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Susan E. Gass
Instructor
susan.gass@dal.ca
Environmental Science Program
Dalhousie University
A Trip to the Beach: Untangling the Mystery of Algal Blooms in the Great Lakes

This interrupted case study, designed for an introductory biology or environmental science course, introduces students to the complexity of ecosystems by examining changes in trophic interactions and abiotic factors in a freshwater ecosystem as a result of human actions. The case narrative describes the recent and undesirable appearance of decomposing algae (Cladophora glomerata) on a public beach in the Laurentian Great Lakes. Students are asked to use the scientific method by creating hypotheses and examining observational data to describe biotic and abiotic components of the Great Lakes ecosystem. The case requires students to differentiate between benthic and pelagic environments (e.g., the influence of depth and phytoplankton density on light availability, and the availability of phosphorus) and the interactions between organisms in both environments. Students also examine shifts in these interactions as a result of the newly introduced zebra and quagga mussels, which have ultimately resulted in the algae's presence on the beach. There are also opportunities to discuss the impact of these ecosystem changes on people who own property and/or visit the beach.


The Canadian Canola Controversy: The Role of Genetically Modified Organisms in Agriculture

This case study reviews a controversial court case that took place in Canada in 2002 concerning an allegation of patent infringement and a genetically modified (GM) canola crop. The multi-national company Monsanto, which produces GM canola seeds called Roundup Ready®, sued Saskatchewan farmer Percy Schmeiser for growing the crop on his farm without a contract. The defendant maintained that the crop seed blew onto his property without his knowledge. In this case study, students learn about the history of seed development and why we use pesticides in agricultural systems as well as the benefits and potential drawbacks of pesticides to society and the environment. They are then presented with the details of the court case and assigned stakeholder roles.  Each stakeholder group considers what the outcome of the court case means for their group. The case concludes with a class discussion in which each stakeholder group shares their views. Originally designed for an introductory environmental science course, the case could also be used in an introductory biology or genetics course.