生物谷報道：對于人類而言,，南極洲大部分的深海水域都還是一片“處女地”。不過,，德國科學(xué)家通過近幾年對南極附近的威德爾海（Weddell Sea,，南極洲的邊緣海）的3次探測，最終發(fā)現(xiàn)了從單細(xì)胞有孔微生物（foraminifera）到形狀奇特的蟹類等700余種新的生物,。新的發(fā)現(xiàn)不僅加深了科學(xué)家對于海洋生物進(jìn)化的理解,，而且有望打破之前關(guān)于極地生物多樣性的認(rèn)識。5月17日的《自然》雜志以封面文章的形式報道了這些發(fā)現(xiàn)和研究成果,。
領(lǐng)導(dǎo)此次研究的德國漢堡大學(xué)動物學(xué)家Angelika Brandt表示,，“我們在廣闊、黑暗的深海中發(fā)現(xiàn)了數(shù)百種新的海洋生物,。生活在威德爾海的食肉海綿,、自由游動的蠕蟲、甲殼類以及軟體動物加深了人類對于海洋生物進(jìn)化以及它們?nèi)绾芜m應(yīng)氣候和環(huán)境變化的理解,。”
2002年到2005年期間,，作為“南極深海底棲生物多樣性計劃”（Antarctic benthic deep-sea biodiversity，簡稱ANDEEP）的一部分,，德國“極地號”（Polarstern）考察船對于威德爾海域進(jìn)行了3次探測研究,。研究人員通過攝像機(jī)“捕獲”了這些生活在數(shù)千米深的南極海底世界的神奇生物。
新發(fā)現(xiàn)的大量物種對黑暗深海中物種的進(jìn)化和傳播研究意義重大,。比如,，一種在威德爾海1000米深處發(fā)現(xiàn)的有孔微生物Epistominella vitrea在相對較淺的麥克默多海峽（McMurdo Sound）水域也大量存在，這表明該物種很可能是經(jīng)過很長時間的冰河運動,，由淺水區(qū)逐漸移居到深海的,。同時，一些相對較大的甲殼類生物還保留著眼睛,，這顯然是一種進(jìn)化的軌跡,。
此外，科學(xué)家通過研究發(fā)現(xiàn),，一些有孔蟲類甚至與北冰洋的類似生物具有相同的遺傳基因,，這很可能意味著這些微小生物是“世界大同，四海一家”（cosmopolitanism）,，分布在全球任何可能的海域,。不過，對極地附近緯度水域的相關(guān)研究表明,，絕大多數(shù)最新發(fā)現(xiàn)的南極深海生物還是獨一無二的,。
此次的發(fā)現(xiàn)有可能推翻科學(xué)家之前關(guān)于極地生物多樣性的認(rèn)識,，即極地深海區(qū)域的生物多樣性會減少。Brandt表示,，“南極深?？赡苁堑厍蚝Ｑ笊锏?lsquo;搖籃’，它豐富的生物多樣性令我們震驚,，人類對極地深海確實還知之甚少,。”
原始出處：
Nature 447, 307-311 (17 May 2007) | doi:10.1038/nature05827; Received 13 September 2006; Accepted 10 April 2007
First insights into the biodiversity and biogeography of the Southern Ocean deep sea
Angelika Brandt1, Andrew J. Gooday2, Simone N. Brandão1, Saskia Brix1, Wiebke Brökeland1, Tomas Cedhagen3, Madhumita Choudhury1, Nils Cornelius2, Bruno Danis4, Ilse De Mesel5, Robert J. Diaz6, David C. Gillan7, Brigitte Ebbe8, John A. Howe9, Dorte Janussen10, Stefanie Kaiser1, Katrin Linse11, Marina Malyutina12, Jan Pawlowski13, Michael Raupach14 & Ann Vanreusel5
Zoological Museum Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
National Oceanography Centre, Southampton, European Way, Southampton SO14 3ZH, UK
Department of Marine Ecology, University of Åarhus, Finlandsgade 14, 8200 Århus N, Denmark
Royal Belgian Institute of Natural Sciences, 29 Rue Vautier, 1000 Brussels, Belgium
Biology Department, Marine Biology Section, Ghent University, Krijgslaan 281/S8, 9000 Ghent, Belgium
Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, Virginia 23062, USA
Marine Biology Laboratory, CP160/15, Université Libre de Bruxelles, 50 Avenue Roosevelt, 1050 Brussels, Belgium
Forschungsinstitut Senckenberg, DZMB-CeDAMar, c/o Forschungsmuseum König, Adenauerallee 160, 53113 Bonn, Germany
Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Dunbeg, Oban, Argyll PA37 1QA, UK
Forschungs und Naturmuseum Senckenberg, Senckenberganlage 25, 60325 Frankfurt am Main, Germany
British Antarctic Survey, Natural Environmental Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
Institute of Marine Biology, FEB RAS, Palchevskogo, 17, 690041 Vladivostok, Russia
Department of Zoology & Animal Biology, University of Geneva, 30 Quai Ernest Ansermet, CH 1211 Genève 4, Switzerland
Ruhr-Universität Bochum, Universitätstrasse 150, 44780 Bochum, Germany
Correspondence to: Angelika Brandt1 Correspondence and requests for materials should be addressed to A.B. (Email: [email protected]).
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Shallow marine benthic communities around Antarctica show high levels of endemism, gigantism, slow growth, longevity and late maturity, as well as adaptive radiations that have generated considerable biodiversity in some taxa1. The deeper parts of the Southern Ocean exhibit some unique environmental features, including a very deep continental shelf2 and a weakly stratified water column, and are the source for much of the deep water in the world ocean. These features suggest that deep-sea faunas around the Antarctic may be related both to adjacent shelf communities and to those in other oceans. Unlike shallow-water Antarctic benthic communities, however, little is known about life in this vast deep-sea region2, 3. Here, we report new data from recent sampling expeditions in the deep Weddell Sea and adjacent areas (748–6,348 m water depth) that reveal high levels of new biodiversity; for example, 674 isopods species, of which 585 were new to science. Bathymetric and biogeographic trends varied between taxa. In groups such as the isopods and polychaetes, slope assemblages included species that have invaded from the shelf. In other taxa, the shelf and slope assemblages were more distinct. Abyssal faunas tended to have stronger links to other oceans, particularly the Atlantic, but mainly in taxa with good dispersal capabilities, such as the Foraminifera. The isopods, ostracods and nematodes, which are poor dispersers, include many species currently known only from the Southern Ocean. Our findings challenge suggestions that deep-sea diversity is depressed in the Southern Ocean and provide a basis for exploring the evolutionary significance of the varied biogeographic patterns observed in this remote environment.
