近日，日本科學家在世界上最深的馬里亞納海溝查林杰海淵附近發(fā)現(xiàn)一種靠從地幔物質中吸收營養(yǎng)的雙殼貝,，這有望成為探索地球上生命誕生之謎的線索,。相關論文刊登在近期的美國《國家科學院院刊》（PNAS）網(wǎng)絡版上。
日本海上保安廳日前說,，其研究小組是在距查林杰海淵80公里處,、約5620米深的海底發(fā)現(xiàn)這些貝類的。這次調查在2010年9月利用日本海洋研究開發(fā)機構的載人深潛器“深海6500號”實施,。
這種雙殼貝是一種白瓜貝,，長12至13厘米，被認為是一個新品種,。附近海底分布著地球內(nèi)部地幔物質形成的巖石,，白瓜貝就在巖石中噴出冷水的地點形成了大規(guī)模集群。
在這個地點,，地幔物質形成的巖石與水發(fā)生反應而變質,，白瓜貝以硫化氫為主要營養(yǎng)來源維持生命，這是世界上首次發(fā)現(xiàn)白瓜貝以這種方式生存,。馬里亞納海溝的海底壓力巨大而寒冷,，曾被認為不適合生命，但近年來科學家已發(fā)現(xiàn)多種生物,。研究小組認為,，在馬里納亞海溝的其他地點和環(huán)境類似的湯加海溝，也有可能有同樣的白瓜貝集群,。
據(jù)推測,，約40億年前地球原始生命誕生的時候，也以起源于地幔的物質作為營養(yǎng)來源,，所以此次發(fā)現(xiàn)將有助于探索地球生命誕生之謎,。（生物谷Bioon.com）
doi:10.1073/pnas.1112005109
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A serpentinite-hosted ecosystem in the Southern Mariana Forearc
Ohara, Yasuhiko; Reagan, Mark K.; Fujikura, Katsunori; Watanabe, Hiromi; Michibayashi, Katsuyoshi; Ishii, Teruaki; Stern, Robert J.; Pujana, Ignacio; Martinez, Fernando; Girard, Guillaume; Ribeiro, Julia; Brounce, Maryjo; Komori, Naoaki; Kino, Masashi
Several varieties of seafloor hydrothermal vents with widely varying fluid compositions and temperatures and vent communities occur in different tectonic settings. The discovery of the Lost City hydrothermal field in the Mid-Atlantic Ridge has stimulated interest in the role of serpentinization of peridotite in generating H2- and CH4-rich fluids and associated carbonate chimneys, as well as in the biological communities supported in highly reduced, alkaline environments. Abundant vesicomyid clam communities associated with a serpentinite-hosted hydrothermal vent system in the southern Mariana forearc were discovered during a DSV Shinkai 6500 dive in September 2010. We named this system the “Shinkai Seep Field (SSF).” The SSF appears to be a serpentinite-hosted ecosystem within a forearc (convergent margin) setting that is supported by fault-controlled fluid pathways connected to the decollement of the subducting slab. The discovery of the SSF supports the prediction that serpentinite-hosted vents may be widespread on the ocean floor. The discovery further indicates that these serpentinite-hosted low-temperature fluid vents can sustain high-biomass communities and has implications for the chemical budget of the oceans and the distribution of abyssal chemosynthetic life.
