VOA慢速英语: 深海岩中的微生物“吃”甲烷（双语）

Small Organisms in Deep Sea Rocks Eat Methane

深海岩中的微生物“吃”甲烷

The gas methane has been linked to rising temperatures on Earth. But methane does not stay in the atmosphere as long as another “greenhouse gas” -- carbon dioxide. Scientists say both gases trap heat from the sun. They prevent heat from escaping into outer space.

气体甲烷已经与地球上上升的气温联系在一起了，但是只要另一种“温室气体”——二氧化碳存在，甲烷就不会在大气中。科学家说这两种气体都能收集自太阳光的热量，都能够阻止热量散到外太空。

Methane can come from wetlands, as a byproduct of raising farm animals, and from human activities, such as leakage from natural gas systems. Methane is also plentiful in the ocean. It can be found in ice, but also rises from deep within the earth through small cracks, or holes, in the ocean floor.

甲烷可以来自湿地，是农场饲养牲畜的副产品，以及人类活动也会产生甲烷，比如：天然气系统的泄露。海洋里也存在有大量的甲烷，冰川中也存在甲烷，在地球深处，通过海底细小的裂缝、孔洞，甲烷气体不断上升。

Little of that methane reaches the atmosphere, thanks to methane-eating organisms that live in sea bed sediments – materials that sink to the sea floor. Now, an American scientist says other deep sea microorganisms are also attacking the gas. These organisms live in an unlikely place – inside rock on the ocean floor!

但是只有很少部分甲烷能到大气中，这得感谢生活在海底沉积物中的以甲烷为生的微生物。现在，美国的科学家说其它深海的微生物也会消耗甲烷。这些微生物生活在意想不到的地方——在海底的岩石里面。

Victoria Orphan is with the California Institute of Technology. She studies microorganisms that live in sediment near methane vents in the ocean. These vents release methane trapped inside the earth. Ms. Orphan says the organisms have changed to survive in this extreme environment.

加州理工学院的维多利亚·欧凡，研究大洋中靠近甲烷排气口的微生物，它们生活在海底的沉积物中。这些通风口释放的甲烷都困在地球内部。欧凡说：“微生物已经发生变化，来适应在这种极端环境下的生存。”

“These organisms would be able to extract energy from methane using sulfate found in sea water rather than oxygen. And as an end product, they would produce hydrogen sulfide, sort of that rotten egg smell. And also as another by-product, these organisms would produce carbonate, sort of like the pavement you see on the sidewalk.”

“在海中，这些微生物能够使用硫酸盐而不是氧气从甲烷中摄取能量，最终，它们会产生硫化氢，这有点像腐烂的鸡蛋的味道。而且还有另一种副产品，这些微生物会产生碳酸盐，这种物质有点像人行道上铺的石板地面。”

Over time, that calcium carbonate forms tall, rocky seamounts around the methane vents. Victoria Orphan suspected that these rocky areas served as a shelter for sea life. So she found a submersible -- a small vehicle like a submarine -- and went down 800 meters to the sea floor to prove it.

随着时间的推移，碳酸钙越积越高，在甲烷排气口周围就有岩石堆积。维多利亚·欧凡怀疑这些岩石区就是海洋生物的庇护所。她找到一种潜水器——有点像潜水艇的小型工具——能够潜到海底800米的地方来证明这一说法。

Ms. Orphan made four such trips between 2006 and 2011. As part of her studies, she collected sediments and seamount particles from the near-freezing water. She says the rocks she collected confirmed her theory.

2006年到2011年期间，欧凡进行了四次航行研究。作为研究的一部分，她收集了一些沉积物的样本和靠近结冰水域的海底山岩的颗粒样本。她说收集的岩石样本证实了她的理论。

“These are not just simply end products of methane oxidation, but they actually maintain a viable community of microorganisms living inside the pore spaces of the rock that turns out are still capable of consuming methane.”

“这些只是甲烷氧化的一些产物，但是在岩石的空隙中确实包含一些存活的微生物，而它们确实能够消耗甲烷。”

However, her research showed the seamount microbes attacked the gas at a slower rate than the methane-eating organisms in the sediment. That is because not as much methane reaches the small holes in the rock.

然而，她的研究表明海底岩石中的微生物消耗气体的比例，比海底沉积物里微生物消耗甲烷的比例要低。那是因为不是所有的甲烷都能到达岩石里的小孔洞中。

“But considering that the volume of rock that’s available to colonize down in these deep-sea environments, it still can be a significant potential source of methane consumption. So instead of just considering this a process that is going on in sediments, we now have this whole other expansive habitat to look at as a sink for methane over time.”

“但是考虑到岩石的体积，可以让这些微生物在深海环境中生存下来，这仍然可能成为消耗甲烷的潜在场所。因此，除了考虑沉积物中的微生物会消耗甲烷，现在还有更多大范围的栖息地来研究，随着时间的推移，它们也能成为甲烷的储藏地。”

The journal Nature Communications published her findings. She says the large number of small organisms – both in the sediment and in rock – explain show the microbes can limit the amount of methane in the world’s oceans. As a result, the gas has trouble reaching the atmosphere. And she notes that the worms, crabs and other creatures living around the rocks eating the microbes may show evidence of an ecosystem formerly unknown to scientists.

《自然通讯》的期刊上发表了她的研究发现。她说存在于沉积物和岩石中的大量的微生物，展示了微生物能够限制世界大洋中甲烷的数量。结果，这种气体就无法进入到大气中。她还指出：寄生虫、螃蟹还有其它生活在岩石周围的生物会吃掉微生物，而这也许为科学家了解先前未知的生态系统提供新的证据。

I’m Anne Ball.

我是安妮·贝尔。

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Words in this Story

gas – n. any substance that is not solid or liquid

byproduct – n. a secondary product made in the manufacture of somethingelse

atmosphere – n. the gases surrounding any star or planet

trap – v. to catch or be caught by being tricked; to be unable to move orescape

deep – adj. going far down; a long way from top to bottom