The Dominance of Cyanobacteria in Ponds of the Hudson Bay Lowlands and the Limiting Factors to their Growth

Seventy and thirty four Churchill ponds were surveyed for physical, chemical and algal data during July 2012 and July 2013, respectively. The physical results confirm that these ponds vary widely in surface area due to different pond origins. Mean pond depth values confirmed that these ponds are shallow. These ponds are high in salinity, pH, specific conductance and range from mesotrophic to oligotrophic. The shallow depths of the ponds in the Hudson Bay Lowlands favoured the growth of benthic cyanobacteria over all other algal groups, likely due to their adaptation to extreme environments. The only instance when benthic cyanobacteria were not dominant was when benthic green algae dominated in organic ponds with very small surface areas. Ponds with small surface areas offered the least-extreme environment to algae in relation to nutrient availability and UV-radiation protection.