Chaetoceros is a genus of diatoms in the family Chaetocerotaceae, first described by the German naturalist C. G. Ehrenberg in 1844. Species of this genus are mostly found in marine habitats, but a few species exist in freshwater. It is arguably the common and most diverse genus of marine planktonic diatoms, with over 200 accepted species. It is the type genus of its family.
Species in the genus Chaetoceros are found in marine waters all over the world, where they can often form algal blooms. Some strains grow quickly and produce high amounts of lipids, sparking interest in potential usage for biofuels.
Description Chaetoceros consists of cells linked together, forming straight, curved or coiled chains (termed filaments). Individual cells are elliptical in valve view, and rectangular in girdle view. One or more plate-like chloroplasts (plastids) are present within the cell.
Like other diatoms, cells of Chaetoceros are surrounded by siliceous cell walls known as frustules, which have two valves. Each valve may or may not have a central area called an annulus and a rimoportula, from which very fine areolae radiate. Each frustule has four hollow processes called setae, or spines, that allow adjacent cells to link together and form colonies. In some species, the setae are penetrated by cytoplasm and chloroplasts along their length.
Some species of Chaetoceros produce resting spores that are highly tolerant to adverse conditions.
Environmental ranges Depth range (m): 0–470 Temperature range (°C): -1.952–29.468 Nitrate (μmol L-1): 0.053 - 34.037 Salinity: 18.564 - 37.775 Oxygen (mL L-1): 4.139 - 9.192 Phosphate (μmol L-1): 0.046 - 2.358 Silicate (μmol L-1): 0.648 - 92.735Ocean Biogeographic Information System (OBIS). 2012. Chaetoceros. http://www.iobis.org/mapper/?taxon_id=611649. Accessed 18 Mar 2012.
Ecology Studies suggest that colonies of Chaetoceros serve as an important food source within the water column and major carbon contributor to the benthic environment. Within the North Water, located in northern Baffin Bay, Chaetoceros has been reported to contribute about 91% of total phytoplankton cells serving as an important primary producer within this area. Therefore, contributing to oxygen production in the North Water. Overall, phytoplankton contributes to over half of Earth's oxygen production.
Chaetoceros blooms have been reported to reach concentrations of 30,100 cells/ml and can persist for multiple months. Blooms are able to persist because individuals can survive at low nutrient levels. When present in large quantities, species with larger, thicker spines can damage organisms' gills.Kraberg, A., Baumann, M. and Durselen, C. D. 2010. Coastal Phytoplankton: Photo Guide for Northern European Seas. Verlag Dr. Friedrich Pfeil, Munchen, Germany. 204. Although, this defensive trait can help the species avoid predation and further promote bloom success. Overall, intensive development of the species of the genus Chaetoceros in the Arctic Ocean has a significant impact on the biogeochemical cycle of organic carbon and silicon, as well as on a wide range of macronutrients, trace and rare earth elements.
Uses Due to its high growth rates, research has been conducted to potentially use of Chaetoceros in biotechnology. Some Chaetoceros species are well-established commercial aquacultures. Many of them are recognized as generally good producers of useful lipids and other biologically active products with high value-added. They have enormous potential for producing nutraceuticals and biofuel.
Diversity Approximately 400 species of Chaetoceros have been described, although many of these descriptions are no longer valid. It is often very difficult to distinguish between different species.C.H. von Quillfeldt., (2001). Identification of Some Easily Confused Common Diatom Species in Arctic Spring Blooms. Botanica Marina Vol. 44: 375–389 Several attempts have been made to restructure this large genus into subgenera and this work is still in progress.Tomas, C. R., Hasle G. R., Syvertsen, E. E., Steidinger, K. A., Tangen, K., Throndsen, J., Heimdal, B. R., (1997). Identifying Marine Phytoplankton, Academic Press.Rines J. E. B., Theriot E. C., (2003). Systematics of Chaetocerotaceae (Bacillariophyceae). I. A phylogenetic analysis of the family, Phycological research 51: 83–98. However, most of the effort to describe species has been focused in boreal areas, and the genus is cosmopolitan, so there are probably many tropical species still undescribed.J.E.B. Rines, P. Boonruang and E.C. Theriot., (2000). Chaetoceros phuketensis sp. nov. (Bacillariophyceae): a new species from the Andaman Sea. Phycological Research 48 (3): 161–168. Some species are known from the fossil record, from the Quaternary of Sweden.
