Blue-Green Algae Documented In Superior’s Canadian Waters – A First?

A picture of Lake Superior surface water some 35 km/21 mi. east of Thunder Bay on September 20th. (Photo:

Green Patches Stretch Offshore

On the evening of September 19th, a boater some 35 km/22 mi. east of Thunder Bay noticed green patches stretching far out into the open waters of the lake. The boater noted water temperature at 15 degrees Celsius or 59 degrees Fahrenheit. The next morning marked the third day of unusually calm conditions on Lake Superior and a kayaker in the same area, noted the same unfamiliar sight: patches of green on the surface of Superior’s waters. 

The kayaker first observed the green patches in a small bay, which area residents refer to as “East Bay.” The green patches continued out into the open waters of Lake Superior to a distance of at least a couple of miles from shore. In the early afternoon of the same day, green patches covered more of this same area. They were also observed in an adjacent small bay, referred to by locals as “North Bay.” By late afternoon, green patche coverage had also increased in the open waters of Superior.

In the late afternoon on September 20th a scum covered the inshore area of “North Bay” to a distance of approximately 50 meters, or 54 yards, from shore. (Photo:

The late afternoon situation in North Bay was intense, with several extensive green patches. Additionally, a surface scum covered the entire inshore area of the bay, out to approximately 50 m/54 yd. from shore. A thick line of dark scum, perhaps a foot in width and less than a foot from the water’s edge, ran along the sand on the bay’s shoreline.

Algae sample collected from Lake Superior on September 20th. Photo taken under the microscope. (Photo:

Testing Confirms Cyanobacteria (Blue-green Algae)

The kayaker collected a sample of the green material which was sent to Lakehead University for identification. Testing determined that the material was dominated by a genus of cyanobacteria (also known as blue-green algae) called Dolichiospermum. 

Next, the sample was tested for toxicity. An enzyme-linked immunosorbent assay (ELISA) test showed microcystin toxin levels were lower than the drinking water threshold. In lay terms, test one came back positive for cyanobacteria, test two came back negative for toxicity. 

To the best of Infosuperior’s knowledge, this event is the first documented incident of a cyanobacteria bloom in the Canadian waters of Lake Superior. Government environment and health agencies were notified about the situation.

Algae extended into the open waters of Lake Superior, even into unprotected waters well beyond the island in the distance, which is approximately 2 km. / 1 mi. from shore. (Photo:

Clear Water Returns

The next morning, on September 21st, waters in the area, including East Bay, North Bay and the open lake, were relatively calm and extremely clear. Beach sand was clean and there was no sign of the scum, which had lined the shoreline the previous day.

Material from the surface of Lake Superior – September 20th. (Photo:

Algae Briefly

Algae are simple aquatic plants without roots, stems or leaves and with primitive reproduction methods. Algae ranges in size from microscopic, or microalgae, to macroalgae, large seaweed that can be over 30 m./100 ft. in length. Cyanobacteria fall within the microalgae size. Most microalgae flourish by harvesting sunlight and a few nutrients, like phosphorous and nitrogen. 

Algae are a natural part of the ecosystem and the foundation of the aquatic food chain. They are primary producers that support fisheries in both inland waters and oceans; however, Cyanobacteria (blue-green algae) are not generally eaten by other aquatic organisms.

Algae blooms usually occur in late summer or fall. Blooms can occur naturally in the absence of any human influences and are even noted in the journals of early explorers. Alexander MacKenzie noted such an occurrence in the seventeen hundreds on Lake of the Woods; however, today’s large-scale nuisance algae blooms like those experienced on Lake Erie and Lake Winnipeg are not “natural.” Nutrient enrichment from humans contributes significantly to these types of algae growth. Phosphorus and Nitrogen are the primary nutrients contributing to increased blooms, and they can enter waterways in surface runoff from sources such as lawn and agriculture fertilizers, soap, and sewage.

Algae blooms are a complex subject. A bloom can include many species and even variants within species. Cyanobacteria blooms, are of particular concern due to their ability to produce several toxins. These toxins can damage liver tissue and/or the brain and can be lethal to animals, including pets and humans. Cyanobacteria can also cause skin irritation, along with taste and odour issues.

