Hydrothermal vent
Chemosynthetic bacteria and archaea found around hydrothermal vents form the base of the food chain, supporting diverse organisms including giant tube worms, clams, limpets, and shrimp.
The most northerly black smokers are a cluster of five named Loki's Castle,[19] discovered in 2008 by scientists from the University of Bergen at 73°N, on the Mid-Atlantic Ridge between Greenland and Norway.
[1] Black and white smokers may coexist in the same hydrothermal field, but they generally represent proximal (close) and distal (distant) vents to the main upflow zone, respectively.
[22] Once the plume is neutrally buoyant, it can no longer continue to rise through the water column and instead begins to spread laterally throughout the ocean, potentially over several thousands of kilometers.
This is because hydrothermal venting releases elevated concentrations of helium-3 relative to seawater, a rare, naturally occurring He isotope derived exclusively from the Earth's interior.
Hydrothermal vents emit a wide variety of trace metals into the ocean, including Fe, Mn, Cr, Cu, Zn, Co, Ni, Mo, Cd, V, and W,[26] many of which have biological functions.
Based on thermodynamic theory, Fe2+ and Mn2+ should oxidize in seawater to form insoluble metal (oxy)hydroxide precipitates; however, complexation with organic compounds and the formation of colloids and nanoparticles can keep these redox-sensitive elements suspended in solution far from the vent site.
[citation needed] The hydrothermal vents are recognized as a type of chemosynthetic based ecosystems (CBE) where primary productivity is fuelled by chemical compounds as energy sources instead of light (chemoautotrophy).
Larger organisms, such as snails, shrimp, crabs, tube worms, fish (especially eelpout, cutthroat eel, Ophidiiformes and Symphurus thermophilus), and octopuses (notably Vulcanoctopus hydrothermalis), form a food chain of predator and prey relationships above the primary consumers.
[citation needed] Siboglinid tube worms, which may grow to over 2 m (6.6 ft) tall in the largest species, often form an important part of the community around a hydrothermal vent.
Sunlight is nonexistent, so many organisms, such as archaea and extremophiles, convert the heat, methane, and sulfur compounds provided by black smokers into energy through a process called chemosynthesis.
The Pompeii worm Alvinella pompejana, which is capable of withstanding temperatures up to 80 °C (176 °F), was found in the 1980s, and a scaly-foot gastropod Chrysomallon squamiferum in 2001 during an expedition to the Indian Ocean's Kairei hydrothermal vent field.
[citation needed] In the early stages of studying life at hydrothermal vents, there were differing theories regarding the mechanisms by which multicellular organisms were able to acquire nutrients from these environments, and how they were able to survive in such extreme conditions.
[citation needed] Experimental research and computer modeling indicate that the surfaces of mineral particles inside hydrothermal vents have similar catalytic properties to enzymes and are able to create simple organic molecules, such as methanol (CH3OH) and formic acid (HCO2H), out of the dissolved CO2 in the water.
This paradox encompasses the fact that water is both required for life and will, in abundance, hydrolyze organic molecules and prevent dehydration synthesis reactions necessary to chemical and biological evolution.
The counter argument relies, among other points, on what the author describes as the unlikelihood of the formation of machinery which produces energy from the pH gradients found in hydrothermal vents without/before the existence of genetic information.
[69] Another reason that the view of deep sea hydrothermal vents as an ideal environment for the origin of life remains controversial is the absence of wet-dry cycles and exposure to UV light, which promote the formation of membranous vesicles and synthesis of many biomolecules.
[82] The high concentration of potassium within most life forms could be readily explained that protocells might have evolved sodium-hydrogen antiporters to pump out Na+ as prebiotic lipid membranes are less permeable to Na+ than H+.
[85] At the beginning of his 1992 paper The Deep Hot Biosphere, Thomas Gold referred to ocean vents in support of his theory that the lower levels of the earth are rich in living biological material that finds its way to the surface.
In June 1976, scientists from the Scripps Institution of Oceanography obtained the first evidence for submarine hydrothermal vents along the Galápagos Rift, a spur of the East Pacific Rise, on the Pleiades II expedition, using the Deep-Tow seafloor imaging system.
Chemosynthetic ecosystems surrounding the Galápagos Rift submarine hydrothermal vents were first directly observed in 1977, when a group of marine geologists funded by the National Science Foundation returned to the Clambake sites.
Corliss and Tjeerd van Andel from Stanford University observed and sampled the vents and their ecosystem on February 17, 1977, while diving in the DSV Alvin, a research submersible operated by the Woods Hole Oceanographic Institution (WHOI).
[96] In 1979, a team of biologists led by J. Frederick Grassle, at the time at WHOI, returned to the same location to investigate the biological communities discovered two year earlier.
[97] Prior to dive operations, expedition member Robert Ballard located near-bottom water temperature anomalies using a deeply towed instrument package.
[114] The world's first "large-scale" mining of hydrothermal vent mineral deposits was carried out by Japan Oil, Gas and Metals National Corporation (JOGMEC) in August – September, 2017.
Nautilus Minerals, in partnership with Placer Dome (now part of Barrick Gold), succeeded in 2006 in returning over 10 metric tons of mined SMS to the surface using modified drum cutters mounted on an ROV, a world first.
[115] Neptune Minerals in 2007 succeeded in recovering SMS sediment samples using a modified oil industry suction pump mounted on an ROV, also a world first.
[118] Inevitably, through the operation of these machines, some level of noise will be created, which presents a problem for hydrothermal vent organisms because, as they are up to 12,000 feet below the surface of the ocean, they experience very little sound.
[118] A large amount of work is currently being engaged in by both of the above-mentioned companies to ensure that the potential environmental impacts of seafloor mining are well understood and control measures are implemented before exploitation commences.
Mining of manganese nodules served as a cover story for the elaborate attempt in 1974 by the CIA to raise the sunken Soviet submarine K-129 using the Glomar Explorer, a ship purpose-built for the task by Howard Hughes.
