{{Short description|Species of microcrustacean}} {{Use dmy dates|date=October 2024}} {{Speciesbox | genus = Daphnia | parent = Ctenodaphnia | species = studeri | authority = Rühe, 1914 | synonyms = *''Daphniopsis studeri'' }}
'''''Daphnia studeri''''' is a species of microcrustacean in the genus ''Daphnia''. ''D. studeri'' lives in oligotrophic freshwater and slightly brackish lakes in Antarctica and sub-Antarctic islands.
Adult ''Daphnia studeri'' are typically {{cvt|1.5|to|2.5|mm}}<ref name="laybourn-parry1992"/> and colorless or slightly pink.<ref name="sawstrom2009"/><ref name="jarvis1988"/>
== Taxonomy ==
''Daphnia studeri'' was originally described in the genus ''Daphniopsis'', but later morphological and DNA studies have placed it and the 9 other ''Daphniopsis'' species in the genus ''Daphnia'' and subgenus ''Ctenodaphnia''.<ref name="colbourne2006" /><ref name="adamowicz2009" />
== Distribution ==
''D. studeri'' lives in freshwater and slightly saline lakes in Antarctica and sub-Antarctic islands.<ref name="sawstrom2009" /><ref name="laybourn-parry1992" /> It is the only cladoceran in Antarctic lakes,<ref name="colbourne2006" /> but one of two microcrustaceans, alongside ''Acanthocyclops mirnyi''.<ref name="laybourn-parry1991" />
Other species in ''Daphnia'' mostly live in salt lakes, and it is likely ''D. studeri'' historically migrated from saltwater back to freshwater.<ref name="colbourne2006" />
Adult females remain active year-round, despite many Antarctic lakes being extremely oligotrophic and ice covered much of the year.<ref name="laybourn-parry1991" /><ref name="laybourn-parry1992" /> The overwintering females have large lipid reserves, which is thought to help them survive in the seasons of low productivity.<ref name="sawstrom2009" />
== Reproduction ==
In the ultra-oligotrophic lakes, including Lake Druzhby and Crooked Lake, ''D. studeri'' produces only one or two broods per year, with one to two eggs per brood. More eggs are produced in lakes which have been enriched by bird or seal feces, allowing for higher algae production.<ref name="sawstrom2009" /> There are no fish or other predators for ''D. studeri'', which allows it to sustain a population with so few offspring.<ref name="laybourn-parry1991" />
== Feeding ==
''D. studeri'' is a filter feeder, feeding primarily on algae, as well as bacteria when algae abundance is low.<ref name="sawstrom2009" /> It grazes mostly at night, accompanied by an upward nocturnal migration.<ref name="jarvis1988" />
== References == <references>
<ref name="laybourn-parry1992">{{Cite journal| doi = 10.1007/BF00237958| issn = 0722-4060| volume = 11| issue = 8| last1 = Laybourn-Parry| first1 = Johanna| last2 = Marchant| first2 = HarveyJ.| title = Daphniopsis studeri (Crustacea: Cladocera) in lakes of the Vestfold Hills, Antarctica| journal = Polar Biology| access-date = 2024-10-07| date = 1992| page = 631| bibcode = 1992PoBio..11..631L| url = http://link.springer.com/10.1007/BF00237958| url-access = subscription}}</ref>
<ref name="sawstrom2009">{{Cite journal| doi = 10.1007/s00300-009-0619-0| issn = 0722-4060| volume = 32| issue = 8| pages = 1195–1202| last1 = Säwström| first1 = Christin| last2 = Karlsson| first2 = Jan| last3 = Laybourn-Parry| first3 = Johanna| last4 = Granéli| first4 = Wilhelm| title = Zooplankton feeding on algae and bacteria under ice in Lake Druzhby, East Antarctica| journal = Polar Biology| access-date = 2024-10-07| date = 2009| bibcode = 2009PoBio..32.1195S| url = http://link.springer.com/10.1007/s00300-009-0619-0| url-access = subscription}}</ref>
<ref name="jarvis1988">{{Cite journal| doi = 10.1007/BF00014346| issn = 0018-8158| volume = 164| issue = 1| pages = 13–21| last = Jarvis| first = Andrew C.| title = Diel zooplankton community feeding activity and filtration rates of Pseudoboeckella volucris and Daphniopsis studeri on sub-antarctic Marion Island| journal = Hydrobiologia| access-date = 2024-10-07| date = 1988| bibcode = 1988HyBio.164...13J| url = http://link.springer.com/10.1007/BF00014346| url-access = subscription}}</ref>
<ref name="colbourne2006">{{Cite journal| doi = 10.1111/j.1095-8312.2006.00687.x| issn = 0024-4066| volume = 89| issue = 3| pages = 469–488| last1 = Colbourne| first1 = J. K.| last2 = Wilson| first2 = C. C.| last3 = Hebert| first3 = P. D. N.| title = The systematics of Australian ''Daphnia'' and ''Daphniopsis'' (Crustacea: Cladocera): a shared phylogenetic history transformed by habitat-specific rates of evolution: AUSTRALIAN ''DAPHNIA'' EVOLUTION| journal = Biological Journal of the Linnean Society| access-date = 2024-10-07| date = 2006| url = https://academic.oup.com/biolinnean/article-lookup/doi/10.1111/j.1095-8312.2006.00687.x}}</ref>
<ref name="adamowicz2009">{{Cite journal| doi = 10.1016/j.ympev.2008.11.026| issn = 1055-7903| volume = 50| issue = 3| pages = 423–436| last1 = Adamowicz| first1 = Sarah J.| last2 = Petrusek| first2 = Adam| last3 = Colbourne| first3 = John K.| last4 = Hebert| first4 = Paul D.N.| last5 = Witt| first5 = Jonathan D.S.| title = The scale of divergence: A phylogenetic appraisal of intercontinental allopatric speciation in a passively dispersed freshwater zooplankton genus| journal = Molecular Phylogenetics and Evolution| access-date = 2024-10-10| date = 2009| pmid = 19124080| bibcode = 2009MolPE..50..423A| url = https://linkinghub.elsevier.com/retrieve/pii/S1055790308005599| url-access = subscription}}</ref>
<ref name="laybourn-parry1991">{{Cite journal| doi = 10.1093/plankt/13.6.1137| issn = 0142-7873 | volume = 13| issue = 6| pages = 1137–1149| last1 = Laybourn-Parry| first1 = Johanna| last2 = Marchant| first2 = H.J.| last3 = Brown| first3 = P.| title = The plankton of a large oligotrophic freshwater Antarctic lake| journal = Journal of Plankton Research| access-date = 2024-10-07| date = 1991| url = https://academic.oup.com/plankt/article-lookup/doi/10.1093/plankt/13.6.1137| url-access = subscription}}</ref>
</references>
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Category:Cladocera Category:Crustaceans described in 1914 Category:Aquatic animals of Antarctica Category:Freshwater crustaceans