''Prymnesium parvum'' is a species of haptophytes (also collectively called Prymnesiophyta). The species is of concern because of its ability to produce the

phycotoxin Phycotoxins (from Greek, ''phykos'', "seaweed"; and ''toxikon'', "toxin") are complex allelopathic chemicals produced by eukaryotic and prokaryotic algal secondary metabolic pathways. More simply, these are toxic chemicals synthesized by photosynth ...

prymnesin. It is a

flagellate A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and the ...

alga Algae ( , ; : alga ) are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from u ...

that is normally found suspended in the

water column A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...

. It was first identified in North America in 1985, but it is not known if it was introduced artificially (e.g., an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...

) or missed in previous surveys. Toxin production mainly kills fish and appears to have little effect on cattle or humans. This distinguishes it from a

red tide A harmful algal bloom (HAB) (or excessive algae growth) is an algal bloom that causes negative impacts to other organisms by production of natural phycotoxin, algae-produced toxins, mechanical damage to other organisms, or by other means. HABs are ...

, which is an

algal bloom An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompas ...

whose toxins lead to harmful effects in people. Although no harmful effects are known, it is recommended not to consume dead or dying fish exposed to a ''P. parvum'' bloom. ''P. parvum'' of Haptophyta is sometimes classified as a golden alga or a golden brown alga, as is Chrysophyceae of

Heterokont Heterokonts are a group of protists (formally referred to as Heterokonta, Heterokontae or Heterokontophyta). The group is a major line of eukaryotes. Most are algae, ranging from the giant multicellular kelp to the unicellular diatoms, which a ...

ophyta, but the taxonomy of algae is under complex revision, leading to contradictions in terms, especially in non-scholarly texts (such as those from state wildlife departments).

Biology

41598 2017 Article BFsrep39892 Fig1b HTML

''P. parvum'' grows in a

salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...

range of 0.5 - 30 psu (Practical Salinity Unit) with an optimum at 15 psu although strains collected in different places appear to have different salinity tolerances. A strain called LB 2797 (isolated from Colorado River in Texas) shows a biphasic growth pattern namely, maximum cell densities increased as salinity increased from 5 to 15 psu but decreased at higher levels in laboratory culture. The alga produces dimethylsulfoniopropionate (DMSP) and other unknown polyols, likely as an adaptation to

osmoregulation Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration ...

. The environment must be between and for ''P. parvum'' to live. Growth at a pH of as low as 5.8 has been observed, but cells typically prefer higher pH ranges. The organism prefers highly light environments, but growth can be inhibited by excessive light ( photoinhibition). The organism is capable of

heterotrophic A heterotroph (; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but ...

growth in the dark in the presence of

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids know ...

and grazes on bacteria, especially when

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...

is limited. It has therefore been hypothesized that ''P. parvum'' satisfies its phosphate needs by consuming bacteria. ''P. parvum'' can use a wide range of

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seve ...

sources, including

ammonium The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternar ...

nitrate Nitrate is a polyatomic ion with the chemical formula . Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are soluble in water. An example of an insoluble ...

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha ...

s (which ones apparently depends on pH), creatine, but is unable to use

urea Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important ...

. New evidence has shown that the toxins produced by this alga are induced by physiological stresses, such as nitrogen and phosphorus depletion due to competition with the environment.

References

External links

*
Literature review of the microalga ''Prymnesium parvum'' and its associated toxicity
* * {{Taxonbar, from=Q7253251 Haptophytes High lipid content microalgae

Biology

See also

References

External links