The deep ocean is fixing carbon in ways no one expected

UC Santa Barbara researchers discovered that deep-ocean carbon fixation works differently than previously thought, solving a decade-long mystery about ocean carbon storage. Scientists had assumed ammonia-oxidizing archaea were responsible for most carbon dioxide fixation in dark ocean waters, but the numbers never matched available nitrogen energy sources. Using a chemical inhibitor to block these archaea, the team found that carbon fixation rates barely dropped, revealing that heterotrophic microbes are doing much more carbon fixing than expected, fundamentally changing our understanding of deep-ocean food webs.