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User:Carcarbug/Mycoplankton

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Mycoplankton are saprotrophic members of the plankton communities of marine and freshwater ecosystems.[1][2] They are composed of filamentous free-living fungi and yeasts that are associated with planktonic particles or phytoplankton.[3] Similar to bacterioplankton, these aquatic fungi play a significant role in heterotrophic mineralization and nutrient cycling.[4] Mycoplankton can be up to 20 mm in diameter and over 50 mm in length.[5]

Overview

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In a typical milliliter of seawater, there are approximately 103 to 104 fungal cells.[6] This number is greater in coastal ecosystems and estuaries due to nutritional runoff from terrestrial communities. Aquatic fungi are found in a myriad of ecosystems, from mangroves, to wetlands, to the open ocean.[7] The greatest diversity and number of species of mycoplankton is found in surface waters (< 1000 m), and the vertical profile depends on the abundance of phytoplankton.[8][9] Furthermore, this difference in distribution may vary between seasons due to nutrient availability.[10] Aquatic fungi survive in a constant oxygen deficient environment, and therefore depend on oxygen diffusion by turbulence and oxygen generated by photosynthetic organisms.[11]

Classification

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There is a large amount of diversity among aquatic fungi. These fungi may be classified using three groups:[11]

The majority of mycoplankton species are higher fungi, found in the Ascomycota and Basidiomycota phyla.[8]

Genome sequencing is a common way to assess and categorize aquatic fungi. Fungi are Eukaryotes, and as such it is often the 18s rDNA which is sequenced.[7]

According to fossil records, fungi date back to the late Proterozoic era, 900-570 million years ago. It is hypothesized that mycoplankton evolved from terrestrial fungi, likely in the Paleozoic era (390 million years ago).[2] The methods and pathways of terrestrial fungi's adaption to the marine environment are still under study.

Biogeochemical Contributions

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There are multiple biogeochemical cycles in the Earth's oceans in which Mycoplankton play a role.[12] They are a part of the microbial loop and other forms of nutrient cycling, including the mycoplankton specific mycoflux and mycoloop.[13]

Cycling of Organic Nutrients

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The primary role of all fungi is to degrade detrital organic matter from plants,[14][15] and mycoplankton are no exception. By working with other microbial communities, mycoplankton efficiently convert particulate organic matter to dissolved organic matter as part of biogeochemical cycling.[12] Mycoplankton and heterotrophic bacteria mediate carbon, nitrogen, oxygen, and other nutrient fluxes in marine ecosystems.[16] The incorporation of dissolved organic carbon into microbe biomass is what is known as the microbial loop.[13]

It has been shown that there are higher concentrations of mycoplankton near the surface and in shallow waters, which indicates their connection with the upwelling of organic matter. This further correlates with abundant phytoplanktoncommunities at the surface, implying that mycoplankton are intimately involved in organic matter consumption in the euphotic zone.[3][10]

Mycoloop and Mycoflux

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Mycoplankton are important in controlling phytoplankton and zooplankton populations. The mycoloop is very similar to the microbial loop, as the basis of both is for microbes to make material accessible to organisms that occupy higher trophic levels. Through the mycoloop phytoplankton are transformed such that they are able to be grazed upon by zooplankton. This function is performed by parasitic marine fungi (mycoplankton).[13]

The mycoflux is understudied, but believed to be a part of carbon capture in aquatic habitats. Functionally, this process involves aquatic fungi breaking down organic matter.[13]

The Benthic Shunt

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Another process which mycoplankton take part in is known as the benthic shunt. This process takes place in the benthic zone, the sediments at the bottom of the water. The benthic shunt is typically referred to in relation to freshwater aquatic environments, but the concept is relevant and takes place in marine habitats as well. The benthic shunt is basically energy and nutrient flow as directed by lower trophic level organisms, such as mycoplankton. [13]

Role in Food Webs

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Due to their significant contributions to nutrient cycling, mycoplankton play a large role in regulation of food webs. Aquatic fungi such as mycoplankton degrade and convert organic matter into other forms. In a way, mycoplankton contributions to aquatic food webs are the biogeochemical services that they perform. The grazer food chain and the microbial food chain are inherently intertwined, as the dissolved organic carbon at the base of the microbial food chain originally comes from material excreted by grazers from the grazer food chain.[8] Not only are the new forms of organic matter more palatable by macro plankton, but the process of conversion releases substrates which support bacterial growth.[7] This in turn allows for the bacteria and macro plankton to support even higher trophic levels. This is a form of bottom-up control of aquatic food webs.

Mycoplankton Communities

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While mycoplankton are found in a variety of aquatic environments, their distribution, abundance, and diversity vary throughout these environments.[7] There is typically a greater amount of diversity and a larger abundance of mycoplankton in coastal waters, due to the extra availability of nutrients. There also exists variation in community composition and diversity at different depths. The control factors for the distribution of mycoplankton is thought to be variable. [8]

See also

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  • Algae – Diverse group of photosynthetic eukaryotic organisms
  • Bacterioplankton – Bacterial component of the plankton that drifts in the water column
  • Biological pump – Carbon capture process in oceans
  • Fungus – Biological kingdom, separate from plants and animals
  • Marine fungi
  • Phytoplankton – Autotrophic members of the plankton ecosystem
  • Zooplankton – Heterotrophic protistan or metazoan members of the plankton ecosystem

