患病的树木会产生大量甲烷-凯发k8官网

患病的树木会产生大量甲烷
文章来源:未知 文章作者:enread 发布时间:2012-08-08 05:43 字体: [ ] 
(单词翻译:双击或拖选)
diseased trees in forests may be a significant new source of 1(甲烷) that causes climate change, according to researchers at the yale school of 2 & environmental studies in geophysical research letters. sixty trees sampled at yale myers forest in northeastern connecticut contained concentrations of methane that were as high as 80,000 times ambient(周围的) levels. normal air concentrations are less than 2 parts per million, but the yale researchers found average levels of 15,000 parts per million inside trees.
 
"these are flammable concentrations," said kristofer covey, the study's lead author and a ph.d. candidate at yale. "because the conditions thought to be driving this process are common throughout the world's forests, we believe we have found a globally significant new source of this 3 greenhouse gas."
 
the estimated 4 rate from an upland(山地的) site at the yale forest is roughly equivalent to burning 40 gallons of gasoline per hectare of forest per year. it also has a global warming potential equivalent to 18 percent of the carbon being 5 by these forests, reducing their climate benefit of carbon sequestration by nearly one-fifth.
 
"if we extrapolate(推断) these findings to forests globally, the methane produced in trees represents 10 percent of global 6," said xuhui lee, a co-author of the study and sara shallenberger brown professor of meteorology at yale. "we didn't know this pathway existed."
 
the trees producing methane are older -- between 80 and 100 years old -- and diseased. although outwardly healthy, they are being hollowed out by a common fungal infection that slowly eats through the trunk, creating conditions favorable to methane-producing microorganisms called methanogens(产烷生物).
 
"no one until now has linked the idea that fungal rot of timber trees, a production problem in commercial forestry, might also present a problem for greenhouse gas and climate change mitigation," said mark bradford, a co-author and assistant professor of terrestrial 7 ecology at f&es.
 
red 8, an abundant species in north america, had the highest methane concentrations, but other common species, including oak, birch and pine were also producers of the gas. the rate of methane emissions was 3.1 times higher in the summer, suggesting that higher temperatures may lead to increasing levels of forest methane that, in turn, lead to ever-higher temperatures.
 
"these findings suggest decay in living trees is important to biogeochemists and 9 scientists seeking to understand global greenhouse gas budgets and associated climate change," said covey.


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1 t1eyx     
n.甲烷,沼气
参考例句:
  • the blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
  • methane may have extraterrestrial significance.甲烷具有星际意义。
2 8ibxk     
n.森林学;林业
参考例句:
  • at present, the chinese forestry is being at a significant transforming period. 当前, 我国的林业正处于一个重大的转折时期。
  • anhua is one of the key forestry counties in hunan province. 安化县是湖南省重点林区县之一。
3 c1uzk     
adj.强有力的,有权势的;有效力的
参考例句:
  • the medicine had a potent effect on your disease.这药物对你的病疗效很大。
  • we must account of his potent influence.我们必须考虑他的强有力的影响。
4 vjnz4     
n.发出物,散发物;发出,散发
参考例句:
  • rigorous measures will be taken to reduce the total pollutant emission.采取严格有力措施,降低污染物排放总量。
  • finally,the way to effectively control particulate emission is pointed out.最后,指出有效降低颗粒排放的方向。
5 0ceab16bc48aa9b4ed97d60eeed591f8     
adj.扣押的;隐退的;幽静的;偏僻的v.使隔绝,使隔离( sequester的过去式和过去分词 );扣押
参考例句:
  • the jury is expected to be sequestered for at least two months. 陪审团渴望被隔离至少两个月。 来自《简明英汉词典》
  • everything he owned was sequestered. 他的一切都被扣押了。 来自《简明英汉词典》
6 1a87f8769eb755734e056efecb5e2da9     
排放物( emission的名词复数 ); 散发物(尤指气体)
参考例句:
  • most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
  • dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。
7 wq4xz     
n.生态系统
参考例句:
  • this destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
  • we all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。
8 bbpxj     
n.槭树,枫树,槭木
参考例句:
  • maple sugar is made from the sap of maple trees.枫糖是由枫树的树液制成的。
  • the maple leaves are tinge with autumn red.枫叶染上了秋天的红色。
9 6eayr     
adj.大气的,空气的;大气层的;大气所引起的
参考例句:
  • sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
  • clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。
tag标签: trees forests methane
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