How bacteria support algae

Algae use armored, fucose-rich sugars as protective barriers, which can however be unlocked by bacteria – some of which are marine relatives of gut bacteria. They use a unique set of enzymes and shared molecular mechanisms with their gut cousins. By breaking the tough sugars of the algae into smaller units which are then available in the environment as “public goods”, these bacteria may act like probiotics for algae and simultaneously shape microbiomes and carbon flow in the ocean.