Scientists see more than fish in Great Lakes
Mar 29, 2022 07:32AM ● By Editor
Researchers from Michigan Tech University braved the cold this winter and drilled holes through the ice for a study of carbon in Lake Superior. Photo: Michigan Tech
By Ann Meyer from the Eagle Herald • March 27, 2022
You might think global warming can’t be detected in Lake Superior in the winter, but researchers say it can.
“For the last 40 years, ice covers in general have been decreasing and water temperatures have been increasing,” said Trista Vick-Majors, an assistant professor at Michigan Technological University in Houghton researching Lake Superior and the Keweenaw Waterway that cuts across the Keweenaw Peninsula in Michigan.
Colder winters might seem to contradict the notion of global warming, but scientists say colder weather is directly related to climate change. When the Arctic polar vortex above the North Pole weakens, it allows frigid air to move south and warmer air to travel north, resulting in unusual weather patterns.
While researchers have studied the Great Lakes during the summer for decades, winter research is far less common. That’s the reason Vick-Majors decided to explore the Keweenaw Waterway this winter. She wants to learn more about what microorganisms are doing under the ice cover in winter and specifically how they process carbon, a key part of the food chain.
Her research, begun in early 2021, also is part of a broader project with over a dozen universities in the U.S. and Canada exploring long-term trends in the Great Lakes and connecting waterways. Each program has its own focus, but they also work together.
Central Michigan University’s Institute for Great Lakes Research focuses on coastal wetlands research. Biology professor Don Uzarski, program director of the CMU institute, said he oversees a research program that’s received $30 million from the U.S. Environmental Protection Agency since 2010. It also works with Environment and Climate Change Canada.
In part, Uzarski’s work has entailed developing protocols for standardizing the research data so it can be more easily analyzed. “We’re doing a ton of spinoff projects, quantifying ecosystem conditions,” he said.
Studying the Great Lakes and related fresh waters during the winter is important to understanding the characteristics of the water and wetlands, he said.
Vick-Majors said she decided to focus her research on winter because “it just hasn’t been studied before, so we’re missing this big part of the year. It’s important because we know the Great Lakes are really changing in the winter.”
For the past 40 years, the amount of ice cover has been decreasing and water temperatures have been increasing, she said. “Warming is very clearly impacting our local waters, and this is not something that is going away,” she said. “You can have big swings in weather as a result of climate change,” Vick-Majors said.
The trend doesn’t mean the winter’s air temperature will be warmer in the Upper Peninsula. “Over here we’ve had a pretty cold January and February. It seems like it was colder than usual. Things like that can be symptoms of climate change even though it’s colder instead of warmer.” A weakened polar vortex can result in brutally cold weather, as frigid air from the Arctic pushes south toward the United States.
Vick-Majors’ research team included two graduate students and between two and five undergraduates. “We’re sampling the Keweenaw Waterway weekly,” Vick-Majors said. “We go out, drill our holes in the ice, and bring water and ice samples back to the lab to measure what organisms are doing.”
They put the water into vials and add organic matter the organisms might like to eat in a form of incubation. Then they look for the matter to show up in the biomass.
While plants, plankton and algae are studied during the summer months, when they’re growing, what happens to the organisms in the winter is less known. “In winter, snow and ice-cover limit light,” retarding the growth of many organisms, Vick-Majors said. “Their ability to fix carbon is limited. All life requires carbon,” she said. Fixing carbon dioxide into biomass creates organic carbon that feeds other organisms in the lake, she said.
Uzarski ‘s program also participated in the winter research. “When my team went out on the ice, I made sure we chose areas near wetlands of interest we study all year long,” Uzarski said.
Researchers at Central Michigan have found concentrations of nitrogen that are 10 times what they should be in Lake Michigan. Nitrogen is a nutrient naturally released into the atmosphere from the Great Lakes, but too much of it can cause algal blooms and produce harmful toxins. “It’s a necessary nutrient for plants and algae, and too much of a good thing is a bad thing,” Uzarski said.
“We did a really good job of keeping phosphorous out of our aquatic ecosystem, out of the lake. But we were contaminating the lake with nitrogen. Now nitrogen is really high,” he said.
Exactly how large the increase in nitrogen is might be impossible to quantify because “nitrogen didn’t used to be studied,” Uzarski said. The word didn’t appear in a 2012 research agreement, he said.
But taking a long-term view, he said, an excess of nitrogen today might represent just a blip in time. “The timescale of the lakes is not one year or ten years or one hundred years. It’s many, many more years,” Uzarski said. “The short time period of toxins and pollutants essentially won’t matter unless it’s long-term and indefinite.”
To see the original post and read related stories, follow this link to the Eagle Herald website. https://www.ehextra.com/news/scientists-see-more-than-fish-in-great-lakes/article_2311ffb0-ac80-11ec...
