''Oxyrrhis marina'' is a species of dinoflagellates with flagella. A marine heterotroph, it is found in much of the world.

Description

This protozoan species has an asymmetrical oval shape to its single-celled body.Lowe, C. D., et al. (2011)
Who is ''Oxyrrhis marina''? Morphological and phylogenetic studies on an unusual dinoflagellate.
''Journal of Plankton Research'' 33(4) 555-67. It has been likened to a

rugby ball A rugby ball is an elongated ellipsoidal ball used in both codes of rugby football. Its measurements and weight are specified by World Rugby and the Rugby League International Federation, the governing bodies for both codes, rugby union and rugby l ...

.Lowe, C. D., et al. (2011)
Collection, isolation and culturing strategies for ''Oxyrrhis marina''.
''Journal of Plankton Research'' 33(4) 569-78. The cell usually measures between 20 and 30 micrometers, but it is known to reach 60. It has two flagella with a protruding, tentacle-like bulge between them. The flagella are covered in scales. Most individuals have scales on the body surface, as well. The two flagella have separate functions. One undulates in waves and the other is coiled, producing a corkscrew-like propulsion to move the cell. The individual appears colorless, but a concentrated culture of cells may have a pink tinge.

Distribution and habitat

The species is thought to have a global distribution except for the polar seas, where it is likely absent or rare, though few samples have been taken of these waters.Watts, P. C., et al. (2011)
The distribution of ''Oxyrrhis marina'': a global disperser or poorly characterized endemic?
''Journal of Plankton Research'' 33(4) 579-89. There are specific records from waters near Europe, North America, Asia,

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, the Canary Islands,Guiry, M .D. & G. M. Guiry. 2013
''Oxyrrhis marina''.
AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Accessed 10 June 2013.

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...

, and the

Azores ) , motto =( en, "Rather die free than subjected in peace") , anthem= ( en, "Anthem of the Azores") , image_map=Locator_map_of_Azores_in_EU.svg , map_alt=Location of the Azores within the European Union , map_caption=Location of the Azores wi ...

. It has been found in isolated inland waters, as well, such as a lake in

Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv ...

. It is less common in the open waters of the oceans. There is a question as to how it came to inhabit so many islands if it is apparently rare in the open ocean. It may have been slowly dispersed on the

currents Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (stre ...

, carried in mats of algae, or transported by humans when shipping arose. It is most common in the intertidal zone and other coastal regions, where it is a member of the

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...

.Montagnes, D. J. S., et al. (2011)
''Oxyrrhis marina'' growth, sex and reproduction.
''Journal of Plankton Research'' 33(4) 615-27. Habitat types include

tide pool A tide pool or rock pool is a shallow pool of seawater that forms on the rocky intertidal shore. Many of these pools exist as separate bodies of water only at low tide. Many tide pool habitats are home to especially adaptable animals that ...

s and

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...

. It was first described from a

salt marsh A salt marsh or saltmarsh, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It is domin ...

. It tolerates wide ranges in salinity, temperature, and pH.Lowe, C. D., et al. (2011)
The transcriptome of the novel dinoflagellate ''Oxyrrhis marina'' (Alveolata: Dinophyceae): response to salinity examined by 454 sequencing.
''BMC Genomics'' 12:519.

Biology

It is

heterotroph 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 ...

ic, obtaining nutrients externally instead of synthesizing them by an internal process such as

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

. It is an

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

grazer Grazer may refer to: *grazer, an animal that grazes *Grazer, a native or inhabitant of Graz *GRAZER, the shoegaze band GRAZER Astronomy * Earth Grazer, Earth-grazing fireball that enters the Earth's atmosphere and leaves again * Mercury grazer, ...

, consuming various types of tiny organisms from its environment. It eats phytoplankton such as minute algaes.Hansen, F. C., et al. (1996)
Grazing in the heterotrophic dinoflagellate ''Oxyrrhis marina'': size selectivity and preference for calcified ''Emiliania huxleyi'' cells.
''Aquatic Microbial Ecology'' 10 307-13. It has been observed eating '' Nannochloris oculata'' and ''

Micromonas pusilla ''Micromonas'' is a genus of green algae in the family ''Mamiellaceae''. Before the characterization in 2016 of a second species, ''Micromonas commoda'', ''Micromonas pusilla'' was considered to be the only species in the genus, which led to a d ...

