Editing Coral (section)

===Climate change impacts===
Increasing [[sea surface temperature]]s in tropical regions (~{{convert|1|C-change|F-change|abbr=on|1}}) the last century have caused major [[coral bleaching]], death, and therefore shrinking coral populations. Although coral are able to adapt and acclimate, it is uncertain if this evolutionary process will happen quickly enough to prevent major reduction of their numbers.<ref name="Hoegh-Guldberg">{{cite journal |author=Hoegh-Guldberg O. |year=1999 |title=Climate change, coral bleaching and the future of the world's coral reefs |journal=Marine and Freshwater Research |volume=50 |issue=8 |pages=839–99 |doi=10.1071/mf99078 |doi-broken-date=16 December 2024 |doi-access=}}</ref> Climate change causes more frequent and more severe storms that can destroy [[coral reef]]s.<ref>{{Cite web|url=https://oceanservice.noaa.gov/facts/coralreef-climate.html|title=How does climate change affect coral reefs?|first=National Oceanic and Atmospheric Administration|last=US Department of Commerce|website=oceanservice.noaa.gov}}</ref>

Annual growth bands in some corals, such as the [[deep sea]] [[bamboo coral]]s (''Isididae''), may be among the first signs of the effects of ocean acidification on marine life.<ref>{{cite web |title=National Oceanic and Atmospheric Administration – New Deep-Sea Coral Discovered on NOAA-Supported Mission |url=http://www.noaanews.noaa.gov/stories2009/20090305_coral.html |access-date=2009-05-11 |publisher=noaanews.noaa.gov}}</ref> The growth rings allow [[geologist]]s to construct year-by-year chronologies, a form of [[incremental dating]], which underlie high-resolution records of past [[paleoclimatology|climatic]] and [[paleoecology|environmental]] changes using [[geochemistry|geochemical]] techniques.<ref name="Schrag">{{cite journal |author1=Schrag, D.P. |author2=Linsley, B.K. |year=2002 |title=Corals, chemistry, and climate |journal=Science |volume=296 |issue=8 |pages=277–78 |doi=10.1126/science.1071561 |pmid=11951026 |s2cid=82449130}}</ref>

Certain species form communities called [[microatoll]]s, which are colonies whose top is dead and mostly above the water line, but whose perimeter is mostly submerged and alive. Average [[tide]] level limits their height. By analyzing the various growth morphologies, microatolls offer a low-resolution record of sea level change. Fossilized microatolls can also be dated using [[radiocarbon dating]]. Such methods can help to reconstruct [[Holocene]] [[sea level]]s.<ref name="Smithers">{{cite journal |last1=Smithers |first1=Scott G. |last2=Woodroffe |first2=Colin D. |year=2000 |title=Microatolls as sea-level indicators on a mid-ocean atoll |journal=Marine Geology |volume=168 |issue=1–4 |pages=61–78 |bibcode=2000MGeol.168...61S |doi=10.1016/S0025-3227(00)00043-8}}</ref>

Though coral have large sexually-reproducing populations, their evolution can be slowed by abundant [[asexual reproduction]].<ref name="Hughes et al.">{{cite journal |author1=Hughes, T. |author2=Baird, A. |author3=Bellwood, D. |author4=Card, M. |author5=Connolly, S. |author6=Folke, C. |author7=Grosberg, R. |author8=Hoegh-Guldberg, O. |author9=Jackson, J. |author10=Klepas, J. |author11=Lough, J. |author12=Marshall, P. |author13=Nystrom, M. |author14=Palumbi, S. |author-link14=Stephen Palumbi |author15=Pandolfi, J. |year=2003 |title=Climate change, human impacts, and the resilience of coral reefs |journal=Science |volume=301 |issue=5635 |pages=929–33 |bibcode=2003Sci...301..929H |doi=10.1126/science.1085046 |pmid=12920289 |author16=Rosen, B. |author17=and Roughgarden, J. |s2cid=1521635}}</ref> [[Gene flow]] is variable among coral species.<ref name="Hughes et al." /> According to the [[biogeography]] of coral species, gene flow cannot be counted on as a dependable source of adaptation as they are very stationary organisms. Also, coral longevity might factor into their adaptivity.<ref name="Hughes et al." />

