Bacteria, as the most diverse trophic group, make up the base of the marine food web. Aerobic anoxygenic phototrophs (AAP) are widespread in the environment and account for up to 25% of the total bacterial population in the sea. They are characterized by high growth rates and significantly larger cells compared to other bacteria. AAPs are under the pressure of the predators and therefore their biomass is transferred to higher trophic levels. This indicates their importance in the marine food web and in biogeochemical cycles. Furthermore, AAPs have its representatives among Alpha-, Beta- and Gammaproteobacteria. Based on the pufM gene analysis, the appropriate marker for AAP light-harvesting centers, this functional group is divided into 12 different phylogroups. Recent research suggests that this bacterial functional group, thanks to genetic diversity, creates its response to ecological factors.</p><p>The project represents the first comprehensive analysis of the AAP bacterial community in the Middle Adriatic, broadening the knowledge of ecology and the composition of the AAP community and their role in the carbon flux toward the higher trophic levels.