Microbes flourish in deepest spot in world’s oceans: study 研究︰微生物在世界海洋最深處生機蓬勃

Wed, May 01, 2013 - Page 10

Microbes are thriving in surprising numbers at the deepest spot in the oceans, the 11,000-meter Mariana Trench in the Pacific, despite crushing pressures in sunless waters, scientists said.

Dead plants and fish were falling as food for microscopic bugs even to the little-known hadal depths, parts of the seabed deeper than 6,000m and named after Hades, the god of the underworld in Greek mythology, they said.

The presence of life in the trench also shows how the greenhouse gas carbon dioxide can eventually get buried in the depths in a natural process that slows climate change.

A Danish-led team of scientists, using a robot to take samples, found double the amount of bacteria and other microbes munching away on debris at the bottom of the Mariana Trench in the western Pacific than at a nearby site 6,000m deep.

“It’s surprising there was so much bacterial activity,” said Ronnie Glud, of the University of Southern Denmark. “Normally life gets scarcer the deeper you go. But when you go very deep, more things start happening again,” he said.

The finding backed up a theory that dead plants and fish falling onto the steep sides of the Mariana Trench often slide to the bottom to form a “hot spot” for microbes.

(Reuters)

科學家說,微生物在海洋最深處,也就是深達一萬一千米的太平洋馬里亞納海溝,儘管承受暗無天日海域的擠壓壓力,以驚人的數量蓬勃生長。

他們說,死亡的植物與魚類甚至落達鮮為人知的超深海層,做為只能透過顯微鏡才看得到的小蟲食物,該水域部分的海床深逾六千米,並以希臘神話的陰間神明「冥王哈帝斯」為名。

該海溝的生命蹤跡也顯示,溫室氣體二氧化碳是如何能自然地被埋藏於深淵中,以減緩氣候變遷。

一個丹麥科學家領軍的團隊,運用機器人採樣,發現在西太平洋馬里亞納海溝的底部,津津有味咀嚼生物殘骸的細菌與其他微生物的數量,比鄰近六千米深海的據點多出一倍。

「那裡有如此多細菌活動令人驚訝,」南丹麥大學科學家格魯德說。「一般越深入海洋,生物就越少,但當下探到極深之處,越多的生物開始再度發生,」他說。

這項發現支持一個理論︰落至馬里亞納海溝陡坡的死去植物與魚類,往往滑到底部形成微生物的「熱點」。

(路透/翻譯:魏國金)