Heterotrophic bacteria in the dark ocean are major contributors to CO 2 fixation

Nature Geoscience, Published online: 26 June 2026; doi:10.1038/s41561-026-02014-0 By quantifying carbon fixation in obligate heterotrophic bacteria across the global ocean, we show that about 20% of dark dissolved inorganic carbon (DIC) fixation arises from anaplerotic processes — reaching up to almost half of dark DIC fixation in some regions or conditions.