Editing Coccolithophore (section)

===Role in the food web===
[[File:Bloom in the Barents Sea.jpg|thumb|upright=1.4| Satellite photograph: The milky blue colour of this [[phytoplankton]] bloom in [[Barents Sea]] strongly suggests it contains coccolithophores]]
[[File:Virus cocco 2.jpg|thumb|upright=1.4| A [[coccolithovirus]], ''[[Emiliania huxleyi virus 86]]'' (arrowed), infecting an ''[[Emiliania huxleyi]]'' coccolithophore.<ref name=ViralZone>{{cite web|title=Viral Zone|url=http://viralzone.expasy.org/all_by_species/589.html|publisher=ExPASy|access-date=15 June 2015}}</ref><ref name=ICTV>{{cite web|last1=ICTV|title=Virus Taxonomy: 2014 Release|url=http://ictvonline.org/virusTaxonomy.asp|access-date=15 June 2015}}</ref> This [[giant marine virus]] has one of the largest known [[virus genome]]s.<ref>[http://www.giantvirus.org/top.html Largest known viral genomes] ''Giantviruses.org''. Accessed: 11 June 2020.</ref>]]

Coccolithophores are one of the more abundant primary producers in the ocean.  As such, they are a large contributor to the [[Marine primary production|primary productivity]] of the tropical and subtropical oceans, however, exactly how much has yet to have been recorded.<ref name=Rost2004>{{citation |journal=Coccolithophores |volume=2 |year=2004 |pages=99–125 |title=Coccolithophores and the biological pump: responses to environmental changes |first1=B. |last1=Rost |first2=U. |last2=Riebesell |doi=10.1007/978-3-662-06278-4_5|isbn=978-3-642-06016-8 |url=http://epic.awi.de/11394/1/Ros2004a.pdf |archive-url=https://web.archive.org/web/20121110122119/http://epic.awi.de/11394/1/Ros2004a.pdf |archive-date=2012-11-10 |url-status=live |citeseerx=10.1.1.455.2864 }}</ref>

====Dependence on nutrients====
The ratio between the concentrations of [[nitrogen]], [[phosphorus]] and [[silicate]] in particular areas of the ocean dictates [[Dominance hierarchy|competitive dominance]] within phytoplankton communities. Each ratio essentially tips the odds in favor of either [[diatom]]s or other groups of phytoplankton, such as coccolithophores. A low silicate to nitrogen and phosphorus ratio allows coccolithophores to outcompete other phytoplankton species; however, when silicate to phosphorus to nitrogen ratios are high coccolithophores are outcompeted by diatoms. The increase in agricultural processes lead to [[eutrophication]] of waters and thus, coccolithophore blooms in these high nitrogen and phosphorus, low silicate environments.<ref name="Yunev2007"/>

====Impact on water column productivity====
The [[calcite]] in calcium carbonate allows coccoliths to scatter more light than they absorb. This has two important consequences: 1) Surface waters become brighter, meaning they have a higher [[albedo]], and 2) there is induced [[photoinhibition]], meaning photosythetic production is diminished due to an excess of light.  In case 1), a high concentration of coccoliths leads to a simultaneous increase in surface water temperature and decrease in the temperature of deeper waters. This results in more [[stratification (water)|stratification]] in the water column and a decrease in the vertical mixing of nutrients. However, a 2012 study estimated that the overall effect of coccolithophores on the increase in [[radiative forcing]] of the ocean is less than that from anthropogenic factors.<ref name="Morrissey2012">{{cite book |last1=Morrissey |first1=J.F. |last2=Sumich |first2=J.L. |year=2012 |pages=67 |title=Introduction to the Biology of Marine Life}}</ref> Therefore, the overall result of large blooms of coccolithophores is a decrease in water column productivity, rather than a contribution to global warming.

====Predator-prey interactions====
Their predators include the common predators of all phytoplankton including small fish, zooplankton, and shellfish larvae.<ref name=Hogan2009 /><ref name=Houdan2004>{{citation |journal=Journal of Plankton Research |volume=26 |issue=8 |year=2004 |pages=875–883 |title=Toxicity of coastal coccolithophores (Prymnesiophyceae, Haptophyta)  |first=A. |last=Houdan |doi=10.1093/plankt/fbh079 |display-authors=etal  |doi-access=free }}</ref> Viruses specific to this species have been isolated from several locations worldwide and appear to play a major role in spring bloom dynamics.

=====Toxicity=====
No environmental evidence of coccolithophore toxicity has been reported, but they belong to the class Prymnesiophyceae which contain orders with toxic species. Toxic species have been found in the genera ''Prymnesium'' Massart and ''Chrysochromulina'' Lackey. Members of the genus ''Prymnesium'' have been found to produce haemolytic compounds, the agent responsible for toxicity.  Some of these toxic species are responsible for large fish kills and can be accumulated in organisms such as shellfish; transferring it through the food chain. In laboratory tests for toxicity members of the oceanic coccolithophore genera ''Emiliania, Gephyrocapsa, Calcidiscus'' and ''Coccolithus'' were shown to be non-toxic as were species of the coastal genus ''Hymenomonas'', however several species of ''Pleurochrysis'' and ''Jomonlithus'', both coastal genera were toxic to ''Artemia''.<ref name="Houdan2004"/>