Scientists investigate impacts of historic ice lack on Great Lakes

Biologists at Michigan Technological University have been observing the fragile wolf population of a remote Lake Superior island every winter since 1958, but they had to shorten the seven-week study planned for this season after just two weeks.

The ski plane from which they study the wolves uses the frozen lake as a landing strip because there is nowhere to land on the island. But this unusually warm winter left the Great Lakes almost ice-free.

As climate change accelerates, scientists are scrambling to understand how ice-free winters could affect the world’s largest freshwater system. Most effects are still theoretical, as the lakes are generally too treacherous for data-gathering expeditions during the colder months and biologists have long thought there is little ecological activity under the ice anyway. But they say the changes could have serious environmental, economic and cultural impacts, including harming certain species of fish, eroding beaches, fueling algae blooms and clogging shipping channels.

“This year really makes it clear to us that we need to collect more data,” said Trista Vick-Majors, an assistant professor of biology who studies aquatic ecosystems at Michigan Tech. “There is simply no way to predict how an ecosystem will respond to large-scale changes.” that we are observing.”

The planet experienced record heat for the eighth consecutive month in January, according to the European climate agency. The upper Midwest has been no exception: Chicago enjoyed temperatures around 70 degrees (21 degrees Celsius) late last month and Wisconsin got its first tornadoes of february.

Ice coverage on the lakes, which have a combined area roughly the size of the United Kingdom, has generally peaked in mid-February over the past 50 years, with up to 91% of lakes covered at times, according to the Great Lakes Ice Tracker Website. In mid-February this year, only 3% of the lakes were covered, the lowest figure since at least 1973, when records of the site began.

Researchers don’t have much data on how years of ice-free winters might change the lakes, but they do have plenty of theories.

Lakes without ice could absorb sunlight faster and warm up sooner in the spring. Some biologists speculate that this could lead to an earlier and larger appearance of blue-green. algae bloomswhich can be toxic to humans and put a brake on summer tourism.

Without ice, the upper levels of the lakes will likely warm even more rapidly than usual, contributing to thermal stratification, in which layers of colder and warmer water form. Some scientists believe that less oxygen would reach the lower, colder and denser levels, which could cause the death of plankton and other organisms. Whitefish and lake trout generally hatch in the spring and feed on plankton, so fewer plankton would likely cause a reduction in fish populations, which could lead to stricter fishing quotas and higher prices. high in grocery stores and restaurants.

Less #fish and more #algae? Scientists are seeking to understand the impacts of the historic lack of ice on the Great Lakes. #ClimateChange #GreatLakes

Less ice could mean longer fishing seasons, but winter storms could destroy nets and traps and destroy whitefish eggs that rely on ice for protection, said Titus Seilheimer, a fisheries specialist at the University of Wisconsin-Madison.

Charlie Henrikson runs a small commercial fishing operation off the Door County Peninsula in Wisconsin. He said his boats have been setting nets in February, when they normally don’t start the season until late March. He said what worries him most is that the lack of ice will cause more evaporation, which would cause lake levels to drop and make it harder for his boats to get into port.

“I’m 71 years old, so of course I like the heat better. I like being able to walk along the dock here and not have icy conditions. Whatever you want to call it, the climate is changing. And we are having more extreme conditions. It will change our strategy and we will be able to find ways to use it. “You always have to adapt.”

Less ice could also lead to a longer lake shipping season. But without ice covering the lakes, powerful winter storms could erode shorelines more than usual, which could push more sediment into harbors and make them shallower and more difficult to navigate, said Eric Peace, vice president of Lake Carriers. Association, a trade group. Coupled with lower lake levels due to increased evaporation, boats may have to carry less cargo to stay higher in the water, he said.

This year’s lack of ice allowed Michigan Tech’s Vick-Majors to launch a project to collect winter-specific data that scientists can compare with summer data. Researchers from across the Great Lakes are participating in sampling this month.

On a recent day, Madeline Magee and Rae-Ann Eifert, lake monitors with the Wisconsin Department of Natural Resources, braved subfreezing temperatures to collect buckets of lake water at a Racine breakwater as part of the Vick-Majors project.

The lake was wide open, an emerald expanse stretching to the horizon, and the wind was howling. High waves hit the beach and washed over Eifert as she stood on the breakwater, leaving her ski pants covered in drops of ice. Magee said the project is worth it.

“Continuing to collect data in the future will only better inform what we know about the Great Lakes and how we could manage them more efficiently. …If we lose the ice sheet, we are really changing the fundamental ecosystem of the Great Lakes in ways that we don’t understand right now,” he said.

Leave a Comment