Editing Lake Baikal (section)

==Ecology==
[[File:Baikal-seal 4747-pho.jpg|thumb|The [[Baikal seal]] is [[Endemism|endemic]] to Lake Baikal.]]
Lake Baikal is rich in [[biodiversity]]. It hosts more than 1,000 species of plants and 2,500 species of animals based on current knowledge, but the actual figures for both groups are believed to be significantly higher.<ref name="FEOW" />

===Flora===
The watershed of Lake Baikal has numerous floral species represented. The [[marsh thistle]] (''Cirsium palustre'') is found here at the eastern limit of its geographic range.<ref>C. Michael Hogan. 2009. [http://www.globaltwitcher.com/artspec_information.asp?thingid=48639 ''Marsh Thistle: Cirsium palustre'', GlobalTwitcher.com, ed. N. Strömberg] {{webarchive|url=https://web.archive.org/web/20121213144520/http://www.globaltwitcher.com/artspec_information.asp?thingid=48639 |date=13 December 2012 }}</ref>

Submerged macrophytic [[vascular plant]]s are mostly absent, except in some shallow bays along the shores of Lake Baikal.<ref name="Shahgedanova2002">{{cite book|author1=Mackay, A. |author2=R. Flower |author3=L. Granina | chapter=Lake Baikal | editor=Shahgedanova, M. | year=2002 | title=The Physical Geography of Northern Eurasia | publisher=Oxford University Press | pages=403–421 | isbn=978-0-19-823384-8}}</ref> More than 85 species of submerged [[macrophytes]] have been recorded, including genera such as ''[[Ceratophyllum]]'', ''[[Myriophyllum]]'', ''[[Potamogeton]]'', and ''[[Sparganium]]''.<ref name="Pomazkina2012" /> The [[invasive species]] ''[[Elodea canadensis]]'' was introduced to the lake in the 1950s.<ref name="Shahgedanova2002" /> Instead of vascular plants, aquatic flora is often dominated by several [[green algae]] species, notably ''[[Draparnaldioides]]'', ''[[Tetraspora]]'', and ''[[Ulothrix]]'' in water shallower than {{convert|20|m|ft|abbr=on|round=5}}; although ''[[Aegagropila linnaei|Aegagrophila]]'', ''[[Cladophora]]'', and ''Draparnaldioides'' may occur deeper than {{convert|30|m|ft|abbr=on|round=5}}.<ref name="Shahgedanova2002" /> Except for ''Ulothrix'', these green algae genera contain species [[Endemism|endemic]] to Baikal.<ref name="Shahgedanova2002" /> More than 400 [[diatom]] species, both [[benthic]] and [[planktonic]], are found in the lake, and about half of these are endemic to Baikal; however, significant [[Taxonomy (biology)|taxonomic]] uncertainties remain for this group.<ref name="Shahgedanova2002" />

=== Mammals ===
[[File:Из жизни байкальской нерпы близ Ушканьих островов 02.jpg|thumb|right|Baikal seal]]

The [[Baikal seal]] or ''nerpa'' (''Pusa sibirica'') is endemic to Lake Baikal.<ref>Peter Saundry. 2010. [http://www.eoearth.org/wiki/Baikal_seal ''Baikal seal'']. Encyclopedia of Earth. Topic ed. C. Michael Hogan, Ed. in chief C. NCSE, Washington D.C.</ref>

