Dependence of cyanobacteria bloom formation and maintenance on anoxia and trace metals in eutrophic lakes
The key driver of cyanobacteria bloom formation is the onset of anoxia (defined as complete loss of dissolved oxygen and nitrate) at the sediment/water boundary which results in release of ferrous iron into overlying water. The discovery of this formation has important management implications because blooms can be averted by preventing complete loss of dissolved oxygen at the sediment/water boundary. This allows managers to set phosphorus targets that protect oxygen levels. The project will continue a survey of metabolically essential trace metals in lakes across Canada to fill in gaps, especially in eutrophic lakes. Preliminary evidence indicates that very low concentrations of certain trace metals (molybdenum, iron and possibly cobalt) can limit growth of cyanobacteria in eutrophic lakes in some regions when nitrogen is in short supply. Funding: Natural Sciences and Engineering Research Council (NSERC) $140,000.