Dr. Kristen Cecala: Using An Ecosystem Services Approach to Water Resources in Biology 210 at Sewanee: the University of the South
About this Course
This is a 200-level course that serves students intending to major in biology with a concentration in ecology and evolution. Though intended for sophomore and junior majors, some students cannot take the course until their senior year resulting in a diversity of experiences and exposure to ecology.
16
students
2 lecture periods of 75 minutes and 1 lab period of 180 minutes weekly
Bio 210 Syllabus (Acrobat (PDF) 160kB Jul5 17)
A survey of the principles and applications of ecological science. Lecture will cover the ecology of individuals, populations, communities, and ecosystems. Lab will emphasize field experimentation in the local environment.
-Students will develop a comprehensive understanding of ecological principles.
- Students will evaluate the application of ecological principles to applied problems.
- Students will explore ecological patterns and processes on Sewanee's campus.
- Students will develop important process skills for ecology including reading, writing, and speaking.
- Students will develop skills and tools to evaluate novel ecological questions.
Ecology regularly integrates expertise developed in other disciplines to allow us to understand interactions in the natural world. Teaching concepts in ecosystem ecology that require rudimentary comprehension of chemistry for nutrient cycling and availability can be challenging for two reasons: 1) students have the misconception that scientific disciplines don't inform one another, and 2) nutrient cycling can seem abstract.
I introduced this module into my ecology course to use easier to understand cycles of water to illustrate and initiate conceptualization of more complex nitrogen cycling while maintaining a conservation-based approach.
My Experience Teaching with InTeGrateMaterials
I used a modified version of the Ecosystems Services Approach to Water Resources module to introduce ecosystem ecology. The modified InTeGrate module and new module that I created complemented each other and provided a visual and familiar model to explore new content. I enjoy exploring the InTeGrate modules to develop new ideas or new uses for tools in my courses. I look forward to using future InTeGrate modules.
Relationship of InTeGrate Materials to my Course
This module was implemented just before beginning our unit on ecosystem ecology (approximately 1/3 of the course). This approach to thinking about systems as a whole rather than as populations or as communities was new to these students, and this module was a great introduction to thinking about systems comprehensively. Linked with a newly developed module on nitrogen cycling also helped to introduce environmental chemistry in an approachable format. We continued practice of designing experiments, collecting data, and analyzing/interpreting data.
I think of this lab in the future as a signature lab for the ecosystem ecology unit for which I have always struggled to develop a lab that acknowledges the interdisciplinary nature of ecosystems and illustrates concepts that are typically invisible.
Ecosystems Services Approach to Water Resources Module
I implemented a combination of information from Unit 1 & 2 and activities from Unit 2 in addition to a new module in two 3-hour lab periods. Though ecology as a discipline requires understanding human dimensions, I wished to focus more on human influences on ecology and have time to implement the new module. Students in this upper-level course have already completed a pre-requisite course including a lab observing changes in stream condition through an urban watershed and a lab investigating the nitrogen cycle through a wastewater treatment facility.
Unit 1
Unit 1.1 – I did not use this module because students in this course are already familiar with ecosystem services provided by freshwater systems.
Unit 1.2
I used slides from this module to introduce concepts surrounding what a watershed is and what the major processes are transforming precipitation to runoff.
Instead of having students calculate rainfall-runoff relationships, we visually evaluated the differences in the Big Creek and Rock Creek watershed land-use and rainfall-runoff relationships.
Unit 1.3
I presented slides on the storm hydrograph followed by a short classroom discussion of what specific mechanisms could result in changes in the rainfall-runoff relationship in response to urbanization.
After this discussion, we left the classroom for ~40 minute walk through an adjacent watershed. Throughout the watershed, we discussed all the various factors in the watershed that could contribute to a higher proportion of rainfall leaving the basin as runoff. We also discussed how rainfall retention was important for primary productivity in our ecosystem. This suburban watershed had opportunities to talk about storm drains, erosion, soil compaction and types, forest removal, and channel straightening. In our town, this stream often floods regularly, so we also walked the outline of the floodplain and where it flows over the road during floods. This watershed is also gauged by a colleague, and I hope to incorporate their flow data into the next iteration of this module.
