Scientists try to understand the impact of lack of ice in the Great Lakes

RACINE, Wis. — Michigan Tech University biologists have been monitoring a remote Lake Superior island’s fragile wolf population every winter since 1958, but they had to cut back just under two weeks from the seven-week survey planned for this season.

The ski plane on which they were studying the wolves uses the frozen lake as a landing pad because there is nowhere to land on the island. But this strangely warm winter left the Great Lakes virtually ice-free.

As climate change accelerates, scientists are trying to understand how ice-free winters might affect the world’s largest freshwater system. Many of the effects are still theoretical, as lakes are often too treacherous for data-gathering expeditions in the coldest months, and biologists have long thought little ecological activity occurs beneath the ice. But they say the changes could have serious environmental, economic and cultural impacts, including harming certain fish species, eroding beaches, fueling algal blooms and clogging shipping channels.

“It drives home the point that we really need to collect more data this year,” said Trista Vick-Majors, an assistant professor of biology at Michigan Tech who studies aquatic ecosystems. “There’s no way to predict how an ecosystem will respond to the large-scale changes we’re looking at.”

The planet experienced record heat for the eighth consecutive month in January, according to the European climate agency. The Upper Midwest was no exception, with Chicago experiencing temperatures near 70 degrees late last month and Wisconsin experiencing its first tornadoes of February.

Ice cover on lakes with a total surface area the size of the United Kingdom has generally peaked in mid-February over the last 50 years relative to the Great Lakes, with 91% of the lakes covered at times. Ice Tracker website. As of mid-February this year, only 3% of the lakes were covered; This was the lowest figure since records began in the area in at least 1973.

Researchers don’t have a lot of data on how years of ice-free winters might change lakes, but they have many theories.

Ice-free lakes can absorb sunlight more quickly and warm up more quickly in the spring. Some biologists think this could lead to earlier and larger blooms of blue-green algae that could be toxic to humans and negatively impact summer tourism.

Without ice, the upper levels of lakes will likely warm faster than normal, contributing to thermal stratification in which layers of colder and warmer water form. Some scientists believe that less oxygen would cause it to drop to lower, colder and denser levels, which could cause plankton and other organisms to die. Whitefish and lake trout generally hatch in the spring and feed on plankton, so less plankton will likely cause fish populations to decline, potentially leading to tighter fishing quotas and higher prices at grocery stores and restaurants.

Less ice may mean a longer fishing season, but winter storms can shatter nets and traps and destroy whitefish eggs that depend on ice for protection, said University of Wisconsin-Madison fisheries expert Titus Seilheimer.

Charlie Henrikson runs a small commercial fishing operation on Wisconsin’s Door County peninsula. He said his boats set up the nets in February and they don’t usually start the season until the end of March. He said he is most concerned that the lack of ice will lead to more evaporation, which will cause lake levels to drop and make it harder for his boats to dock.

“I’m 71, so of course I like warmer weather. I love walking along the dock here without any ice. Whatever you call it, the weather is changing. And we are faced with increasingly extreme conditions. We will change our strategy and find ways to benefit from it. “You always have to adapt.”

Less ice could also lead to a longer shipping season on the lake. But without ice covering lakes, strong winter storms could erode shorelines more than usual, pushing more sediment into harbors and making them shallower and more difficult to navigate, said Eric Peace, vice president of the Lake Haulers Association, a trade group. As lake levels drop due to increased evaporation, ships may need 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 could compare with summer data. Researchers from around the Great Lakes are participating in the sampling this month.

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

The lake was wide open, an emerald green field stretched to the horizon, and the wind was howling. High waves pounded the beach and showered Eifert as he stood on the breakwater, leaving his ski pants covered in beads of ice. Magee said the project was worth it.

“Continuing to collect data moving forward will further inform what we know about the Great Lakes and how we can manage the lakes more efficiently. … If we lose ice cover, we’re really changing the underlying ecosystem of the Great Lakes in ways that we don’t really understand right now,” he said.