Marine and terrestrial ecosystems of the Prince Edward islands (PEIs) are reciprocally connected and any changes in the community composition of one ecosystem will directly influence the other. In the present study, we investigated the pelagic marine microbial community structure (Bacteria, Phytoplankton and Archaea) and dynamics in the PEIs inshore coastline by high throughput sequencing technologies (pyrosequencing). The study revealed temporal shifts in the bacterial community composition during the period of 2012 to 2015.