A wide range of land mammals can be found in the habitats around the lake, such as the [[brown bear]] (''Ursus arctos''), [[Eurasian wolf]] (''Canis lupus lupus''), [[red fox]] (''Vulpes vulpes''), [[sable]] (''Martes zibellina''), [[stoat]] (''Mustela erminea''), [[least weasel]] (''[[Mustela nivalis]]''), [[Eurasian otter]] (''Lutra lutra''), [[snow leopard]] (''Panthera uncia''), [[Siberian tiger]] (''[[Panthera tigris tigris]]''), [[Amur leopard]] (''[[Panthera pardus orientalis]]''), [[moose]] (''Alces alces''), [[elk]] (''Cervus canadensis''), [[reindeer]] (''Rangifer tarandus''), [[Siberian roe deer]] (''Capreolus pygargus''), [[Siberian musk deer]] (''Moschus moschiferus''), [[wild boar]] (''Sus scrofa''), [[red squirrel]] (''Sciurus vulgaris''), [[Siberian chipmunk]] (''Eutamias sibiricus''), [[marmot]]s (''Marmota'' sp.), [[lemming]]s (''Lemmus'' sp.), and [[mountain hare]] (''Lepus timidus'').<ref>{{cite web| title=Wildlife of Lake Baikal | url=http://www.bww.irk.ru/baikalfauna/baikalwildlife.html | publisher=bww.irk.ru | access-date=9 June 2017}}</ref> Until the [[Early Middle Ages]], populations of the [[European bison]] (''Bison bonasus'') were found near the lake; this represented the easternmost range of the species.<ref>Sipko P.T.. 2009. [http://www.smz.waw.pl/wydawnictwa/biuletyn2/20_Sipko.pdf European bison in Russia – past, present and future] (pdf). the European Bison Conservation Newsletter Vol 2 (2009). pp.148–159. the Institute of Problems Ecology and Evolution RAS. Retrieved on 31 March 2017</ref>

=== Birds ===
[[File:Chayki v Chivyrkuyskom zalive.JPG|thumb|[[Mongolian gull]]s on Baikal]]

There are 236 species of birds that inhabit Lake Baikal, 29 of which are [[waterfowl]].<ref>{{cite web|url=http://www.zooeco.com/strany/str-01-9-3.html|title=Животный мир Байкала. Озеро Байкал: экология. Озеро Байкал. Природа. Пресноводные водоемы, растительность, животный мир.|website=www.zooeco.com|language=en|access-date=30 June 2018}}</ref> Although named after the lake, both the [[Baikal teal]] and [[Baikal bush warbler]] are widespread in eastern Asia.<ref>{{cite book | author1=Flint, V.E. | author2=R.L. Boehme | author3=Y.V. Kostin | author4=A.A. Kuznetsov | year=1984 | title=Birds of the USSR | page=38<!-- not the same as "plate 38" with illustrations --> | publisher=Princeton University Press | isbn=0-691-02430-8 <!-- | url=https://archive.org/details/fieldguidetobird00flin/page/38 -- wrong link, page 38 is not the same as "plate 38" with illustrations. Page 38 is not currently available for free preview --> }}</ref><ref>{{cite iucn |author=BirdLife International |date=2016 |title=''Locustella davidi'' |volume=2016 |page=e.T22732200A95043817 |doi=10.2305/IUCN.UK.2016-3.RLTS.T22732200A95043817.en |access-date=12 November 2021}}</ref>

===Fish===
[[File:Thymallus baikalensis, Baikal-Museum, Listvyanka, Irkutsk Oblast, Russia - 20080405.jpg|thumb|left|Two species of [[Thymallus|grayling]] (''[[Thymallus baicalensis|Thymallus baikalensis]]'' and ''T. brevipinnis'') are found only in Baikal and rivers that drain into the lake.<ref name=ThymallusBaikalensis>{{fishBase|Thymallus|baikalensis|year=2014}}</ref><ref name=ThymallusBrevipinnis>{{fishBase|Thymallus|brevipinnis|year=2014}}</ref>]]