Species Chaetoceros abnormis A.I. Proshkina-Lavrenko Chaetoceros aculeatus I.V. Makarova Chaetoceros adelianus E.E. Manguin Chaetoceros aduncus I.N. Sukhanova Chaetoceros aequatorialis var. antarcticus Manguin Chaetoceros aequatorialis Cleve Chaetoceros affinis f. pseudosymmetricus (E. Steemann Nielsen) M. Torrington-Smith Chaetoceros affinis f. parallelus M. Thorrington-Smith Chaetoceros affinis f. inaequalis M. Thorrington-Smith Chaetoceros affinis Lauder Chaetoceros amanita A. Cleve-Euler Chaetoceros anastomosans Grunow Chaetoceros angularis Schütt Chaetoceros angulatus F. Schütt Chaetoceros anostomosans var. speciosus F. Schütt Chaetoceros armatus T. West Chaetoceros astrabadicus A. Henckel Chaetoceros atlanticus var. compactus (F. Schütt) P.T. Cleve Chaetoceros atlanticus var. neapolitanus (Schroeder) Hustedt Chaetoceros atlanticus var. tumescens A. Grunow Chaetoceros atlanticus Cleve Chaetoceros atlanticus f. audax (F. Schütt) H.H. Gran Chaetoceros atlanticus var. cruciatus (G. Karsten) M. Thorrington-Smith Chaetoceros audax F. Schütt Chaetoceros bacteriastrius G.C. Wallich Chaetoceros bacteriastroides f. imbricatus (L.A. Mangin) M. Thorrington-Smith Chaetoceros bacteriastroides G.H.H. Karsten Chaetoceros bermejense D. U. Hernández-Becerril Chaetoceros bisetaceus J. Schumann Chaetoceros borealis J.W. Bailey Chaetoceros borealoides H.L. Honigmann Chaetoceros breve F. Schütt Chaetoceros brevis Schütt Chaetoceros brussilowi A. Henckel Chaetoceros buceros G.H.H. Karsten Chaetoceros buceros Karsten Chaetoceros bulbosus (Ehrenberg) Heiden Chaetoceros bulbosus f. cruciatus (G. Karsten) H. Heiden Chaetoceros bulbosus f. schimperana (G. Karsten) H. Heiden Chaetoceros bungei Honigmann Chaetoceros calcitrans (Paulsen) Takano, 1968 (or synonym of Chaetoceros simplex var. calcitrans Paulsen, 1905) Chaetoceros calcitrans f. pumilus Takano Chaetoceros californicus A. Grunow Chaetoceros capense G.H.H. Karsten Chaetoceros caspicus C.E.H. Ostenfeld Chaetoceros caspicus var. karianus A. Henckel Chaetoceros caspicus f. pinguichaetus A. Henckel & P. Henckel Chaetoceros castracanei Karsten Chaetoceros castracanei G.H.H. Karsten Chaetoceros ceratospermus var. minor A.F. Meunier Chaetoceros ceratosporus var. brachysetus Rines & Hargraves Chaetoceros ceratosporus Ostenfeld Chaetoceros chunii G.H.H. Karsten Chaetoceros cinctus Gran Chaetoceros clavigera C.E.H. Ostenfeld Chaetoceros clavigerus A. Grunow Chaetoceros clevei F. Schütt Chaetoceros coarctatus Lauder Chaetoceros cochleus F. Schütt Chaetoceros compactus F. Schütt Chaetoceros compressus var. gracilis F. Hustedt Chaetoceros compressus var. hirtisetus J.E.B. Rines & P.E. Hargraves Chaetoceros concavicorne Mangin Chaetoceros confervoides J. Ralfs Chaetoceros confusus S.L. VanLandingham Chaetoceros constrictus Gran Chaetoceros convolutus Castracane Chaetoceros convolutus f. trisetosus Brunel Chaetoceros convolutus f. volans L.I. Smirnova Chaetoceros cornutus G. Leuduger-Fortmorel Chaetoceros coronatus Gran Chaetoceros costatus Pavillard Chaetoceros crenatus (C.G. Ehrenberg) T. Brightwell Chaetoceros crinitus Schütt Chaetoceros criophilus Castracane Chaetoceros cruciatus G.H.H. Karsten Chaetoceros curvatus Castracane Chaetoceros curvisetus Cleve Chaetoceros dadayi Pavillard Chaetoceros danicus Cleve Chaetoceros debilis Cleve Chaetoceros decipiens f. singularis H.H. Gran Chaetoceros decipiens Cleve Chaetoceros delicatulus C.E.H. Ostenfeld Chaetoceros densus Cleve Chaetoceros diadema (Ehrenberg) Gran Chaetoceros dichaeta f. unicellularis H. Heiden Chaetoceros dichaetus Ehrenberg Chaetoceros