SSS 2008-07-02

（单词翻译）

This is Scientific American's 60-second Science, I am Karen Hopkin. This'll just take a minute.

 Methane¹ is a greenhouse gas that traps heat even better than carbon dioxide. It comes from a variety of sources, including fossil fuel production and even farming. Cows give off methane, you know, after they eat. Even the surface waters of the ocean contain substantial amounts of this gas. But where marine² methane comes from was a mystery. Until now. Scientists collected seawater off the coast of Hawaii. And they found that bacteria that live in these waters scarf up certain phosphorous-containing chemicals, and then release methane as a byproduct. The results appear online in the journal Nature Geoscience. What’s surprising is that scientists had previously³ thought that methane is only produced by bacteria that live in places where there is no oxygen, think of the smell you associate with a swamp or with the muck at the bottom of a murky⁴ pond. This marine methane could contribute to global warming by adding more greenhouse gases to the atmosphere. What’s worse, the hotter it is, the more stressed these seafaring bacteria get, and the more methane they’re likely to put out. Which was certainly not the kind of feedback that atmospheric⁵ scientists were hoping to get. 

Thanks for the minute,for Scientific American's 60-Second-Science.I'm Karen Hopkin.