Changes in Lake Ice: Ecosystem Response to Global Change

By Robert E. Bohanan1, Marianne Krasny2, Adam Welman3

1. Center for Biology Education, University of Wisconsin 2. Cornell University 3. Center for the Environment, Cornell University

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Ecological Question

Is there evidence for global warming in long term data on changes in dates of ice cover in three Wisconsin Lakes?

This activity uses ice cover records from three lakes in Madison, Wisconsin. Students work in groups to make predictions based on prior knowledge and assumptions, manipulate and summarize data, interpret the data by suggesting trends, and construct arguments from the data related to evidence of global change. In the main exercise, students work in small groups and attempt to see patterns in 20 years of data; all groups then combine data and only then can the long-term trend be seen.


Cite this work

Researchers should cite this work as follows:

  • Bohanan, Robert E., Marianne Krasny, and Adam Welman. April 2005, posting date. Changes in Lake Ice: Ecosystem Response to Global Change, Teaching Issues and Experiments in Ecology, Vol. 3: Issues: Data Set #1 [online].


  • Robert E. Bohanan; Marianne Krasny; Adam Welman (2015), "Changes in Lake Ice: Ecosystem Response to Global Change,"

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Wendy Jo Levenson

University of Pittsburgh