Twin Ports Freshwater Folk invites you to our May 7, 2025, event from 11:30 a.m. to 1:00 p.m CT. This month's speaker is University of Minnesota Duluth Professor of Physics and Astronomy Jay Austin.
In-person attendees are invited to the Minnesota Pollution Control Agency (MPCA) Conference Room for networking, sandwiches, and plenty of fresh water at 11:30 a.m. The online and in-person presentation will begin at noon. Sadly, the Zoom option is sandwich-free.
This event is free and open to the public.
Location:
Duluth MPCA Conference Room
525 Lake Ave. S., Suite 400
Duluth, MN 55802
Registration
Event schedule
- 11:30 a.m. Lunch and networking (in-person only)
- 12:00 p.m. Attendee announcements
- 12:05 p.m. Seminar(s)
- 12:45 p.m. Moderated question and answer session
- Adjourning by 1 p.m. at latest.
Presenter Bio
Jay Austin, Ph.D., is a physical limnologist specializing in observational approaches to develop a better understanding of physical processes in deep lakes. He has wide-ranging interests across a broad range of temporal and spatial scales, including winter structure and processes, the role of ice, springtime convection, the response of large lakes to climate change, seasonal connectivity within lakes, and the impact of physical processes on ecosystem function.
He has undergraduate degrees in math and physics, and did his graduate work in physical oceanography at the joint program between MIT and the Woods Hole Oceanographic Institution. He has been at University of Minnesota Duluth since 2005, serving in both the Department of Physics and Astronomy and at the Large Lakes Observatory.
Presentation Abstract
Only recently have multi-year, whole year time series of whole water column thermal structure been available for the Laurentian Great Lakes. These data show that the formation of winter stratification and thermal structure in general across the Great Lakes varies in character not just between lakes, but interannually within individual lakes.
This presentation will explore relationships between winter air temperatures, how cold the lakes get in each winter, and whether they form winter stratification. These relationships, when combined with a recently compiled record of daily air temperatures from 1897 to the present, allow us to hindcast which lakes stratified in which years. This analysis suggests that Lake Superior reliably forms winter stratification; Lake Huron is in the process of transitioning from forming winter stratification to cooling below 4C (the temperature of maximum density) but not forming stratification; and Michigan is experiencing more frequent years in which it does not even cool to 4C.
There is a great deal of interannual variability on top of the long-term trend towards warmer stratification status, and lakes, especially Huron and Michigan, display different behavior from year to year. This makes putting traditional limnological labels on these lakes difficult in any meaningful sense.
About TPFF
Twin Ports Freshwater Folk (TPFF) is an informal gathering of people from the Twin Ports who are engaged in freshwater research, policy, or regulation issues. Meetings take place on the first Wednesday of every month and include networking, informal discussion, and a seminar.
Event Sponsors
- Minnesota Sea Grant
- Great Lakes Toxicology and Ecology Division of the U.S. Environmental Protection Agency
- Minnesota Pollution Control Agency
- Large Lakes Observatory at the University of Minnesota Duluth
- Natural Resources Research Institute at the University of Minnesota Duluth
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Contact:
Alex Frie, research and fellowship coordinator, Minnesota Sea Grant, University of Minnesota and University of Minnesota Duluth.
Image credit: Cait Dettmann/MNSG.