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SSS 2011-04-11

时间:2011-05-12 03:37来源:互联网 提供网友:wp661375   字体: [ ]
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    (单词翻译:双击或拖选)

This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.

Landfills produce methane1—which can be valuable as an energy source. But scientists haven't known why landfills make so much methane. The solid waste in landfills is typically at a pH that's considered too acidic to host methanogens, methane-producing microbes.

So scientists did some digging, literally2, to investigate. They found a particularly hearty3 methanogen called Methanosarcina barkeri, or just M. barkeri, that can survive at low pH levels.

M. barkeri eats the acids and produces some methane. At the same time, it raises the pH level in the area around it. The less-acidic environment that results becomes a better host for other methanogens. As liquid leaches4 through the landfill, it carries higher pH materials and the methanogens living among them to other areas of the landfill.

M. barkeri repeats this cycle, making the landfill environment even more methanogen-friendly. The research was published in the journal Applied5 and Environmental Microbiology.

M. barkeri not only produces methane that could be harvested for fuel—the microbes also make the whole trash mound6 more compact. The finding could help in the development of ways to accelerate the process. Leading to more methane collection and more room for waste without more landfills.

Thanks for the minute. For Scientific American's 60-Second Science, I'm Cynthia Graber.


点击收听单词发音收听单词发音  

1 methane 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 literally 28Wzv     
adv.照字面意义,逐字地;确实
参考例句:
  • He translated the passage literally.他逐字逐句地翻译这段文字。
  • Sometimes she would not sit down till she was literally faint.有时候,她不走到真正要昏厥了,决不肯坐下来。
3 hearty Od1zn     
adj.热情友好的;衷心的;尽情的,纵情的
参考例句:
  • After work they made a hearty meal in the worker's canteen.工作完了,他们在工人食堂饱餐了一顿。
  • We accorded him a hearty welcome.我们给他热忱的欢迎。
4 leaches ba6e67646d542ca254c729e49bae451a     
n.(将化学品、矿物质等)过滤( leach的名词复数 );(液体)过滤,滤去
参考例句:
  • People consume it when it leaches from plastic into baby formula, water or food in container. 当它被从塑料中经沥滤而入婴儿配方奶粉、水或罐装食品当中的时候,人们将其摄入。 来自互联网
  • After this article uses is also the microwave pretreatment, leaches the method with the solution. 本文采用的也是微波预处理后用溶液浸取的方法。 来自互联网
5 applied Tz2zXA     
adj.应用的;v.应用,适用
参考例句:
  • She plans to take a course in applied linguistics.她打算学习应用语言学课程。
  • This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。
6 mound unCzhy     
n.土墩,堤,小山;v.筑堤,用土堆防卫
参考例句:
  • The explorers climbed a mound to survey the land around them.勘探者爬上土丘去勘测周围的土地。
  • The mound can be used as our screen.这个土丘可做我们的掩蔽物。
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