Fewer than 65 native fish species occur in the lake basin, but more than half of these are endemic.<ref name=FEOW/><ref name=FishbaseList>FishBase: [http://www.fishbase.org/trophiceco/FishEcoList.php?ve_code=156 Species in Lake Baikal.] Retrieved 6 April 2017.</ref> The families [[Abyssocottidae]] (deep-water sculpins), [[Comephoridae]] (golomyankas or Baikal oilfish), and [[Cottocomephoridae]] (Baikal sculpins) are entirely restricted to the lake basin.<ref name=FEOW/><ref>{{cite journal|doi=10.1016/S1055-7903(02)00376-7 |title=Endemic diversification of the monophyletic cottoid fish species flock in Lake Baikal explored with mtDNA sequencing |journal=Molecular Phylogenetics and Evolution |volume=27 |pages=143–155 |year=2003 |last1=Kontula |first1=Tytti |last2=Kirilchik |first2=Sergei V. |last3=Väinölä |first3=Risto |issue=1 |pmid=12679079 |bibcode=2003MolPE..27..143K }}</ref> All these are part of the [[Cottoidea]] and are typically less than {{convert|20|cm|in|abbr=on|0}} long.<ref name=Shahgedanova2002/> Of particular note are the two species of [[golomyanka]] (''Comephorus baicalensis'' and ''C. dybowskii''). These long-finned, translucent fish typically live in open water at depths of {{convert|100|-|500|m|ft|abbr=on}}, but occur both shallower and much deeper. Together with certain abyssocottid sculpins, they are the deepest living freshwater fish in the world, occurring near the bottom of Lake Baikal.<ref name=hunt>Hunt, D. M., et al. (1997). Molecular evolution of the cottoid fish endemic to Lake Baikal deduced from nuclear DNA evidence. Molecular Phylogenetics and Evolution 8(3): 415–22.</ref> The golomyankas are the primary prey of the Baikal seal and represent the largest fish [[biomass]] in the lake.<ref>Pastukhov, V.D: ''[http://www.bww.irk.ru/baikalseals/baikalseals_01.html Lake Baikal Seals – NERPA.]'' Retrieved 19 July 2014.</ref> Beyond members of Cottoidea, there are few endemic fish species in the lake basin.<ref name=FEOW/><ref name=FishbaseList/>

[[File:Omul Fish.jpg|The [[omul]] (''Coregonus migratorius'') is [[Endemism|endemic]] to Lake Baikal, and is a source of income to locals.|thumb]]
The most important local species for fisheries is the [[omul]] (''Coregonus migratorius''), an endemic [[Coregonus|whitefish]].<ref name=FEOW/> It is caught, [[Smoking (food)|smoked]], and then sold widely in markets around the lake. Also, a second endemic whitefish inhabits the lake, ''[[Coregonus baicalensis|C. baicalensis]]''.<ref>{{fishBase|Coregonus|baicalensis|year=2014}}</ref> The [[Thymallus baicalensis|Baikal black grayling]] (''Thymallus baicalensis''), [[Thymallus brevipinnis|Baikal white grayling]] (''T. brevipinnis''), and [[Siberian sturgeon|Baikal sturgeon]] (''Acipenser baerii baicalensis'') are other important species with commercial value. They are also endemic to the Lake Baikal basin.<ref name=ThymallusBaikalensis/><ref name=ThymallusBrevipinnis/><ref>Baikal.ru: ''[http://baikal.ru/en/baikal/excursion/pisces/Thymallus_arcticus_baicalensis.html Baikal grayling.]'' Retrieved 19 July 2014.</ref><ref>Baikal.ru: ''[http://baikal.ru/en/baikal/excursion/pisces/acipenser.html Baikal sturgeon.]'' Retrieved 19 July 2014.</ref>

===Invertebrates===
The lake hosts a rich endemic fauna of invertebrates. Among the most diverse invertebrate groups are the [[amphipod]] and [[ostracod]] crustaceans, [[freshwater snail]]s, [[annelid]] worms and [[turbellaria]]n worms:

====Crustaceans====
[[File:Baikal-Flohkrebs.jpg|thumb|''[[Brachyuropus reicherti]]'' ([[Acanthogammaridae]]), "giant" amphipod caught during [[ice fishing]] in the lake. This species is naturally red-orange in color]]

