Mixotroph

A mixotroph is an organism that uses a mix of different sources of energy and carbon, instead of having a single trophic mode, on the continuum from complete autotrophy to complete heterotrophy. It is estimated that mixotrophs comprise more than half of all microscopic plankton.^[1] There are two types of eukaryotic mixotrophs. There are those with their own chloroplasts - including those with endosymbionts providing the chloroplasts. And there are those that acquire them through kleptoplasty, or through symbiotic associations with prey, or through 'enslavement' of the prey's organelles.^[2]

Possible combinations are photo- and chemotrophy, litho- and organotrophy (osmotrophy, phagotrophy and myzocytosis), auto- and heterotrophy or other combinations of these. Mixotrophs can be either eukaryotic or prokaryotic.^[3] They can take advantage of different environmental conditions.^[4]

If a trophic mode is obligate, then it is always necessary for sustaining growth and maintenance; if facultative, it can be used as a supplemental source.^[3] Some organisms have incomplete Calvin cycles, so they are incapable of fixing carbon dioxide and must use organic carbon sources.

^ Beware the mixotrophs - they can destroy entire ecosystems 'in a matter of hours'
^ [S. G. Leles et al, Oceanic protists with different forms of acquired phototrophy display contrasting biogeographies and abundance, Proceedings of the Royal Society B: Biological Sciences (2017).]
^ ^a ^b Eiler A (December 2006). "Evidence for the Ubiquity of Mixotrophic Bacteria in the Upper Ocean: Implications and Consequences". Appl Environ Microbiol. 72 (12): 7431–7. Bibcode:2006ApEnM..72.7431E. doi:10.1128/AEM.01559-06. PMC 1694265. PMID 17028233.
^ Katechakis A, Stibor H (July 2006). "The mixotroph Ochromonas tuberculata may invade and suppress specialist phago- and phototroph plankton communities depending on nutrient conditions". Oecologia. 148 (4): 692–701. Bibcode:2006Oecol.148..692K. doi:10.1007/s00442-006-0413-4. PMID 16568278. S2CID 22837754.

[1] Beware the mixotrophs - they can destroy entire ecosystems 'in a matter of hours'

[2] [S. G. Leles et al, Oceanic protists with different forms of acquired phototrophy display contrasting biogeographies and abundance, Proceedings of the Royal Society B: Biological Sciences (2017).]

[Eiler-3] Eiler A (December 2006). "Evidence for the Ubiquity of Mixotrophic Bacteria in the Upper Ocean: Implications and Consequences". Appl Environ Microbiol. 72 (12): 7431–7. Bibcode:2006ApEnM..72.7431E. doi:10.1128/AEM.01559-06. PMC 1694265. PMID 17028233.

[4] Katechakis A, Stibor H (July 2006). "The mixotroph Ochromonas tuberculata may invade and suppress specialist phago- and phototroph plankton communities depending on nutrient conditions". Oecologia. 148 (4): 692–701. Bibcode:2006Oecol.148..692K. doi:10.1007/s00442-006-0413-4. PMID 16568278. S2CID 22837754.

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