'', other flagellates such as '' Goniomonas amphinema'', ''

Pfiesteria piscicida ''Pfiesteria piscicida'' is a dinoflagellate species of the genus '' Pfiesteria'' that some researchers claim is responsible for many harmful algal blooms in the 1980s and 1990s on the coast of North Carolina and Maryland. North Carolinian media ...

'', and '' Stoeckeria algicida'', and some

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

.Roberts, E. C., et al. (2011)
Feeding in the dinoflagellate ''Oxyrrhis marina'': linking behaviour with mechanisms.
''Journal of Plankton Research'' 33(4) 603-14. It often eats the

coccolithophore Coccolithophores, or coccolithophorids, are single celled organisms which are part of the phytoplankton, the autotrophic (self-feeding) component of the plankton community. They form a group of about 200 species, and belong either to the king ...

'' Cricosphaera elongata'', and, in experimental situations, readily eats ''

Tetraselmis suecica ''Tetraselmis suecica'' is a marine green alga. It grows as single, motile cells visible under light microscope up to concentrations over one million cells per milliliter. It can be grown as a foodstock in aquaculture, being amenable to species ...

'', '' Isochrysis galbana'', and ''

Rhodomonas ''Rhodomonas'' is a genus of cryptomonads. It is characterized by its red colour, the square-shaped plates of its inner periplast, its short furrow ending in a gullet, and a distinctly shaped chloroplast closely associated with its nucleomorph. Hi ...

'' sp. Some of these food items are relatively large, as large as the ''O. marina'' cell itself. It is selective in its grazing, showing clear preferences for certain food taxa. It can also pick certain individuals over others, as evidenced by its preference for

virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsk ...

-infected '' Emiliana huxleyi'' cells over healthy cells.Breckels, M. N., et al. (2011)
The role of dissolved infochemicals in mediating predator–prey interactions in the heterotrophic dinoflagellate ''Oxyrrhis marina''.
''Journal of Plankton Research'' 33(4) 629-39. It is

cannibalistic Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded in more than 1,500 species. Human cannibalism is well documented, bo ...

, as well. It feeds by

phagocytosis Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is ...

, totally engulfing its prey. It has been observed spinning one of its flagella in such a way that it creates a current, pulling the item closer so it can seize it. It is also raptorial, approaching and pouncing on the prey item, especially when the item is a protist. ''O. marina'' can sense and respond to certain chemicals that are exuded by algal prey. The locomotion of the ''O. marina'' cell is

helical Helical may refer to: * Helix, the mathematical concept for the shape * Helical engine, a proposed spacecraft propulsion drive * Helical spring, a coilspring * Helical plc, a British property company, once a maker of steel bar stock * Helicoil A t ...

due to the simultaneous movement of its two flagella. It mostly swims in a straight line, but it makes turns when it detects food.Boakes, D. E., et al. (2011)
Analysis and modelling of swimming behaviour in ''Oxyrrhis marina''.
''Journal of Plankton Research'' 33(4) 641-49. In terms of reproduction, ''O. marina'' is

isogamous Isogamy is a form of sexual reproduction that involves gametes of the same morphology (indistinguishable in shape and size), found in most unicellular eukaryotes. Because both gametes look alike, they generally cannot be classified as male or fe ...

, with reproductive cells smaller than the body cell, but very little is known about these. This species sometimes forms

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 algae-produced toxins, mechanical damage to other organisms, or by other means. HABs are sometimes ...

s, but will also feed on the raphidophyte, ''

Heterosigma akashiwo ''Heterosigma akashiwo'' is a species of microscopic algae of the class Raphidophyceae. It is a swimming marine alga that episodically forms toxic surface aggregations known as harmful algal bloom. The species name ''akashiwo'' is from the Japa ...

'', another organism responsible for red tides.Jeong, H. J., et al. (2003)
Feeding by the heterotrophic dinoflagellate ''Oxyrrhis marina'' on the red-tide raphidophyte ''Heterosigma akashiwo'': a potential biological method to control red tides using mass-cultured grazers.
''The Journal of Eukaryotic Microbiology'' 50(4) 274-82. Its blooms when forming red tides are likely stimulated by environmental factors, such as drops in salinity or increases in prey abundance. ''O. marina'' may also affect the environment by producing dimethyl sulfide, which is released when it grazes on some prey types, such as ''E. huxleyi''. Predators of ''O. marina'' include protozoa such as the

ciliate The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a differen ...

