Genus: Dinophysis

Classification
General Dinoflagellate
Description
Shape Oval to D-shaped cells with a "wing" on one side and a "crown" on top
Size Length 22 - 105 μm, width 22 - 66 μm
Colour Golden brown to reddish brown
Connection Solitary
Covering Cellulose Close

Theca

(plural: thecae) Cell wall. In dinoflagellates, it is composed of cellulose plates within vesicles (Horner 2002).

theca
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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 chloroplasts
Behaviour
Lifestyle Close

Autotroph/autotrophic

An organism that can use inorganic materials for primary production of complex organic compounds by practicing photosynthesis or chemosynthesis. For example, plants are autotrophic organisms.

Autotrophic
, Close

Mixotroph/mixotrophic

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.

mixotrophic
. 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
Abundant in sheltered areas
Harmful effects Diarrhetic shellfish poisoning Close

Diarrhetic Shellfish Poisoning

(DSP) Mainly caused by okadaic acid, a toxin produced by some diatoms. When shellfish consume phytoplankton, they can bioconcentrate the toxin leading to non-life threatening symptoms that may include diarrhea, nausea, vomiting and cramps (Yasumoto et al. 1985).

(DSP
)
Distribution
Habitat Close

Neritic

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).

Neritic
and oceanic
Geographic Temperate to tropical waters
Seasonal Late spring to 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 - 39
Temperature 12 - 22°C
D. acuminata D. acuta
D. fortii D. parva

Classification


Empire Eukaryota
Kingdom Protozoa
Subkingdom Biciliata
Infrakingdom Alveolata
Phylum Dinoflagellata
Subphylum
Class Dinophyceae
Subclass
Order Dinophysiales
Family Dinophysiaceae
Genus Dinophysis

(Guiry and Guiry 2012)

Lifestyle


Most of the species in the genus are autotrophic, but some are mixotrophic (e.g., D. acuminata and D. rotundata; Dodge 1982). They reproduce asexually (Smithsonian 2012).

Description


Most species in this genus have clamshell-shaped cell, with a crown on top and wing or fin at the side. Some species are more rounded (e.g., D. parva; Horner 2002).

Measurements


Length: 22 - 105 μm
Width: 22 - 66 μm
(Horner 2002)

Key to local species


Cell with almost straight Close

Posterior

The back end of a cell. Opposite of anterior.

posterior
sides meeting at acute angle, a fairly sharp tip and widest below the middle section. D. acuta
Cell with round or oval posterior sides. D. acuminata
Cell with round or oval posterior sides with a bulge on one side. D. fortii
Overall round, relatively small cell. D. parva

Harmful effects


Cells produce Close

Lipophilic

Having the ability to combine with or dissolve lipids.

lipophilic
toxins (okadaic acid derivatives and pectenotoxins) causing diarrhetic shellfish poisoning (DSP), which affects humans (Hoshial et al. 2003).

Habitat


Neritic and oceanic (Horner 2002).

Distribution


Cosmopolitan in temperate to tropical waters worldwide (Horner 2002).

Environmental Ranges


Depth range (m): 0 - 305
Temperature range (°C): -1.314 - 28.429
Nitrate (μmol L-1): 0.551 - 10.777
Salinity: 18.564 - 39.252
Oxygen (mL L-1): 4.915 - 9.116
Phosphate (μmol L-1): 0.048 - 0.745
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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): 0.754 - 36.110
(EOL 2012)

References


Dodge J. D. 1982. Marine Dinoflagellates of the British Isles. Her Majesty's Stationary Office, London, UK. 303.

Encyclopedia of Life (EOL). 2012. Dinophysis fortii Pavillard 1923. http://eol.org/pages/901388/overview. Accessed 18 Sept 2011.

Guiry, M. D. and Guiry, G. M. 2011. Dinophysis fortii Pavillard 1923. http://www.algaebase.org/search/species/detail/?species_id=52238. Accessed on 18 Sept 2011.

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

Hoshial, G., Suzuki, T., Kamiyama, T., Yamasaki, M. and Ichimi, K. 2003. Water temperature and salinity during the occurrence of Dinophysis fortii and Dinophysis acuminata in Kesennuma Bay, northern Japan. Fisheries Science. 69: 1303-1305.


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