Polykrikos schwartzii

General Dinoflagellate
Shape Oval or cylindrical
Size Width 100 - 160 μm, length 60 - 100 μm
Colour Green or pink
Connection Solitary cells composed of 2 - 4 zooids
Covering None Close


(dinoflagellates) Describes a cell without a theca, i.e., without cellulose walls (Hoppenrath and Saldarriaga 2010).



(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.

Harmful effects None known
Habitat Coastal and Close


Of or relating to estuaries.

Geographic Worldwide except for polar seas
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).

12 - 39 (optimal)
Temperature 0 - 28 °C (optimal)




Empire Eukaryota
Kingdom Protozoa
Subkingdom Biciliata
Infrakingdom Alveolata
Phylum Myzozoa
Subphylum Dinoflagellata
Class Dinophyceae
Order Gymnodiniales
Family Polykikaceae
Genus Polykrikos
Species P. schwartzii Butschli 1873

(Guiry and Guiry 2012)


Polykrikos schwartzii is a marine athecate dinoflagellate (Smithsonian 2012). It reproduces both sexually and asexually. It is heterotrophic and therefore lacks chloroplasts (Smithsonian 2012).


Polykrikos schwartzii cells are cylindrical but slightly compressed giving them a barrel shape (Smithsonian 2012). P. schwartzii occurs in colonies of 2, 4, 8 or 16 individual units called zooids (Kraberg et al. 2010). Each zooid is closely connected to its neighbour, sharing a cell membrane and a common Close


"In dinokont dinoflagellates, the longitudinal area on the ventral surface that forms a furrow or depression and houses the longitudinal (trailing) flagellum" (Horner 2002).

(Kraberg et al. 2010). Usually, two zooids share a single Close


(plural: nuclei) In eukaryotic cells, a membrane-bound organelle that contains the cell's genetic information; the nucleus controls the activities of the cell by controlling gene expression.

(Smithsonian 2012). Cell Close


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

is green or pink, depending on the cell's food source (Smithsonian 2012). Cells lack chloroplasts but have Close


An ejectable organelle with stinging, sticky threads. Nematocysts are used by some dinoflagellates to capture prey (Smithsonian 2012). This term is primarily used to describe specialized stinging cells in jellyfish.

and food Close


A membrane-bound organelle found in some protists, containing a water solution of organic and inorganic molecules (including enzymes). In some cases, vacuoles may contain engulfed solids (Falkowski et al. 2004).

placed centrally (Kraberg et al. 2010). P. schwartzii has spherical Close


"A thick-walled dormant cell" (Horner 2002).

with a network of protrusions that form a mesh around the cell (Horner 2002).


Length: 100 - 160 μm (colony of 8 zooids) Width: 60 - 100 μm (Kraberg et al. 2010)

Similar species

Polykrikos schwartzii is most commonly misidentified as Polykrikos kofoidii Chatton 1914. P. schwartzii has a straight, centrally placed sulcus while P. kofoidii has an Close


At a slanted angle (i.e., not parallel or perpendicular).

sulcus displaced towards the left side of the cell (Kraberg et al. 2010).

Harmful effects

None known.


This species is mainly coastal and estuarine (Horner 2002).


Polykrikos schwartzii is common in coastal waters throughout the world except for polar seas. It is mostly confused for P. kofoidii hence, exact distribution is not known (Smithsonian 2012). It is also often seen in surface sediments from tropical to sub-arctic coastal regions (Matsuoka et al. 2009).
Polykrikos schwartzii is mostly seen in summer and autumn (Kraberg et al. 2010).

Growth conditions

High abundance of P. schwartzii cysts is used to indicate high 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.

levels and turbulent water conditions (Matsuoka et al. 2003).

Environmental Ranges

Depth range (m): 0 - 824
Temperature range (°C): -0.164 - 28.438
Nitrate (μmol L-1): 0.153 - 21.810
Salinity: 12.594 - 39.013
Oxygen (mL L-1): 3.529 - 9.046
Phosphate (μmol L-1): 0.091 - 1.482

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): 0.927 - 25.813
(EOL 2012)

Bloom characteristics

No information available.


Encylopedia of Life (EOL) 2012. Polykrikos schwartzii Butschli 1873. http://eol.org/pages/90350/details. Accessed 29 Feb 2012.

Guiry, M. D. and Guiry, G. M. 2012. Polykrikos schwartzii Butschli 1873. http://www.algaebase.org/search/species/detail/?species_id=56363. Accessed 29 Feb 2012.

Kraberg, A., Baumann, M. and Durselen, C. D. 2010. Coastal Phytoplankton Photo Guide for Northern European Seas. Verlag Dr. Friedrich Pfeil, Munchen, Germany. 203.

Matsuoka, K., Joyce, L., Kotani, Y. and Matsuyama, Y. 2003. Modern dinoflagellate cysts in hypertrophic coastal waters of Tokyo Bay, Japan. Journal of Planktonic Research. 25(12): 1462-1470.

Matsuoka, K., Kawami, H., Nagai, S., Iwataki, M. and Takayama, H. 2009. Re-examination of cyst-motile relationships of Polykrikos kofoidii Chatton and Polykrikos schwartzii Bütschli (Gymnodiniales, Dinophyceae). Review of Palaeobotany and Palynology. 154(1-4): 79-90.

Smithsonian Institution. 2012. Polykrikos schwartzii Butschli 1873. http://www.sms.si.edu/irlspec/Polykr_schwar.htm. Accessed 29 Feb 2012.

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