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Coccolithophore

Coccolithophore
Paraphyletic grouping of algae
Temporal range:
Coccolithus pelagicus
Coccolithus pelagicus
Scientific classificationEdit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Phylum: Haptista
Subphylum: Haptophytina
Class: Prymnesiophyceae
Groups included
Coccolithophore cells are covered with protective calcified (chalk) scales called coccoliths

Coccolithophores, or coccolithophorids, are single-celled organisms which are part of the phytoplankton, the autotrophic (self-feeding) component of the plankton community. They form a group of about 200 species, and belong either to the kingdom Protista, according to Robert Whittaker's five-kingdom system, or clade Hacrobia, according to a newer biological classification system. Within the Hacrobia, the coccolithophores are in the phylum or division Haptophyta, class Prymnesiophyceae (or Coccolithophyceae). Coccolithophores are almost exclusively marine, are photosynthetic and mixotrophic, and exist in large numbers throughout the sunlight zone of the ocean.

Coccolithophores are the most productive calcifying organisms on the planet, covering themselves with a calcium carbonate shell called a coccosphere. However, the reasons they calcify remain elusive. One key function may be that the coccosphere offers protection against microzooplankton predation, which is one of the main causes of phytoplankton death in the ocean.[1]

Coccolithophores are ecologically important, and biogeochemically they play significant roles in the marine biological pump and the carbon cycle.[2][1] Depending on habitat, they can produce up to 40 percent of the local marine primary production.[3] They are of particular interest to those studying global climate change because, as ocean acidity increases, their coccoliths may become even more important as a carbon sink.[4] Management strategies are being employed to prevent eutrophication-related coccolithophore blooms, as these blooms lead to a decrease in nutrient flow to lower levels of the ocean.[5]

The most abundant species of coccolithophore, Emiliania huxleyi, belongs to the order Isochrysidales and family Noëlaerhabdaceae.[6] It is found in temperate, subtropical, and tropical oceans.[7] This makes E. huxleyi an important part of the planktonic base of a large proportion of marine food webs. It is also the fastest growing coccolithophore in laboratory cultures.[8] It is studied for the extensive blooms it forms in nutrient depleted waters after the reformation of the summer thermocline.[9][10] and for its production of molecules known as alkenones that are commonly used by earth scientists as a means to estimate past sea surface temperatures.[11]

  1. ^ a b Haunost, Mathias; Riebesell, Ulf; D'Amore, Francesco; Kelting, Ole; Bach, Lennart T. (30 June 2021). "Influence of the Calcium Carbonate Shell of Coccolithophores on Ingestion and Growth of a Dinoflagellate Predator". Frontiers in Marine Science. 8. Frontiers Media SA. doi:10.3389/fmars.2021.664269. ISSN 2296-7745. Material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.
  2. ^ Rost, Björn; Riebesell, Ulf (2004). "Coccolithophores and the biological pump: Responses to environmental changes". Coccolithophores. Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 99–125. doi:10.1007/978-3-662-06278-4_5. ISBN 978-3-642-06016-8.
  3. ^ Cite error: The named reference de Vries2021 was invoked but never defined (see the help page).
  4. ^ Smith, H.E.K.; et al. (2012), "Predominance of heavily calcified coccolithophores at low CaCO3 saturation during winter in the Bay of Biscay", Proceedings of the National Academy of Sciences, 109 (23): 8845–8849, Bibcode:2012PNAS..109.8845S, doi:10.1073/pnas.1117508109, PMC 3384182, PMID 22615387
  5. ^ Yunev, O.A.; et al. (2007), "Nutrient and phytoplankton trends on the western Black Sea shelf in response to cultural eutrophication and climate changes", Estuarine, Coastal and Shelf Science, 74 (1–2): 63–67, Bibcode:2007ECSS...74...63Y, doi:10.1016/j.ecss.2007.03.030
  6. ^ Cite error: The named reference Hay1967 was invoked but never defined (see the help page).
  7. ^ "Biogeography and dispersal of micro-organisms: a review emphasizing protists", Acta Protozoologica, 45 (2): 111–136, 2005
  8. ^ Buitenhuis, Erik T.; Pangerc, Tanja; Franklin, Daniel J.; Le Quéré, Corinne; Malin, Gill (2008), "Growth Rates of Six Coccolithoripd Strains as a Function of Temperature", Limnology and Oceanography, 53 (3): 1181–1185, Bibcode:2008LimOc..53.1181B, doi:10.4319/lo.2008.53.3.1181, S2CID 16601834
  9. ^ Egge, JK; Aksnes, DL (1992), "Silicate as regulating nutrient in phytoplankton competition", Marine Ecology Progress Series, 83 (2): 281–289, Bibcode:1992MEPS...83..281E, doi:10.3354/meps083281
  10. ^ "Life at the Edge of Sight — Scott Chimileski, Roberto Kolter | Harvard University Press". www.hup.harvard.edu. Retrieved 2018-01-26.
  11. ^ Bentaleb, I.; et al. (1999), "Silicate as regulating nutrient in phytoplankton competition", Marine Chemistry, 64 (4): 301–313, doi:10.1016/S0304-4203(98)00079-6.

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