Mesodinium is a genus of

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 ...

s that are widely distributed and are abundant in marine and brackish waters. Currently, six marine species of ''Mesodinium'' have been described and grouped by nutritional mode: plastidic (''M. chamaeleon'', ''M. coatsi'', ''M. major'', and ''M. rubrum'') or

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 ...

(''M. pulex'' and ''M. pupula''). There is some debate as to whether the nutritional mode of plastidic ''Mesodinium ''species is

phototroph Phototrophs () are organisms that carry out photon capture to produce complex organic compounds (e.g. carbohydrates) and acquire energy. They use the energy from light to carry out various cellular metabolic processes. It is a common misconce ...

ic (permanent plastid) or

mixotrophic A mixotroph is an organism that can use a mix of different sources of energy and carbon, instead of having a single trophic mode on the continuum from complete autotrophy at one end to heterotrophy at the other. It is estimated that mixotrophs comp ...

. Among the plastidic species, wild ''M. major'' and ''M. rubrum'' populations possess red plastids belonging to genera ''

Teleaulax Geminigeraceae is a family of cryptophytes containing the five genera ''Geminigera'', ''Guillardia'', ''Hanusia'', ''Proteomonas'' and ''Teleaulax''. They are characterised by chloroplast A chloroplast () is a type of membrane-bound organ ...

'', ''

Plagioselmis ''Plagioselmis'' is a genus of cryptophytes, including the species ''Plagioselmis punctata''. ''Plagioselmis'' was first described by Butcher in 1967 as a saltwater life form. In 1994, Novarino placed the freshwater Fresh water or fresh ...

'', and ''

Geminigera ''Geminigera'' /ˌdʒɛmɪnɪˈdʒɛɹə/ is a genus of cryptophyte from the family Geminigeraceae Geminigeraceae is a family of cryptophytes containing the five genera ''Geminigera'', ''Guillardia'', ''Hanusia'', ''Proteomonas'' and ''Tele ...

'', while wild ''M. chamaeleon'' and ''M. coatsi'' populations normally contain green plastids.Moestrup, Ø., Garcia-Cuetos, L., Hansen, P. J. & Fenchel, T. (2012) Studies on the genus Mesodinium I: ultrastructure and description of Mesodinium chamaeleon n. sp., a benthic marine species with green or red chloroplasts. J. Eukaryot. Microbiol. 59, 20–39.Nam, S. W., Shin, W., Kang, M., Yih, W. & Park, M. G. (2015) Ultrastructure and molecular phylogeny of Mesodinium coatsi sp. nov., a benthic marine ciliate. J. Eukaryot. Microbiol. 62, 102–120. The availability of suitable cryptophyte prey is important for bloom formation of plastidic ''Mesodinium'' species. The most common species, ''

Mesodinium rubrum ''Mesodinium rubrum'' (or ''Myrionecta rubra'') is a species of ciliates. It constitutes a plankton community and is found throughout the year, most abundantly in spring and fall, in coastal areas. Although discovered in 1908, its scientific i ...

'', causes

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 ...

s in many coastal ecosystems. Although ''M. rubrum'' is known as a nontoxic species, blooms of the ciliate can be potentially harmful to aquaculture industries.Nishitani, G. and Yamaguchi, M. (2018) "Seasonal succession of ciliate ''Mesodinium'' spp. with red, green, or mixed plastids and their association with cryptophyte prey". ''Scientific reports'', 8(1): 1–9. . CC-BY icon

Material was copied from this source, which is available under
Creative Commons Attribution 4.0 International License
''M. rubrum'' photosynthesizes by sequestering the nucleus of its cryptophyte prey, in order to maintain stolen plastids and other organelles. In this way, the genus ''Mesodinium'' plays an important role in linking cryptophycean prey and diverse predators in the aquatic microbial food web. For example, the dinoflagellates ''

Dinophysis ''Dinophysis'' is a genus of dinoflagellates AlgaeBase''Dinophysis'' Ehrenberg, 1839/ref> common in tropical, temperate, coastal and oceanic waters.Hallegraeff, G.M., Lucas, I.A.N. 1988: The marine dinoflagellate genus Dinophysis (Dinophyceae): p ...

'' spp., which are a predator of ''M. rubrum'' and the source of their cryptophyte-derived plastids, have been frequently observed to precede or to coincide with high densities of ''M. rubrum''.Velo-Suárez, L., González-Gil, S., Pazos, Y. & Reguera, B. (2014) The growth season of ''Dinophysis acuminata'' in an upwelling system embayment: a conceptual model based on in situ measurements. Deep-Sea Res. II 101, 141–151.

References

{{reflist Mesodinium

See also

References