A team of experts is working to better understand the spread of blue-green algae in Alberta lakes by combining satellite technology with near-simultaneous water sampling. The project, funded through Alberta Innovates, is a collaboration between several groups, including Alberta Lake Management Society (ALMS), the Alberta Biodiversity Monitoring Institute (ABMI), and researcher Rolf Vinebrooke from the University of Alberta.
Six Alberta lakes are being monitored for the project — Pigeon Lake, Sylvan Lake, Wabamun Lake, Nakamun Lake, Ethel Lake and Lac la Biche — though there is hope that the data can help create a model or algorithm that can be applied to other lakes. When a satellite passes over the lake, water samples are collected at the same time to provide a clearer picture of the algae content. 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’s happening in a lake. “Blue-green algal blooms can be there one day and gone the next … satellite imagery data, once we’ve got a ground truth and the algorithms constructed, can provide near real-time estimates of how bad the blooms are on a variety of different lakes.“
Blue-green algae, or cyanobacteria, can form on slow-moving or stagnant water. The blooms can produce toxins that are harmful to humans, pets and wildlife. The growth of the algae can be driven by water rich in nitrogen and phosphorus. There are currently dozens of cyanobacteria warnings issued by Alberta Health Services for lakes in the province. The researchers believe the information they gather will be important for lake management associations to get a better understanding of what’s going on, and use that insight for phosphorus management programs to help reduce the blooms.
Vinebrooke said that once scientists have enough data, they can go back and compare the previous satellite images and have a more complete understanding of what the blooms in the lake and be able to track trends.
Fiona Gregory from ABMI said it’s been difficult for researchers to track trends due to a lack of continuous data. Gregory is the lead of the earth observation analysis part of the project. She takes the results from the lake sampling program and compares them with the satellite imagery, working out what the relationship is and then applying the model to satellite imagery. “At best the sampling is only like a snapshot in time,” Gregory said. “It can only be done, maybe several times a year, but with the satellite modelling, we hope to see what’s going on almost all the time throughout the season.“
The project uses Google Earth Engine, which allows the researchers to access and process large amounts of satellite imagery at scale.
