Dynamics of Prokaryotic Community in the Montenegrin Part of the South Adriatic Sea

This chapter addresses the dynamics of the prokaryotic community in Montenegrin open sea area of the South Adriatic. This included a comprehensive survey, from August 2009 to January 2011, of bacteria (the abundance of heterotrophic bacteria; high nucleic acid content (HNA) bacteria; low nucleic acid content (LNA) bacteria), abundance of autotrophic picoplankton (Prochlorococcus) and heterotrophic nanoflagellates as the main factor influencing abundance of both heterotrophic and autotrophic picoplankton. The bacterial abundance varied from 0.04 × 106 cells mL−1 to 1.58 × 106 cells mL−1, with domination of the LNA group which is an additional contribution to the conclusion of mainly oligotrophic conditions under the investigated area. Abundance of autotrophic picoplankton Prochlorococcus ranged from 0 to 104 cells mL−1 with increasing abundance during the spring and summer with maximum abundance in November. Weak coupling between bacteria and HNF suggests that nutrient control (bottom-up control) was dominant in controlling the bacterial abundance.