Bacterioplankton abundance, biomass and production in a Brazilian coastal lagoon and in two German lakes

The bacterioplanktonic abundance, biomass, and production within a tropical lagoon (Cabiunas; Brazil) and two temperate lakes (Stechlin and Dagow, Ger many) were compared. Bacterial abundance and production were significantly different among the three water bodies, The lowest bacterial production (0. 8 mug C 1(-1) d(-l)) was observed in the tropical Cabiunas Lagoon despite: its higher mean temperature and dissolved organic carbon concentration. Hig hest bacterioplankton abundance (2.6 x 10(9) cells 1(-1)) and production (6 8.5 mug C 1(-1) d(-1)) were measured in eutrophic Lake Dagow. In oligotroph ic Lake Stechlin, the lowest bacterial biomnss (48.05 mug C1(-1)) was obser ved because of lower bacterial biovolume (0.248 mum(3)) and lower bacterial abundance. Bacterial populations in the temperate lakes show higher activi ty (production/biomass ratio) than in the tropical lagoon. The meaning of i sotopic dilution and leucine incorporation by non-bacterial micro-organisms were evaluated in the oligotrophic temperate system. Leucine uptake by non -bacterial micro-organisms did not have significant influence on bacterial production.