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Alberta scientists track blue-green algae blooms using satellite imagery | CBC News

A team of experts is working to better understand the spread of blue-green algae in Alberta's lakes by combining satellite technology with near-simultaneous water sampling.

Funded by Alberta Innovates, the project is a collaboration between several groups including the Alberta Lake Management Society (ALMS), the Alberta Biodiversity Monitoring Institute (ABMI) and University of Alberta researcher Rolf Vinebrooke.

Six lakes in Alberta are being monitored for the project – Pigeon Lake, Sylvan Lake, Wabamun Lake, Nakamun Lake, Ethel Lake and Lac la Biche – but it is hoped the data can help create a model or algorithm which can be applied to other lakes.

When a satellite flies over the lake, water samples are collected at the same time to get a clearer picture of algae levels.

Unlike previous methods of water sampling, which are not always processed in a timely manner, satellite imagery can help provide a better overall picture of what is happening in a lake.

“Blue-green algae blooms can be very, very dynamic,” said Vinebrooke, a professor in the U of A's Department of Life Sciences.

“They can be there one day and gone the next… Satellite imagery, once we have a baseline truth and built the algorithms, can provide near real-time estimates of how bad blooms are in different lakes.”

Several satellite images of a lake with different amounts of blue and green.
This slide shows the algal content in Pigeon Lake using various satellite images in 2020. (Submitted by Fiona Gregory)

Blue-green algae or cyanobacteria can form on slow-moving or stagnant water. The flowers can produce toxins that are harmful to humans, pets, and wildlife. Algae growth can be promoted by water rich in nitrogen and phosphorus.

There are currently dozens of Alberta Health Services cyanobacteria alerts for lakes in the province.

The researchers believe the information they have gathered will be important for lake management associations to gain a better understanding of what is happening and to use this knowledge for phosphorus management programs to help reduce flowering.

Vinebrooke said once scientists have enough data, they can compare previous satellite imagery to gain a fuller understanding of blooms in the lake and track trends.

“I think a lot of people in Alberta and across North America have been wondering for a long time whether or not these harmful algal blooms are becoming more common,” he said. “Or does it just seem so because people in general are a lot more environmentally conscious than the public?”

“This means that this question can be answered quantitatively.”

Clear picture

ABMI's Fiona Gregory said the lack of continuous data has made it difficult for researchers to follow trends.

A woman sits in front of a computer screen.
Fiona Gregory is the lead of the Earth Observation analysis part of the project. (Submitted by Fiona Gregory)

Gregory is the leader of the Earth Observation analysis part of the project. She takes the results of the sea sampling program and compares them to the satellite imagery, establishes the correlation, and then applies the model to satellite imagery.

“At best, the sampling is just a snapshot,” Gregory said. “It's only possible, maybe several times a year, but with satellite modeling we're hoping to see what's going on for most of the season.”

Sentinel-2 satellite

While the initiative may seem straightforward, there are some logistical challenges.

The satellite used for the project does not fly over Alberta every day, giving researchers and volunteers a relatively tight data collection window.

“The satellite we're using is called the Sentinel-2 satellite and it flies by about every five days,” said Bradley Peter, managing director of ALMS.

“So we schedule our sampling on the lake, often with volunteers and partners steering the boat. We coordinate all of these schedules to be on the lake.”

Peter noted that the sampling needs to be done on a clear day without too much cloud or smoke obscuring the images.

Eventually the data will be available via an online mapping application. The public can access the information on the six lakes and possibly other lakes in Alberta and get accurate information about the algal blooms.

The project uses the Google Earth Engine, which allows researchers to access and process large amounts of large-scale satellite imagery.

The initiative follows the success of a similar pilot project that began in 2019 and monitored Pigeon Lake. whose data are already available online. The map shows the concentration of chlorophyll-a found in algae.

Algal bloom warnings

A health warning sign for blue-green algae.
Blue-green algae warnings are posted by Alberta Health Services on signs along Alberta Lakes. (Kory Siegers/CBC)

AHS recommends that people and pets should avoid all contact with water when a blue-green algae alert is in effect. Cyanobacteria can make humans sick and deadly to pets.

Those who come into contact with or swallow blue-green algae may experience skin irritation, sore throat, swollen lips, fever, nausea, vomiting or diarrhea.

As of August 25, AHS has warning notices for the following lakes:

  • Taubensee.
  • Enchanted Lake.
  • Wizard Lake.
  • Alix lake.
  • Buck Lake.
  • Moonlight Lake.
  • Bonnie Lake.
  • Winagami Lake.
  • crow lake.
  • Wabamun Lake.
  • Matchayaw (Devil's) Lake.
  • Fork Lake.
  • Garner lake.
  • Floating stone lake.
  • Wapasu Lake.
  • goose lake.
  • Hastings Sea.
  • Lake Kehewin.
  • Elinor Lake.
  • lake reesor
  • Nakamun Lake.
  • sturgeon lake
  • Hutch Lake.
  • Vermillion Lake.
  • Stoney Lake.
  • Eagle Lake.
  • Square Lake.
  • Lac Ste. Anne.
  • thunder lake
  • Astotin Lake.
  • Small fish lake.
  • Severn Dam reservoir.
  • Lac la Biche.
  • Isle Lake.
  • Enchant the city park.
  • Lower Therien Lake.
  • Gregoire Lake.
  • Twin Valley Reservoir.
  • Lessard Lake.
  • Steele Lake.
  • Skeleton Lake.
  • Baptiste Lake.
  • pine lake.
  • moose lake.
  • Lake Muriel.

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