Coccolithophore


Coccolithophore
Coccolithaceae
The coccolithophore Gephyrocapsa oceanica
Scientific classification
Domain: Eukaryota
Kingdom: Chromalveolata
Phylum: Haptophyta
Class: Prymnesiophyceae
Order: Isochrysidales,
Coccolithales

Coccolithophores (also called coccolithophorids) are single-celled algae, protists and phytoplankton belonging to the division of haptophytes. They are distinguished by special calcium carbonate plates (or scales) of uncertain function called coccoliths (calcareous nanoplankton), which are important microfossils. Coccolithophores are almost exclusively marine and are found in large numbers throughout the surface euphotic zone of the ocean. An example of a globally significant coccolithophore is Emiliania huxleyi.

The arrangement of coccolithophores are as spherical cells about 5–100 micrometres across, enclosed by calcareous plates, coccoliths, about 2–25 micrometres across. Coccolithophores that are alive today have two brown pigment chloroplasts in their cell with the nucleus located between them. The pigments are home to the chlorophyll which carry out photosynthesis. In order to obtain the sunlight needed for photosynthesis, coccolithophores live near the surface of the ocean. Although they have the capability to swim, coccolithophores dominant mode of transport is drifting with ocean current and circulation patterns. However, they may maneuver individually to remain in the euphotic zone during times of extremely favorable conditions.[1]

Due to their microscopic size and the broad distribution of many of their taxa, coccoliths have become very important as index fossils for solving various stratigraphic problems. Microfossils are sensitive indicators of changes in the temperature and salinity of the ocean and sea surface water. The quantitative analysis of calcareous nanoplankton assemblages is being employed to reveal such changes. They also produce alkenones, biomarkers of great utility in reconstructing ancient temperatures.

Coccolithophores have long been thought to respond to increased ocean acidity, caused by increasing CO2 levels, by becoming less calcified. In 2008, Iglesias-Rodriguez et al. were surprised to learn that in fact the opposite can happen in at least some circumstances, with the model species E. huxleyi becoming 40% heavier and more abundant in waters of higher CO2 concentration.[2]

See also

References

  1. ^ Prothero, D. R. (2004), Bringing fossils to life: an introduction to paleobiology (2nd ed.), Boston: McGraw Hill, pp. 210–213, ISBN 0073661708 .
  2. ^ Iglesias-Rodriguez, M. Debora; Halloran, Paul R.; Rickaby, Rosalind E. M.; Hall, Ian R.; Colmenero-Hidalgo, Elena; Gittins, John R.; Green, Darryl R. H.; Tyrrell, Toby et al. (2008), "Phytoplankton Calcification in a High-CO2 World", Science 320 (5874): 336–340, doi:10.1126/science.1154122, PMID 18420926 .

External links


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • coccolithophore — ● coccolithophore nom masculin Algue chrysophycée unicellulaire de haute mer, très abondante au large de certains estuaires (Sénégal) et caractérisée par les écailles microscopiques ou coccolithes qui la recouvrent. (Les coccolithes du crétacé… …   Encyclopédie Universelle

  • coccolithophore — noun Any of many minute mostly marine planktonic biflagellated organisms with brown chromatophores and complex calcareous, less commonly siliceous, shells. See Also: coccolithophorid …   Wiktionary

  • coccolithophore — [ˌkɒkə(ʊ) lɪθəfɔ:] noun Biology a single celled planktonic flagellate that secretes a calcareous shell. [Order Coccolithophorida.] Derivatives coccolithophorid noun & adjective …   English new terms dictionary

  • coccolithophore — coc·co·lith·o·phore …   English syllables

  • coccolithophore — …   Useful english dictionary

  • Ocean acidification — Change in sea water acidity pH caused by anthropogenic CO2 between the 1700s and the 1990s Ocean acidification is the name given to the ongoing decrease in the pH and increase in acidity of the Earth …   Wikipedia

  • Algal bloom — Algal blooms can present problems for ecosystems and human society An algal bloom is a rapid increase or accumulation in the population of algae (typically microscopic) in an aquatic system. Algal blooms may occur in freshwater as well as marine… …   Wikipedia

  • Haptophyte — Taxobox name = Haptophytes image width = 250px image caption = Coccolithophore ( Emiliania huxleyi ) domain = Eukaryota regnum = Chromalveolata phylum = Haptophyta phylum authority = Hibberd 1976 subdivision ranks = Orders subdivision =Class… …   Wikipedia

  • Emiliania huxleyi — Taxobox name = Emiliania huxleyi image width = 250px image caption = Emiliania huxleyi domain = Eukaryota regnum = Chromalveolata phylum = Haptophyta classis = Prymnesiophyceae ordo = Isochrysidales familia = Noelaerhabdaceae genus = Emiliania… …   Wikipedia

  • algae — algal, adj. /al jee/, n.pl., sing. alga / geuh/. any of numerous groups of chlorophyll containing, mainly aquatic eukaryotic organisms ranging from microscopic single celled forms to multicellular forms 100 ft. (30 m) or more long, distinguished… …   Universalium


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.