Editing Bryozoa (section)

=== Habitats and distribution ===
Most marine species live in tropical waters at depths less than {{convert|100|m|ft fathom|sp=us}}. However, a few have been found in deep-sea [[Oceanic trench|trenches]],<ref>{{cite book|last=Emiliani|first=C.|author-link=Cesare Emiliani|title=Planet Earth: Cosmology, Geology, & the Evolution of Life & the Environment|publisher=Cambridge University Press|year=1992|pages=[https://archive.org/details/dictionaryofphys00emil/page/488 488–490]|chapter=The Paleozoic|isbn=978-0-19-503652-7|chapter-url=https://books.google.com/books?id=MfAGpVq8gpQC&q=bryozoa%20marine%20tropical&pg=PA489|access-date=2009-08-11|url=https://archive.org/details/dictionaryofphys00emil/page/488}}</ref> especially around [[cold seep]]s, and others near the [[Geographical pole|poles]].<ref name="Jones2006AppliedPaleo">{{cite book|last=Jones|first=R.W.|title=Applied palaeontology|publisher=Cambridge University Press|year=2006|page=116|chapter=Principal fossil groups|isbn=978-0-521-84199-3|chapter-url=https://books.google.com/books?id=KJBKC4qvV8AC&q=bryozoa+marine+tropical&pg=RA5-PA116|access-date=2009-08-11|archive-date=8 March 2023|archive-url=https://web.archive.org/web/20230308183244/https://books.google.com/books?id=KJBKC4qvV8AC&q=bryozoa+marine+tropical&pg=RA5-PA116|url-status=live}}</ref><ref>{{cite journal|last1=Kuklinski|first1=P.|year=2007|title=Comparison of bryozoan assemblages from two contrasting Arctic shelf regions |journal=[[Estuarine, Coastal and Shelf Science]]|volume=73|issue=3–4|pages=835–843|doi=10.1016/j.ecss.2007.03.024|last2=Bader|first2=Beate |bibcode = 2007ECSS...73..835K }}</ref>

The great majority of bryozoans are [[Sessility (zoology)|sessile]]. Typically, sessile bryozoans live on hard substrates including rocks, sand or shells.<ref>{{cite news|last1=Brusca|first1=R|last2=Brusca|first2=G|title=Invertebrates (2nd Edition)|publisher=Sunderland, MA: Sinauer Associates}}</ref> Boring bryozoans leave unique borehole traces after dissolving [[calcium carbonate]] substrates.<ref>{{Cite journal |last1=Johnson |first1=Mildred J. |last2=Lemer |first2=Sarah |last3=Hirose |first3=Masato |last4=Decker |first4=Sebastian H. |last5=Schwaha |first5=Thomas |date=2024-12-31 |title=Ecology of endolithic bryozoans: colony development, growth rates and interactions of species in the genus Immergentia |journal=Zoological Letters |volume=10 |issue=1 |pages=23 |doi=10.1186/s40851-024-00246-9 |doi-access=free |issn=2056-306X |pmc=11686985 |pmid=39736804}}</ref> Encrusting forms are much the commonest of these in shallow seas, but erect forms become more common as the depth increases.<ref name="Jones2006AppliedPaleo" /> An example of incrustation on pebbles and cobbles is found in the diverse Pleistocene bryozoans found in northern Japan, where fossils have been found of single stones covered with more than 20 bryozoan species.{{Sfn|Taylor|2020|p=159}} Sediments with smaller particles, like sand or silt, are usually unsuitable habitat for bryozoans, but tiny colonies have been found encrusting grains of coarse sand.{{Sfn|Taylor|2020|p=164}} Some bryozoan species specialize in colonizing marine algae, seagrasses, and even mangrove roots; the genus ''Amphibiobeania'' lives on the leaves of mangrove trees and is called "amphibious" because it can survive regular exposure to air at low tide.{{Sfn|Taylor|2020|p=162–163}}