References

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  1. ^ Jones, E.B.G., Hyde, K.D., & Pang, K.-L., eds. (2014). Freshwater fungi: and fungal-like organisms. Berlin/Boston: De Gruyter.
  2. ^ a b Jones, E.B.G.; Pang, K.-L., eds. (2012). Marine Fungi, and Fungal-like Organisms. Marine and Freshwater Botany. Berlin, Boston: De Gruyter (published August 2012). ISBN 978-3-11-026406-7. Retrieved September 3, 2015.
  3. ^ a b Wang, X; Singh, P; Gao, Z; Zhang, X; Johnson, ZI; Wang, G (2014). "Distribution and Diversity of Planktonic Fungi in the West Pacific Warm Pool". PLOS ONE. 9 (7): e101523. Bibcode:2014PLoSO...9j1523W. doi:10.1371/journal.pone.0101523.s001. PMC 4081592. PMID 24992154.
  4. ^ Wang, G.; Wang, X.; Liu, X.; Li, Q. (2012). "Diversity and biogeochemical function of planktonic fungi in the ocean". In Raghukumar, C. (ed.). Biology of marine fungi. Berlin, Heidelberg: Springer-Verlag. pp. 71–88. doi:10.1007/978-3-642-23342-5. ISBN 978-3-642-23341-8. S2CID 39378040. Retrieved September 3, 2015.
  5. ^ Damare, Samir; Raghukumar, Chandralata (2007-11-11). "Fungi and Macroaggregation in Deep-Sea Sediments". Microbial Ecology. 56 (1): 168–177. doi:10.1007/s00248-007-9334-y. ISSN 0095-3628. PMID 17994287. S2CID 21288251.
  6. ^ Kubanek, Julia; Jensen, Paul R.; Keifer, Paul A.; Sullards, M. Cameron; Collins, Dwight O.; Fenical, William (2003-06-10). "Seaweed resistance to microbial attack: A targeted chemical defense against marine fungi". Proceedings of the National Academy of Sciences. 100 (12): 6916–6921. Bibcode:2003PNAS..100.6916K. doi:10.1073/pnas.1131855100. ISSN 0027-8424. PMC 165804. PMID 12756301.
  7. ^ a b c d Jobard, Marlène; Rasconi, Serena; Sime-Ngando, Télesphore (2010-06-01). "Diversity and functions of microscopic fungi: a missing component in pelagic food webs". Aquatic Sciences. 72 (3): 255–268. doi:10.1007/s00027-010-0133-z. ISSN 1420-9055.
  8. ^ a b c d Gao, Zheng; Johnson, Zackary I.; Wang, Guangyi (2009-07-30). "Molecular characterization of the spatial diversity and novel lineages of mycoplankton in Hawaiian coastal waters". The ISME Journal. 4 (1): 111–120. doi:10.1038/ismej.2009.87. ISSN 1751-7362. PMID 19641535.
  9. ^ Panzer, Katrin; Yilmaz, Pelin; Weiß, Michael; Reich, Lothar; Richter, Michael; Wiese, Jutta; Schmaljohann, Rolf; Labes, Antje; Imhoff, Johannes F. (2015-07-30). "Identification of Habitat-Specific Biomes of Aquatic Fungal Communities Using a Comprehensive Nearly Full-Length 18S rRNA Dataset Enriched with Contextual Data". PLOS ONE. 10 (7): e0134377. Bibcode:2015PLoSO..1034377P. doi:10.1371/journal.pone.0134377. PMC 4520555. PMID 26226014.
  10. ^ a b GUTIERREZ, Marcelo H; PANTOJA, Silvio; QUINONES, Renato A and GONZALEZ, Rodrigo R. First record of flamentous fungi in the coastal upwelling ecosystem off central Chile. Gayana (Concepc.) [online]. 2010, vol.74, n.1, pp. 66-73. ISSN 0717-6538.
  11. ^ a b Sridhar, K.R. (2009). "10. Aquatic fungi – Are they planktonic?". Plankton Dynamics of Indian Waters. Jaipur, India: Pratiksha Publications. pp. 133–148.
  12. ^ a b Kiørboe, Thomas; Jackson, George A. (2001-09-01). "Marine snow, organic solute plumes, and optimal chemosensory behavior of bacteria". Limnology and Oceanography. 46 (6): 1309–1318. Bibcode:2001LimOc..46.1309K. CiteSeerX 10.1.1.570.5719. doi:10.4319/lo.2001.46.6.1309. ISSN 1939-5590.
  13. ^ a b c d e Grossart, H.P. (2019). "Fungi in aquatic ecosystems". Nature Reviews Microbiology. 17: 339–354.
  14. ^ Carlile MJ, Watkinson SC, Gooday GW (2001) The fungi. San Diego: Academic Press.
  15. ^ Pang, Ka-Lai; Mitchell, Julian I. (2005). "Molecular approaches for assessing fungal diversity in marine substrata". Botanica Marina. 48 (5–6). doi:10.1515/bot.2005.046.
  16. ^ Buesing, Nanna; Gessner, Mark O. (2006-01-01). "Benthic Bacterial and Fungal Productivity and Carbon Turnover in a Freshwater Marsh". Applied and Environmental Microbiology. 72 (1): 596–605. Bibcode:2006ApEnM..72..596B. doi:10.1128/AEM.72.1.596-605.2006. ISSN 0099-2240. PMC 1352256. PMID 16391096.