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Corethron criophilum

Classification
General Close

Centric

(diatoms) Having radial symmetry, i.e., cell is shaped like a coin or a tuna can or a soup can.

Centric diatom
Description
Shape Cylindrical
Size Length 20 - 300 μm
Colour Yellow-brown
Connection None, solitary
Covering Silica Close

Frustule

In diatoms, the hard and porous silica cell wall (Horner 2002).

frustule. Rounded Close

Valve

In diatoms, the structurally distinct halves of the cell wall (Becker 1996).

valves.
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Flagellum

(plural: flagella) A tail-like projection that sticks out from the cell body and enables movement.

Flagella		 None
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Chloroplast

An organelle in the cell that contains the cell pigments (Horner 2002). This is where photosynthesis occurs. A chloroplast is a specialized chromatophore.

Chloroplast		 Numerous
Behaviour
Lifestyle Close

Photosynthesis

The chemical process by which light energy, water and carbon dioxide are combined to produce oxygen and organic compounds. Photoautotrophic organisms (plants and algae) use this reaction to produce their own food.

Photosynthetic. Sexual/asexual.
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Bloom

A rapid increase or accumulation of algal populations in an aquatic system. This will likely involve one or a few dominant phytoplankton species. This follows seasonal patterns (i.e., spring, summer or fall bloom) with dominant species being those that are best adapted to the environmental conditions of that time period. Discolouration of the water may be observed because of the algae's pigmentation. Blooms are often green but may be yellow-brown or red depending on the species present.

Bloom		 Never in large numbers.
Harmful effects Physical obstuction of fish gills.
Distribution
Habitat Oceanic
Geographic Most abundant in Antarctic waters
Seasonal Spring and fall, occasionally in summer
Growth Conditions
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Salinity

The dissolved ion content of a body of water. Can be measured in the following units: parts per thousand (PPT or ‰), practical salinity units (PSU), and absolute salinity (g/kg). PPT is measured by weight, denoting the number of parts salt per thousand total parts or a value of 10-3. PSU measures the conductivity of saltwater and compares it in a ratio to a standard KCl solution (because this is a ratio, salinity measured in this way can also be written without units). The newest unit of salinity is absolute salinity, which uses the mass fraction of salt in seawater (g salt per kg seawater) rather than its conductivity (TEOS-20 2010).

Salinity		 28 - 36
Temperature -2 - 30 °C

Synonym(s)

Corethron hystrix Hensen 1887
Corethron valdivae Karsten 1904
(Guiry 2011)

Classification

Empire Eukaryota
Kingdom Chromista
Subkingdom Chromobiota
Infrakingdom Heterokonta
Phylum Bacillariophyta
Subphylum
Class Coscinodiscophyceae
Subclass Corethrophycidae
Order Corethrales
Family Corethraceae
Genus Corethron
Species C. criophilum Castracane 1886

(Guiry and Guiry 2011)

Lifestyle

Photosynthetic. Reproduces sexually and asexually (Guiry 2011). Close

Auxospore

In diatoms, the special cells that restore normal size following cell division. Auxospores are associated with sexual reproduction (Horner 2002).

Auxospores present (Cupp 1943).

Description

Cells are solitary and cylindrical, with semi-spherical valves. One valve has a ring of long Close

Spine

In some diatoms, "closed or solid structures projecting from the cell wall;" in dinoflagellates, solid projections that usually taper to a point.

spines directed outwards. The other valve has a set of similar spines facing inwards and another ring of short, hooked spines also directed outwards. Chloroplasts are numerous and Close

Discoid

Disc-shaped.

discoid (Cupp 1943, Horner 2002).
"The spines are attached to the valve by a kind of ball and socket joint. Hooked spines are delicate and easily lost" (Horner 2002). Close

Intercalary bands

Girdle bands that are furthest away from the valve (Smithsonian 2011).

Intercalary bands are collar-like but indistinct (Cupp 1943).

Measurements

Length Close

Pervalvar axis

The axis through the centre point of the two valves of a frustule. This axis is perpendicular to the valve face.

(pervalvar axis): 20 - 300 μm
Diameter: 5 - 38 μm
(Hendey 1937, cited in Hasle and Syvertsen 1997; Cupp 1943)

Similar species

None. Has unique pill shape with two rings of long spines directed towards one end and a crown of shorter hooked spines pointed the opposite way (pers. comm. D. Cassis).

