The Mariana Trench is located in the Western Pacific, to the east of the Philippines and to the south of Japan. It is formed by the subduction of the Pacific Plate under the smaller Mariana Plate, and contains the deepest point in Earth's oceans, the Challenger Deep, at 10.91 km bellow sea level.
A diagrammatic cross section through the Mariana Trench. From Wikipedia.
The 9 February 2012 edition of the Proceedings of the National Academy of Sciences contains a paper by a team of scientists lead by Yasuhiko Ohara of the Hydrographic and Oceanographic Department of Japan and the Japan Agency for Marine-Earth Science and Technology, detailing the discovery of a hydrothermal vent community in the southern part of the Mariana Trench, about 80 km northeast of the Challenger Deep, at a depth of 5550-5861 m. The discovery was made during a study of the trench by the Japanese research ship R/V Yokosuka and was found by the diving vehicle DSV Shinkai 6500; the site has been named the Shinkai Seep Field.
Map of the Mariana Trench showing the location of the Shinkai Seep Field (SSF). WSRBF stands for TheWest Santa Rosa Bank Fault. Colours represent sea-floor depth, see key at top of map. From Ohara et al. (2012).
The research team did not have the means to collect water samples from the sight, as they were visiting it to study the geology of the area, and had not expected to find hydrothermal vent communities, but they note that the site was located on serpentinized peridotite, so by comparison with other sites conclude that the vents are probably emitting water at between 40 °C and 90 °C that is rich in hydrogen (H₂) and Methane (CH₄), but poor in metal compounds. Methane is easily oxidized to Hydrogen Sulphide (H₂S), which can provide an energy source for sulphur-bacteria, likely to form the base of the food chain at the vents.
Photographs from the Shinkai Seeps. (A) Vesycomyid clams on a serpentinized peridotite outcrop. (B) Clam community at 5622 m. (C) Serpentinized peridote outcrop, with aragonite intrusions. (D) Clam community, also showing zoanthid corals (Zo) and Beroe, a type of comb jelly. (E) Clam community, also showing zoanthid corals (Zo), an actiniarian sea anemone (Ac) and a galatheid crab (GC). From Ohara et al. (2012).
The communities were dominated by vesycomyid clams of the genus Abyssogena, which are known to host chemotropic symbiotic bacteria. In addition corals, sea anemones, comb jellies, gastropods (snails) and crabs were witnessed at the Seeps. Samples of the clams were gathered for DNA analysis, which showed them to be most closely related to vesycomyid clams from the Caribbean. This is not a total surprise, as the Caribbean Plate is know to have migrated eastwards from the Pacific (Central America is a very young landmass in geological terms), and benthic organisms in the Caribbean have been demonstrated to have close affinities with Pacific organisms before.
A vesycomyid clam from the Shinkai Seep Field. From Ohara et al. (2012).
Bonde la Mariana liko katika Pasifiki ya Magharibi, mashariki mwa Ufilipino na kusini mwa Japani. Mto huo umefanyizwa na subduction ya sahani ya Pasifiki chini ya sahani ndogo ya Mariana, na ina sehemu ya kina zaidi katika bahari za Dunia, Challenger Deep, katika 10.91 km chini ya usawa wa bahari. Mchoro wa sehemu ya msalaba kupitia Bonde la Mariana. Kutoka Wikipedia. "Kama ilivyoelezwa katika toleo la Februari 9, 2012 la Proceedings of the National Academy of Sciences, utafiti uliofanywa na Yasuhiko Ohara, Mtaalamu wa Utafiti wa Bahari na Bahari wa Japani, na Shirika la Japani la Sayansi ya Bahari na Sayansi ya Teknolojia, unaelezea ""ukumbusho wa jamii ya chemchemi ya maji katika sehemu ya kusini ya Mariana Trench, karibu kilomita 80 kaskazini mashariki mwa Challenger, katika kina cha mita 5550-586.""" Ramani ya Mariana Trench kuonyesha eneo la Shinkai Seep Field (SSF). WSRBF inasimama kwa TheWest Santa Rosa Bank Fault. Rangi zinawakilisha kina cha sakafu ya bahari, angalia ufunguo juu ya ramani. Kutoka Ohara et al. (2012). Watafiti hawajaweza kukusanya sampuli za maji kutoka kwa eneo hilo, kwani walikuwa wakitembelea eneo hilo kusoma jiolojia ya eneo hilo, na hawakufikiria kupata jamii za chemchemi za maji, lakini wanasema eneo hilo lilikuwa kwenye peridotiti ya serpentini, kwa hivyo kwa kulinganisha na maeneo mengine, wanakubali kwamba chemchemi hizo zinaweza kutoa maji ya kati ya 40 ° C na 90 ° C ambayo ni tajiri katika hidrojeni (H2) na methani (CH4). Methane huondolewa kwa urahisi kuwa hidrojeni sulfidi (H2S), ambayo inaweza kutoa chanzo cha nishati kwa bakteria za sulfuri, ambazo zinaweza kuunda msingi wa mlolongo wa chakula kwenye vents. Picha kutoka kwa Shinkai Seeps. (A) Vesycomyid clams juu ya serpentinized peridotite outcrop. (B) Jamii ya Clam katika 5622 m. (C) Serpentinized peridote outcrop, na aragonite intrusions. (D) Jamii ya Clam, pia inaonyesha matumbawe ya zoanthid (Zo) na Beroe, aina ya jelly ya comb. Mnyama wa aina ya Clam, na pia huonyesha corals zoanthid (Zo), actinarian anemone ya bahari (Ac) na galatheid crab (GC). Kutoka Ohara et al. (2012). Jamii hizo zilikuwa zimetawaliwa na vipepeo wa aina ya vesycomyid wa jamii ya Abyssogena, ambao wanajulikana kuwa wenyeji wa bakteria za kimetropiki zenye ushirikiano. Kwa kuongezea, matumbawe, anemoni za baharini, jellycombs, gastropods (sneaks) na crabs zilionekana katika Seeps. Kwa mfano, samaki hao walichukuliwa kwa ajili ya kuchunguzwa kwa DNA, na hivyo kuonekana kuwa na uhusiano wa karibu sana na samaki aina ya vesicomyid wa Karibea. Hii si mshangao kamili, kama Caribbean Plate inajulikana kuwa kuhamia mashariki kutoka Pasifiki (Amerika ya Kati ni landmass mchanga sana katika suala la kijiolojia), na viumbe benthic katika Karibea wameonyeshwa kuwa na uhusiano wa karibu na viumbe Pasifiki kabla. Mnyama anayeitwa vesycomyid kutoka kwenye Shamba la Shinkai Seep. Kutoka Ohara et al. (2012).