When Harry Met Gabby
A Hypoxia Story
Ohio University Southern
This case study addresses several concepts related to water hypoxia including physical laws governing dissolved oxygen levels and impacts to living systems during hypoxia. A survey of different factors causing reduced oxygen saturation levels on small aquatic life gives students the opportunity to develop hypotheses, pose potential experiments, and interpret data to develop a better understanding of not only the importance of water quality, but also how to answer questions using the scientific method. The case study incorporates group discussion, analysis of experimental design, and data evaluation as central activities and includes an option for laboratory experimentation to observe hypoxia effects on fresh water tank shrimp and rotifers. It is intentionally designed as a crossover between lecture and lab, including a “flipped” approach to economize on time needed for applications of the concepts. Students prepare outside of class by watching short videos (made by the author) that teach the basics of water chemistry, scientific method, and abiotic and biotic forces in the environment that influence water quality.
- Understand the scientific method.
- Collect data and interpret experimental results.
- Explain the processes leading to hypoxia in waterways.
- Synthesize results from different studies and evaluate their larger significance (e.g., how human activities influence the heath of waterways).
KeywordsHypoxia; aquatic ecology; dissolved oxygen; eutrophication; dead zone; salinity; osmosis; pH; aquatic bioindicators; water chemistry; oxygen consumption; oxygen production; Atya gabonensis; rotifera
Topical AreasScientific method
Educational LevelHigh school, Undergraduate lower division
Type / MethodsAnalysis (Issues), Discussion, Flipped, Laboratory
Subject HeadingsBiology (General) | Ecology | Environmental Science | Science (General) | Science Education |
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The following video(s) are recommended for use in association with this case study.
- When Harry Met Gabby, Part I
This video introduces the concept of hypoxia, how it becomes a problem in nature, how human activity has altered the balance of our waterways, and factors that alter levels of dissolved atmospheric oxygen. Running time: 9:10 min. Created by Orianna Carter for the National Center for Case Study Teaching in Science, 2016.
- When Harry Met Gabby, Part II
This video reviews oxygen production vs. oxygen consumption, and detrimental impacts from decreased oxygen levels in waterways, including eutrophication and dead zones. Running time: 9:09 min. Created by Orianna Carter for the National Center for Case Study Teaching in Science, 2016.
- Atya Gabonensis
Close-up of the viper shrimp showing its habitat and social behavior. The unique fanned filter feeding claws are fascinating to watch. Running time: 1:23 min.
- Rotifer Feeding
Video clip of a rotifer feeding on phytoplankton using its cilia in a swirling motion to bring the food source to its mouth. Running time: 1:09 min.