Deep-sea hydrothermal systems are important sources of carbon and reduced sulfur to the deeP-ocean.While the biotic and abiotic cycling of inorganic carbon,nitrogen and sulfur has been well documented in deep-sea hydrothermal environments,the cycling of organic carbon,nitrogen and sulfur has received less attention.Here,we present metagenomic,metatranscriptomic,and geochemical insights into the microbial metabolisms of organic carbon,nitrogen and sulfur in deep-sea hydrothermal plumes of the Mid-Cayman Rise (Caribbean).