Community level physiological study of algicidal bacteria in the phycospheres of Skeletonema costatum and Scrippsiella trochoidea

•Bacteria in phycosphere of S. costatum and S. trochoidea can lyse their host algae.•The bacterial community in the phycospheres had low metabolic activity.•The bacterial community showed low physiological diversity and simple structures.•The bacterial community structure changed significantly during lysis of algal cells.