text: Phytoplankton produces DOC by extracellular release commonly accounting between 5 and 30% of their total primary production, although this varies from species to species. Nonetheless, this release of extracellular DOC is enhanced under high light and low nutrient levels, and thus should increase relatively from eutrophic to oligotrophic areas, probably as a mechanism for dissipating cellular energy. Phytoplankton can also produce DOC by autolysis during physiological stress situations e.g., nutrient limitation. Other studies have demonstrated DOC production in association with meso- and macro-zooplankton feeding on phytoplankton and bacteria.