More than 350 species and subspecies of [[amphipod]]s are endemic to the lake.<ref name="Eulimnogammarus">Rivarola-Duartea; Otto; Jühling; Schreiber; Bedulina; Jakob; Gurkov; Axenov-Gribanov; Sahyoun; Lucassen; Hackermüller; Hoffmann; Sartoris; Pörtner; Timofeyev; Luckenbach; and Stadler (2014). ''A First Glimpse at the Genome of the Baikalian Amphipod Eulimnogammarus verrucosus.'' Journal of Experimental Zoology Part B: Molecular and Developmental Evolution 322(3): 177–189.</ref> They are exceptionally diverse in [[ecology]] and appearance, ranging from the pelagic ''[[Macrohectopus]]'' to the relatively large deep-water ''[[Abyssogammarus]]'' and ''[[Garjajewia]]'', the tiny herbivorous ''[[Micruropus]]'', and the parasitic ''[[Pachyschesis]]'' ([[parasitizing]] other [[Amphipoda|amphipods]]).<ref name=Sherbakov>Sherbakov; Kamaltynov; Ogarkov; and Verheyen (1998). ''Patterns of Evolutionary Change in Baikalian Gammarids Inferred from DNA Sequences (Crustacea, Amphipoda).'' Molecular Phylogenetics and Evolution 10(2): 160–167</ref> The "[[gigantism]]" of some Baikal amphipods, which has been compared to that seen in Antarctic amphipods, has been linked to the high level of [[dissolved oxygen]] in the lake.<ref>BBC News (13 May 1999). ''[http://news.bbc.co.uk/2/hi/science/nature/342906.stm Oxygen boosts polar giants.]'' Retrieved 17 July 2014.</ref> Among the "giants" are several species of spiny ''[[Acanthogammarus]]'' and ''[[Brachyuropus]]'' ([[Acanthogammaridae]]) found at both shallow and deep depths.<ref name=Acanthogammarus>Daneliya, M.E.; Kamaltynov, R.M.; and Väinölä, R. (2011). ''Phylogeography and systematics of Acanthogammarus s. str., giant amphipod crustaceans from Lake Baikal.'' Zoologica Scripta 40(6): 623–637.</ref> These conspicuous and common amphipods are essentially carnivores (will also take [[detritus]]), and can reach a body length up to {{convert|7|cm|in|abbr=on}}.<ref name=Sherbakov/><ref name=Acanthogammarus/> Another common species is another unique inhabitant of the lake: the pelagic amphipod ''[[Macrohectopus branickii]]'' lives its entire life in the water column, which is unique among freshwater amphipods and has been compared to [[krill]].<ref name="Parallel">{{cite journal |last1=Takhteev |first1=V. V. |title=Trends in the evolution of Baikal amphipods and evolutionary parallels with some marine malacostracan faunas |journal=Advances in Ecological Research |date=2000 |volume=31 |pages=197–220 |doi=10.1016/S0065-2504(00)31013-3 |bibcode=2000AdER...31..197T |isbn=0-12-013931-6 |url=https://www.sciencedirect.com/science/article/abs/pii/S0065250400310133 |access-date=18 May 2025}}</ref>

