Contribution of bacteria in the mucilage of Microcystis spp. (Cyanobacteria) to benthic and pelagic bacterial production in a hypereutrophic lake

The mucilage of cyanobacteria represents a unique habitat for both water co lumn and sediment bacteria. In Lake Vallentunasjon, Sweden, the pelagic Mic rocystis-associated bacteria constituted 19-40% of the total bacterial abun dance, and their contribution to the total bacterial production was 7-30%. In the sediment, the mucilage bacteria constituted only 1-5% of the total b acterial abundance, but contributed with 8-13% to the total bacterial produ ction during the summer. Microcystis-associated bacteria thus were less act ive (bacterial production/cell) than ambient water column bacteria, while i n the sediments the Microcystis colonies were 'hot spots' with enhanced bac terial activity as compared to other sediment bacteria. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.