“There are lots of ways in which ice and winter conditions can affect the ecosystem. We don’t fully understand all of them. We have a general idea of how it should work but in many cases we haven’t done the footwork to see,” Ozersky said.

Crews from more than a dozen U.S. and Canadian universities and government agencies will make their way onto frozen sections of lakes Erie, Huron, Michigan, Ontario and Superior during the week of Feb. 14. That's typically around the time of maximum ice cover.

They'll take what Ozersky described as a midwinter “snapshot,” measuring characteristics such as light levels at different depths, water movement and the presence of carbon, bacteria and nutrients that feed fish but also can damage the environment.