It is mid-March, and two researchers trudge on snowshoes through feet of snow on a wooded trail, dragging a small plastic sled full of equipment. Scientist Carl Watras’ snowshoes are rigged with rubber from bicycle tires to bind the webbed contraptions to his feet. His research assistant, Jeff Rubsam, runs ahead to guide the sled down a steep, snowy slope towards a frozen lake. Watras descends, planting one long leg slowly after another. Watras has been making this trek for 32 years.