Racine, Wis. — Michigan Tech University biologists have been monitoring the wolf population on a remote Lake Superior island every winter since 1958, but we 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 pad because there is nowhere to land on the island. But this strangely sultry winter has left the Great Lakes almost ice-free.
Now scientists are trying to understand how ice-free winters could affect the world’s largest freshwater system. Most of the effects are still theoretical because lakes are generally too treacherous for data-gathering expeditions during the coldest months, and biologists have long believed that little happens under the ice anyway.
But they say the changes could have sedate environmental, economic and cultural impacts, including by harming some fish species, eroding beaches, fueling algal blooms and clogging shipping channels.
“This year has really made us realize that we need to collect more data,” said Trista Vick-Majors, an assistant professor of biology who studies aquatic ecosystems at Michigan Tech. “There’s simply no way to predict how the ecosystem will respond to the large-scale changes we’re seeing.”
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According to Great Lakes, ice cover on the lakes, which have a combined area roughly equal to the size of the UK, has typically peaked in mid-February over the past 50 years, with at times as much as 91% of the lakes being covered on the ice tracking website. As of mid-February this year, only 3% of the lakes were filled, which was the lowest result since at least 1973, when recording of the area began.
What are the theories?
Scientists don’t have much data on how years of ice-free winters might change the lakes, but they have plenty of theories.
Ice-free lakes could absorb sunlight more quickly and sultry up more quickly in spring. Some biologists speculate that this may lead to earlier and larger blooms of cyanobacteria, which could be toxic to humans and hamper summer tourism.
Without ice, the upper levels of lakes will likely sultry up even faster than usual, contributing to thermal stratification that creates layers of colder and warmer water.
Less oxygen will reach lower, colder and denser levels, which could kill plankton and other organisms, some scientists believe. Whitefish and lake trout typically hatch in the spring and feed on plankton, so less plankton would likely result in lower fish populations, potentially leading to tighter fishing quotas and higher prices at grocery stores and restaurants.
Less ice could translate into 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.
“This will change our strategy”
Charlie Henrikson runs a diminutive commercial fishing operation on the Door County Peninsula in Wisconsin. He said his boats set their nets in February, when the season usually doesn’t start until behind schedule March. He said his biggest concern is the lack of ice leading to more evaporation, which could lower lake levels and make it more complex for boats to enter the harbor.
“I’m 71, so of course I like it when it’s warmer.
I like that I can go out on the waterfront here and not experience ice,” Henrikson said. “Whatever you want to call it, the weather is changing. Our conditions are becoming more and more extreme. This 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 an extended sailing season on the lakes. But without ice cover on lakes, powerful winter storms could erode the shoreline more than usual, which could push more sediment into ports and make lakes shallower and more complex to navigate, said Eric Peace, vice president of the Lake Carriers Association, a trade group. Combined with lower lake levels due to increased evaporation, ships may have to carry less cargo to get higher in the water, he added.
This year’s lack of ice allowed Michigan Tech’s Vick-Majors to launch a project to collect winter data that scientists can compare with summer data. Researchers from around the Great Lakes are participating in sampling this month.
Recently, Madeline Magee and Rae-Ann Eifert, lake monitors for the Wisconsin Department of Natural Resources, braved freezing temperatures to collect buckets of lake water from the Racine seawall as part of Project Vick-Majors.
The lake was completely open, the emerald expanse stretching to the horizon, and the wind howled. High waves flooded the beach and buried Eifert as she stood on the breakwater, leaving her ski pants covered in ice balls. Magee said the project is worth it.
“Continuing to collect data will only provide us with further information about what we know about the Great Lakes and how we might be able to manage the lakes more effectively. … If we lose the ice sheet, we are really changing the core ecosystem of the Great Lakes in ways that we don’t currently understand,” she said.
(Story by Todd Richmond/Associated Press)
