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 Live Ammonia tepida (Rotaliida)
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Allogromiida |
The Foraminifera, ("Hole Bearers") or forams for short, are a large group of amoeboid protists with reticulating pseudopods, fine strands of cytoplasm that branch and merge to form a dynamic net. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex The Rhizaria are a species-rich supergroup of Protists They vary considerably in form but for the most part they are Amoeboids with filose reticulose or microtubule-supported For the Brachiopod Genus, see Retaria (brachiopod. Retaria is a clade within the supergroup Rhizaria containing Alcide Charles Victor Marie Dessalines d'Orbigny ( September 6, 1802 - June 30, 1857) was a great French naturalist The Allogromiida are a small group of Foraminiferans including those that produce organic tests (Lagynacea The fusulinids are an extinct group of Foraminiferan protozoa The Globigerinida are a common group of Foraminiferans that are found as marine Plankton (other groups are primarily benthic The miliolids are a group of Foraminiferans abundant in shallow waters such as estuaries and coastlines though they also include oceanic forms The Textulariida are a group of common Foraminiferans that produce agglutinated shells composed of foreign particles in an organic or calcareous cement Xenophyophores are marine Protozoans giant single-celled organisms found throughout the world's oceans but in their greatest numbers on the Abyssal plains Amoeboids are Unicellular lifeforms that mainly consist of Contractile vacuoles, a nucleus, and cytoplasm as their basic structure Protists (ˈproʊtɨst are a diverse group of eukaryotic Microorganisms Historically protists were treated as the kingdom Protista but this Pseudopods or pseudopodia (from the Greek word ψευδοπόδια, ψευδός "fake false" The cytoplasm is the contents of a cell that is enclosed within the Plasma membrane. [1] They typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate in structure. [2] About 275,000 species are recognized, both living and fossil. FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. They are usually less than 1 mm in size, but some are much larger, and the largest recorded specimen reached 19 cm. The largest organism found on earth can be measured using a variety of methods
Although as yet unsupported by morphological correlates, molecular data strongly suggest that Foraminifera are closely related to the Cercozoa and Radiolaria, both of which also include amoeboids with complex shells; these three groups make up the Rhizaria. The Cercozoa are a group of Protists including most Amoeboids and Flagellates that feed by means of filose pseudopods Radiolarians (also radiolaria) are Amoeboid Protozoa that produce intricate Mineral Skeletons typically with a central capsule The Rhizaria are a species-rich supergroup of Protists They vary considerably in form but for the most part they are Amoeboids with filose reticulose or microtubule-supported [3] However, the exact relationships of the forams to the other groups and to one another are still not entirely clear.
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Living forams
Modern forams are primarily marine, although they can survive in brackish conditions. [4] A few species survive in fresh water and one even lives in damp rainforest soil. They are very common in the meiobenthos, and about 40 morphospecies are planktonic. Meiofauna are small benthic invertebrates that live in both marine and fresh water environments. Plankton consist of any drifting Organisms ( Animals Plants Archaea, or Bacteria) that inhabit the Pelagic zone of [1] This count may however represent only a fraction of actual diversity, since many genetically discrepant species may be morphologically indistinguishable. [5] The cell is divided into granular endoplasm and transparent ectoplasm. The pseudopodial net may emerge through a single opening or many perforations in the test, and characteristically has small granules streaming in both directions. [4]
The pseudopods are used for locomotion, anchoring, and in capturing food, which consists of small organisms such as diatoms or bacteria. Diatoms ( Greek: (dia = "through" + (temnein = "to cut" i [1] A number of forms have unicellular algae as endosymbionts, from diverse lineages such as the green algae, red algae, golden algae, diatoms, and dinoflagellates. Algae ( sing. alga are a large and diverse group of simple typically Autotrophic organisms ranging from Unicellular to Multicellular forms An endosymbiont is any Organism that lives within the body or cells of another organism i The green algae (singular green alga) are the large group of Algae from which the Embryophytes (higher plants emerged The red algae (Rhodophyta ˌroʊdəˈfaɪtə roʊˈdɒfɨtə from Greek: ῥόδον (rhodon = rose + φυτόν (phyton = plant thus red plant are The golden algae or chrysophytes are a large group of Heterokont Algae found mostly in freshwater Diatoms ( Greek: (dia = "through" + (temnein = "to cut" i The dinoflagellates are a large group of Flagellate Protists Most are marine Plankton, but [1] Some forams are kleptoplastic, retaining chloroplasts from ingested algae to conduct photosynthesis. Kleptoplasty is a phenomenon whereby Plastids from Algae are sequestered by a host organism Chloroplasts are Organelles found in Plant cells and eukaryotic Algae that conduct Photosynthesis. Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. [6]
