Variations in seaweed-associated and planktonic bacterial communities along the coast of Ghana

ABSTRACT Seaweed associated bacteria can be exploited for sustainable production and conservation of seaweeds, although limited information exists in several coastal waters in West Africa. Here, the diversity and abundance of bacteria on five seaweeds, Sargassum vulgare, Padina durvillaei, Hydropuntia dentata, Hypnea musciformis and Ulva fasciata, and surrounding seawaters across five coastal sites in the Central and Western regions of Ghana were investigated. Biochemical tests and MALDI–TOF identification system were used to determine the bacteria diversity and abundance on the seaweeds and seawater. A total of 530 bacterial isolates, belonging to 28 species (and mostly Proteobacteria and Firmicutes) were identified. A higher diversity of bacteria species was found associated with the seaweeds (83%) than in seawater (17%). Bacterial composition was similar among taxonomically-related seaweeds. The brown (S. vulgare) and red (H. musciformis) seaweeds recorded the most and least diverse bacterial assemblage, respectively. Seasonally, bacterial diversity and abundance were marginally higher in the wet season. The study provides important baseline information on the spatial, temporal and taxonomic distribution of bacteria associated with commercially valuable seaweed species in the coastal areas of Ghana. The results are also important for the sustainable exploitation and conservation of these important macroalgae in Ghana and elsewhere.