How does water quality change with the seasons?
The St. Louis River Estuary is a complex system that’s affected by many natural and human factors. One example of the complex natural interactions in the estuary is water quality. Water quality varies throughout the estuary as a result of interactions with Lake Superior, the St. Louis River watershed and other important tributaries like the Pokegama River. Our water quality monitoring is an important step in understanding the complex interactions of these water bodies, but our monitoring is more limited in the winter when surface ice inhibits data collection.
In fact, under-ice water quality has been a scientific blind spot for decades, not just in the St. Louis River Estuary, but in freshwater science as a whole. Scientists have been working on filling in that research gap around the world in recent years, and we’re doing the same here at the Reserve. We’re interested in how water quality changes in the winter, when ice layers affect the amount of sunlight reaching water and inhibit interaction between water and the atmosphere.
In recent years, we’ve drilled through ice in locations throughout the estuary to measure water quality parameters like dissolved oxygen and turbidity. Our goal is to document how water quality changes in the winter, and how it’s affected by vastly different water sources like Lake Superior and the clay-bottomed Pokegama River. These data could help us understand how winter conditions might influence water quality throughout the year and how climate change might affect water quality.