The number of [[Isopoda|isopods]] is low; all belonging to the family [[Asellidae]]. There are four species of the genus [[Baicalasellus]], and the two species ''[[Mesoasellus dybowskii]]'' and ''[[Limnoasellus poberezhnii]]''.<ref>{{Cite book|url=https://books.google.com/books?id=hMxKEAAAQBAJ&dq=The+four+species+of+Baikalasellus&pg=PA463|title=Evolution and Phylogeny of Pancrustacea: A Story of Scientific Method|first1=Frederick R.|last1=Schram|first2=Stefan|last2=Koenemann|date=2 November 2021|publisher=Oxford University Press|isbn=978-0-19-009598-7 |via=Google Books}}</ref><ref>{{Cite web|url=https://hal.science/hal-03623375/document|title=A new obligate groundwater species of Asellus (Isopoda, Asellidae) from Iran}}</ref> These six endemic species are found on rocky substrata in depths varying from 3–10 meters (''Baicalasellus angarensis'') to more than hundred meters (''Mesoasellus dybowskii'').<ref>{{Cite book|url=https://books.google.com/books?id=ix7ZDwAAQBAJ&dq=Baicalasellus+endemic+rocky+substrata&pg=PA289|title=Evolution and Biogeography: Volume 8|first1=Martin|last1=Thiel|first2=Gary|last2=Poore|date=18 June 2020|publisher=Oxford University Press|isbn=978-0-19-009497-3 |via=Google Books}}</ref>
[[File:Байкальская эпишура.jpg|thumb|''[[Epischurella baikalensis]]'']]
''[[Epischurella baikalensis]]'' is a [[copepod]] endemic to the lake, being a very abundant species there; it was estimated that they make up 80 to 90% of the total [[Biomass (ecology)|biomass]].<ref>{{cite web |url=http://baikal.mobi/ |title=Зоопланктон в экосистеме озера Байкал / О Байкале.ру – Байкал. Научно и популярно |publisher=Baikal.mobi |access-date=2 January 2012 |archive-url=https://web.archive.org/web/20110930202148/http://baikal.mobi/ |archive-date=30 September 2011  }}</ref><ref>{{cite web |url=http://www.obaykale.ru/baykal-fauna_06.htm |script-title=ru:Зоопланктон в экосистеме озера Байкал |author=Пенькова О.Г. |publisher=Иркутский государственный педагогический институт |others=Пробл. сохранения биол. разнообразия Юж. Сиб. : 1 Межрегион. науч.-практ. конф., Кемерово, 19-22 мая, 1997 |location=[[Kemerovo]] |year=1997 |pages=87 |language=Russian |access-date=2008-05-15 |archive-url=https://web.archive.org/web/20080419084852/http://www.obaykale.ru/baykal-fauna_06.htm |archive-date=2008-04-19 |url-status=dead }}</ref> It is estimated that as a species, they filter as much as a thousand cubic kilometers of water a year, or the lake's entire volume every twenty-three years.<ref>{{Cite web|url=https://epdf.pub/sacred-sea-a-journey-to-lake-baikal.html|title=Sacred Sea: A Journey to Lake Baikal - PDF Free Download|website=epdf.pub}}</ref>

There are about 60 known species of native [[Diplostraca|cladocerans]] (water fleas), several of them endemic.<ref>[https://iopscience.iop.org/article/10.1088/1755-1315/962/1/012034/pdf Cladocera species (Crustacea, Branchiopoda) in the littoral zone of Lake Baikal: some representatives of Daphniidae families]</ref>

Similar to another ancient lake, [[Lake Tanganyika|Tanganyika]], Baikal is a center for [[ostracod]] diversity. About 90% of the Lake Baikal ostracods are endemic,<ref name=Karanovic2017a>Karanovic, I.; and T.Y. Sitnikova (2017). ''Morphological and molecular diversity of Lake Baikal candonid ostracods, with a description of a new genus.'' Zookeys. 2017(684): 19–56. {{doi|10.3897/zookeys.684.13249}}</ref> meaning that there are {{circa}} 200 endemic species.<ref>Martens; Schön; Meisch; and Horne (2008). ''Global diversity of ostracods (Ostracoda, Crustacea) in freshwater.'' Hydrobiologia 595: 185–193. {{doi|10.1007/s10750-007-9245-4}}</ref> This makes it the second-most diverse group of crustacean in the lake, after the amphipods.<ref name=Karanovic2017a/> The vast majority of the Baikal ostracods belong to the families [[Candonidae]] (more than 100 described species) and [[Cytherideidae]] (about 50 described species),<ref name=Karanovic2017a/><ref>Karanovic, I.; and T.Y. Sitnikova (2017). ''Phylogenetic position and age of Lake Baikal candonids (Crustacea, Ostracoda) inferred from multigene sequence analyses and molecular dating.'' Ecol Evol. 7(17): 7091–7103. {{doi|10.1002/ece3.3159}}</ref> but genetic studies indicate that the true diversity in at least the latter family has been heavily underestimated.<ref>Schön; Pieri; Sherbakov; and Martens (2017). ''Cryptic diversity and speciation in endemic Cytherissa (Ostracoda, Crustacea) from Lake Baikal.'' Hydrobiologia 800(1): 61–79. {{doi|10.1007/s10750-017-3259-3}}</ref> The morphology of the Baikal ostracods is highly diverse.<ref name=Karanovic2017a/>

