Editing Coral reef (section)

==Other reef builders==
[[Corals]] are the most prodigious reef-builders. However many other organisms living in the reef community contribute skeletal calcium carbonate in the same manner as corals. These include [[coralline algae]], [[Sclerosponge|some sponges]] and [[bivalve]]s.<ref>{{cite book |vauthors=Jennings S, Kaiser MJ, Reynolds JD |year=2001 |url={{google books |plainurl=y |id=oTVyeNQyoiMC}}|title=Marine Fisheries Ecology |pages=291–293 |publisher=Wiley-Blackwell |isbn=978-0-632-05098-7}}</ref> Reefs are always built by the combined efforts of these different [[Phylum (biology)|phyla]], with different organisms leading reef-building in different [[geological period]]s.<ref>{{cite journal |last1=Kuznetsov |first1=Vitaly |title=The evolution of reef structures through time: Importance of tectonic and biological controls |journal=Facies |date=1 December 1990 |volume=22 |issue=1 |pages=159–168 |doi=10.1007/BF02536950|bibcode=1990Faci...22..159K |s2cid=127193540 }}</ref>

===Coralline algae===
{{main|Coralline algae}}
{{See also|Coralline rock}}
[[File:Coralline algae 2.jpg|thumb|[[Coralline algae]] ''[[Lithothamnion]] sp.'']]
[[Coralline algae]] are important contributors to reef structure. Although their mineral deposition rates are much slower than corals, they are more tolerant of rough wave-action, and so help to create a protective crust over those parts of the reef subjected to the greatest forces by waves, such as the reef front facing the open ocean. They also strengthen the reef structure by depositing limestone in sheets over the reef surface. Furthermore, in locations unfavorable to the growth of corals, coralline algae can be the primary builders of an algal reef.<ref>{{Cite web |last=Johnson |first=Maggie D. |title=Coralline Algae: The Unsung Architects of Coral Reefs {{!}} Smithsonian Ocean |url=https://ocean.si.edu/ocean-life/plants-algae/coralline-algae-unsung-architects-coral-reefs |access-date=2025-05-06 |website=ocean.si.edu |language=en}}</ref><ref>Ballesteros E., 2006 Mediterranean coralligenous assemblages: A synthesis of present knowledge. Oceanography and Marine Biology - an Annual Review 44: 123–130</ref>

===Sponges===
{{main|Sponge reef}}
[[File:Aphrocallistes vastus.jpg|thumb|left|Deep-water [[cloud sponge]]]]
Sponge reefs are reefs produced by [[sea sponge]]s. [[Hexactinellid]] sponges are known to form reefs off the coast of [[British Columbia]], southeast [[Alaska]] and [[Washington (state)|Washington state]].<ref>{{cite news | first1=Lisa | last1=Stiffler | date=2007-07-27  | title=Reef of glass sponges found off Washington's coast | newspaper=[[Seattle Post-Intelligencer]] | url=http://www.seattlepi.com/local/325489_sponge28.html | via=seattlepi.com }}</ref> Reefs discovered in [[Hecate Strait]], British Columbia, have grown to up to 7&nbsp;kilometres long and 20&nbsp;metres high.<ref>{{cite news |title=B.C.'s reefs among science's great finds |date=2005-02-24 |work=Georgia Straight Vancouver's News & Entertainment Weekly |url=https://www.straight.com/article/b-c-s-reefs-among-sciences-great-finds |via=straight.com |access-date=2017-05-22 |lang=en }}</ref> Hexactinellid sponge reefs were first identified in the Middle [[Triassic]] (245–208&nbsp;million years ago). The sponges reached their full extent in the late [[Jurassic]] (201–145&nbsp;million years ago) when a discontinuous reef system 7,000&nbsp;km long stretched across the northern [[Tethys Ocean|Tethys]] and North Atlantic basins,<ref name="krautter2001">{{cite journal |author1=Krautter, M. |author2=Conway, K. |author3=Barrie, J.V. |author4=Neuweiler, M. |year=2001 |title=Discovery of a "living dinosaur": Globally unique modern hexactinellid sponge reefs off British Columbia, Canada |journal=Facies |volume=44 |issue=1 |pages=265–282 |bibcode=2001Faci...44..265K |doi=10.1007/BF02668178 |s2cid=128410530}}</ref> but have since declined and were thought to be extinct until existing reefs were discovered in 1987–1988.<ref name=dfo2000>{{cite report |publisher=Department of Fisheries and Oceans |date=February 2000 |title=Hexactinellid sponge reefs on the British Columbia continental shelf: Geological and biological structure |series=DFO Pacific Region Habitat Status Report}}</ref>