The foraminiferal life-cycle involves an alternation between haploid and diploid generations, although they are mostly similar in form. "Haplo" redirects here For the fictional character see The Death Gate Cycle. "Haplo" redirects here For the fictional character see The Death Gate Cycle. The haploid or gamont initially has a single nucleus, and divides to produce numerous gametes, which typically have two flagella. Hagal ( Hagall) redirects here For the rune see Haglaz Chusuk redirects here In Cell biology, the nucleus (pl nuclei; from Latin la ''nucleus'' or la ''nuculeus'' "little nut" or kernel is a membrane-enclosed A gamete (from Ancient Greek γαμέτης; translated gamete = wife gametes = husband is a cell that fuses with another gamete A flagellum ( plural flagella) is a tail-like structure that projects from the Cell body of certain Prokaryotic and Eukaryotic cells and it The diploid or schizont is multinucleate, and after meiosis fragments to produce new gamonts. Multinucleate (also multinucleated, coenocytic) cells have more than one nucleus per cell, which is the result of nuclear division not being In Biology or life science meiosis (pronounced my-oh-sis is a process of reductional division in which the number of chromosomes per cell is cut in half Multiple rounds of asexual reproduction between sexual generations is not uncommon in benthic forms. Asexual reproduction is a form of reproduction which does not involve Meiosis, Ploidy reduction or Fertilization. [4] Foramanifera typically live for about a month. [7]
Tests
The form and composition of the test is the primary means by which forams are identified and classified. Most have calcareous tests, composed of calcium carbonate. Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3 [4] In other forams the test may be composed of organic material, made from small pieces of sediment cemented together (agglutinated), and in one genus of silica. The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide Openings in the test, including those that allow cytoplasm to flow between chambers, are called apertures.
Tests are known as fossils as far back as the Cambrian period,[8] and many marine sediments are composed primarily of them. The Cambrian is a geologic period and system that began about Ma (million years ago at the end of the Proterozoic eon and ended about Ma with For instance, the limestone that makes up the pyramids of Egypt is composed almost entirely of nummulitic benthic foraminifera. [9] Production estimates indicate that reef foraminifera annually generate approximately 43 million tons of calcium carbonate and thus play an essential role in the production of reef carbonates. [10]
Genetic studies have identified the naked amoeba "Reticulomyxa" and the peculiar xenophyophores as foraminiferans without tests. Xenophyophores are marine Protozoans giant single-celled organisms found throughout the world's oceans but in their greatest numbers on the Abyssal plains A few other amoeboids produce reticulose pseudopods, and were formerly classified with the forams as the Granuloreticulosa, but this is no longer considered a natural group, and most are now placed among the Cercozoa. [11]
Evolutionary significance
Dying planktonic foraminifera continuously rain down on the sea floor in vast numbers, their mineralized tests preserved as fossils in the accumulating sediment. Beginning in the 1960s, and largely under the auspices of the Deep Sea Drilling, Ocean Drilling, and International Ocean Drilling Programmes, as well as for the purposes of oil exploration, advanced deep-sea drilling techniques have been bringing up sediment cores bearing foraminifera fossils by the millions. The Deep Sea Drilling Project (DSDP was anocean drilling project running from 1968 to 1983 The Ocean Drilling Program ( ODP) was an international cooperative effort to explore and study the composition and structure of the earth's ocean basins The effectively unlimited supply of these fossil tests and the relatively high-precision age-control models available for cores has produced an exceptionally high-quality planktonic foraminifera fossil record dating back to the mid-Jurassic, and presents an unparalleled record for scientists testing and documenting the evolutionary process. The exceptional quality of the fossil record has allowed an impressively detailed picture of species inter-relationships to be developed on the basis of fossils, in many cases subsequently validated independently through molecular genetic studies on extant specimens.
Uses of forams
Because of their diversity, abundance, and complex morphology, fossil foraminiferal assemblages are useful for biostratigraphy, and can accurately give relative dates to rocks. Biostratigraphy is the branch of Stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the Fossil assemblages contained The oil industry relies heavily on microfossils such as forams to find potential oil deposits. The petroleum industry includes the global processes of exploration, extraction, refining, transporting (often by Oil tankers and pipelines Micropaleontology (also sometimes spelled as micropalaeontology) is that branch of Paleontology which studies microfossils [12]
Calcareous fossil foraminifera are formed from elements found in the ancient seas they lived in. Thus they are very useful in paleoclimatology and paleoceanography. Paleoclimatology (also Palaeoclimatology) is the study of Climate change taken on the scale of the entire History of Earth. Paleoceanography is the study of the history of the Oceans in the geologic past with regard to circulation Chemistry, Biology, geology and patterns They can be used to reconstruct past climate by examining the stable isotope ratios of oxygen, and the history of the carbon cycle and oceanic productivity by examining the stable isotope ratios of carbon;[13] see δ18O and δ13C. Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge Geographic patterns seen in the fossil records of planktonic forams are also used to reconstruct ancient ocean currents. An ocean current is continuous directed movement of Ocean water. Because certain types of foraminifera are found only in certain environments, they can be used to figure out the kind of environment under which ancient marine sediments were deposited.