A green patch in the Canadian waters of Lake Superior on a hazy September 20th morning. A sample was collected and examined under the microscope and determined to be blue-green algae. Algae coverage in this area expanded throughout the day. (Photo:

Algae in the U.S. Waters of Superior

Algae blooms in Lake Superior are rare, and until recently, were almost unknown. In the last few years however, algae blooms have been observed in the U.S. waters of Superior. The New York Times link below provides an overview of this situation. Other links provide information about algae blooms in lakes large and small, including Lake Baikal in Russia. Like Superior, Lake Baikal is known for its clear waters and holds an almost spiritual significance to Russians. Due to its extreme depth, Lake Baikal holds more water than all of the Great Lakes combined.

Reporting Blue-green Algae in Ontario

If you observe blue-green algae in Ontario call the Spills Action Centre, 1-866-MOETIPS (6638477), TTY: 1-855-889-5775.

Local Algae Information:

After reporting any suspected algae blooms to the Ontario Ministry of the Environment, Conservation and Parks, through the Spills Action Centre, local residents looking for additional information on blooms are encouraged to contact us. Our research team offers a wide range of expertise including phytoplankton identification.

Lake Superior Research Center (contact via – offering educational information on phytoplankton blooms in Northwestern Ontario. 

U.S. Algae Information:

More Photos:

View More Pictures of the September 20th Situation Described in this Article.

After reporting any suspected algae blooms residents looking for additional information on blooms are encouraged to contact us. Our research team offers a wide range of expertise including phytoplankton identification.


August 29, 2018 NYTimes Article: Lake Superior Algae Raises Concerns

June 3, 2019 Infosuperior Article by Nathan Wilson: Classifying Lakes: Eutrophication in the Boreal Forest Ecozone

November 29, 2016 Infosuperior Article: It Could Never Happen Here

Province of Ontario Information About Blue-green Algae

Learn About Research Carried Out By Lakehead University Doctoral Student Nathan Wilson at Cloud Lake Near Thunder Bay

Globe and Mail Article Updated April 3, 2018: Algae and Property Values

September 10th, 2019 Waukesha Patch Article: Invasive Algae Found in Two Wisconsin Lakes

Environment and Climate Change Canada Algae Identification Field Guide

Northern Kentucky University Algae Field Guide

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Lakehead Research – Cyanobacteria in Northwestern Ontario Lakes

Nathan Wilson
Nathan Wilson, PhD candidate at Lakehead University, collects a sample from Cloud Lake. He will be collecting samples from some more Northwestern Ontario lakes this summer as part of his field work for his PhD. (Photo credit:

Nathan Wilson is a PhD candidate at Lakehead University. Infosuperior conducted the following interview with Nathan to learn more about his research on nutrients and cyanobacteria in Northwestern Ontario lakes before he gets started out in the field this Summer.

What is the main question that you are trying to answer with your PhD research?

The main question, at this point, I am looking to answer for my PhD would be, Have cyanobacteria (a known toxic producing phytoplankton) existed in Northwestern Ontario lakes historically? On lakes that currently have cyanobacteria have they increased since people have settled the shore? This is somewhat of a basic or simple question that has some very important information within it. Understanding if cyanobacteria have been in Northwestern Ontario’s oligotrophic lakes historically or not will provide an insight into how best to move forward with managing this possible future problem.

Little is currently known about the distribution and abundance of cyanobacteria in Northern Ontario lakes because they are assumed to be cold, clean, oligotrophic lakes buffered against problems such as phytoplankton blooms. I am looking to better understand what the phytoplankton community composition on lakes in this region is/was. By understanding what phytoplankton communities currently and previously existed on a lake it is possible to better manage a lake if it starts to change beyond what would be expected for that lake. An example would be for lakes where development, cottages, or mining, is being proposed. Having the predevelopment community composition allows us to monitor resulting disruptions in the phytoplankton community that may result. 

What made you interested in this question?

What sparked my interest in this topic, work from my Master’s. I was looking at a lake just south of Thunder Bay when we observed cyanobacteria blooms. The more I looked into this problem the more I realized how much this topic was an emerging issue and how little was known or understood outside the major lakes like Winnipeg, and Erie.  

The main focus of my research is to raise awareness regarding lakes and phytoplankton in Northwestern Ontario. 

What are phytoplankton and what types of phytoplankton do you expect to find in a Northwestern Ontario Lake?

