Ice worm | |
---|---|
Mesenchytraeus solifugus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Annelida |
Clade: | Pleistoannelida |
Clade: | Sedentaria |
Class: | Clitellata |
Order: | Tubificida |
Family: | Enchytraeidae |
Genus: | Mesenchytraeus Eisen, 1878 [1] |
Type species | |
Mesenchytraeus primaevus Eisen, 1878 | |
Species | |
Ice worms (also written as ice-worms or iceworms, or also called glacial or glacier worms) are enchytraeid annelids of the genus Mesenchytraeus. The majority of the species in the genus are abundant in gravel beds or the banks of riverine habitats, [2] [3] but the best-known members of the genus are found in glacial ice. They include the only annelid worms known to spend their entire lives in glacial ice, [4] and some of the few metazoans to complete their entire life cycle at conditions below 0 °C (32 °F). [5]
They were discovered in a wide range of environments, which include level snowfields, steep avalanche cones, crevasse walls, glacial rivers and pools, and hard glacier ice. These organisms are unique in that they can simply move between tightly packed ice crystals. They utilize setae, which are small bristles found on the outside of their bodies, to grip the ice and pull themselves along.
The genus contains 77 species, including the North American glacier ice worm ( Mesenchytraeus solifugus ) and the Yosemite snow worm ( Mesenchytraeus gelidus ). [6] [7] [8]
Ice worms eat snow algae and bacteria. [9] They live at zero degrees Celsius (32 degrees Fahrenheit), but if temperatures dip even slightly below that, according to a Washington State University researcher, the worms die. [10]
In North America, the first ice worms species were discovered in 1887 in Alaska, on the Muir Glacier. These glacier ice worms can be found on glaciers in Alaska, Washington, Oregon and British Columbia. They have not been found in other glaciated regions of the world.[ citation needed ]
The specific name solifugus for the North American species, Mesenchytraeus solifugus , is Latin for "sun-avoiding," as ice worms retreat underneath the ice before dawn. Enzymes in ice worms have very low optimal temperatures, and can be denatured at even a few degrees above 0 °C (32 °F). When ice worms are exposed to temperatures as modest as 5 °C (41 °F), their membrane structures disassociate and fall apart (i.e., "melt") causing the worm itself to "liquefy." Ice worms are several centimeters long, and can be black, blue, or white. They come to the surface of the glaciers in the evening and morning. On Suiattle Glacier in the North Cascades, population counts indicated over 7 billion ice worms.[ citation needed ]
It is not known how ice worms tunnel through the ice. Some scientists believe they travel through microscopic fissures in ice sheets, while others believe they secrete some chemical which can melt ice by lowering its freezing point, like an antifreeze. They feed on snow algae. [9]
The genus contains 77 species. They are the following: [6] [7] [11]
Mesenchytraeus franzi is a junior synonym of Cognettia clarae . [6] Mesenchytraeus megachaetae Shen, Chen & Xie, 2011 has been renamed Mesenchytraeus gigachaetus Xie, 2012 due to the previous name being preoccupied by Mesenchytraeus megachaetae Bretscher, 1901, a junior synonym of Mesenchytraeus armatus. [7] [12]
The Holocene extinction, or Anthropocene extinction, is the ongoing extinction event caused by humans during the Holocene epoch. These extinctions span numerous families of plants and animals, including mammals, birds, reptiles, amphibians, fish, and invertebrates, and affecting not just terrestrial species but also large sectors of marine life. With widespread degradation of biodiversity hotspots, such as coral reefs and rainforests, as well as other areas, the vast majority of these extinctions are thought to be undocumented, as the species are undiscovered at the time of their extinction, which goes unrecorded. The current rate of extinction of species is estimated at 100 to 1,000 times higher than natural background extinction rates and is increasing. During the past 100–200 years, biodiversity loss and species extinction have accelerated, to the point that most conservation biologists now believe that human activity has either produced a period of mass extinction, or is on the cusp of doing so. As such, after the "Big Five" mass extinctions, the Holocene extinction event has also been referred to as the sixth mass extinction or sixth extinction; given the recent recognition of the Capitanian mass extinction, the term seventh mass extinction has also been proposed for the Holocene extinction event.
Mesenchytraeus solifugus, commonly called an ice worm, is a species of oligochaete worm that inhabits coastal glaciers in northwestern North America. M. solifugus is dark brown and grows to about 15 mm long and 0.5 mm wide. It has a high population density and is common in suitable habitat. It can only survive at temperatures of approximately –7 °C to 5 °C. The ice worm is studied for its ability to survive in low temperatures. It has heavy pigment, absorbing most colors; however, it burrows into the glacier to avoid strong sunlight.
Enchytraeidae is a family of microdrile oligochaetes. They resemble small earthworms and include both terrestrial species known as potworms that live in highly organic terrestrial environments, as well as some that are marine. The peculiar genus Mesenchytraeus is known as "ice worms", as they spend the majority of their lives within glaciers, only rising to the surface at certain points in the summer. Enchytraeidae also includes the Grindal worm, which is commercially bred as aquarium fish food.
Mary is a feminine given name, the English form of the name Maria, which was in turn a Latin form of the Greek name Μαρία, María or Μαριάμ, Mariam, found in the Septuagint and New Testament. The latter reflects the original Hebrew pronunciation of the name מרים, as attested by the Septuagint. The vowel "a" in a closed unaccented syllable later became "i", as seen in other names such as "Bil'am" (Balaam) and "Shimshon" (Samson).
Gustavus Augustus Eisen was a Swedish-American polymath. He became a member of California Academy of Sciences in 1874 and a Life Member in 1883. In 1893, he became the 'Curator of Archaeology, Ethnology, and Lower Animals' at the academy. He later changed titles to 'Curator of Marine Invertebrates'. In 1938, he was appointed as an 'Honorary Member', which is considered the highest honor from the academy.
2022 in sports describes the year's events in world sports. The main events for this year were the 2022 Winter Olympic Games in Beijing and the 2022 FIFA World Cup in Qatar.
The following scientific events occurred in 2022.
The following scientific events occurred in 2023.
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