Experts: Minnesota lakes can benefit from subzero weather

February 2, 2019

ST. PAUL, Minn. (AP) — Minnesota’s bitterly cold weather this week may have driven many residents to stay cooped up indoors, but environmental experts say the frigid temperatures are good for the state’s many lakes.

Extended cold weather covers lakes with thick ice, keeping water temperatures cooler in the spring as the ice slowly thaws out. Lakes often see fewer harmful algal blooms in the summer because snow-covered ice blocks the sun and slows the growth of plants and algae, Minnesota Public Radio News reported .

Some native fish species benefit from lower temperatures, such as Lake Superior’s lake trout, brook trout and lake herring, said Cory Goldsworthy, an area fisheries supervisor with the Minnesota Department of Natural Resources. The recent extreme cold weather can also help reduce some invasive species that don’t thrive in cold waters, such as alewife and sea lamprey, Goldsworthy said.

Another positive benefit of the cold is that it slows the loss of water due to evaporation, a growing issue due to Minnesota’s warmer weather, said Valerie Brady, an aquatic biologist with the Natural Resources Research Institute at the University of Minnesota Duluth

Minnesota’s lake temperatures have been on the rise, and the state’s famously bitter winters are warming at a rate 13 times faster than its summers, according to scientists.

But Lee Engel, supervisor of the Minnesota Pollution Control Agency’s water quality monitoring unit, said the benefits of the recent cold weather could diminish if the state gets warmer temperatures earlier in the year, melting the ice cover off lakes.

“It really comes down to what happens this spring,” Engel said. “Do we get a warm spell that’s going to negate this cold temperature and ice that we’re forming, or does it stay cool?”


Information from: Minnesota Public Radio News, http://www.mprnews.org