深邃黝暗的南極深海，向來被視為是生機渺茫的絕域。但根據科學家最新探索，南極深海其實擁有豐富生態，目前已發現七百多種前所未見的生物，等最後鑑定完成，新物種總數可能接近一千五百種。
執行「南極深海生物多樣性」專案的國際科學團隊，二○○二至二○○五年間從事了三次學術探險，在南極洲威得爾海及鄰近水域水深七七四公尺至六三四八公尺處，蒐集到五萬至十萬件生物標本，研究後成果驚人。
例如，他們發現六七四種等腳類動物，其中八成以上前所未見。另外還有一六○種看來像蛇的腹足類、雙殼類動物與七十六種海綿。這項研究成果發表在昨日出版的最新一期《自然》期刊。
論文主撰人、德國漢堡大學「動物學研究所暨動物學博物館」專家布蘭特表示，南極深海可能是全球海生物種的生命搖籃；目前科學界對海生物種的演化與其如何因應氣候與環境而調變，已有更進一步的了解。
參與研究的英國專家琳絲表示，南極深海區動物數量之多，推翻了科學界以往的認定，她自己都嚇了一跳。能找到這樣不尋常的海洋生命「藏寶窟」，科學界便邁出第一步。
琳絲表示，初步的去氧核醣核酸分析顯示，全球其它深海地區的生物可能都是由南極遷徙過去的。南極區之能成為深海生命的搖籃，原因在深水區與淺水區溫度相差不多。在南極，深水水溫約攝氏二度，淺水區將近攝氏零下一度。相形之下，赤道地區的海洋其深水水溫約攝氏四度，但海面溫度可達攝氏廿五度。
琳絲表示，在全球較溫暖區域的淺水區，動物必須克服巨大的溫度差異，才能移居到深水區；相形之下，在南極深、淺水區的溫差就小得多。
科學界在南極發現的新物種當中，有肉食性的海綿、貝類、長五公分的潮蟲等。最令布蘭特驚訝的是一種微小的變形蟲，牠似乎在水下六千公尺及淺水區都能存活，水壓差異如此之大，該變形蟲有能力適應，真是前所未料。
Scientists Discover New Life In Antarctic Deep Sea
Science Daily — Scientists have found hundreds of new marine creatures in the vast, dark deep-sea surrounding Antarctica. Carnivorous sponges, free-swimming worms, crustaceans, and molluscs living in the Weddell Sea provide new insights into the evolution of ocean life.
This carnivorous moonsnail lives in the Antarctic deep sea. It can detect food from a wide distance and will moved towards it. Polyps, covering its shell, use the moonsnail as transport to food sources. (Credit: Image courtesy of British Antarctic Survey)
Reporting this week in the journal Nature, scientists describe how creatures in the deeper parts of the Southern Ocean - the source for much of the deep water in the world ocean -- are likely to be related to animals living in both the adjacent shallower waters and in other parts of the deep ocean.
A key question for scientists is whether shallow water species colonised the deep ocean or vice versa. The research findings suggest the glacial cycle of advance and retreat of ice led to an intermingling of species that originated in shallow and deep water habitats.
Lead author Professor Angelika Brandt from the Zoological Institute and Zoological Museum, University Hamburg says,
"The Antarctic deep sea is potentially the cradle of life of the global marine species. Our research results challenge suggestions that the deep sea diversity in the Southern Ocean is poor. We now have a better understanding in the evolution of the marine species and how they can adapt to changes in climate and environments."
British Antarctic Survey (BAS) 英國南極勘查組位在南極的基地
Dr Katrin Linse, marine biologist from British Antarctic Survey, says,
"What was once thought to be a featureless abyss is in fact a dynamic, variable and biologically rich environment. Finding this extraordinary treasure trove of marine life is our first step to understanding the complex relationships between the deep ocean and distribution of marine life."
Three research expeditions, as part of the ANDEEP project (Antarctic benthic deep-sea biodiversity), onboard the German research ship Polarstern took place between 2002 and 2005. An international team from 14 research organisations investigated the seafloor landscape, its continental slope rise and changing water depths to build a picture of this little known region of the ocean. They found over 700 new species.
Note: This story has been adapted from a news release issued by British Antarctic Survey.
原始報導：
ScienceDaily：Scientists Discover New Life In Antarctic Deep Sea
原始論文：
"First insights into the biodiversity and biogeography of the Southern Ocean deep sea", Nature. 2007, 447, 307
摘要：http://www.nature.com/nature/journal/v447/n7142/abs/nature05827.html