mixotroof

Mixotrophy is a nutritional strategy in which an organism obtains energy and carbon through both photosynthesis (phototrophy) and heterotrophic means such as ingestion of prey or absorption of organic molecules. In standard usage, the term mixotroph refers to an organism that combines these modes, while mixotrophy denotes the condition; the spelling mixotroof is not widely recognized in scientific literature.

Mixotrophic organisms can operate as true mixotrophs, maintaining photosynthetic machinery while also performing heterotrophy, or they can engage in kleptoplasty, in which they steal and temporarily use functional chloroplasts from their prey. Some mixotrophs absorb dissolved organic carbon (osmotrophy) or actively phagocytose prey to supplement energy and nutrients when light is limited.

Common examples include the freshwater and marine protists Euglena gracilis and Ochromonas species, as well as certain dinoflagellates such as Dinophysis spp. These organisms can switch or blend nutritional modes depending on environmental conditions, light availability, and nutrient status.

Ecologically, mixotrophs contribute to primary production while also consuming bacterial or algal prey, influencing nutrient cycling and food web dynamics. They are found in marine, freshwater, and soil ecosystems, often in environments with fluctuating resources or low inorganic nutrient availability. Their existence challenges simple binary classifications of autotrophy and heterotrophy.

See also mixotrophy, kleptoplasty, photosynthesis, phagotrophy.