====Snails and bivalves====
{{As of|2006}}, almost 150 freshwater snails are known from Lake Baikal, including 117 endemic species from the subfamilies Baicaliinae (part of the [[Amnicolidae]]) and Benedictiinae (part of the [[Lithoglyphidae]]), and the families [[Planorbidae]] and [[Valvatidae]].<ref name=gastropod>{{cite journal|last1=Sitnikova|first1=T.Y.|title=Endemic gastropod distribution in Baikal|journal=Hydrobiologia|date=2006|volume=568|issue=S1|pages=207–211|doi=10.1007/s10750-006-0313-y|bibcode=2006HyBio.568..207S |s2cid=35020631}}</ref> All endemics have been recorded between {{convert|20|and|30|m|ft|abbr=on}}, but the majority mainly live at shallower depths.<ref name=gastropod/> About 30 freshwater snail species can be seen deeper than {{convert|100|m|ft|abbr=on}}, which represents the approximate limit of the [[sunlight zone]], but only 10 are truly deepwater species.<ref name=gastropod/> In general, Baikal snails are thin-shelled and small. Two of the most common species are ''[[Benedictia]] baicalensis'' and ''[[Megalovalvata baicalensis]]''.<ref name=BaikalGastropoda>Baikal.ru: ''[http://baikal.ru/en/baikal/excursion/gastropoda.html Gastropoda.]'' Retrieved 17 July 2014.</ref> [[Bivalve]] diversity is lower with more than 30 species; about half of these, all in the families Euglesidae, [[Pisidiidae]], and [[Sphaeriidae]], are endemic (the only other family in the lake is the [[Unionidae]] with a single nonendemic species).<ref name=BaikalGastropoda/><ref>{{cite journal|last1=Slugina|first1=Z.V.|title=Endemic Bivalvia in ancient lakes|journal=Hydrobiologia|date=2006|volume=568|issue=S1|pages=213–217|doi=10.1007/s10750-006-0312-z|bibcode=2006HyBio.568..213S |s2cid=22330810}}</ref> The endemic bivalves are mainly found in shallows, with few species from deep water.<ref>Slugina; Starobogatov; and Korniushin (1994). ''Bivalves (Bivalvia) of Lake Baikal.'' Ruthenica 4(2): 111–146.</ref>

====Aquatic worms====
With almost 200 described species, including more than 160 endemics, the center of diversity for aquatic freshwater [[oligochaetes]] is Lake Baikal.<ref name=SegersMartens>Segers, H.; and Martens, K; editors (2005). ''The Diversity of Aquatic Ecosystems.'' pp. 43–44. Developments in Hydrobiology. Aquatic Biodiversity. {{ISBN|1-4020-3745-7}}</ref> A smaller number of other freshwater annelids is known: 30 species of [[leech]]es (Hirudinea),<ref>Kaygorodova, I.A.; and N.M. Pronin (2013). ''New Records of Lake Baikal Leech Fauna: Species Diversity and Spatial Distribution in Chivyrkuy Gulf.'' ScientificWorldJournal. 2013(2013): 206590. {{doi|10.1155/2013/206590}}</ref> and 4 [[polychaetes]].<ref name=SegersMartens/> Several hundred species of [[nematode]]s are known from the lake, but a large percentage of these are [[Undescribed taxon|undescribed]].<ref name=SegersMartens/>
[[File:Lubomirskia-baicalensis.jpg|thumb|upright|Museum specimen of the branching sponge ''[[Lubomirskia baicalensis]]'' (living are brighter green)]]
More than 140 endemic [[flatworm]] (Plathelminthes) species are in Lake Baikal, where they occur on a wide range of bottom types.<ref name=flatworm>Baikal.ru: [http://baikal.ru/en/baikal/excursion/planaria.html Flatworms (Plathelminthes).] Retrieved 7 June 2017.</ref> Most of the flatworms are predatory, and some are relatively brightly marked. They are often abundant in shallow waters, where they are typically less than {{convert|2|cm|in|abbr=on|0}} long, but in deeper parts of the lake, the largest, ''Baikaloplana valida'', can reach up to {{convert|30|cm|ft|abbr=on|0}} when outstretched.<ref name=Shahgedanova2002/><ref name=flatworm/>