dichaetus var. polygonus (F. Schütt) H. Heiden Chaetoceros didymus var. praelongus E.J. Lemmermann Chaetoceros didymus f. aestivus H.H. Gran Chaetoceros didymus f. autumnalis H.H. Gran Chaetoceros didymus C.G. Ehrenberg Chaetoceros difficilis Cleve Chaetoceros distichus F. Schütt Chaetoceros distinguendus E.J. Lemmermann Chaetoceros diversicurvatus Van Goor Chaetoceros diversus var. mediterraneus J.L.B. Schröder Chaetoceros diversus Cleve Chaetoceros eibenii (Grunow) Meunier Chaetoceros elmorei Boyer Chaetoceros elongatus Honigmann Chaetoceros exospermus Meunier Chaetoceros externus Gran Chaetoceros fallax Prosckina-Lavrenko Chaetoceros femur F. Schütt Chaetoceros filiferus G.H.H. Karsten Chaetoceros filiforme Meunier Chaetoceros flexuosus Mangin Chaetoceros fragilis Meunier Chaetoceros furca var. macroceras J.L.B. Schröder Chaetoceros furcellatus J.W. Bailey Chaetoceros fusus F. Schütt Chaetoceros galvestonense Collier & Murphy Chaetoceros gastridius (C.G. Ehrenberg) T. Brightwell Chaetoceros gaussii Heiden & Kolbe Chaetoceros gracialis A. Henckel Chaetoceros glandazii Mangin Chaetoceros gobii A. Henckel Chaetoceros gracilis Pantocsek Chaetoceros grunowii F. Schütt Chaetoceros hendeyi Manguin Chaetoceros hispidus var. monicae A. Grunow Chaetoceros hohnii Graebn. & Wujek Chaetoceros holsaticus Schütt Chaetoceros ikari B.V. Skvortzov Chaetoceros imbricatus Mangin Chaetoceros incurvus var. umbonatus Castracane Chaetoceros incurvus Bailey Chaetoceros indicus Karsten Chaetoceros ingolfianus Ostenfeld Chaetoceros intermedius A. Henckel Chaetoceros karianus Grunow Chaetoceros karyanus A. Henckel Chaetoceros knipowitschii A. Henckel Chaetoceros laciniosus Schüt Chaetoceros laciniosus f. protuberans M. Thorrington-Smith Chaetoceros laciniosus f. pelagicus H.H. Gran Chaetoceros lauderi Ralfs Chaetoceros leve F. Schütt Chaetoceros littorale litorale E.J. Lemmermann Chaetoceros lorenzianus var. forceps A.F. Meunier Chaetoceros lorenzianus Grunow Chaetoceros malygini A. Henckel Chaetoceros medius F. Schütt C Chaetoceros meridiana (F. Schütt) G. Karsten Chaetoceros mertensii H.L. Honigmann Chaetoceros messanense Castracane C Chaetoceros minimus (Levander) D. Marino, G. Giuffre, M. Montresor & A. Zingone Chaetoceros misumensis H.H. Gran & K. Yendo Chaetoceros mitra (J.W. Bailey) Cleve Chaetoceros muelleri var. duplex E.J. Lemmermann Chaetoceros muelleri var. subsalsum J.R. Johansen & S. Rushforth Chaetoceros muelleri E.J. Lemmermann Chaetoceros muellerii var. subsalsus J.R. Johansen & Rushforth Chaetoceros nansenii A. Henckel Chaetoceros natatus E.E. Manguin Chaetoceros neglectus Karsten Chaetoceros neobulbosus T.V. Desikachary, S. Gowthaman & Y. Latha Chaetoceros neocompactus S.L. VanLandingham Chaetoceros neogracile S.L. VanLandingham Chaetoceros neupokojewii A. Henckel Chaetoceros nipponicus J. Ikari Chaetoceros odontella (C.G. Ehrenberg) G.L. Rabenhorst Chaetoceros okamurae var. tetrasetus J. Ikari Chaetoceros okamurae J. Ikari Chaetoceros ostenfeldii P.T. Cleve Chaetoceros pachtussowii A. Henckel Chaetoceros pachyceros R. Margalef Chaetoceros pacificus J. Ikari Chaetoceros paradoxus Cleve Chaetoceros paradoxus var. luedersii Engler Chaetoceros parvus F. Schütt Chaetoceros paulsenii f. robustus A. Henckel Chaetoceros pavillardii J. Ikari Chaetoceros pelagicus Chaetoceros pendulus Karsten Chaetoceros perpusillus Cleve Chaetoceros peruvianus var. victoriae Karsten Chaetoceros peruvianus var. gracilis J.L.B. Schröder Chaetoceros peruvianus Brightwell Chaetoceros peruvianus var. robustum P.T. Cleve Chaetoceros peruvianus var. suadivae Karsten