Cyanobacteria (Blue-Green Algae)

What is blue-green algae? 

Blue-green algae is also known as cyanobacteria. However, this harmful “algae” is actually a bacteria. These bacteria are single-cell, microscopic organisms that are naturally occurring. They are found in all types of water: freshwater, marine water, and brackish waters (combined salt and freshwater). They are found in both warm and cold climates, even as far south and north as the poles. 

Cyanobacteria use sunlight to make their own food. In warm, nutrient-rich environments, they can multiply quickly. When these bacteria multiply quickly, they form what are known as blooms. These blooms severely impact the drinking as well as recreational water quality for humans, as well as aquatic life and any animals using the water as a drinking or food source. Some can get so big and bright that they can even be seen from space!

Cyanobacteria fall into a category called Harmful Algal Blooms, or HABS. 

How does it impact water quality?

As the bacteria multiplies the blooms can become toxic. Cyanotoxins are the toxins cyanobacteria can produce. These can have very serious health consequences for humans, as well as on the animals living in or near the water. 

How is it identified?

Cyanobacteria is identified in waterbodies in two ways: through visual observation or through sampling. Samples require a specialized lab for processing, meaning our kits can’t test for it currently. The concentration of cyanobacteria in a water sample is typically measured as cells per milliliter.

In Canada, the federal government’s recommended guidelines for quantifying cyanobacteria are as follows:

  • Total cyanobacteria: 50 000 cells/mL
  • Total cyanobacterial biovolume: 4.5 mm3/L

Learn more

To learn more about HABs, including how to report them, check out this post on our blog.

When in doubt, take a picture!

We don’t have a way to test for cyanobacteria in the field (yet), but that doesn’t mean you can’t keep track of your observations. Take pictures of suspected algae and upload them to our data platform using the “report an issue” feature. Note: this feature is only available on our website, and not on our app!