The St. Louis River has had a history of water quality issues, including at its estuary. 

“The estuary was established as a so-called area of concern back in the 1980s to deal with a whole suite of environmental issues such as nutrient pollution, problems with the organisms living in the estuary. Obvious esthetic issues and all these sorts of things that have, for the most part, been dealt with in the last few decades,” said UMD Natural Resources Research Institute (NRRI) Senior Research Associate Euan Reavie. “Currently, though, given that we are seeing issues with algal blooms, we don’t have a monitoring program in place to determine why that’s happening.”

Algal blooms can be toxic to people, but in Minnesota, the issue is usually pets drinking the water from a bloom and dying from it. 

“We have seen blooms that are formed after storm events because a lot of nutrient is being flushed down into the system and likely forms in the estuary. And then it’s hugging along the southern shore of Lake Superior all the way up to the Apostle Islands,” said Reavie. “And these are fairly dense blooms of cyanobacteria or what we call blue green algae that again, are becoming a problem because it appears to be a new thing. We don’t have any real anecdotal evidence going back more than a decade that these blooms occurred before. Why are they happening now? It’s something we don’t really understand.”

UMD NRRI has partnered with Lake Superior National Estuarine Research Reserve to take over 300 water samples from eight different locations in the St. Louis River estuary. 

“For this project, we’re trying to get a better idea of how nutrient and water chemistry parameters are affecting our communities in the estuary and get a better understanding of how to keep an eye on the estuary, thinking about harmful algal blooms and things like that going into the future,” said Research Assistant Peter Birschbach. 

Sampling will be done weekly this summer into the fall, with field work in the winter. 

“We’re really interested in areas that have really low or no oxygen. And then we also go out several times in the winter and collect all the different parameters that we do in the summertime, too,” said Monitoring Coordinator Hannah Ramage. “So looking at nutrients and looking at the algae, that’s actually maybe thriving under the ice, which can tell us a lot about what the conditions are.”

The Lake Superior National Estuarine Research Reserve has monitored four locations for over a decade through its System Wide Monitoring Program (SWMP). Each location logs water quality readings every 15 minutes. 

“Those four locations are on your way on the river as you’re making your way. So they kind of get a stratification from the river as it starts to mix with the lake,” said Ramage. “So it’s really a great opportunity for any additional research projects that we have, that data that’s logging continuously and for so long that we have it as sort of a reference of water quality in the estuary.”

The ongoing sampling project monitors eight new locations that have a history of water quality issues. 

“What we’re really concerned about now with seeing algal blooms is what are the conditions like in the back bays? What are the conditions like, especially some of these sheltered bays in the upper river where you have some sort of constriction so you’re not getting as much flow and fresh water into those bays and also places where you have higher inputs of nutrients, like where a tributary comes into the st Louis River or where you have urban streams that are maybe impaired for sediment or for E coli,” explained Ramage. “So the sites that we’re sampling for this project so frequently are in places that we’re calling hotspots. So they’re not what is typical in the estuary there, what is usual. So are there places where in the past we know there’s higher concentrations of nutrients like ammonia nitrate, phosphorus, or are there places where we’ve seen in the past that there’s really low dissolved oxygen?”

The project is expected to wrap up in 2024 and include a monitoring recommendation report going into the future based on analysis of the data collected. 

“We can try and deal with the climate change problem head on. You know, that is the ultimate solution,” said Reavie. “I think in some ways, just knowing where this is going will allow us to make predictions and be able to, you know, manage the water system better, at least having an idea where it’s going. If this is a problem that’s going to continue to get worse, whether we can deal with it or not, it’s something we need to understand.”