Editing Ice worm (section)

{{Short description|Genus of annelid worms}}
{{for|methane ice worms|Hesiocaeca methanicola}}
{{for|US military project|Project Iceworm}}
{{Automatic taxobox
| image = Mesenchytraeus solifugus anterior.png
| image_caption = ''[[Mesenchytraeus solifugus]]''
| taxon = Mesenchytraeus
| authority = [[Gustav Eisen|Eisen]], 1878<ref>{{cite web |url=http://www.inhs.uiuc.edu/~mjwetzel/EnchytraeidaeNA.html |title=The aphanoneuran and clitellate Annelida occurring in the United States and Canada: families Enchytraeidae and Propappidae |author1=Kathryn A. Coates |author2=Jan M. Locke |author3=Brenda M. Healy |author4=Mark J. Wetzel |publisher=[[University of Illinois at Urbana-Champaign]] |accessdate=January 22, 2010 |date=August 26, 2008}}</ref>
| type_species =''[[Mesenchytraeus primaevus]]''
| type_species_authority = [[Gustav Eisen|Eisen]], 1878
| subdivision_ranks = Species
| subdivision = [[#Species|See text]]
}}

'''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 [[river]]ine habitats,<ref name="shain">{{cite book|author=Paula L. Hartzell & Daniel H. Shain|editor =Daniel H. Shain|title =Annelids in Modern Biology|chapter =Glacier Ice Worms|publisher =Wiley-Blackwell|year =2009|page=305|isbn =9780470455197|chapter-url =https://books.google.com/books?id=9HTIa_JMS1UC&pg=PA305}}</ref><ref name="healy">{{cite journal|author=Brenda Healy & Steve Fend |year=2002|title=The occurrence of ''Mesenchytraeus'' (Enchytraeidae: Oligochaeta) in riffle habitats of north-west Subnautica below zero rivers, with description of a new species|journal=Journal of Natural History|volume=36|issue=1|pages=15&ndash;23|doi=10.1080/713833842|s2cid=84290342}}</ref> but the best-known members of the genus are found in [[glacier|glacial]] ice. They include the only annelid worms known to spend their entire lives in [[glacier|glacial]] ice,<ref>{{cite journal|doi=10.1002/1097-4687(200012)246:3<192::AID-JMOR3>3.0.CO;2-B|title=Morphologic characterization of the ice worm ''Mesenchytraeus solifugus''|year=2000|last1=Shain|first1=Daniel H.|last2=Carter|first2=Melissa R.|last3=Murray|first3=Kurt P.|last4=Maleski|first4=Karen A.|last5=Smith|first5=Nancy R.|last6=McBride|first6=Taresha R.|last7=Michalewicz|first7=Lisa A.|last8=Saidel|first8=William M.|journal=Journal of Morphology|volume=246|issue=3|pages=192–7|pmid=11077431 |s2cid=30143253 }}</ref> and some of the few [[metazoan]]s to complete their entire life cycle at conditions below {{convert|0|C|F}}.<ref name="farrell">{{cite journal|author=A.H. Farrell, K.A.Hohenstein, & D.H. Shain|year=2004|title=Molecular adaptation in the ice worm, ''Mesenchytraeus solifugus'': divergence of energetic-associated genes.|journal=Journal of Molecular Evolution|volume=59|issue=5|pages=666&ndash;673|doi= 10.1007/s00239-004-2658-z|pmid=15693622|bibcode=2004JMolE..59..666F|s2cid=22139929}}</ref>

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.

[[File:Ice Worm against Fingernail.jpg|thumb|Unknown species of ice worm]]

The genus contains 77 [[species]], including the North American glacier ice worm (''[[Mesenchytraeus solifugus]]'') and the Yosemite snow worm (''[[Mesenchytraeus gelidus]]'').<ref name="schmelz">{{cite journal|author=Rüdiger M. Schmelz & Rut Collado|year=2012|title=An updated checklist of currently accepted species of Enchytraeidae (Oligochaeta, Annelida)|journal=VTI Agriculture and Forestry Research |volume=357|pages=67&ndash;87|url=https://www.researchgate.net/publication/275099637}}</ref><ref name="schmelz2">{{cite journal|author=Rüdiger M. Schmelz & Rut Collado|year=2015|title=Checklist of taxa of Enchytraeidae (Oligochaeta): an update|journal=Soil Organisms|volume=87|issue=2|pages=149&ndash;152|url=http://www.senckenberg.de/files/content/forschung/publikationen/soilorganisms/volume_87_2/7_87-2-08.pdf|access-date=2017-01-23|archive-url=https://web.archive.org/web/20161220045625/http://www.senckenberg.de/files/content/forschung/publikationen/soilorganisms/volume_87_2/7_87-2-08.pdf|archive-date=2016-12-20|url-status=dead}}</ref><ref name="shen">{{cite journal|author=Qi Shen, Jing Chen, & Zhicai Xie|year=2012|title=''Mesenchytraeus monodiverticulus'' sp. nov. (Annelida: Cliterllata: Enchytraeidae) from Changbai Mountain, with a key to ''Mesenchytraeus'' with enlarged chaetae|journal=Proceedings of the Biological Society of Washington|volume=125|issue=3|pages=215&ndash;227|doi=10.2988/12-08.1|s2cid=84234028}}</ref>

Ice worms eat [[snow algae]] and bacteria.<ref name="nichols">{{cite web |title=Ice Worms (''Mesenchytraeus solifugus'') and Their Habitats on North Cascade Glaciers-North Cascade Glacier Climate Project |url=http://www.nichols.edu/departments/glacier/iceworm.htm |website=North Cascade Glacier Climate Project |access-date=17 July 2021 |date=November 6, 2008|archive-url=https://web.archive.org/web/20090209012557/http://www.nichols.edu/departments/glacier/iceworm.htm |archive-date=2009-02-09 }}</ref> The specimens researched by Scott Hotaling, researcher at [[Washington State University]], live at zero degrees Celsius (32 degrees Fahrenheit) and die if temperatures dip even slightly below that.<ref>{{cite news |last1=Greenfieldboyce |first1=Nell |title=It's Summer, And That Means The Mysterious Return Of Glacier Ice Worms |url=https://www.npr.org/2021/07/13/1011376403/its-summer-and-that-means-the-mysterious-return-of-glacier-ice-worms |access-date=17 July 2021 |work=NPR |date=July 13, 2021}}</ref>