VOA慢速英語(yǔ): 深海巖中的微生物“吃”甲烷（雙語(yǔ)）

Small Organisms in Deep Sea Rocks Eat Methane

深海巖中的微生物“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.

氣體甲烷已經(jīng)與地球上上升的氣溫聯(lián)系在一起了，但是只要另一種“溫室氣體”——二氧化碳存在，甲烷就不會(huì)在大氣中?？茖W(xué)家說(shuō)這兩種氣體都能收集自太陽(yáng)光的熱量，都能夠阻止熱量散到外太空。

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.

甲烷可以來(lái)自濕地，是農(nóng)場(chǎng)飼養(yǎng)牲畜的副產(chǎn)品，以及人類活動(dòng)也會(huì)產(chǎn)生甲烷，比如：天然氣系統(tǒng)的泄露。海洋里也存在有大量的甲烷，冰川中也存在甲烷，在地球深處，通過(guò)海底細(xì)小的裂縫、孔洞，甲烷氣體不斷上升。

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氣中，這得感謝生活在海底沉積物中的以甲烷為生的微生物。現(xiàn)在，美國(guó)的科學(xué)家說(shuō)其它深海的微生物也會(huì)消耗甲烷。這些微生物生活在意想不到的地方——在海底的巖石里面。

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.

加州理工學(xué)院的維多利亞·歐凡，研究大洋中靠近甲烷排氣口的微生物，它們生活在海底的沉積物中。這些通風(fēng)口釋放的甲烷都困在地球內(nèi)部。歐凡說(shuō)：“微生物已經(jīng)發(fā)生變化，來(lái)適應(yīng)在這種極端環(huán)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，這些微生物能夠使用硫酸鹽而不是氧氣從甲烷中攝取能量，最終，它們會(huì)產(chǎn)生硫化氫，這有點(diǎn)像腐爛的雞蛋的味道。而且還有另一種副產(chǎn)品，這些微生物會(huì)產(chǎn)生碳酸鹽，這種物質(zhì)有點(diǎn)像人行道上鋪的石板地面。”

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.

隨著時(shí)間的推移，碳酸鈣越積越高，在甲烷排氣口周圍就有巖石堆積。維多利亞·歐凡懷疑這些巖石區(qū)就是海洋生物的庇護(hù)所。她找到一種潛水器——有點(diǎn)像潛水艇的小型工具——能夠潛到海底800米的地方來(lái)證明這一說(shuō)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年期間，歐凡進(jìn)行了四次航行研究。作為研究的一部分，她收集了一些沉積物的樣本和靠近結(jié)冰水域的海底山巖的顆粒樣本。她說(shuō)收集的巖石樣本證實(shí)了她的理論。

“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.”

“這些只是甲烷氧化的一些產(chǎn)物，但是在巖石的空隙中確實(shí)包含一些存活的微生物，而它們確實(shí)能夠消耗甲烷。”

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，她的研究表明海底巖石中的微生物消耗氣體的比例，比海底沉積物里微生物消耗甲烷的比例要低。那是因?yàn)椴皇撬械募淄槎寄艿竭_(dá)巖石里的小孔洞中。

“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.”

“但是考慮到巖石的體積，可以讓這些微生物在深海環(huán)境中生存下來(lái)，這仍然可能成為消耗甲烷的潛在場(chǎng)所。因此，除了考慮沉積物中的微生物會(huì)消耗甲烷，現(xiàn)在還有更多大范圍的棲息地來(lái)研究，隨著時(shí)間的推移，它們也能成為甲烷的儲(chǔ)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.

《自然通訊》的期刊上發(fā)表了她的研究發(fā)現(xiàn)。她說(shuō)存在于沉積物和巖石中的大量的微生物，展示了微生物能夠限制世界大洋中甲烷的數(shù)量。結(jié)果，這種氣體就無(wú)法進(jìn)入到大氣中。她還指出：寄生蟲(chóng)、螃蟹還有其它生活在巖石周圍的生物會(huì)吃掉微生物，而這也許為科學(xué)家了解先前未知的生態(tài)系統(tǒng)提供新的證據(jù)。

I’m Anne Ball.

我是安妮·貝爾。

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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