Ceratium fusus

General Dinoflagellate
Shape Needle-shaped, broadest at the Close


(dinoflagellates) "In dinokont dinoflagellates, a furrow encircling the cell one or many times" (Horner 2002). It is also known as the girdle or transverse groove and may be located at, above, or below the midpoint of the cell with the left and right ends meeting or displaced form one another (Horner 2002). In diatoms, this term describes the collective elements of a diatom girdle: "The cingulum is made up of delicate silica bands that join the two valves of a frustule. Most diatoms possess a cingulum, although some may not" (Spaulding et al. 2010).

Size Length 150 - 230 μm, width 15 - 30 μm
Colour Yellow-brown
Connection None (solitary)
Covering Cellulose Close


(plural: thecae) Cell wall. In dinoflagellates, it is composed of cellulose plates within vesicles (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.

Numerous yellow-brown
Lifestyle Close


An organism that is both autotrophic (photosynthesizes or chemosynthesizes) and heterotrophic. That is, it can gain energy both from light (or chemical) energy and also by consuming other organisms. This allows such organisms to take advantage of different environmental conditions.

. Sexual/asexual.


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.

Below a salinity-stratified surface water layer.
Harmful effects Forms extensive blooms
Habitat Coastal, Close


Of or relating to estuaries.

and oceanic
Geographic Cold temperate to tropical waters
Seasonal June - July and autumn
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).

< 34 (optimal)
Temperature > 16 °C (optimal)


Peridinium fusus Ehrenberg 1834
(EOL 2012)


Empire Eukaryota
Kingdom Protozoa
Subkingdom Biciliata
Infrakingdom Alveolata
Phylum Dinoflagellata
Class Dinophyceae
Subclass Peridniphycidae
Order Gonyaulacales
Family Ceritiaceae
Genus Ceratium
Species C. fusus (Ehrenberg) Dujardin 1841

(Guiry and Guiry 2012)


Ceratium fusus is a solitary cell that contains numerous yellow-brown chloroplasts (EOL 2012). It has both sexual and asexual cycles of reproduction and is mixotrophic (Scott and Brandt 2011).


Ceratium fusus cell is very long and Close


Torpedo-shaped. Shaped like a small boat when viewed from above.

. Cell Close


In thecate dinoflagellates, the anterior part of a dinokont cell above the cingulum. The equivalent of epicone for naked dinoflagellates.

ends in a long straight Close


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



The apical or antapical extensions found in some armoured dinoflagellates; they contain cytoplasm, are covered in thecal plates and can be hollow or partially solid (Horner 2002).

while the Close


In thecate dinoflagellates, the posterior part of a dinokont cell above the cingulum. The equivalent of a hypocone for naked dinoflagellates.

ends in a fully developed left Close


Referring to the most posterior point of a cell. The opposite of apical.

horn and a reduced right antapical horn (Montagnes 2006). The right antapical horn is so reduced that it looks like a bump, often giving the cell a gentle curve.


Length: 150 - 230 μm
Width: 15 - 30 μm

Similar species

Ceratium fusus is similar to Ceratium inflatum, but Ceratium inflatum has hypotheca and epitheca that narrow abruptly into horns. Ceratium fusus narrows gently into horns (Montagnes 2006).

Harmful effects

This species is not known to produces toxins, but has been linked to deaths of invertebrate larvae (Montagnes 2006). Ceratium fusus forms extensive blooms forming red tides in Eastern Asia regions (China, Philippines and Thailand; Baek et al. 2007).


Ceratium fusus is mainly a coastal species, but it can be found in estuarine and oceanic environments (Montagnes 2006, Horner 2002).


This species is Close


Widely distributed; occurring in many parts in the world.

in cold temperate to tropical waters (Horner 2002). It is widely observed in sheltered waters in South China Sea and the coast of Hong Kong (Red-Tide 2012).
Blooms in late summer to autumn (EOL 2012).

Growth conditions

Ceratium fusus grows better when water temperature is above 16 °C and salinity is below 34 (Baek et al. 2007).

Environmental Ranges

Depth range (m): 0 - 470
Temperature range (°C): -1.743 - 28.751
Nitrate (μmol L-1): 0.142 - 28.280
Salinity: 25.879 - 34
Oxygen (mL L-1): 0.935 - 8.617
Phosphate (μmol L-1): 0.051 - 2.337

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): 0.648 - 59.039

Bloom characteristics

High cell concentrations of Ceratium fusus have been observed mostly near Close


(pycno- dense; -cline gradient) The depth in the water column at which the density changes rapidly. This density gradient can be caused by temperature (thermocline), salinity (halocline) or both. Because of the difference in density, bodies of water will often stay as distinct layers and not mix.

in Close


The development of distinct non-mixing layers in the water column resulting from a steep gradient in density, which is caused by differences in temperature and/or salinity.


Water column

Referring to a water system from the surface to the bottom sediments. This can be used to understand processes of stratification, mixing and their relationship to nutrient transport. Temperature, salinity, pH, and nutrient levels often vary along the length of the water column.

water columns
(Baek et al. 2007). Blooms are initiated when surface water salinity drops after heavy rainfall, which creates strong pycnocline near the surface of the water (Baek et al. 2007).


Baek, S. H., Shimode, S. and Kikuchi, T. 2007. Reproductive Ecology of the Dominant Dinoflagellate, Ceratium fusus, in Coastal Area of Sagami Bay, Japan. Journal of Oceanography. 63: 35-45.

Encylopedia of Life (EOL) 2012. Ceratium fusus (Ehrenberg) Dujardin 1841. http://eol.org/pages/899358/overview. Accessed 17 Jan 2012.

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

Guiry, M. D. and Guiry, G. M. 2012. Ceratium fusus (Ehrenberg) Dujardin 1841. http://www.algaebase.org/search/species/detail/?species_id=54755. Accessed 17 Jan 2012.

Montagnes, D. 2006. Guide to Harmful Phytoplankton. University of Liverpool, UK. http://www.liv.ac.uk/hab/Data%20sheets/c_fusu.htm. Accessed 17 Jan 2012.

Scott, F. and Brandt, S. 2011. Ceratium fusus (Ehrenberg) Dujardin 1841. http://www.marinespecies.org/aphia.php?p=taxdetails&id=109951. Accessed 17 Jan 2012.

Red-Tide. 2012. Ceratium fusus (Ehrenberg) Dujardin 1841. http://www.red-tide.org/new_site/cfus.htm. Accessed 17 Jan 2012.

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