In coastal regions, seaweed biomass turnover influences ecosystem functions both at local and global scales. It largely relies on specialized bacteria able to breakdown intact algal tissues and release degradation products in the water column. The ALGAVOR project will explore the ecological and metabolic strategies of such poorly known specialized marine bacteria of the genus Zobellia. We will combine cultivation-dependent and 'omics approaches to (i) evaluate the biodiversity, distribution, abundance, activity and catabolic functions of Zobellia spp in marine environments, (ii) decipher which metabolic pathways they use to degrade fresh seaweed biomass and (iii) study their cooperative interactions with scavenger bacteria that can profit from degradation products. Altogether, ALGAVOR will unveil the strategies of crucial bacteria considered as a bottleneck controlling the fate of organic matter in coastal habitats.