Chemoautotrophic Carbon Fixation Favors Iron-Bound Organic Carbon Formation in Estuarine and Coastal Sediments

─and sulfide-enriched field sediments, and a positive feedback relationship was observed between Fe-OC formation and the CCF process. These results highlighted that the chemoautotrophic process favors Fe-OC formation, in which the enhanced Fe-OC may restrain microbial degradation of organic carbon, thereby facilitating carbon retention and preservation. This preservation mechanism provided a robust pathway for carbon sequestration in estuarine and coastal wetlands, representing a negative climate warming feedback loop.