| Molecular tools were used to monitor the dynamics of Microcystis populations and the potential microcystin producers in Missisquoi Bay (the Canadian part of Lake Champlain). This study showed the GF/C filters, which are typically used to prepare samples for microcystin analysis, were not ideal for the characterization of total bacterial communities, but were sufficient for the chemical analyses of cyanobacterial microcystins. The mcyD gene copy number determined by Q-PCR correlated well with the microcystin concentration determined by ELISA and HPLC in 2006; therefore mcyD Q-PCR could be used as a rapid and sensitive method and as an effective monitoring system for toxic cyanobacterial blooms in Lake Champlain. Escherichia coli was also monitored as an indicator of manure contamination of lake water. Manure application and rain events positively related to the high nitrogen concentration in the lake in 2006, suggested that good manure management is necessary for the reduction of agricultural nutrient loads into Missisquoi Bay, believed to be a major cause of cyanobacterial blooms. |
