Influence of nitrate and dissolved organic carbon loading on the interaction of Microcystis aeruginosa and heterotrophic bacteria from hyper-eutrophic lake (Taihu Lake, China)

Abstract

a b s t r a c tTo investigate the interaction between cyanobacteria and heterotrophic bacteria under gradients of glucose and nitrate, a cyanobacterial strain of Microcystis aeruginosa was grown in microcosms with and without a freshwater bacterial mixture, which was collected from Lake Taihu. Concentrations of glucose (1350, 975, 600, 300, 150, and 37.5 mol C L −1 ) and nitrate (150, 300, and 9000 mol N L −1 ) were used in a range of combinations giving 9 different treatments of glucose:nitrate. In the microcosm without the bacterial mixture, M. aeruginosa abundance gradually increased with days in all treatments. However, M. aeruginosa had much lower density in some treatments with the bacterial mixture. The difference in M. aeruginosa growth could be explained by competition with bacteria in the cultures in which these were added. The abundance of M. aeruginosa and bacteria when grown together was nearly equal and the number of the bacterial species was highest in the treatment with 300 mol C L −1 and 150 mol N L −1 . Our results suggest that at this glucose:nitrate ratio M. aeruginosa and the bacterial mixture maintain a balance, and bacteria maintain diversity. In conclusion, we propose that dissolved organic carbon and nitrate availability fundamentally affects the structure as well as stoichiometry of pelagic associations.

Characterization of the cyanobacteria and associated bacterial community from an ephemeral wetland in New Zealand

“…, Jingjing et al. ). Cyanobacterial colonies are associated with heterotroph communities that exhibit high levels of metabolic activity and form an important component of bacterial secondary production (Worm and Søndergaard , Brunberg , Eiler et al.…”

“…, Jingjing et al. ). Long‐term associations of heterotrophic bacteria with cyanobacteria have been reported, particularly with the heterocysts of filamentous diazotrophs where the heterotrophs receive fixed carbon and nitrogen from the cyanobacterial host (Paerl , Behrens et al.…”

The importance of calcium in improving resistance of Daphnia to Microcystis

“…vulgaris ) (FACHB-1227) were provided by the Freshwater Algae Culture Collection of the Institute of Hydrobiology (FACHB), Chinese Academy of Sciences, Wuhan, China. They were mass cultured separately in BG-11 medium at 25°C under a light intensity of approximately 50 μmol m -2 s -1 with a 12: 12 h light: dark cycle [ 38 ]. The log phase algae were harvested by centrifugation for 10–12 min at 3300 rpm.…”