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 column and sediment bacteria. In Lake Vallentunasjön, Sweden, the pelagic Microcystis-associated bacteria constituted 19–40% of the total bacterial abundance, and their contribution to the total bacterial production was 7–30%. In the sediment, the mucilage bacteria constituted only 1–5% of the total bacterial abundance, but contributed with 8–13% to the total bacterial production during the summer. Microcystis-associated bacteria thus were less active (bacterial production/cell) than ambient water column bacteria, while in the sediments the Microcystis colonies were ‘hot spots’ with enhanced bacterial activity as compared to other sediment bacteria.