Oligotroph

An oligotroph is an organism that can live in a very low carbon concentration, less than one part per million. They may be contrasted with copiotrophs, which prefer environments rich in carbon. Most oligotrophs are bacteria, though archaean oligotrophs also exist. Oligotrophs are characterized by slow growth, low rates of metabolism, and generally low population density. Low-carbon environments are ubiquitous; oligotrophs may be found a wide range of environments including in deep oceanic sediments, caves, glacial and polar ice, deep subsurface soil, aquifers, and ocean water.

An example of an oligotrophic organism is the bacteria, Pelagibacter ubique, which is the most abundant organism in the oceans with an estimated 1027 individuals in total.