However, [[adaptation to climate change]] has been demonstrated in many cases, which is usually due to a shift in coral and zooxanthellae [[genotype]]s. These shifts in [[allele frequency]] have progressed toward more tolerant types of zooxanthellae.<ref name="Parmesan">{{cite journal |author=Parmesan, C. |year=2006 |title=Ecological and evolutionary responses to recent climate change |journal=Annual Review of Ecology, Evolution, and Systematics |volume=37 |pages=637–69 |doi=10.1146/annurev.ecolsys.37.091305.110100}}</ref> Scientists found that a certain [[scleractinia]]n zooxanthella is becoming more common where sea temperature is high.<ref name="Baker">{{cite journal |author=Baker, A. |year=2004 |title=Corals' adaptive response to climate change |journal=Nature |volume=430 |issue=7001 |page=741 |bibcode=2004Natur.430..741B |doi=10.1038/430741a |pmid=15306799 |doi-access=free |s2cid=32092741}}</ref><ref name="Donner et al.">{{cite journal |author=Donner, S. |author2=Skirving, W. |author3=Little, C. |author4=Oppenheimer, M. |author5=Hoegh-Guldberg, O. |year=2005 |title=Global assessment of coral bleaching and required rates of adaptation under climate change |url=http://www.princeton.edu/step/people/faculty/michael-oppenheimer/recent-publications/Global-assessment-of-coral-bleaching-and-required-rates.pdf |url-status=dead |journal=Global Change Biology |volume=11 |issue=12 |pages=2251–65 |bibcode=2005GCBio..11.2251D |citeseerx=10.1.1.323.8134 |doi=10.1111/j.1365-2486.2005.01073.x |pmid=34991281 |archive-url=https://web.archive.org/web/20170814144112/http://www.princeton.edu/step/people/faculty/michael-oppenheimer/recent-publications/Global-assessment-of-coral-bleaching-and-required-rates.pdf |archive-date=2017-08-14 |access-date=2017-10-25 |s2cid=84890014}}</ref> Symbionts able to tolerate warmer water seem to photosynthesise more slowly, implying an evolutionary trade-off.<ref name="Donner et al." />

In the Gulf of Mexico, where sea temperatures are rising, cold-sensitive [[Staghorn coral|staghorn]] and [[elkhorn coral]] have shifted in location.<ref name="Parmesan" />
Not only have the symbionts and specific species been shown to shift, but there seems to be a certain growth rate favorable to selection. Slower-growing but more heat-tolerant corals have become more common.<ref name="Baskett et al.">{{cite journal |author1=Baskett, M. |author2=Gaines, S. |author3=Nisbet, R. |name-list-style=amp |year=2009 |title=Symbiont diversity may help coral reefs survive moderate climate change |url=https://escholarship.org/content/qt3d58b2w2/qt3d58b2w2.pdf?t=o17qaf |journal=Ecological Applications |volume=19 |issue=1 |pages=3–17 |doi=10.1890/08-0139.1 |pmid=19323170 |bibcode=2009EcoAp..19....3B |s2cid=1189125}}</ref> The changes in temperature and acclimation are complex. Some reefs in current shadows represent a [[Refugium (population biology)|refugium]] location that will help them adjust to the disparity in the environment even if eventually the temperatures may rise more quickly there than in other locations.<ref name="McClanahan et al.">{{cite journal |author1=McClanahan, T. |author2=Ateweberhan, M. |author3=Muhando, C. |author4=Maina, J. |author5=Mohammed, M. |name-list-style=amp |year=2007 |title=Effects of Climate and Seawater Temperature Variation on Coral Bleaching and Morality |journal=Ecological Monographs |volume=77 |issue=4 |pages=503–25 |citeseerx=10.1.1.538.970 |doi=10.1890/06-1182.1|bibcode=2007EcoM...77..503M }}</ref> This [[vicariance|separation of populations]] by climatic barriers causes a [[realized niche]] to shrink greatly in comparison to the old [[fundamental niche]].

====Geochemistry====
Corals are shallow, colonial organisms that integrate oxygen and trace elements into their skeletal [[aragonite]] ([[Polymorphism (materials science)|polymorph]] of [[calcite]]) crystalline structures as they grow. Geochemical anomalies within the crystalline structures of corals represent functions of temperature, salinity and oxygen isotopic composition. Such geochemical analysis can help with climate modeling.<ref>{{cite journal |last1=Kilbourne |first1=K. Halimeda |last2=Quinn |first2=Terrence M. |last3=Taylor |first3=Frederick W. |last4=Delcroix |first4=Thierry |last5=Gouriou |first5=Yves |year=2004 |title=El Niño-Southern Oscillation-related salinity variations recorded in the skeletal geochemistry of a ''Porites'' coral from Espiritu Santo, Vanuatu |journal=Paleoceanography |volume=19 |issue=4 |pages=PA4002 |bibcode=2004PalOc..19.4002K |doi=10.1029/2004PA001033|doi-access=free }}</ref> The [[δ18O|ratio of oxygen-18 to oxygen-16]] (δ<sup>18</sup>O), for example, is a proxy for temperature.

=====Strontium/calcium ratio anomaly=====
Time can be attributed to coral geochemistry anomalies by correlating [[strontium]]/[[calcium]] minimums with [[sea surface temperature|sea surface temperature (SST)]] maximums to data collected from [http://www.esrl.noaa.gov/psd/gcos_wgsp/Timeseries/Nino34/ NINO 3.4 SSTA].<ref name="Ren, L. 2002">{{cite journal |last1=Ren |first1=Lei |last2=Linsley |first2=Braddock K. |last3=Wellington |first3=Gerard M. |last4=Schrag |first4=Daniel P. |last5=Hoegh-guldberg |first5=Ove |year=2003 |title=Deconvolving the δ<sup>18</sup>O seawater component from subseasonal coral δ<sup>18</sup>O and Sr/Ca at Rarotonga in the southwestern subtropical Pacific for the period 1726 to 1997 |journal=Geochimica et Cosmochimica Acta |volume=67 |issue=9 |pages=1609–21 |bibcode=2003GeCoA..67.1609R |doi=10.1016/S0016-7037(02)00917-1}}</ref>
<!-- [[WP:NFCC]] violation: [[File:Linsley2006 figure1.png|thumb|The position of the [[South Pacific convergence zone]] as a function of precipitation and salinity]] -->

