Strong emission of methyl chloride from tropical plants
Strong emission of methyl chloride from tropical plants
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DOI：
10.1038/416163a
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发表时间：
2002-03
期刊：
影响因子：
64.8
通讯作者：
Y. Yokouchi;M. Ikeda;Y. Inuzuka;T. Yukawa
中科院分区：
文献类型：
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作者：
Y. Yokouchi;M. Ikeda;Y. Inuzuka;T. Yukawa
氯甲烷是消耗臭氧的氯化合物的最大天然来源，约占目前大气氯含量的15%。在工业化前时期，这种贡献可能相对更大，因为当时不存在其他人为来源，如氯氟烃。尽管有证据表明，热带沿海地区的甲基氯排放量很大，但甲基氯的总体预算仍存在很大缺口。在这里，我们提出了一些常见的热带植物（某些类型的蕨类植物和龙脑香科）的大量氯甲烷排放量的观测结果，范围为每小时每克干叶0.1至3.7微克。这些初步测量的基础上，仅在东南亚的龙脑香科氯甲烷通量估计为0.91 Tg yr-1，这可以解释很大一部分失踪的氯甲烷来源。随着热带森林的持续砍伐，氯化合物的自然来源今后可能会相应减少。相反，石炭纪大量的蕨类植物可能创造了富含氯甲烷的大气。
Methyl chloride is the largest natural source of ozone-depleting chlorine compounds, and accounts for about 15 per cent of the present atmospheric chlorine content. This contribution was likely to have been relatively greater in pre-industrial times, when additional anthropogenic sources—such as chlorofluorocarbons—were absent. Although it has been shown that there are large emissions of methyl chloride from coastal lands in the tropics,, there remains a substantial shortfall in the overall methyl chloride budget. Here we present observations of large emissions of methyl chloride from some common tropical plants (certain types of ferns and Dipterocarpaceae), ranging from 0.1 to 3.7 µg per gram of dry leaf per hour. On the basis of these preliminary measurements, the methyl chloride flux from Dipterocarpaceae in southeast Asia alone is estimated at 0.91 Tg yr-1, which could explain a large portion of missing methyl chloride sources. With continuing tropical deforestation, natural sources of chlorine compounds may accordingly decrease in the future. Conversely, the abundance of massive ferns in the Carboniferous period may have created an atmosphere rich in methyl chloride.