Expansion, toxicity and impact of cyanobacteria in a changing world

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Cyanobacteria, commonly referred to as blue-green algae, are frequently in the news because of their tendency to form surface blooms in lakes and coastal areas, some large enough to be seen by satellites. Excess nutrients (phosphorus and nitrogen) from agricultural or municipal sources are largely responsible for increases in cyanobacteria, but climate change may also be contributing to this “rise of slime”. Canada is now experiencing unusual cyanobacterial blooms in relatively low nutrient lakes and at high latitudes close to the Arctic Circle, where there is no traditional knowledge of such blooms. Cyanobacterial dominance can have negative effects because of the potential production of potent toxins, which can affect drinking water supplies, recreational activities and property values.******* This research programme will apply novel techniques to the study of lake sediments in order to discover the origin and causes of cyanobacterial blooms over the scale of centuries. We have shown that it is possible to extract quality DNA from ancient sediments and amplify cyanobacterial and other microbial genes to begin the reconstruction of the history of cyanobacterial populations and communities in the absence of current monitoring data. The goal of this research for the next five years is to explain the apparent geographic expansion, increase and impact of toxic cyanobacteria, in light of land use changes and global climate change. The specific objectives are to: 1) validate the interpretation of sediment DNA (paleoDNA) records, 2) determine if climate change is leading to changes in cyanobacterial dominance, toxic species and cyanotoxins at northern latitudes, 3) determine if increases in cyanobacteria are affecting ecosystem services, particularly the capacity for lakes to serve as a carbon sink. These objectives are part of my long-term goal to provide tools for the management and protection of freshwater resources. Understanding the past trajectories of temperate and high latitude lakes will enable us to better predict how northern lakes will respond to climate and land use change, and inform environmental and public health policies.*The research programme will train several highly qualified personnel (8 B.Sc., 4 M.Sc. and 2 Ph.D.), who will be exposed to classical and modern techniques in aquatic sciences and molecular biology thus gaining valuable skills for careers in water resources management and environmental sciences.***