Great Lakes-Lake Ontario

greatlakesThis week we’re looking at Lake Ontario, the smallest of the Great Lakes by surface area. The lake’s primary source is the Niagara River, draining Lake Erie, with the St. Lawrence River serving as the outlet. Other major rivers draining into Lake Ontario include the Don River, the Humber River, the Trent River, the Cataraqui River, the Genesee River, the Oswego River, the Black River, and the Salmon River.


hi-lake-ontario-blue-algaeIn our post on Lake Erie, we explored the detrimental effect of algal bloom on Lake Erie, which messes with the color and safety of the water. Algal bloom can come in many colors, from red to green and blue. Lake Ontario experienced a recent electric, neon blue phenomenon, covering nearly the entire lake from shore to shore. An astronaut captured the sight from the space station. The color change was due to a “whiting event.”


“Whiting” occurs when warm-water micro-organisms photosynthesize. They cause the water’s pH to rise, which in turn makes calcium and carbonate ions that are naturally present in the lake condense into white blocks of calcite on the organisms’ surface. Unlike the algal bloom on Lake Erie however, the algae produced in Lake Ontario as a side-effect of a whiting event is harmless and does not effect drinking or recreational usage. You can read more about Lake Ontario’s recent whiting event here.