Protoperidinium steinii

General Dinoflagellate
Shape Round with a slender cone on the top and two thin Close


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

at the bottom
Size Length 39 - 60 μm, width 22 - 44 μm
Colour Clear, pink or yellow (live). Brown (fixed with Close

Lugol's iodine solution

A solution of elemental iodine and potassium iodide in water; it was first used in 1829 by French physician Jean Lugol as a disinfectant. Lugol's iodine can be used as fixative to preserve phytoplankton samples for visual analysis at a later time (Leakey et al. 1994).

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.

Lifestyle Close


An organism that cannot convert inorganic carbon into a usable energy source. Instead, it consumes other organisms to obtain organic carbon for growth.

. 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.

Information not available
Harmful effects Information not available
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).

and oceanic
Geographic Close


Widely distributed; occurring in many parts in the world.

, worldwide
Seasonal Summer to 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).

33 - 36 (optimal)
Temperature 2 - 25 °C (optimal)


Peridinium steinii Jorgensen 1889
Peridinium michaelis Stein 1883
(Horner 2002)


Empire Eukaryota
Kingdom Protozoa
Subkingdom Biciliata
Infrakingdom Alveolata
Phylum Myzozoa
Subphylum Dinoflagellata
Class Dinophyceae
Order Peridiniales
Family Protoperidiniaceae
Genus Protoperidinium
Species P. steinii (Jorgensen) Balech 1974

(Guiry and Guiry 2012)


This species is a heterotrophic dinoflagellate that reproduces both sexual and asexually. It also has a 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 stage
(Kraberg et al. 2010). Cells are pink or yellow, depending on their food source. Cells feed by extruding their Close


In a eukaryotic cell, a gel-like substance within the cell membrane that contains all the organelles except for the nucleus.

out of their theca in the form of a Close


A semi-permanent extension of the cytoplasm used for locomotion and feeding by some flagellate protozoans.

and engulfing the prey items. Once it has absorbed the contents of the prey, it retracts itself back into its theca. This is called Close


(feeding) A mode of feeding used by some heterotrophic dinoflagellates. The dinoflagellate extrudes its cytoplasm, engulfing its food (often a cell or chain of cells). The food is digested outside the dinoflagellate's cell. The dinoflagellate then pulls its cytoplasm and its newly digested meal back inside its theca. This method of feeding allows dinoflagellates to eat food that is bigger than itself.

feeding (Menden-Deuer et al. 2005, Kraberg et al. 2010).


Protoperidinium steinii is round with a long 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).

(Horner 2002). The Close


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

is round and has two three-winged long spines (Horner 2002).


Length: 39 - 60 μm
Width: 22 - 44 μm
(Kraberg et al. 2010)

Similar species

It similar to Protoperidinium cerasus but the apical horn in P. cerasus is more offset (not centred) than that of P. steinii (Kraberg et al. 2010). P. steinii is also similar to P. pyriforme, but P. steinii has a more pronounced apical horn (Kraberg et al. 2010)

Harmful effects

No information available.


Neritic and oceanic (Horner 2002).


P. steinii has a worldwide distribution (Kraberg et al. 2010).
It is commonly seen in coastal waters in the summer to autumn (Kraberg et al. 2010).

Growth conditions

Information not available.

Environmental Ranges

Depth range (m): 0 - 470
Temperature range (°C): 2.465 - 25.489
Nitrate (μmol L-1): 0.149 - 9.593
Salinity: 33.935 - 35.667
Oxygen (mL L-1): 4.709 - 7.728
Phosphate (μmol L-1): 0.074 - 1.452

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): 1.245 - 10.970
(EOL 2012)

Bloom characteristics

No information available.


Encylopedia of Life (EOL). 2012. Protoperidinium steinii (Jorgensen) Balech 1974. Accessed 24 Mar 2012.

Guiry, M. D. and Guiry, G. M. 2012. Protoperidinium steinii (Jorgensen) Balech 1974. Accessed 14 Mar 2012.

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. 203.

Menden-Deuer, S., Lessard, E. J., Satterberg, J. and Grunbaum, D. 2005. Growth rates and starvation survival of three species of the pallium-feeding, thecate dinoflagellate genus Protoperidinium. Aquatic Microbial Ecology. 41: 145-152.

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