For the same reasons they make useful biostratigraphic markers, living foraminiferal assemblages have been used as bioindicators in coastal environments, including indicators of coral reef health. Bioindicators are Species used to monitor the health of an environment or ecosystem Because calcium carbonate is susceptible to dissolution in acidic conditions, foraminifera may be particularly affected by changing climate and ocean acidification.
References
- ^ a b c d Hemleben, C. ; Spindler, M. & Anderson, O. R. (1989). Modern Planktonic Foraminifera. Springer-Verlag, 363. Springer Science+Business Media or Springer (ˈʃpʁɪŋɐ is a worldwide Publishing company based in Germany, which publishes textbooks academic
- ^ Kennett, J. P. ; Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera: A Phylogenetic Atlas. Hutchinson Ross, 265.
- ^ Cavalier-Smith, T. (2003). "Protist phylogeny and the high-level classification of Protozoa". European Journal of Protistology 34 (4): 338-348.
- ^ a b c d Sen Gupta, B. K. (1983). Modern Foraminifera. Springer, 384. Springer Science+Business Media or Springer (ˈʃpʁɪŋɐ is a worldwide Publishing company based in Germany, which publishes textbooks academic
- ^ Kucera, M. ; Darling, K. F. (2002). "Genetic diversity among modern planktonic foraminifer species: its effect on paleoceanographic reconstructions". Philosophical Transactions of the Royal Society of London A360 (4): 695-718.
- ^ Bernhard, J. M. ; Bowser, S. M. (1999). "Benthic foraminifera of dysoxic sediments: chloroplast sequestration and functional morphology". Earth Science Reviews 46: 149-165.
- ^ Crowley, T. J. ; Zachos, J. C. (2000). "Comparison of zonal temperature profiles for past warm time periods". Warm Climates in Earth History: 50-76.
- ^ http://www.newscientist.com/channel/life/mg19826553.500-sea-creatures-had-a-thing-for-bling.html
- ^ Foraminifera: History of Study, University College London, retrieved 20 September 2007
- ^ Langer, M. University College London ( UCL) is a multi-faculty university institution based in the United Kingdom and a constituent college of the University of London Events 451 - The Battle of Chalons takes place in North Eastern France. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. R. ; Silk, M. T. B. , Lipps, J. H. (1997). "Global ocean carbonate and carbon dioxide production: The role of reef foraminifera". Journal of Foraminiferal Research 27 (4): 271-277.
- ^ Adl, S. M. ; Simpson, A. G. B. , Farmer, M. A. , Anderson, R. A. , Anderson, O. R. , Barta, J. A. , Bowser, S. M. , Brugerolle, G. , Fensome, R. A. , Fredericq, S. , James, T. Y. , Karpov, S. , Kugrens, P. , Krug, J. , Lane, C. E. , Lewis, L. A. , Lodge, J. , Lynn, D. H. , Mann, D. G. , McCourt, R. M. , Mendoza, L. , Moestrup, O. , Mozley-Standridge, S. E. , Nerad, T. A. , Shearer, C. A. , Smirnov, A. E. , Speigel, F. W. , Taylor, M. F. J. R. (2005). "The new higher level classification of Eukaryotes with emphasis on the taxonomy of Protists". Journal of Eukaryotic Microbiology 52 (5): 399-451.
- ^ Boardman, R. S. (1987). Fossil Invertebrates. Blackwell, 714. Blackwell Publishing Ltd was a Learned society publishing company based in Oxford, England.
- ^ Zachos, J. C. ; Pagani, M. , Sloan, L. , Thomas, E. , and Billups, K. (2001). "Trends, Rhythms, and Aberrations in Global Climate, 65 Ma to Present". Science 292: 686-693.
Foraminifera can also be utilised in archaeology in the provenancing of some stone Raw Material types. Some stone types, such as chert, are commonly found to contain fossilised foraminifera. The types and concentrations of these fossils within a sample of stone can be used to match that sample to a source known to contain the same 'fossil signature'.
External links
- General information
- Researchers at the University of South Florida developed a system using foraminifera for monitoring coral reef environments
- University College London's micropaleontology site has an overview of foraminifera, including many high-quality SEMs
- Illustrated glossary of terms used in foraminiferal research is the Lukas Hottinger's glossary published in the OA e-journal "Carnets de Géologie - Notebooks on Geology"
- Information on Foraminifera Martin Langer's Micropaleontology Page
- Benthic foraminifera information from the 2005 Urbino Summer School of Paleoclimatology
- Resources
- The star*sand project (part of micro*scope) is a cooperative database of information about foraminifera
- 3D models of forams, generated by X-ray tomography
- CHRONOS has several foraminifera resources, including a taxon search page and a micro-paleo section
- eForams is a web site focused on foraminifera and modeling of foraminiferal shells
- Foraminifera Gallery Illustrated catalog of recent and fossil Foraminifera by genus and locality
Dictionary
foraminifera
-noun
- A large group of amoeboid protists, of the order Foraminifera, that are mostly marine.
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