Lake Metabolism Module

This module was initially developed by D.C. Richardson, J.L. Klug and C.C. Carey. 26 Jun 2015. Project EDDIE: Lake Metabolism. Project EDDIE Module 2, Version 1. cemast.illinoisstate.edu/data-for-students/modules/lake-metabolism.shtml. Module development was supported by NSF DEB 1245707.

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Summary

Different lakes exhibit a range of catchment sizes, morphometry, and land use that contribute to differences in lake function. These functional differences mean that lakes vary in ecosystem services such as habitat quality and recreational value. In this module, students will explore high-frequency water quality datasets from several lakes around the world, graph high-frequency data, and use simple conceptual and mathematical models to calculate estimates of metabolism (gross primary production and respiration). Finally, students will compare metabolic rates across different lakes to examine gradients of eutrophication. 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.

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Learning Goals

  • Discuss eutrophication of aquatic ecosystems
  • Compare and contrast structural vs. functional ecosystem metrics
  • Explain the drivers of diel variation in sensor data
  • Calculate metabolism rates (for Gross Primary Production and Respiration) from high-frequency data
  • Compare rates of Gross Primary Production and Respiration from lakes with different trophic status

Context for Use

This entire module can be completed in one 2-3 hour lab period or two 1 hour lecture periods. Students will need 1-2 hours before class to prepare for the exercise. The module can be extended or shortened depending on how the instructor wants to present the PowerPoint slides.

This module has been used in several intermediate to upper-level freshwater ecology and limnology courses. Module materials can be tailored to increase or decrease the background information depending on students' familiarity with the material.

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: Graphing high-frequency sensor data from a lake and analyzing temporal variability
  • Activity B: Calculating gross primary production and respiration
  • Activity C: Comparing gross primary production and respiration across lakes.

Workflow of this module:

  1. Assign pre-class readings.
  2. Give students their handout when they arrive to class: Student Handout (Microsoft Word 2007 (.docx) 1004kB Dec27 16) and Student Datasets (Excel 2007 (.xlsx) 65kB Dec27 16).
  3. Discuss pre-class readings (this could be a separate activity or embedded as part of the PowerPoint lecture)
  4. Instructor gives PowerPoint presentation on metabolism and the study lakes (this PowerPoint can be edited as desired) - Lake Metabolism Module - Instructor's PPT (PowerPoint 2007 (.pptx) 18.1MB Dec17 20)
  5. Halfway through the presentation, the students divide into teams and are each assigned a different lake from the 5 available lakes. Students graph high-frequency data to look at temporal trends and examine what is gained from high-frequency data (Activity A)
  6. The instructor then presents slides detailing the metabolism conceptual model.
  7. Students then calculate respiration rates over 4 nights from dissolved oxygen data for their lake. The students will also calculate 3 days of gross primary production rates using dissolved oxygen data and their estimates of respiration (Activity B)
  8. Students will ultimately compare metabolism rates across the class and to literature values to make predictions about the trophic status of their lake (Activity C).

Teaching Materials:

Teaching Notes and Tips

See the Instructor's Manual (Microsoft Word 2007 (.docx) 871kB Dec27 16) and Instructor's PowerPoint (PowerPoint 2007 (.pptx) 18.1MB Dec17 20) for notes and tips for carrying out this exercise.


Assessment

In Activity A, students graph high-frequency sensor data from a lake and analyzing temporal variability.

In Activity B, students are tasked with calculating gross primary production and respiration.

In Activity C, students compare gross primary production and respiration across lakes.

Notes, tips, and an answer key are provided in the following files:

References and Resources

Suggested pre-class readings:

Other possible useful readings and resources for instructors:

Data providers citation:

  • Solomon, C. T., Bruesewitz, D. A., Richardson, D. C., Rose, K. C., Van de Bogert, M. C., et al. 2013. Ecosystem respiration: drivers of daily variability and background respiration in lakes around the globe. Limnology and Oceanography 58(3): 849-866. Open access http://onlinelibrary.wiley.com/doi/10.4319/lo.2013.58.3.0849/full.