Chaetoceros debilis

General Close


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

Shape Elliptic cylinder
Size Large diameter 8 - 40 μm, length 6 - 20 μm
Colour Yellow-brown
Connection Crossing of adjacent Close


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

Covering Silica Close


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



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



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

Lifestyle Close


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.

. Sexual/asexual. Close

Resting spore

In diatoms, a cell that requires a dormancy period prior to germination and can survive for several years; usually developed to survive adverse conditions. They are commonly observed in centric but not pennate diatoms. The morphology of the spore may be similar or different from a vegetative cell; they usually have heavily silicified walls and are rich in storage products (Horner 2002).

Resting spores


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.

Information not available
Harmful effects May cause physical damage to fish gills
Habitat Close


Describing shallow, near-shore areas and the organisms that live there. Refers to shallow marine waters ranging from the low tide mark to the continental shelf. Varying amounts of sunlight penetrate the water, allowing photosynthesis by both phytoplankton and bottom-dwelling organisms. Close proximity to land favours high nutrient content and biological activity (Encyclopedia Britannica 2011).

Geographic Close


Widely distributed; occurring in many parts in the world.

, more common in cooler to temperate regions
Seasonal Late winter to spring
Growth Conditions


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).

19 - 36
Temperature -2 - 29 °C


Chaetoceros vermiculatus Schütt 1895 Close


A difference in type. In naming species, a heterotypic synonym is one that comes into being when a taxon becomes part of a different taxon. Compare to homotypic.

(Guiry and Guiry 2012)
*Sometimes referred to as C. debile (Guiry 2012).


Empire Eukaryota
Kingdom Chromista
Subkingdom Harosa
Infrakingdom Heterokonta
Phylum Ochrophyta
Subphylum Khakista
Class Bacillariophyceae
Subclass Coscinodiscophycidae
Order Chaetocerotales
Family Chaetocerotaceae
Genus Chaetoceros
Species C. debilis Cleve 1894

(Guiry and Guiry 2012)


Photosynthetic. Reproduces sexually and asexually (Guiry 2012). Resting spores present (see Description; Cupp 1943).


Cells are roughly rectangular in Close


In diatoms, the portion of the cell wall between the two valves of a cell; made up of intercalary bands (bands closest to the valves) and connecting bands (bands in the middle of the girdle). In dinoflagellates, the equivalent of a cingulum or transverse furrow (Horner 2002).

view and connected in spiralling chains. Close


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

are flat or slightly convex (although the spines make it seem concave). Close


"In some diatoms, the space between the valves of adjacent cells in chains" (Horner 2002).

are narrowly oval and sometimes slightly constricted in the middle. Spines are thin and arise just within the Close


The outline or border that defines the shape of an organism or cell.

, crossing just outside their base and extending outwards from the spiral. One chloroplast per cell (Cupp 1943). Cells are yellow-brown in colour.
When present, a resting spore is located in the centre of the cell. The primary valve has two humps and two spines protruding into the corners of the mother cell; the secondary valve is smooth, vaulted and occasionally has humps and/or spines (Cupp 1943, Horner 2002).


Large diameter Close


(axis, spine) The region of the apex or point. Refers to the most anterior point or region of the cell (HPP 2003).

axis): 8 - 40 μm
Small diameter Close

Transapical axis

In diatoms, the longitudinal axis of the valve.

(transapical axis
): 5 - 25 μm
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
): 6 - 20 μm
(Kraberg et al. 2010)

Similar species

C. curvisetus, which forms spirals with wider diameter, and the apertures are larger and widely oval (Kraberg et al. 2010).

Harmful effects

May cause physical damage to fish gills (Kraberg et al. 2010).


Neritic (Cupp 1943).


Cosmopolitan, but mainly found in cooler to temperate regions (Hasle and Syvertsen 1997, Kraberg et al. 2010).
Present from spring to fall around Northern European seas, with highest abundance in the spring (Kraberg et al. 2010). An important contributor to spring blooms in NE Atlantic and in Arctic waters (Degerlund and Eilertsen 2010).
Often very abundant from late winter to spring off California, and sometimes from late fall to early winter (Cupp 1943). In some years, it has bloomed during the summer off the west coast of Vancouver Island (Harris et al. 2009).

Growth conditions

May be favoured by high iron levels (Assmy et al. 2007). Can survive under a wide range of light intensities and Close


Various chemical substances that an organism needs for metabolism (i.e., to live and grow). These are usually taken up from the environment. Some examples include nitrate, phosphate, silica (for diatoms), iron, copper, etc. Some nutrients, like copper, are required for growth, but can also be toxic at high levels.

conditions, but does not grow well under iron- and silica-limited conditions (Hoffman et al. 2007).

Environmental Ranges

Depth range (m): 0 - 270
Temperature range (°C): -1.894 - 29.365
Nitrate (μmol L-1): 0.056 - 24.783
Salinity: 18.564 - 35.565
Oxygen (mL L-1): 4.524 - 9.192
Phosphate (μmol L-1): 0.051 - 2.131

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).

(μmol L-1): 1.153 - 50.314
(OBIS 2012, cited in EOL 2012)

Bloom characteristics

Information not available.


Assmy, P., Henjes, J., Klaas, C. and Smetacek, V. 2007. Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean. Deep-Sea Research I. 54: 340-362.

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

Degerlund, M. and Eilertsen, H. C. 2010. Main species characteristics of phytoplankton spring blooms in NE Atlantic and Arctic waters (68 - 80° N). Estuaries and Coasts. 33: 242-269.

Encyclopedia of Life (EOL). 2012. Chaetoceros debile. Accessed 18 Mar 2012.

Guiry, M. D. 2012. Chaetoceros debilis Cleve, 1894. Accessed 18 Mar 2012.

Guiry, M. D. and Guiry, G. M. 2012. Chaetoceros debilis Cleve. Accessed 18 Mar 2012.

Harris, S. L., Varela, D. E., Whitney, F. W. and Harrison, P. J. 2009. Nutrient and phytoplankton dynamics off the west coast of Vancouver Island during the 1997/98 ENSO event. Deep-Sea Research II. 56: 2487-2502.

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.

Hoffman, L. J., Peeken, I. and Lochte, K. 2007. Co-limitation by iron, silicate, and light of three Southern Ocean diatom species. Biogeosciences Discussions. 4: 209-247.

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

Kraberg, A., Baumann, M. and Durselen, C. D. 2010. Coastal Phytoplankton: Photo Guide for Northern European Seas. Verlag Dr. Friedrich Pfeil, Munchen, Germany. 204.

Ocean Biogeographic Information System (OBIS). 2012. Chaetoceros debilis. Accessed 18 Mar 2012.

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