Unit 2
Unit 2.1
I assigned the EPA Stormwater Calculator YouTube video for homework for this lab.
I used the Unit 2.1 Tutorial modified to investigate the watershed visited above.
I provided computers for the students to use because the EPA Stormwater Calculator can only be used on a PC. I also had to troubleshoot the download and installation part for those computers.
Unit 2.2
I adapted the Unit 2.2 exercise to develop recommendations for stormwater management on campus.
Students used the suburban stream visited in lab as the reference condition to test different hypotheses about managing stormwater runoff on campus.
Students were instructed to develop guidelines for stormwater management using the EPA Stormwater Calculator assuming a 20% increase in impervious surfaces. Students were instructed to explore the LID controls to determine which LIDs could be implemented and in what capacity to mitigate the increases in runoff with conversion of 20% of the watershed to impervious surfaces.
Students provided a hypothesis for their exploration of LID controls, plotted a figure of their results and an interpretation of the data. They ultimately provided a recommendation to the town of Sewanee to better manage stormwater runoff with increasing development.
Unit 3 – We did not cover Unit 3 in favor of doing the exercise below.
New Module:
Pre-class summative assessment due on Unit 2 and a formative question about how controls on stormwater runoff may also influence nitrogen runoff.
Short (10 minute) introduction to nitrogen and phosphorus cycles along with human influences on both cycles.
Students in groups of 4 completed a concept map of factors contributing to nitrogen export from watersheds online using Bubbl.us.
Brief introduction to our goals for the lab activity and overview of the two sampled watersheds.
Groups were split in half to collect stream water samples. One half of the class (2 people from each lab group) went to an urban stream to collect samples, and the other half went to a fully forested watershed on campus to collect samples. The group sampling the urban watershed returned to the lab first and began development of standard calibration curves.
Once all lab members returned, they completed development of the standard curve and tested their water samples and a rainwater sample I provided for nitrate. This required them to plot data and develop the equation for a best fit line. From this equation and absorbance of their samples, they back calculated nitrate concentrations of their samples.
Students completed a summative assessment discussing their hypothesis for which watershed would have higher nitrate export and how nitrate export should compare to rainwater. I intended for them to sample nitrate and phosphate, but students ran out of time before completing any phosphate analyses. I would like to find time for these phosphate analyses though to demonstrate one of the fundamental differences between nitrogen and phosphorus cycles.
Assessments
I adapted the pre-class questions to my classroom. Students answered questions on a formative assessment that was graded for completion before the first lab period. They were asked the same questions as a summative assessment linked with one formative question for the next lab period. They also turned in a short summary of their two experiments including a hypothesis, figure, statement of results, and recommendations/conclusions. The two short experiments done in groups were similar to previous lab assignments, and students were prepared before these modules to complete these assignments.
Outcomes
My goal was to introduce system thinking to students as a way to introduce ecosystem ecology though I think these labs would work better if they had occurred simultaneous to teaching the ecosystem ecology section rather than ~2 weeks before. We discussed the results of the experiment when discussing nutrient cycling, but it was clear that too much time had elapsed between completion of the lab and learning this material.
Students split up and had the flexibility to learn more about the development of standard curves or spend more time in the field. It allowed them to cater the lab to their interests. Students enjoyed connecting field work with lab work and learning more about local watershed differences. They reported enjoying learning how to do basic environmental chemistry to answer ecological questions but were frustrated with some technical issues that we had with our spectrophotometers. A few students also wished that they had more time to explore the EPA Stormwater Calculator.
In future iterations, I will provide more information about LIDs in introductory material and provide a more detailed description of standard calibration curves. I am also likely to move our concept mapping of drivers on nitrogen cycling to lecture to provide more time in the field and in the lab to complete both nitrogen and phosphorus sampling.
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