南极冰盖下储藏着大量甲烷-凯发k8官网

南极冰盖下储藏着大量甲烷
文章来源:未知 文章作者:enread 发布时间:2012-08-30 06:53 字体: [ ] 
(单词翻译:双击或拖选)
the antarctic ice sheet could be an overlooked but important source of 1(甲烷), a 2(有效的) greenhouse gas, according to a report in the august 30 issue of nature by an international team of scientists. the new study demonstrates that old organic matter in sedimentary basins located beneath the antarctic ice sheet may have been converted to methane by micro-organisms living under oxygen-deprived conditions. the methane could be released to the atmosphere if the ice sheet shrinks and exposes these old sedimentary basins.
 
coauthor slawek tulaczyk, a professor of earth and planetary sciences at uc santa cruz, said the project got its start five years ago in discussions with first author jemma wadham at the university of bristol school of 3 sciences, where tulaczyk was on sabbatical.
 
"it is easy to forget that before 35 million years ago, when the current period of antarctic glaciations started, this continent was 4 with life," tulaczyk said. "some of the organic material produced by this life became trapped in 5, which then were cut off from the rest of the world when the ice sheet grew. our modeling shows that over millions of years, microbes may have turned this old organic carbon into methane."
 
the science team estimated that 50 percent of the west antarctic ice sheet (1 million square kilometers) and 25 percent of the east antarctic ice sheet (2.5 million square kilometers) overlies pre-glacial sedimentary basins containing about 21,000 billion metric tons of organic carbon.
 
"this is an immense amount of organic carbon, more than ten times the size of carbon stocks in northern permafrost regions," wadham said. "our laboratory experiments tell us that these sub-ice environments are also biologically active, meaning that this organic carbon is probably being metabolized to carbon dioxide and methane gas by microbes."
 
the researchers numerically simulated the accumulation of methane in antarctic sedimentary basins using an established one-dimensional hydrate model. they found that sub-ice conditions favor the accumulation of methane hydrate (that is, methane trapped within a structure of water 6, forming a solid similar to regular ice).
 
they also calculated that the potential amount of methane hydrate and free methane gas beneath the antarctic ice sheet could be up to 4 billion metric tons, a similar order of magnitude to some estimates made for arctic permafrost. the predicted shallow depth of these potential reserves also makes them more 7 to climate forcing than other methane hydrate(水合物) reserves on earth.
 
coauthor sandra arndt, a nerc fellow at the university of bristol, who conducted the numerical modeling, said, "it's not surprising that you might expect to find significant amounts of methane hydrate trapped beneath the ice sheet. just like in sub-seafloor sediments, it is cold and pressures are high, which are important conditions for methane hydrate formation."


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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 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。
3 cgjxb     
adj.地理的;地区(性)的
参考例句:
  • the current survey will have a wider geographical spread.当前的调查将在更广泛的地域范围內进行。
  • these birds have a wide geographical distribution.这些鸟的地理分布很广。
4 855ef2b5bd20950d32245ec965891e4a     
adj.丰富的v.充满( teem的现在分词 );到处都是;(指水、雨等)暴降;倾注
参考例句:
  • the rain was teeming down. 大雨倾盆而下。
  • the teeming streets of the city 熙熙攘攘的城市街道
5 8b3acb612b624abdf2c2881bc6928565     
沉淀物( sediment的名词复数 ); 沉积物
参考例句:
  • when deposited, 70-80% of the volume of muddy sediments may be water. 泥质沉积物沉积后,体积的70-80%是水。
  • oligocene erosion had truncated the sediments draped over the dome. 覆盖于穹丘上的沉积岩为渐新世侵蚀所截削。
6 187c25e49d45ad10b2f266c1fa7a8d49     
分子( molecule的名词复数 )
参考例句:
  • the structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
  • inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里,大分子裂变为小分子。
7 4rrw7     
adj.过敏的,敏感的;易动感情的,易受感动的
参考例句:
  • children are more susceptible than adults.孩子比成人易受感动。
  • we are all susceptible to advertising.我们都易受广告的影响。
tag标签: ice antarctica methane
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