by Marlis Reich Marine fungi were assumed to have a minor role in carbon cycling, unable to compete with bacteria. A new PLOS Biology study challenges this dogma, showing fungi can dominate labile dissolved organic matter assimilation, reshaping our understanding of ocean carbon retention and storage. Marine fungi were assumed to have a minor role in the carbon cycling, unable to compete with bacteria. A new PLOS Biology study challenges this dogma, showing fungi can dominate labile dissolved organic matter assimilation, reshaping our understanding of ocean carbon retention and storage.