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Alvinellidae | |
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Paralvinella sulfincola | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Scorpaeniformes |
Family: | Alvinellidae Desbruyères & Laubier, 1986 |
Genera | |
Alvinella |
The Alvinellidae are a family of small, deep-sea polychaete worms endemic to hydrothermal vents in the Pacific Ocean. Belonging to the order Terebellida, the family contains two genera, Alvinella and Paralvinella; the former genus contains two valid species and the latter eight. Members of the family are termed alvinellids.
The family was first described in 1979 after discoveries made off the Galápagos Islands by the crew of the DSV Alvin . The ship subsequently lent its name to the family and genera within it.
The worms build mucus tubes and extend red feathery gills. Members of the Alvinellidae are noted for their exceptional heat tolerance: one species, the Pompeii worm (Alvinella pompejana), is thought to be the most heat-tolerant complex organism on Earth. Mitochondria start to break down at temperatures of 122–131 °F (50–55 °C), apparently providing an upper limit for eukaryotes. Under laboratory conditions, in a pressurized aquarium with a heat gradient, worms of the species Paralvinella sulfincola, chose water heated to 122 °F (50 °C) and made brief forays into water as hot as 131 °F (55 °C). [1] Unlike other (chemosynthetic) vent-dwelling worms, alvinellid worms possess a digestive tract. However, they do rely on an episymbiotic relationship with thermophilic bacteria; hair-like growths of the bacteria living on the worm's back are thought to offer thermal protection to the worm.
A genus is a taxonomic rank used in the biological classification of living and fossil organisms, as well as viruses, in biology. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus.
Siboglinidae is a family of polychaete annelid worms whose members made up the former phyla Pogonophora and Vestimentifera. They are composed of about 100 species of vermiform creatures and live in thin tubes buried in sediments (Pogonophora) or in tubes attached to hard substratum (Vestimentifera) at ocean depths from 100 to 10,000 m. They can also be found in association with hydrothermal vents, methane seeps, sunken plant material, or whale carcasses.
The Polychaeta, also known as the bristle worms or polychaetes, are a paraphyletic class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm and the sandworm or clam worm Alitta.
A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater that rises from the Earth's crust. While some of these springs contain water that is a safe temperature for bathing, others are hot enough that immersion can be harmful, i.e., lead to scalding and, potentially, a death.
A hydrothermal vent is a fissure on the seafloor from which geothermally heated water discharges. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart at spreading centers, ocean basins, and hotspots. Hydrothermal deposits are rocks and mineral ore deposits formed by the action of hydrothermal vents.
Alvinella pompejana, the Pompeii worm, is a species of deep-sea polychaete worm. It is an extremophile found only at hydrothermal vents in the Pacific Ocean, discovered in the early 1980s off the Galápagos Islands by French marine biologists.
Water heating is a heat transfer process that uses an energy source to heat water above its initial temperature. Typical domestic uses of hot water include cooking, cleaning, bathing, and space heating. In industry, hot water and water heated to steam have many uses.
Riftia pachyptila, commonly known as the giant tube worm, is a marine invertebrate in the phylum Annelida related to tube worms commonly found in the intertidal and pelagic zones. R. pachyptila lives on the floor of the Pacific Ocean near hydrothermal vents, and can tolerate extremely high hydrogen sulfide levels. These worms can reach a length of 3 m, and their tubular bodies have a diameter of 4 cm (1.6 in). Ambient temperature in their natural environment ranges from 2 to 30°C.
A hyperthermophile is an organism that thrives in extremely hot environments—from 60 °C upwards. An optimal temperature for the existence of hyperthermophiles is often above 80 °C. Hyperthermophiles are often within the domain Archaea, although some bacteria are able to tolerate temperatures of around 100 °C, as well. Some bacteria can live at temperatures higher than 100 °C at large depths in sea where water does not boil because of high pressure. Many hyperthermophiles are also able to withstand other environmental extremes such as high acidity or high radiation levels. Hyperthermophiles are a subset of extremophiles.
The Alicyclobacillaceae are a family of Gram-positive bacteria. All members of this family are aerobic and form endospores.
Paralvinella sulfincola, also known as the sulfide worm, is a species of polychaete worm of the Alvinellidae family that thrives on undersea hot-water vents. It dwells within tubes in waters surrounding hydrothermal vents, in close proximity to super-heated fluids reaching over 300 °C. The upper thermal limit for this polychaete is unknown; however, it is unlikely they can survive in constant temperatures over 50 °C. It may tentatively be named a metazoan extremophile or, more specifically, a thermophile.
