Keeping an Eye on Lake Superior

Lake Superior is famous for its cold, clear waters, not its harmful algal blooms. However, that reputation is being tested as the lake warms and conditions change. At Wisconsin’s Lake Superior Reserve, monitoring coordinator Hannah Nicklay is watching those changes happen in real time.

Just outside the Reserve’s office on Barker’s Island sits a System-Wide Monitoring Program (SWMP) water quality station, which collects data every 15 minutes. Nearby is a popular public beach where people swim, boat, and enjoy being on the water. That proximity has made the station an important tool for understanding a growing concern in the area: that toxic algal blooms will endanger people and animals.

Photos courtesy of Lake Superior Reserve.

The concern began after major flooding in 2012 sent nutrient-rich sediment into Lake Superior. That year, one of the first recorded algal blooms was recorded along the Lake’s shores. Another major bloom followed in 2018, which was extensive enough to be visible in satellite imagery. While these events were short-lived and nontoxic, blooms near the beach have become increasingly frequent. 

“In 2018, I spotted a bloom near the beach and realized there was no straightforward process for determining who should be notified or whether the beach should close,” says Nicklay. “People, toddlers, and dogs were in the water and on the beach.” 

Since then, the Reserve and partners built a rapid response network that alerts regional scientists, natural resource managers, and public health officials when a bloom is spotted, allowing experts to investigate and close the beach if necessary.

Photos courtesy of Lake Superior Reserve.

“The Lake Superior Reserve’s monitoring work helps us keep an eye on bloom-prone areas such as the Duluth-Superior inner harbor,” says Gina LaLiberte, Statewide Harmful Algal Bloom Coordinator with the Wisconsin Department of Natural Resources. “This helps local public health departments and park managers to keep visitors and swimmers informed when blue-green algae blooms, which can pop up quickly, might pose a risk to their families and pets.”

Now, the Reserve and Nicklay are interested in whether continuous monitoring can help predict blooms before they happen. To do so, they are developing algorithms that look for changes and anomalies in continuous sensor data that could signal a developing bloom. New monitoring stations in bloom-prone areas are adding even more high-frequency data. This research is sponsored by Wisconsin Sea Grant. 

People experience many benefits from the St. Louis River Estuary, where the Reserve is located. Those include outdoor recreation, relaxation, creating art inspired by its natural landscape, habitat for birds and fish, education, and sense of place. The estuary is also home to the Port of Duluth-Superior, which supported nearly 8,000 jobs and generated about $1.4 billion in regional business revenue, $504 million in wages, and roughly $240 million in state and federal tax revenue in 2017. 

“The Reserve’s SWMP stations document more than a decade of environmental change, while some stations in the St. Louis River system build on water quality records dating back to 1953,” says Nicklay. “Together, they provide a baseline for protecting this resource for generations to come.”

Photos courtesy of Lake Superior Reserve.