Harmful effects

May cause physical obstructions in gills of farmed salmon (Whyte et al. 1997). Concentrations of ∼400 to ∼800 cells mL-1 have been recorded with low-level irritation but no fish mortalities; harmful concentration is probably around 500 cells mL-1 (Haigh 2010).

Habitat

Oceanic (Cupp 1943).

Distribution

Geographic:
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Cosmopolitan

Widely distributed; occurring in many parts in the world.

Cosmopolitan, recorded as far north as ∼80 °N (Heimdal 1983, cited in Hasle and Syvertsen 1997) and most abundant in Antarctic waters (Fryxell and Hasle 1971, cited in Hasle and Syvertsen 1997).
Seasonal:
Usually found in spring and fall, occasionally in the summer (Haigh 2010).
Local:
"Fairly common off California, in Gulf of California, and north to Scotch Cap, Alaska. North temperate species" (Cupp 1943).

Growth conditions

Grows normally within a narrow salinity range between 28 and 32 (Aizdaicher and Markina 2010).
Minimum Si Close

Quota

(as in, cell quota for a nutrient) The amount of a macro- or micronutrient required by an organism to fulfill its life cycle.

quota: 0.041 Si:C
Saturating cell quota: 0.158 Si:C
N-saturating cell quota: > 0.106 N:C
(Sommer 1991).

Environmental Ranges

Depth range (m): 0 - 3300
Temperature range (°C): -1.596 - 29.468
Nitrate (μmol L-1): 0.053 - 34.037
Salinity (PSU): 30.119 - 36.252
Oxygen (mL L-1): 3.946 - 8.562
Phosphate (μmol L-1): 0.046 - 2.366
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Silicic acid

A general term to describe chemical compounds containing silicon, oxygen and hydrogen with a general formula of [SiOx(OH)4-2x]n. Diatoms polymerize silicic acid into biogenic silica to form their frustules (Azam and Chisholm 1976).

Silicate (μmol L-1): 0.648 - 116.089
(OBIS, cited in EOL)

Bloom characteristics

Never in large numbers (Cupp 1943).

References

Aizdaicher, N. A. and Markina, Z. V. 2010. The Effect of Decrease in Salinity on the Dynamics of Abundance and the Cell Size of Corethron hystrix (Bacillariophyta) in Laboratory Culture. Ocean Science Journal. 45(1): 1-5.

Cupp, E. E. 1943. Marine Plankton Diatoms of the West Coast of North America. University of California Press. Berkeley, California. 238.

Encyclopedia of Life. Corethron criophilum Castracane. http://www.eol.org/pages/911906. Accessed 15 Jun 2011.

Fryxell, G. A. and Hasle, G. R. 1971. Corethron criophilum Castracane: Its distribution and structure. Antarctic Research Series 17, Biology of the Antarctic Seas. 4: 335-346.

Guiry, M. D. 2011. Corethron criophilum Castracane, 1886. World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=149110. Accessed 15 Jun 2011.

Guiry, M. D. and Guiry, G. M. 2011. Corethron criophilum Castracane. http://www.algaebase.org/search/species/detail/?species_id=37635. Accessed 15 Jun 2011.

Haigh, N. 2010. Harmful Plankton Handbook. HAMP 2010.

Hasle, G. R. and Syvertsen, E. E. 1997. Marine diatoms. In: Tomas, C. R. (ed.) Identifying marine Phytoplankton. Academic Press, Inc., San Diego. 5-385.

Heimdal, B. R. 1983. Phytoplankton and nutrients in the waters north-west of Spitsbergen in the autumn of 1979. Journal of Plankton Research. 5: 901-918.

Hendey, N. I. 1937. The plankton diatoms of the Southern Seas. Discovery Reports. 16: 151-364.

Horner, R. A. 2002. A Taxonomic Guide To Some Common Phytoplankton. Biopress Limited, Dorset Press, Dorchester, UK. 200.

Ocean Biogeographic Information System. Corethron criophilum. http://www.iobis.org/mapper/?taxon_id=426899. Accessed 15 Jun 2011.

Sommer, U. 1991. Comparative nutrient status and competitive interactions of two Antarctic diatoms (Corethron criophilum and Thalassiosira antarctica). Journal of Plankton Research. 13(1): 61-75.

Whyte, J. N. C., David, J. C. and Forbes, J. R. 1997. Harmful algae in Canadian waters and management strategies. Ocean Research. 19(2): 161-171.