This research will identify the role of drying and re-wetting on sediment nutrient flux in Lake Kabetogama and assess whether water level management to reduce this nutrient flux would also reduce toxicity by phytoplankton. Existing data on the relationship between water level and the area of exposed sediment can then be used in conjunction with the results of this study to estimate the rate of dissolved inorganic nitrogen (DIN) and soluble reactive phosphorus (SRP) release to the water column, and role of potential water level management scenarios in driving the presence and production of cyanotoxins. Data on the water level fluctuations will be associated to the sediment nutrient release and cyanotoxin production via statistical and causal models.