Microbial dietary preference and interactions affect the export of lipids to the deep ocean.

Lipids comprise a significant fraction of sinking organic matter in the ocean and play a crucial role in the carbon cycle. Despite this, our understanding of the processes that control lipid degradation is limited. We combined nanolipidomics and imaging to study the bacterial degradation of diverse algal lipid droplets and found that bacteria isolated from marine particles exhibited distinct dietary preferences, ranging from selective to promiscuous degraders. Dietary preference was associated with a distinct set of lipid degradation genes rather than with taxonomic origin. Using synthetic communities composed of isolates with distinct dietary preferences, we showed that lipid degradation is modulated by microbial interactions. A particle export model incorporating these dynamics indicates that metabolic specialization and community dynamics may influence lipid transport efficiency in the ocean's mesopelagic zone.