The Class Gammaproteobacteria belongs to the Proteobacteria phylum and contains about 250 genera, which makes it the most genera-rich taxa of the Prokaryotes. Several medically, ecologically, and scientifically important groups of bacteria belong to this class. It is composed by all Gram-negative microbes and is the most phylogenetically and physiologically diverse class of Proteobacteria. The word Gammaproteobacteria comes from three Greek words: the Greek letter "gamma" (γ) meaning "changeable", the word proteakos (πρωτεϊκός) "little stick", and βακτήριον, that means "bacterium", so it means "changeable little stick bacterium". The name refers to Proteus, the Greek sea god who could change his shape. These microorganisms can live in several terrestrial and marine environments, in which they play various important roles, including extreme environments like the hydrothermal vents. They generally have different shapes, like rods, curved rods, cocci, spirilla, and filaments and include free living bacteria, biofilm formers, commensals and symbionts, some also have the distinctive trait of being bioluminescent. Metabolisms found in the different genera are very different; there are both aerobic and anaerobic species, chemolithoautotrophics, chemoorganotrophics, photoautotrophs and heterotrophs.
Terebellida make up an order of the Polychaeta class, commonly referred to as "bristle worms". Together with the Sabellida, the Spionida and some enigmatic families of unclear taxonomic relationship, they make up the subclass Canalipalpata, one of the three main clades of polychaetes. Like most polychaetes, almost all members of the Terebellida are marine organisms. Most are small, sessile detritivores which live in small tubes they build from mud or similar substrate, or burrow in the sand. Their central nervous system displays characteristic apomorphies.
An extreme environment is a habitat that is considered very hard to survive in due to its considerably extreme conditions such as temperature, accessibility to different energy sources or under high pressure. For an area to be considered an extreme environment, it must contain certain conditions and aspects that are considered very hard for other life forms to survive. Pressure conditions may be extremely high or low; high or low content of oxygen or carbon dioxide in the atmosphere; high levels of radiation, acidity, or alkalinity; absence of water; water containing a high concentration of salt or sugar; the presence of sulphur, petroleum, and other toxic substances.
Monera is a kingdom that contains unicellular organisms with a prokaryotic cell organization, such as bacteria. They are single-celled organisms with no true nuclear membrane.
Provannidae is a family of deep water sea snails, marine gastropod mollusks in the superfmaily Abyssochrysoidea.
Nautilia profundicola is a Gram-negative chemolithoautotrophic epsilonproteobacterium found around hydrothermal vents in the deep ocean. It was first discovered in 1999 on the East Pacific Rise at depth of 2,500 metres (8,200 ft), on the surface of the polychaete worm Alvinella pompejana. Nautilia profundicola lives symbiotically on the dorsal hairs of A. pompejana but they may also form biofilms and live independently on the walls of hydrothermal vents. The ability of N. profundicola to survive in an anaerobic environment rich in sulfur, H2 and CO2 of varying temperature makes it a useful organism to study, as these are the conditions that are theorized to have prevailed around the time of the earliest life on earth.
Sulfurimonas is a bacterial genus within the class of Epsilonproteobacteria, known for reducing nitrate, oxidizing both sulfur and hydrogen, and containing Group IV hydrogenases. This genus consists of four species: Sulfurimonas autorophica, Sulfurimonas denitrificans, Sulfurimonas gotlandica, and Sulfurimonas paralvinellae. The genus' name is derived from "sulfur" in Latin and "monas" from Greek, together meaning a “sulfur-oxidizing rod”. The size of the bacteria varies between about 1.5-2.5 μm in length and 0.5-1.0 μm in width. Members of the genus Sulfurimonas are found in a variety of different environments which include deep sea-vents, marine sediments, and terrestrial habitats. Their ability to survive in extreme conditions is attributed to multiple copies of one enzyme. Phylogenetic analysis suggests that members of the genus Sulfurimonas have limited dispersal ability and its speciation was affected by geographical isolation rather than hydrothermal composition. Deep ocean currents affect the dispersal of Sulfurimonas spp., influencing its speciation. As shown in the MLSA report of deep-sea hydrothermal vents Epsilonproteobacteria, Sulfurimonas has a higher dispersal capability compared with deep sea hydrothermal vent thermophiles, indicating allopatric speciation.
Microbial symbiosis in marine animals was not discovered until 1981. In the time following, symbiotic relationships between marine invertebrates and chemoautotrophic bacteria have been found in a variety of ecosystems, ranging from shallow coastal waters to deep-sea hydrothermal vents. Symbiosis is a way for marine organisms to find creative ways to survive in a very dynamic environment. They are different in relation to how dependent the organisms are on each other or how they are associated. It is also considered a selective force behind evolution in some scientific aspects. The symbiotic relationships of organisms has the ability to change behavior, morphology and metabolic pathways. With increased recognition and research, new terminology also arises, such as holobiont, which the relationship between a host and its symbionts as one grouping. Many scientists will look at the hologenome, which is the combined genetic information of the host and its symbionts. These terms are more commonly used to describe microbial symbionts.
The hydrothermal vent microbial community includes all unicellular organisms that live and reproduce in a chemically distinct area around hydrothermal vents. These include organisms in the microbial mat, free floating cells, or bacteria in an endosymbiotic relationship with animals. Chemolithoautotrophic bacteria derive nutrients and energy from the geological activity at Hydrothermal vents to fix carbon into organic forms. Viruses are also a part of the hydrothermal vent microbial community and their influence on the microbial ecology in these ecosystems is a burgeoning field of research.