Many high school students learn about nutrient cycling in science classes, but the lessons often focus on soil and plants. Scientists know that animals, including fish, can have strong effects on nutrient cycling (i.e., nitrogen and phosphorus) in ecosystems and that excretion rates of animals increase with water temperatures. Thus, we worked with high school students to design and conduct nutrient excretion experiments using common fish (zebrafish) at three different temperatures to explore the impact of climate change on nutrient cycling by aquatic animals. Students completed pre- and post-surveys on their understanding of nutrient cycling, climate change, and science skills. In 2021, we worked with advanced students participating in a residential summer program in Georgia. Then, in 2022, students enrolled in a general science class at the local high school visited the university campus on two occasions to conduct the same experiments. Students from both groups acclimated fish to temperature treatments for one week before conducting the 1-hour excretion experiments and completing the post-survey. The surveys allowed us to understand the impact of this learning experience on different student populations.
Results/Conclusions
The pre-surveys showed that students in both general and advanced (IB/AP) science classes had many misunderstandings about the role of animals in nutrient cycling before the experiment, and few students had studied how climate change impacts nutrient cycling. The post-surveys showed increased understanding of the role of animals in nutrient cycling and climate impacts; after the experiments, many students were able to communicate their understanding via written responses and more content vocabulary was utilized. Additionally, the surveys showed that students had increased confidence in various science skills. However, the results between the student populations differed, with students from Georgia showing the most growth in their confidence in designing experiments and communicating science via journal articles and presentations, while the students from Ohio showed the most growth in their confidence in being part of the scientific community and being successful in future science courses. Because the excretion experiment results conform to predictions of metabolic ecology and the surveys show student learning, these experiments seem to be effective in teaching these concepts to high school students. Ultimately, we believe these experiments can be done in high school classrooms to expand students’ understanding of the scientific process, nutrient cycling, and climate change.
