Bacterial biomass and production rates in the central Adriatic

Abstract

      Study of bacterioplankton biomass and production as well as of the rela­tionship between bacterioplankton biomass and total microbial biomass were carried out in the coastal and open middle Adriatic on a monthly basis from January 1980 to September 1982.

      Bacterioplankton biomass ranged from 1.8 to 24.6 mg C m^-3 in Kaštela Bay and from 2.18 to 9.88 mg C m^-3 in the open sea. The highest bacteriopla­nkton biomass values in the open sea were twice lower than the highest values in the Bay. The proportion of bacterioplan biomass in total microbial biomas is significant, on the average 14.7% in Kaštela Bay and twice that (26.3%) in the open sea. The peak bacterioplankton production was recorded from both study areas in summer. However, the Kaštela Bay may be assigned among very productive areas with the values which are highly in excess of the values in the open sea. The ratio of bacterioplankton production in Kaštela Bay to that in the open sea was 1.3 in winter to 6.3 in summer. This shows an explosive growth of bacterioplankton population in Kaštela Bay in summer (on the ave­rage 59.17 mg C m^-3 day^-1) persisting over a long period (from July to October).