What is an algal bloom?

    An algal bloom is a rapid increase in the population of algae in a body of water. Algal  blooms can be toxic or non-toxic, so it’s best to treat them with caution. Like in many other lakes, bacteria (Anabaena bacteria) has been found in Sherbrooke Lake, which means that algal blooms that occur have the potential to be toxic (a sure sign is evidence of fish kills).

    Algal blooms float and can be moved from area to area by the wind, so all parts of the Lake may be affected. They can also move up and down in the water column.


    Why is there uncertainty about the safety of the water when a bloom appears?

    Not all algal blooms are toxic, and even if there are toxins present, they may be too diluted to be harmful. The only way to determine the presence of toxins and their strength is to take a sample and send it to a laboratory.

    What causes algal blooms?

    A combination of variables, such as available nutrients (like phosphorous and nitrogen), sunlight, water flow, and temperature can trigger an algae bloom. Many lakes have these conditions present, but we can control excessive nutrient supply by restricting our fertilizer use, preventing septic waste from leaching into the lake, and cleaning up animal waste.

    How can algae blooms be prevented?

    • Stop using lawn fertilizer.
    • Ensure your septic system is functioning properly by maintaining it and pumping it out regularly
    • Ensure that gray water is not escaping into the environment. Gray water is waste water from baths, sinks, washing machines, and some kitchen appliances.
    • Clean up animal waste on your property, especially near shore.
    • Support zoning strategies that better protect the Lake.