In the inlet of the Bayfront Park boat launch during the summer months of July, August and September, the water often turn a brilliant green. The green pea soup appearance is due to the proliferation and aggregation of billions of algal cells! These cells clump together to form mats or blooms. The area surrounding the boat launch is particularly sensitive to algal blooms because the water is so shallow and there is little current. The algae thrive in these warm, still waters.

Although algae is a natural part of the Harbour’s ecosystem, in excess it is a huge ecological threat – it block’s sunlight, depletes dissolved oxygen and some species of algae, release toxins into the water as they decompose.

During the summer months, the City of Hamilton regularly tests the water for toxins and will issue a warning should levels become too high. Local water treatment plants are currently undergoing major upgrades to improve their ability to remove algae-causing nutrients such as phosphotus and nitrogen from wastewater prior to it entering the Harbour.