Lake Ice Phenology Module
Summary
Lakes are changing worldwide due to altered climate. Many lakes that were historically frozen in the winter are now experiencing fewer days of ice cover and earlier ice-off dates. In this module, students will explore long-term ice-off datasets from several lakes and use linear regression to make predictions about ice-off dates in the future. Project EDDIE modules are designed with an A-B-C structure to make them flexible and adaptable to a range of student levels and course structures.
Learning Goals
- Understand how global climate change impacts local aquatic ecosystems
- Analyze a long-term ice-off dataset with understanding of statistical differences, biological relevance, and sources of variation
- Predict future scenarios of ice-off using linear models
- Develop rudimentary skills using excel for graphing and statistics
- Calculate lake heat budgets, and understand the interactions between lake ice-off date and heat storage
Context for Use
This entire module can be completed in one 2-3 hour lab period or two 50 minute lecture periods for introductory or intermediate level students. Activities A and B could be completed with upper level students in one 50-60 minute lecture period. Students will need 1-2 hours outside of class to prepare for the exercise and complete the homework activities.
This module has been used in a non-majors Environmental Science course (Part A) and several Freshwater Ecology and limnology courses (Parts A and B for lower-level courses; Parts A, B, and C for upper-level courses). We anticipate the module could be used in a variety of courses. Module materials can be tailored to increase or decrease the background information depending on students' quantitative skills.
Description and Teaching Materials
Quick overview of the activities in this module
See the teaching materials files, provided below, for a step-by-step description for carrying out this module. A student handout, describing Activities A, B, and C, and instructor answer key are also provided.
- Activity A: Interannual variation in ice-off dates, introduction to regression, change over time, comparison of rates across lakes, prediction
- Activity B: Examination of potential breakpoints doing segmented regressions and how the length of record can impact the magnitude of change
- Activity C: Calculating heat budgets, impacts of changes in ice cover on lakes
Workflow of this module:
- Assign pre-class readings
- Give students their handout when they arrive to class: Student Handout (Microsoft Word 2007 (.docx) 854kB Dec27 16) and Student Datasets (Excel 146kB Dec27 16)
- Discuss pre-class readings.
- Instructor gives brief PowerPoint presentation on ice-off and intro to linear regression (PowerPoint can be edited as desired). - Lake Ice Phenology Module- Instructor's PPT (PowerPoint 2007 (.pptx) 5.3MB Dec27 16)
- As part of the presentation, the instructor gives a demo on how to create a regression line for the ice-off date of Lake Sunapee, New Hampshire, USA
- After the presentation, the students divide into teams to construct a regression line for different lakes (using the entire dataset) and predict future ice-off dates (Activity A).
- Students then use a set break-point at 1970 to conduct two regression lines and predict future ice-off dates (Activity B)
- Students then calculate an annual heat budget for Mirror Lake, New Hampshire, USA for two years with an early and late ice-off date (Activity C).
Teaching Materials:
- Lake Ice Phenology Module- Instructor's Manual (Microsoft Word 2007 (.docx) 862kB Dec27 16)
- Lake Ice Phenology Module- Instructor's PPT (PowerPoint 2007 (.pptx) 5.3MB Dec27 16)
- Lake Ice Phenology Module- Student Handout (Microsoft Word 2007 (.docx) 854kB Dec27 16)
- Lake Ice Phenology Module- Student Datasets (Excel 146kB Dec27 16)
- Lake Ice Phenology Module- Instructor's Homework Part C Answer Key (Excel 2007 (.xlsx) 15kB Dec27 16)
Teaching Notes and Tips
See the Instructor's Manual (Microsoft Word 2007 (.docx) 862kB Dec27 16) and Instructor's PowerPoint (PowerPoint 2007 (.pptx) 5.3MB Dec27 16) for notes and tips for carrying out this exercise.
Assessment
In Activity A, after the presentation, the students divide into teams to construct a regression line for different lakes (using the entire dataset) and predict future ice-off dates.
In Activity B, students then use a set break-point at 1970 to conduct two regression lines and predict future ice-off dates.
In Activity C, students then calculate an annual heat budget for Mirror Lake, New Hampshire, USA for two years with an early and late ice-off date.
Notes, tips, and an answer key are provided in the following files:
- Lake Ice Phenology Module- Instructor's Manual (Microsoft Word 2007 (.docx) 862kB Dec27 16)
- Lake Ice Phenology Module- Instructor's PPT (PowerPoint 2007 (.pptx) 5.3MB Dec27 16)
- Lake Ice Phenology Module- Instructor's Homework Part C Answer Key (Excel 2007 (.xlsx) 15kB Dec27 16)
References and Resources
Suggested pre-class readings:
- Seidl, A. 2009. "Water," Pages 69-87 in Early Spring (Beacon Press, Boston).
- Magnuson, J.J. et al. 2000. Historical Trends in Lake and River Ice Cover in the Northern Hemisphere. Science 289: 1743-1746.
- Winder, M. and D.E. Schindler. 2004. Climate change uncouples trophic interactions in an aquatic ecosystem. Ecology. 85: 2100-2106.
Data providers citation:
- Benson, B. and J. Magnuson. 2000, updated 2012. Global Lake and River Ice Phenology Database, Version 1. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5W66HP8
- Wetzel, R.G., and G.E. Likens. 2000. Limnological Analyses, 3rd edition. Springer Science and Business Media, Inc. New York.
- Likens, G.E., and T.C. Winter. 2010. Mirror Lake Thermal Profiles (1981-present). Durham, NH. Hubbard Brook Data Archive [Database]. http://hubbardbrook.org/data/dataset.php?id=83