大气甲增长速度放缓的主要驱动因素.
- 用同位素分析来区分各种甲来源和沉积点的贡献.
主要方法:
- 对大气CH4混合比率和碳同位素比率 ((13) C/ ((12) C) 的同步时间序列的分析.
- 利用一个两盒大气模型来模拟CH4的演变.
- 将观察到的同位素变化与源和沉变化的建模场景进行了比较.
主要成果:
- 北半球微生物来源减少最能解释观察到的CH4生长率变化.
- 同位素数据排除了减少的化石燃料排放作为减速的主要原因.
- 北半球的农业排放,特别是亚洲的水种植,约占排放减少的51%,与肥料使用和水资源管理有关.
结论:
- 20世纪后期大气甲放缓的主要原因是北半球微生物排放量减少.
- 亚洲大米农业的变化对这一减少做出了重大贡献.
- 对微生物甲来源和农业实践的进一步研究是有必要的.
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