近日，日本科學(xué)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(zhì)中吸收營(yíng)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(guān)論文刊登在近期的美國(guó)《國(guó)家科學(xué)院院刊》（PNAS）網(wǎng)絡(luò)版上,。
日本海上保安廳日前說(shuō)，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(diào)查在2010年9月利用日本海洋研究開(kāi)發(fā)機(jī)構(gòu)的載人深潛器“深海6500號(hào)”實(shí)施。
這種雙殼貝是一種白瓜貝,，長(zhǎng)12至13厘米,，被認(rèn)為是一個(gè)新品種。附近海底分布著地球內(nèi)部地幔物質(zhì)形成的巖石,，白瓜貝就在巖石中噴出冷水的地點(diǎn)形成了大規(guī)模集群,。
在這個(gè)地點(diǎn),，地幔物質(zhì)形成的巖石與水發(fā)生反應(yīng)而變質(zhì)，白瓜貝以硫化氫為主要營(yíng)養(yǎng)來(lái)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(rèn)為不適合生命,，但近年來(lái)科學(xué)家已發(fā)現(xiàn)多種生物,。研究小組認(rèn)為，在馬里納亞海溝的其他地點(diǎn)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(cè)，約40億年前地球原始生命誕生的時(shí)候,，也以起源于地幔的物質(zhì)作為營(yíng)養(yǎng)來(lái)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.