====Sponges====

At least 18 species of [[sponge]]s occur in the lake,<ref name=Kaluzhnaya2005>Kaluzhnaya; Belikov; Schröder; Rothenberger; Zapf; Kaandorp; Borejko; Müller; and Müller (2005). ''Dynamics of skeleton formation in the Lake Baikal sponge Lubomirskia baicalensis. Part I. Biological and biochemical studies.'' Naturwissenschaften 92: 128–133.</ref> including about 15 species from the endemic family [[Lubomirskiidae]] (the remaining are from the nonendemic family [[Spongillidae]]),<ref name=Paradina2003>Paradina; Kulikova; Suturin; and Saibatalova (2003). ''The Distribution of Chemical Elements in Sponges of the Family Lubomirskiidae in Lake Baikal.'' International Symposium – Speciation in Ancient Lakes, SIAL III – Irkutsk 2002. Berliner Paläobiologische Abhandlungen 4: 151–157.</ref><ref>{{cite WoRMS |author=de Voogd, N.J.; Alvarez, B.; Boury-Esnault, N.; Carballo, J.L.; Cárdenas, P.; Díaz, M.-C.; Dohrmann, M.; Downey, R.; Hajdu, E.; Hooper, J.N.A.; Kelly, M.; Klautau, M.; Manconi, R.; Morrow, C.C. Pisera, A.B.; Ríos, P.; Rützler, K.; Schönberg, C.; Vacelet, J.; van Soest, R.W.M. |year=2021 |title=Lubomirskiidae Weltner, 1895 |id=167011 |access-date=24 November 2021}}</ref> which colonized the lake about 3.4 million years ago. The lake's sponges makes up around 44% of the [[benthic]] animal biomass.<ref>{{Cite journal|url=https://academic.oup.com/mbe/article/36/11/2462/5522662?login=false|title=Symbiosis, Selection, and Novelty: Freshwater Adaptation in the Unique Sponges of Lake Baikal|first1=Kenny, Nathan|last1=J|first2=Plese|last2=Bruna|first3=Riesgo|last3=Ana|first4=Itskovich, Valeria|last4=B|date=1 November 2019|journal=Molecular Biology and Evolution|volume=36|issue=11|doi=10.1093/molbev/m|doi-broken-date=20 February 2025 }}</ref> ''[[Lubomirskia baicalensis]]'', ''[[Lubomirskiidae|Baikalospongia bacillifera]]'', and ''[[Lubomirskiidae|B. intermedia]]'' are unusually large for freshwater sponges and can reach {{convert|1|m|ft|abbr=on}} or more.<ref name=Kaluzhnaya2005/><ref>Belikov; Kaluzhnaya; Schröder; Müller; and Müller (2007). Lake Baikal endemic sponge Lubomirskia baikalensis: structure and organization of the gene family of silicatein and its role in morphogenesis. Porifera Research: Biodiversity, Innovation and Sustainability, pp. 179–188.</ref> These three are also the most common sponges in the lake.<ref name=Kaluzhnaya2005/> While the ''Baikalospongia'' species typically have encrusting or carpet-like structures, ''L. baikalensis'' often has branching structures and in areas where common may form underwater "forests".<ref name=Kozhov1963>{{cite book| author=Kozhov, M. | year=1963 | title=Lake Baikal and Its Life | series=Monographiae Biologicae | volume=11 | pages=63–67 | isbn=978-94-015-7388-7}}</ref> Most sponges in the lake are typically green when alive because of [[symbiotic]] [[chlorophyte]]s ([[zoochlorella]]), but can also be brownish or yellowish.<ref>Müller; and Grachev, eds. (2009). ''Biosilica in Evolution, Morphogenesis, and Nanobiotechnology: Case Study Lake Baikal'', pp. 81–110. [[Springer Publishing]]. {{ISBN|978-3-540-88551-1}}.</ref>