'' Strombidinopsis jeokjo'', copepods such as '' Acartia tonsa'' and rotifers. The mixotrophic flagellate ''

Prymnesium parvum ''Prymnesium parvum'' is a species of haptophytes (also collectively called Prymnesiophyta). The species is of concern because of its ability to produce the phycotoxin prymnesin. It is a flagellated alga that is normally found suspended in the ...

'' is a prey item for ''O. marina'' when the former is nutrient-replete, but can become a predator when it is nutrient-stressedYang, Z., et al. (2011)
The role of ''Oxyrrhis marina'' as a model prey: current work and future directions.
''Journal of Plankton Research'' 33(4) 665-75. It has been used as food for

fish larvae Ichthyoplankton (from Greek: ἰχθύς, , "fish"; and πλαγκτός, , "drifter") are the eggs and larvae of fish. They are mostly found in the sunlit zone of the water column, less than 200 metres deep, which is sometimes called the epi ...

, including those of black porgy (''Mylio macrocephalus''), lemonpeel angelfish (''Centropyge flavissima''), and

grey mullet Grey mullet can mean any of several fish in the family ''Mugilidae'' (the mullets) and having a greyish hue: * Flathead grey mullet, ''Mugil cephalus'' * Thicklip grey mullet, ''Chelon labrosus'' * Boxlip grey mullet, ''Oedalechilus labeo The bo ...

(''Mugil cephalus'').

Bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a ...

ns have been grown on a mixture of the protist and

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constit ...

Research

This protist has been studied extensively. It is a model organism for the study of many aspects of protist biology, including feeding behavior,

physiology Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical ...

ecology Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overl ...

growth Growth may refer to: Biology * Auxology, the study of all aspects of human physical growth * Bacterial growth * Cell growth * Growth hormone, a peptide hormone that stimulates growth * Human development (biology) * Plant growth * Secondary growth ...

, trophic position,

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

, genomics, and biogeography.Montagnes, D. J. S., et al. (2011)
An introduction to the special issue: ''Oxyrrhis marina'', a model organism?
''Journal of Plankton Research'' 33(4) 549-54. Many more studies of its genetics are now underway. There are some limitations to using the species as a model, in part because dinoflagellates are so diverse. ''O. marina'' itself is very diverse, with many varied strains, and their biology is influenced by the environment, so it can be hard to find a representative specimen to use as a model.Davidson, K., et al. (2011)
''Oxyrrhis marina''-based models as a tool to interpret protozoan population dynamics.
''Journal of Plankton Research'' 33(4) 651-63. In fact, some experts deny that it is a dinoflagellate at all, or at least a "true" dinoflagellate.Saldarriaga, J. F., et al. (2003)
Multiple protein phylogenies show that ''Oxyrrhis marina'' and ''Perkinsus marinus'' are early branches of the dinoflagellate lineage.
''International Journal of Systematic and Evolutionary Microbiology'' 53(1) 355-65. In general, it is still very useful for scientific experiments, and researchers recommend it. ''O. marina'' has

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

s that have evidently been transferred to it from bacteria. It also has some genes that are related to plastids, indicating that it may have had an ancestor that could perform photosynthesis. Also, it has some genes related to

essential amino acid An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life form ...

synthesis, something that is uncommon in heterotrophs, as they usually obtain essential amino acids by eating them. It is easy to isolate from the environment and easy to grow in the laboratory. Cultures are fed ''

Dunaliella primolecta ''Dunaliella'' is a single-celled, photosynthetic green alga, that is characteristic for its ability to outcompete other organisms and thrive in hypersaline environments. It is mostly a marine organism, though there are a few freshwater species t ...

'' or any of a number of other readily available protists. Dead '' E. coli'' cells can also be used for food. It can also be sustained on a nutritional medium. Cultures can be maintained for years.

Taxonomy

This protist has been called a morphospecies. As it is now understood, it is composed of a number of

isolates {{About, , the linguistics term dealing with languages unrelated to any other language in the world, Language isolate, other uses, Isolate (disambiguation){{!Isolate Isolates is a term used in developmental psychology and family studies, to describ ...

, some of which are quite distinct. There are 50 to 80 wild isolates. In the future some of these could be divided into separate taxa, perhaps on the species level. One of these may become ''Oxyrrhis maritima''. Another called ''O. tenticulifera'' may be valid, as well.

Description

Distribution and habitat

Biology

Research

Taxonomy

References

Further reading