ANN ARBOR, Mich. — Snow isn’t only a soft, slick cushion under our sleds or skis.

At the Michigan Winters Roundtable on Dec. 9 in Ann Arbor, University of Michigan Biological Station Director Aimée Classen explained to nearly 30 students, faculty and staff at the University of Michigan how snow is a critical insulating blanket for microbial activity and nutrient accumulation in the soil that benefits forest ecosystems in the summer and year-round.

“It’s like a huge party underground for microbes all winter long,” she said. “They’re producing nutrients for plants like flowers and trees to suck up later in the spring and bloom.”

The spring snow melt has historically controlled the timing and magnitude of the annual nutrient export.

However, winters are changing.

Michigan is experiencing more rain-on-snow events in the winter.

“Fresh snow gets washed away by rain,” said Classen, who also is a professor in the U-M Department of Ecology and Evolutionary Biology. “And warmer winters that speed up when nutrients enter the ecosystems can cause problems.”

Classen’s research lab has been exploring how declining snowpack in the winter has cascading impacts on forest productivity, water quality and human health.

“We think it’s a problem. For example, if nutrients — especially nitrogen — are moving into these aquatic systems in the winter, then maybe there’s none left for plants to take up in the spring and summer,” Classen said. “Agricultural systems are at risk of losing tons of nutrients.”

Plus, pulses of these nutrients washing into the watershed throughout the winter are already causing issues, feeding toxins that can get people and animals sick.

“Just look at the maps of harmful algal blooms in the Mississippi Delta,” Classen said.

Classen told the crowd in Ann Arbor that the first snow of the season arrived earlier this month at the U-M Biological Station, the more than 11,000-acre research and teaching campus in northern Michigan about 20 miles south of the Mackinac Bridge.

Starting next week, the public can access live, hourly data through the UMBS Snowpack Dashboard, which measures snow depth using a sonic rangefinder. (For more information, read: U-M Biological Station Activates Snowpack Sensor to Study Changing Winters.)

The public also is invited throughout the winter to use UMBS ski trails, which are groomed.

The Michigan Winters Roundtable was organized by the sustainability team at the University of Michigan College of Literature, Science, and the Arts (LSA) to round out the LSA Year of Sustainability.

Caitlin Jacobs, LSA sustainability program manager, is responsible for climate action throughout the college. She gave participants at the Michigan Winters Roundtable a list of local opportunities in the Ann Arbor area to support biodiversity throughout the season including a Winter Stonefly Search with the Huron River Watershed Council and a Christmas Bird Count with the Washtenaw Bird and Nature Alliance.

“I was impressed by the turnout, enthusiasm and questions on the last day of classes for the fall semester,” Classen said. “It was an honor to discuss UMBS research focused on changing winters and an absolute pleasure to catch up with alumni of the field station.”

Founded in 1909, the U-M Biological Station is one of the nation’s largest and longest continuously operating field research stations. Laboratories, classrooms and cabins are nestled along Douglas Lake in Pellston to support long-term science research and education.

The University of Michigan Biological Station is where students and scientists from across the globe live and work as a community to learn from the place.

Subscribe to the UMBS monthly e-newsletter and follow the field station on LinkedIn, Instagram, Facebook and X (formerly Twitter).

Students: Explore 2025 field-based courses and scholarships at the U-M Biological Station and apply for the four-week spring and summer terms on the UMBS Courses website. Applications are open for the spring term, which is from May 20 through June 19, and the summer 2025 term, which is from July 1 through July 31. The priority application deadline is March 15, 2025.

Researchers: Submit new research proposals or renewals and fellowship applications on the UMBS Research Application website. The deadline for research and fellowships during the 2025 field season is Feb. 1, 2025.

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