An endosymbiont or endobiont is an organism that lives within the body or cells of another organism. Typically the two organisms are in a mutualistic relationship. Examples are nitrogen-fixing bacteria, which live in the root nodules of legumes, single-cell algae inside reef-building corals, and bacterial endosymbionts that provide essential nutrients to insects.
Symbiosis is any type of a close and long-term biological interaction, between two organisms of different species. The two organisms, termed symbionts, can be either in a mutualistic, a commensalistic, or a parasitic relationship. In 1879, Heinrich Anton de Bary defined symbiosis as "the living together of unlike organisms".
Siboglinidae is a family of polychaete annelid worms whose members made up the former phyla Pogonophora and Vestimentifera. The family is composed of around 100 species of vermiform creatures which live in thin tubes buried in sediment (Pogonophora) or in tubes attached to hard substratum (Vestimentifera) at ocean depths ranging from 100 to 10,000 m. They can also be found in association with hydrothermal vents, methane seeps, sunken plant material, and whale carcasses.
Any worm that lives in a marine environment is considered a water worm. Marine worms are found in several different phyla, including the Platyhelminthes, Nematoda, Annelida, Chaetognatha, Hemichordata, and Phoronida. For a list of marine animals that have been called "sea worms", see sea worm.
Hydrothermal vents are fissures on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hotspots. The dispersal of hydrothermal fluids throughout the global ocean at active vent sites creates hydrothermal plumes. Hydrothermal deposits are rocks and mineral ore deposits formed by the action of hydrothermal vents.
A cold seep is an area of the ocean floor where seepage of fluids rich in hydrogen sulfide, methane, and other hydrocarbons occurs, often in the form of a brine pool. Cold does not mean that the temperature of the seepage is lower than that of the surrounding sea water; on the contrary, its temperature is often slightly higher. The "cold" is relative to the very warm conditions of a hydrothermal vent. Cold seeps constitute a biome supporting several endemic species.
Riftia pachyptila, commonly known as the giant tube worm and less commonly known as the giant beardworm, 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. The vents provide a natural ambient temperature in their environment ranging from 2 to 30 °C, and this organism 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).
Osedax is a genus of deep-sea siboglinid polychaetes, commonly called boneworms, zombie worms, or bone-eating worms. Osedax is Latin for "bone-eater". The name alludes to how the worms bore into the bones of whale carcasses to reach enclosed lipids, on which they rely for sustenance. They utilize specialized root tissues for bone-boring. It is possible that multiple species of Osedax reside in the same bone. Osedax worms are also known to feed on the collagen itself by making holes in the whale's skeletal structure. These holes can also serve as a form of protection from nearby predators.
Symbiotic bacteria are bacteria living in symbiosis with another organism or each other. For example, rhizobia living in root nodules of legumes provide nitrogen fixing activity for these plants.
Horizontal transmission is the transmission of organisms between biotic and/or abiotic members of an ecosystem that are not in a parent-progeny relationship. Because the evolutionary fate of the agent is not tied to reproductive success of the host, horizontal transmission tends to evolve virulence. It is therefore a critical concept for evolutionary medicine.
Lamellibrachia is a genus of tube worms related to the giant tube worm, Riftia pachyptila. They live at deep-sea cold seeps where hydrocarbons leak out of the seafloor, and are entirely reliant on internal, sulfide-oxidizing bacterial symbionts for their nutrition. The symbionts, gammaproteobacteria, require sulfide and inorganic carbon. The tube worms extract dissolved oxygen and hydrogen sulfide from the sea water with the crown of plumes. Species living near seeps can also obtain sulfide through their "roots", posterior extensions of their body and tube. Several sorts of hemoglobin are present in the blood and coelomic fluid to bind to the different components and transport them to the symbionts.
A tubeworm is any worm-like sessile invertebrate that anchors its tail to an underwater surface and secretes around its body a mineral tube, into which it can withdraw its entire body.
Lamellibrachia luymesi is a species of tube worms in the family Siboglinidae. It lives at deep-sea cold seeps where hydrocarbons are leaking out of the seafloor. It is entirely reliant on internal, sulfide-oxidizing bacterial symbionts for its nutrition. These are located in a centrally located "trophosome".
A trophosome is a highly vascularised organ found in some animals that houses symbiotic bacteria that provide food for their host. Trophosomes are contained by the coelom of tube worms and in the body of symbiotic flatworms of the genus Paracatenula.
Gigantopelta chessoia is a species of deep sea snail from hydrothermal vents, a marine gastropod mollusk in the family Peltospiridae.
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.
Tevnia is a genus of giant tube worm in the family Siboglinidae, with only one species, Tevnia jerichonana, living in a unique deep-sea environment. These deep sea marine species survive in environments like hydrothermal vents. These vents give off gas and toxic chemicals with the addition of having superheated temperatures. The giant tube worm prefers environments such as these despite the harsh temperature and toxic sea water.
Hydrogen sulfide chemosynthesis is a form of chemosynthesis which uses hydrogen sulfide. It is common in hydrothermal vent microbial communities Due to the lack of light in these environments this is predominant over photosynthesis
Lamellibrachia satsuma is a vestimentiferan tube worm that was discovered near a hydrothermal vent in Kagoshima Bay, Kagoshima at the depth of only 82 m (269 ft) the shallowest depth record for a vestimentiferan. Its symbiotic sulfur oxidizer bacteria have been characterised as ε-Proteobacteria and γ-Proteobacteria. Subspecies have been later found associated with cold seeps at Hatsushima in Sagami Bay and at the Daini Tenryu Knoll in the Nankai Trough with specimens obtained at up to 1,170 m (3,840 ft) depth.
Frenulata, "beard worms", is a clade of Siboglinidae, "tube worms". They are one of four lineages with numerous species. They may be the most basal clade in the family. Despite being the first tube worms to be encountered and described, they remain the least studied group. This is because of their slender shape, they often get destroyed as a result of being caught as bycatch or poor preservation. They are found primarily in deep, muddy sediments, cold seeps, and anoxic firth sediments.
