Bacterioplankton biomass and production during destratification in a monomictic eutrophic bay of a tropical lagoon

Abstract

Vertical profiles of bacterial biomass (AODC method), production of biomass (thymidine method) and total ETS (Electron Transport System) activity were recorded on 14 dates during the destratification process in the monomictic eutrophic Bietri Bay (Ebrie Lagoon, Ivory Coast). Bacterial biomass and production were both very high, indicating the importance of heterotrophic processes in this system. Integrated bacterial production of biomass represented ca 80% of carbon produced by primary producers. Destratification appears to be of less importance than suggested by the physical and chemical characteristics, resulting in a decrease of bacterial biomass and production by a factor of 2 in the epilimnion. In the hypolimnion, the "anaerobic community" characterized by low specific incorporation rates (3.4 x 10 super(-20) mol/cell/h) and high mean cellular volume (0.203 mu m super(3)) during stratification is replaced by an "aerobic community" with higher specific thymidine incorporation rates (6.6 x 10 super(-20) mol/cell/h) and lower mean cellular volumes (0.151 mu m super(3)).