Phytoplankton are microscopic plants that live and grow in water. They contain chlorophyll and require sunlight to grow and live. You can think of them as the grasses of the water. They take in nutrients from the water and use photosynthesis to supply themselves and, just like plants on land, they are the base of the food chain. There are several kinds of phytoplankton – green algae, brown algae, golden algae, dinoflagellates, diatoms, cyanobacteria, and many more. Many phytoplankton can be found in both salt and freshwater systems. It is fairly likely that I will find a number of green algae, dinoflagellates, diatoms, and I expect to find at least a few cyanobacteria. 

Your research also looks at internal loading with relation to cyanobacteria. Can you explain this concept and how it relates to lakes in Northwestern Ontario?

Internal loading refers to the resuspension of biologically available phosphorus into the water at the bottom of a lake. Most phytoplankton is unable to access this very important nutrient. Unfortunately, cyanobacteria is able to regulate its buoyancy and therefore it is able to access this nutrient and outcompete other less harmful or problematic phytoplankton. Internal loading also poses a major issue when addressing the management of human-induced eutrophication because the cyanobacteria are not limited by reductions of external phosphorus inputs.

The initial plan to combat the major issues of anthropogenic eutrophication came from work done at the Experimental Lakes Area by Kenora, Ontario. The research there showed that increases in phosphorus in the lake water resulted in more phytoplankton and specifically more cyanobacteria blooms. The immediate management approach of lakes experiencing problems was to address the sources of phosphorus that were entering into the lake. Lake Erie is an example of this problem.

Strict regulations were put in place for water treatment and industrial water and the removal of phosphorus from that water before it was allowed back into the lake. This approach worked initially and there was a reduction in the size and distribution of cyanobacteria blooms on Lake Erie. However, as most know Erie is still experiencing problematic blooms. This is because of a number of additional factors that we can not account for as easily. One of which is the continued development of anoxic bottom water which is associated with internal loading and allows cyanobacteria to out-compete other phytoplankton and dominate the community composition. Therefore, despite the limiting of external phosphorus, cyanobacteria are able to proliferate and bloom due to internal loading of phosphorus. 

These factors are very important for Northern Ontario as currently, the accepted knowledge is that Northern Ontario lakes do not experience internal loading. If they do or have the potential to experience internal loading, this is very important for the management of lakes. It will help better understand the number of camps/cottages a lake can have on it without overloading, and if a lake is already overloaded, it will help better understand the best options to protect that lake from further human impacts (as we see in other parts of Canada and the world). 

I am hoping my research will be able to provide information that can be used to better understand internal loading specifically within Northern Ontario Lakes. I am hoping to do this through the examination of sediment cores and monitoring current lake conditions and phytoplankton communities. Lakes in Northwestern Ontario are usually thought to be Oligotrophic (low nutrients, clean, cold water lakes). 

Fieldwork for your research begins this summer, what questions will you be focusing on? What type of data do you need to collect and how will it be collected?

For this season I am focused on collecting data that provides a baseline of the current conditions for the lakes I have selected. To do this I will be focusing on collecting data that tells me about the current state of the lakes. Things like temperature and dissolved oxygen profiles, secchi depth, some basic water chemistry like nutrient composition, and most importantly phytoplankton samples. I will also be taking sediment cores from the bottom of the lakes to gain data about how the lake has changed in the last few decades.

Most of this data is relatively simple to collect using a boat to get on the water so I can measure the temperature, dissolved oxygen and secchi depth. Collection of water samples for both chemical analysis and phytoplankton requires sample bottles to and a preservative to keep the phytoplankton from degrading or losing small identification features like their flagella. The sediment samples are a bit more tricky. Using a long rod with a tube on the end I will push the tube into the sediment in the deepest part of the lake. A one-way valve on the top of the apparatus causes a seal with the sediment in the tube, this has to be pulled out. Trying to do this from a boat can be rather difficult. Usually, cores are taken during the winter when the lake is frozen and you can stand on the ice for more leverage. The analysis of all this data is more difficult.

Infosuperior is grateful to Nathan Wilson for sharing some more information about his research. Nathan Wilson studies various aspects of lakes and lake management through the environmental biotechnology program at Lakehead University, working with Dr Carney Matheson and Dr Rob Stewart. His focus is on examining lakes within Northwestern Ontario to better understand nutrients and cyanobacteria.

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