There are a variety of "free-living" bryozoans that live un-attached to a substrate. A few forms such as ''[[Cristatella]]'' can move. Lunulitiform cheilostomes are one group of free-living bryozoans with mobile colonies. They form small round colonies un-attached to any substrate; colonies of the genus Selenaria have been observed to "walk" around using setae.{{Sfn|Taylor|2020|p=112–113}} Another cheilostome family, the Cupuladriidae, convergently evolved similarly shaped colonies capable of movement. When observed in an aquarium, Selenaria maculata colonies were recorded to crawl at a speed of one meter per hour, climb over each other, move toward light, and right themselves when turned upside-down.{{Sfn|Taylor|2020|p=79}} Later study of this genus showed that neuroelectrical activity in the colonies increased in correlation with movement toward light sources. It is theorized that the capacity for movement arose as a side effect when colonies evolved longer setae for unburying themselves from sediment.{{Sfn|Taylor|2020|p=79}}
[[File:Alcyonidium (Charleston, South Carolina, 1851).jpg|alt=Watercolor of alcyonidium|thumb|1851 watercolor of ''Alcyonidium'' by Jacques Burkhardt.]]
Other free-living bryozoans are moved freely by waves, currents, or other phenomena. An [[Antarctic]] species, ''Alcyonidium pelagosphaera'', consists of floating colonies. The pelagic species is between {{cvt|5.0 and 23.0|mm}} in diameter, has the shape of a hollow sphere and consists of a single layer of autozooids. It is still not known if these colonies are pelagic their whole life or only represents a temporarily and previously undescribed juvenile stage.<ref name="Jones2006AppliedPaleo" /><ref>{{Cite journal |url=https://link.springer.com/article/10.1007/BF00349118 |title= A pelagic bryozoan from Antarctica|journal=Marine Biology |date=October 1995 |volume=123 |issue=4 |pages=757–762 |doi=10.1007/BF00349118 |access-date=28 August 2017 |archive-date=3 August 2017 |archive-url=https://web.archive.org/web/20170803131921/https://link.springer.com/article/10.1007/BF00349118 |url-status=live |last1=Peck |first1=L. S. |last2=Hayward |first2=P. J. |last3=Spencer-Jones |first3=M. E. |bibcode= 1995MarBi.123..757P|s2cid=83529565 }}</ref> Colonies of the species ''Alcyonidium disciforme'', which is disc-shaped and similarly free-living, inhabit muddy seabeds in the Arctic and can sequester sand grains they have engulfed, potentially using the sand as ballast to turn themselves right-side-up after they have been overturned. Some bryozoan species can form bryoliths, sphere-shaped free-living colonies that grow outward in all directions as they roll about on the seabed.{{Sfn|Taylor|2020|p=114}}

In 2014 it was reported that the bryozoan ''[[Fenestrulina rugula]]'' had become a dominant species in parts of Antarctica. [[Global warming]] has increased the rate of scouring by [[iceberg]]s, and this species is particularly adept at recolonizing scoured areas.<ref>{{Cite news|title='Weedy thing' thrives as Antarctic shores warm|author=Matt McGrath|newspaper=BBC News|url=https://www.bbc.co.uk/news/science-environment-27831958|date=16 June 2014|access-date=16 June 2014|archive-date=17 June 2014|archive-url=https://web.archive.org/web/20140617181747/http://www.bbc.co.uk/news/science-environment-27831958|url-status=live}}</ref>

The phylactolaemates live in all types of freshwater environment – lakes and ponds, rivers and streams, and estuaries<ref name="MassardGeimer2008FreshwaterBryoDiversity" /> – and are among the most abundant sessile freshwater animals.<ref name="WoodLore2005PhylactolaemateMolPhylo">{{cite book|last=Wood|first=T.S.|author2=Lore M.|title=Bryozoan Studies 2004: Proceedings of the 13th International Bryozoology Association|editor=Moyano, H. I. |editor2=Cancino, J.M. |editor3=Wyse-Jackson, P.N.|publisher=Taylor & Francis Group|location=London|year=2005|pages=361–367|chapter=The higher phylogeny of phylactolaemate bryozoans inferred from 18S ribosomal DNA sequences|chapter-url=http://bryotechnologies.com/pdf/18S_rDNA.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bryotechnologies.com/pdf/18S_rDNA.pdf |archive-date=2022-10-09 |url-status=live|access-date=2009-08-24}}</ref> Some ctenostomes are exclusively freshwater while others prefer brackish water but can survive in freshwater.<ref name="MassardGeimer2008FreshwaterBryoDiversity" /> Scientists' knowledge of freshwater bryozoan populations in many parts of the world is incomplete, even in some parts of Europe. It was long thought that some freshwater species occurred worldwide, but since 2002 all of these have been split into more localized species.<ref name="MassardGeimer2008FreshwaterBryoDiversity" />

Bryozoans grow in [[cloning|clonal]] colonies. A larval Bryozoan settles on a hard substance and produces a colony asexually through budding. These colonies can grow thousands of individual zooids in a relatively short period of time. Even though colonies of zooids grow through asexual reproduction, Bryozoans are hermaphrodites and new colonies can be formed through sexual reproduction and the generation of free swimming larvae. When colonies grow too large, however, they can split in two. This is the only case where asexual reproduction results in a new colony separate from its predecessor. Most colonies are stationary. Indeed, these colonies tend to be settled on immobile substances such as sediment and coarse substances. There are some colonies of freshwater species such as ''[[Cristatella|Cristatella mucedo]]'' that are able to move slowly on a creeping foot.<ref>{{cite web |last1=Ramel |first1=Gordon |date=2020-03-05 |title=Bryozoans: The Fascinating Colonies Of Phylum Ectoprocta |url=https://www.earthlife.net/inverts/bryozoa.html |access-date=2022-05-19 |website=Earthlife |archive-date=27 March 2022 |archive-url=https://web.archive.org/web/20220327220537/https://www.earthlife.net/inverts/bryozoa.html |url-status=live }}</ref>