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What Is Blue Green Algae?

Updated: Aug 2, 2022

We're here in cottage country, specifically Chemong Lake checking on some floating, emerging wild rice.

Checking on the overall water quality - It's been really hot so far this spring. With the heat (and climate change) the temperature of these lakes are constantly rising and with that you get what is called "blue green algae bloom".

This can be very dangerous to both animals and humans. With farming and ageing septics from cottages here (that we see along the shoreline) comes nutrient overload and with that nutrient overload comes an environment for this blue green algae to bloom and really take hold of this watershed.

We're checking on the state of the wild rice and as you can see it has become more prevalent. With wild rice, it actually purifies the water and creates great ecosystems for both birds and fish (for cover).

What is Blue Green Algae?

Cyanobacteria, or blue green algae is a type of bacteria that is most commonly found in wetlands and waterways (rivers, lakes and ponds).

Given the right conditions (such as a hot and humid summer), blue green algae can multiply quickly to form what are called "blue green algae blooms".

What Causes Blue Green Algae Bloom?

Nutrient overload from fertilizers and run offs from agriculture (and waste water) can contribute to blue green algae growth. Any type of nutrient run off can contribute to the growth of blue green algae.

Blue green algae flourishes in hot and humid climate conditions.

What Is The Danger of Blue Green Algae?

Once blue green algae dies it can release toxins into the water that can be dangerous for livestock, humans and pets. Any contact with infected waterways (from blue green algae) either through swimming, boating, canoeing, etc can cause a host of physical ailments (to humans) such as:

  • skin irritation

  • sore throat

  • sore, itchy eyes

  • stuffed up feeling

If ingested, side effects may include

  • sickness or vomiting

  • joint pain

  • muscle pain

  • cramps

  • headache

  • diarrhea

For pets, ingesting infected water from blue green algae can cause severe illness and death.

What Does Blue Green Algae Look Like?

Often forming on the top of calm waterways, blue green algae blooms appears blue-green or greyish (brown) in colour that resembles pond scum (on top of the water surface).

Here's what blue green algae looks like along the shoreline
Blue green algae along the shoreline
Here's a photo of blue green algae on top of water, staining it.
Blue green algae staining the water
Here's an aerial shot of blue green algae
Aerial shot of blue green algae

Does Blue Green Algae Smell?

Yes, blue green algae will often smell musty (and foul).

How Does My Community Manage Blue Green Algae?

If your community has blue green algae problems, the best course of action is to monitor and limit the amount of nutrients that go into your communities waterways.

Be mindful of cottages and homes beside lakes and rivers that may have run off problems. In addition, lawn fertilizers can contribute to nutrient run off into your communities waterways contributing to blue green algae bloom.

Practice sound watershed management for the prevention of blue green algae.

Wild rice and other healthy water vegetation such as cat tail and water lilies can help to purify your communities waterways.

Does your community need help treating or developing a plan for healthy water ways? We can help! Contact us today at:

(705) 657-1126 or via email:

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