''Prymnesium parvum'' is a species of

haptophyte The haptophytes, classified either as the Haptophyta, Haptophytina or Prymnesiophyta (named for '' Prymnesium''), are a clade of algae. The names Haptophyceae or Prymnesiophyceae are sometimes used instead. This ending implies classification at ...

(also collectively called Prymnesiophyta). The species is of concern because of its ability to produce the phycotoxin 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 ) is an informal term for any organisms of a large and diverse group of photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular microalgae, suc ...

that is normally found suspended in the

water column The (oceanic) water column is a concept used in oceanography to describe the physical (temperature, salinity, light penetration) and chemical ( pH, dissolved oxygen, nutrient salts) characteristics of seawater at different depths for a defined ...

. It was first identified in

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

in 1985, but it is not known if it was introduced artificially (e.g., an

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

) 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, sometimes called a red tide in marine environments, is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, water deoxygenation, ...

, which is an

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

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. ''Prymnesium parvum'' of Haptophyta is sometimes colloquially misnamed "golden alga" causing confusion with

golden alga The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae, or golden algae, are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer to a single species, '' Prymnesium parvum'', wh ...

or Chrysophyceae of

Heterokont The stramenopiles, also called heterokonts, are protists distinguished by the presence of stiff tripartite external hairs. In most species, the hairs are attached to flagella, in some they are attached to other areas of the cellular surface, an ...

ophyta, 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 (chemistry), 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 dimensio ...

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 Dimethylsulfoniopropionate (DMSP), is an organosulfur compound with the formula (CH3)2S+CH2CH2COO−. This zwitterionic metabolite can be found in marine phytoplankton, seaweeds, and some species of terrestrial and aquatic vascular plants. ...

(DMSP) and other unknown

polyol In organic chemistry, a polyol is an organic compound containing multiple hydroxyl groups (). The term "polyol" can have slightly different meanings depending on whether it is used in food science or polymer chemistry. Polyols containing two, th ...

s, 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 Photoinhibition is light-induced reduction in the photosynthetic capacity of a plant, alga, or cyanobacterium. Photosystem II (PSII) is more sensitive to light than the rest of the photosynthetic machinery, and most researchers define the term as ...

). 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 () is a simple triol compound. It is a colorless, odorless, sweet-tasting, viscous liquid. The glycerol backbone is found in lipids known as glycerides. It is also widely used as a sweetener in the food industry and as a humectant in pha ...

and grazes on bacteria, especially when

phosphate Phosphates are the naturally occurring form of the element phosphorus. 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 orthop ...

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 a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

sources, including

ammonium Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) polyatomic ion, molecular ion with the chemical formula or . It is formed by the protonation, addition of a proton (a hydrogen nucleu ...

nitrate Nitrate is a polyatomic ion with the chemical formula . salt (chemistry), Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are solubility, soluble in wa ...

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

s (which ones apparently depends on pH),

creatine Creatine ( or ) is an organic compound with the nominal formula . It exists in various tautomers in solutions (among which are neutral form and various zwitterionic forms). Creatine is found in vertebrates, where it facilitates recycling of ...

, but is unable to use

urea Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...

. 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.

Notable ''Prymnesium'' harmful algal blooms

harmful algal bloom A harmful algal bloom (HAB), or excessive algae growth, sometimes called a red tide in marine environments, is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, water deoxygenation, ...

of ''Prymnesium parvum'' producing their prymnesin toxins was reportedly responsible for the death of approximately 360 tonnes of fish in the

Oder river The Oder ( ; Czech and ) is a river in Central Europe. It is Poland's second-longest river and third-longest within its borders after the Vistula and its largest tributary the Warta. The Oder rises in the Czech Republic and flows through west ...

during the

2022 Oder environmental disaster During the summer of 2022, a mass mortality event involving fish, beavers, clams, crayfish and other wildlife occurred in the Oder river. Over 100 tonnes of fish kill, dead fish were removed from the Polish section of the river, and a further ...

. The pre-prymnesin precursors have been named as PKZILLA-1 and PKZILLA-2 with the first consisting of 45,212 amino acids making it the largest known protein.

References

External links

*
Literature review of the microalga ''Prymnesium parvum'' and its associated toxicity
* * {{Authority control Haptophyte species High lipid content microalgae

Biology

Notable ''Prymnesium'' harmful algal blooms

See also

References

External links