=====Oxygen isotope anomaly=====
The comparison of coral strontium/calcium minimums with sea surface temperature maximums, data recorded from [http://www.esrl.noaa.gov/psd/gcos_wgsp/Timeseries/Nino34/ NINO 3.4 SSTA], time can be correlated to coral strontium/calcium and [[Δ18O|δ<sup>18</sup>O]] variations. To confirm the accuracy of the annual relationship between Sr/Ca and [[Δ18O|δ<sup>18</sup>O]] variations, a perceptible association to annual coral growth rings confirms the age conversion. [[Geochronology]] is established by the blending of Sr/Ca data, growth rings, and [[Stable isotope ratio|stable isotope]] data. [[El Nino-Southern Oscillation|El Nino-Southern Oscillation (ENSO)]] is directly related to climate fluctuations that influence coral [[Δ18O|δ<sup>18</sup>O]] ratio from local salinity variations associated with the position of the [[South Pacific convergence zone|South Pacific convergence zone (SPCZ)]] and can be used for [[El Niño Southern Oscillation|ENSO]] modeling.<ref name="Ren, L. 2002" />

=====Sea surface temperature and sea surface salinity=====
[[File:Global Sea Surface Temperature - GPN-2003-00032.jpg|thumb|Global sea surface temperature (SST)]]
The global moisture budget is primarily being influenced by tropical sea surface temperatures from the position of the [[Intertropical Convergence Zone]] (ITCZ).<ref>{{cite journal |last1=Wu |first1=Henry C. |last2=Linsley |first2=Braddock K. |last3=Dassié |first3=Emilie P. |last4=Schiraldi |first4=Benedetto |last5=deMenocal |first5=Peter B. |year=2013 |title=Oceanographic variability in the South Pacific Convergence Zone region over the last 210 years from multi-site coral Sr/Ca records |journal=Geochemistry, Geophysics, Geosystems |volume=14 |issue=5 |pages=1435–53 |bibcode=2013GGG....14.1435W |doi=10.1029/2012GC004293 |doi-access=free}}</ref> The [[Southern Hemisphere]] has a unique meteorological feature positioned in the southwestern Pacific Basin called the [[South Pacific convergence zone|South Pacific Convergence Zone (SPCZ)]], which contains a perennial position within the Southern Hemisphere. During [[El Niño Southern Oscillation|ENSO]] warm periods, the [[South Pacific convergence zone|SPCZ]] reverses orientation extending from the equator down south through [[Solomon Islands]], [[Vanuatu]], [[Fiji]] and towards the French [[Polynesian islands|Polynesian Islands]]; and due east towards [[South America]] affecting geochemistry of corals in tropical regions.<ref>{{cite journal |last1=Kiladis |first1=George N. |last2=von Storch |first2=Hans |last3=van Loon |first3=Harry |year=1989 |title=Origin of the South Pacific Convergence Zone |journal=Journal of Climate |volume=2 |issue=10 |pages=1185–95 |bibcode=1989JCli....2.1185K |doi=10.1175/1520-0442(1989)002<1185:OOTSPC>2.0.CO;2 |doi-access=free}}</ref>

Geochemical analysis of skeletal coral can be linked to sea surface salinity (SSS) and [[sea surface temperature]] (SST), from [http://www.esrl.noaa.gov/psd/gcos_wgsp/Timeseries/Nino34/ El Nino 3.4 SSTA] data, of tropical oceans to seawater [[Δ18O|δ<sup>18</sup>O]] ratio anomalies from corals. [[El Niño Southern Oscillation|ENSO]] phenomenon can be related to variations in sea surface salinity (SSS) and [[sea surface temperature|sea surface temperature (SST)]] that can help model tropical climate activities.<ref name="Lukas, R. 1991">{{cite journal |last1=Lukas |first1=Roger |last2=Lindstrom |first2=Eric |year=1991 |title=The mixed layer of the western equatorial Pacific Ocean |journal=Journal of Geophysical Research |volume=96 |issue=S1 |pages=3343–58 |bibcode=1991JGR....96.3343L |doi=10.1029/90JC01951}}</ref>

=====Limited climate research on current species=====
[[File:Porites lutea.jpg|thumb|''Porites lutea'']]
Climate research on live coral species is limited to a few studied species. Studying ''[[Porites]]'' coral provides a stable foundation for geochemical interpretations that is much simpler to physically extract data in comparison to ''[[Platygyra]]'' species where the complexity of ''[[Platygyra]]'' species skeletal structure creates difficulty when physically sampled, which happens to be one of the only multidecadal living coral records used for coral [[paleoclimate]] modeling.<ref name="Lukas, R. 1991" />