[[Archaeocyatha]], an extinct clade of sponges, were the planet's first reef-building animals and are an [[index fossil]]<ref>{{cite web |author=Anderson, Dr. John R. |url=http://facstaff.gpc.edu/~janderso/historic/paleolif.htm |title=Paleozoic Life |access-date=2010-07-06 |publisher=[[Georgia Perimeter College]] |url-status=dead |archive-url=https://web.archive.org/web/20110720202106/http://facstaff.gpc.edu/~janderso/historic/paleolif.htm |archive-date=2011-07-20 |df=dmy-all}}</ref> for the Lower Cambrian worldwide. Similarly, [[Stromatoporoidea]] were another extinct clade of reef-building sponges. Unlike corals, stromatoporoids usually settled on soft substrates, so their ‘reefs’ occupied only a single level rather than a multi-tiered vertical framework of built-up skeletons.<ref name=":3">{{Cite book |last=Kershaw |first=Stephen |url=https://journals.ku.edu/InvertebratePaleo/issue/view/538 |title=Part E, Porifera (Revised). Volumes 4 & 5 |publisher=Geological Society of America; University of Kansas |year=2015 |isbn=978-0-9903621-2-8 |editor-last=Selden |editor-first=Paul A. |edition= |series=[[Treatise on Invertebrate Paleontology]] |volume= |location=Boulder, Colorado; Lawrence, Kansas |pages=631–651 |chapter=Chapter 10 (part): Paleoecology of the Paleozoic Stromatoporoidea |display-authors= |chapter-url=https://journals.ku.edu/InvertebratePaleo/article/view/5761/5230}}</ref>

===Bivalves===
{{Main article|Bivalve reef}}
[[File:Oyster bed, Brunswick, GA, US.jpg|thumb|[[Eastern oyster]]s (''Crassostrea virginica'')]]
[[Oyster reef]]s are dense aggregations of [[oyster]]s living in colonial communities. Other regionally-specific names for these structures include oyster beds and oyster banks. Oyster larvae require a hard substrate or surface to attach on, which includes the shells of old or dead oysters. Thus reefs can build up over time as new larvae settle on older individuals. ''[[Crassostrea virginica]]'' were once abundant in [[Chesapeake Bay]] and shorelines bordering the [[Atlantic coastal plain]] until the late nineteenth century.<ref>Newell, R.I.E. 1988. Ecological changes in Chesapeake Bay: are they the results of [[overharvesting]] the American oyster, ''Crassostrea virginica''? In: M. Lynch and E.C. Krome (eds.) Understanding the estuary: advances in Chesapeake Bay research, Chesapeake Research Consortium, Solomons MD pp.536–546.</ref> ''[[Ostrea angasi]]'' is a species of flat oyster that had also formed large reefs in South Australia.<ref name=good>{{cite web |title=4 things you might not know about South Australia's new shellfish reef |website=Government of South Australia. [[Department for Environment and Water]] |date=10 May 2019 |url=https://www.environment.sa.gov.au/goodliving/posts/2019/05/windara-reef |access-date=28 February 2021}}</ref>

Hippuritida, an extinct order of bivalves known as [[rudists]], were major reef-building organisms during the [[Cretaceous]]. By the mid-Cretaceous, rudists became the dominant tropical reef-builders, becoming more numerous than scleractinian corals. During this period, ocean temperatures and saline levels—which corals are sensitive to—were higher than it is today, which may have contributed to the success of rudist reefs.<ref name=Johnson_2002>{{cite journal |author=Johnson, C. |year=2002 |title=The rise and fall of Rudist reefs |journal=American Scientist |volume=90 |issue=2 |page=148 |doi=10.1511/2002.2.148 |bibcode=2002AmSci..90..148J |s2cid=121693025 }}</ref>

===Gastropods===
Some gastropods, like family [[Vermetidae]], are sessile and cement themselves to the substrate, contributing to the reef building.<ref>{{cite journal | url=https://www.sciencedirect.com/science/article/abs/pii/S0031018208003672 | doi=10.1016/j.palaeo.2008.06.008 | title=Vermetid reefs and their use as palaeobathymetric markers: New insights from the Late Miocene of the Mediterranean (Southern Italy, Crete) | journal=Palaeogeography, Palaeoclimatology, Palaeoecology | date=19 September 2008 | volume=267 | issue=1 | pages=89–101 | last1=Vescogni | first1=Alessandro | last2=Bosellini | first2=Francesca R. | last3=Reuter | first3=Markus | last4=Brachert | first4=Thomas C. | bibcode=2008PPP...267...89V }}</ref>

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