The ecological impact of eutrophication can be challenging for the nonscientist to fully comprehend. Described here is a series of activities developed as part of an NSF funded GK12 project. It is based on a marine ecology scenario that results in a hypothetical fish kill in Raritan Bay, New Jersey. The main objective was to employ a series of thought provoking hands-on exercises using authentic data to model the eutrophication process. These activities have been field tested with over 300 middle school students in a unique educational setting - the Rutgers Science Explorer Bus - a 40 foot, custom-designed mobile laboratory staffed by graduate students, including this author.
Results/Conclusions
The lesson began with students “sampling” and identifying the organisms that live in the Bay (life size images are posted) and constructing a food web depicting the interactions in the ecosystem and the roles of plankton and bacteria. Using a Pasco water quality instrument they tested the changing abiotic factors of the Bay (salinity, temperature and dissolved oxygen). Low salinity values attributed to excess rainfall led to a discussion about runoff. An enviroscape (a coastal town) was used to model conditions prior to the eutrophication event. Landscapes were polluted with animal waste (chocolate sprinkles), sand, soil, litter/trash, and simulated auto oil, fertilizer and pesticides. "Thunderstorms" roll in and runoff into the Bay was observed; there was an increase in Bay temperature and decrease in dissolved oxygen (DO). Excess nutrients followed by warm, sunny days resulted in a plankton bloom. Samples of phytoplankton blooms were observed in bay water with different concentration of fertilizer. Decomposing bacteria populations boomed from the dead plankton and waste from the consumers, DO levels plummeted from bacterial respiration, and sensitive marine species died. A DO puzzle and bromothymol blue demonstration explained the process and consequences of the decreased DO. This was followed with a discussion about how eutrophication can be prevented and the importance of salt marshes. Simulated salt marshes (a row of sponges) were fitted into the enviroscapes. The process of pollution and rain was repeated and cleaner bay water was observed. Gaps and fragments in some of the “restored marshes” (sponges) allowed pollutants to pass symbolizing the difficulties of a successful restoration and the value of the remaining undisturbed salt marshes. Surveys collected at the end of each session indicated that students understood the concepts and learned from the activities.
