my-server
← Wiki

Chaetoceros

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<br /> Temperature range (°C): -1.952–29.468<br /> Nitrate (μmol L-1): 0.053 - 34.037<br /> Salinity: 18.564 - 37.775<br /> Oxygen (mL L-1): 4.139 - 9.192<br /> Phosphate (μmol L-1): 0.046 - 2.358<br /> Silicate (μmol L-1): 0.648 - 92.735<br />

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. 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. Several attempts have been made to restructure this large genus into subgenera and this work is still in progress. 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. Some species are known from the fossil record, from the Quaternary of Sweden.

Species

See also

Viruses associated with Chaetoceros species:

References

External links