Adrienne Gibson

The Behavioral Effects of Caffeine on Freshwater Angelfish

This study was devoted to the analysis of the effects of dissolved caffeine on aquatic systems. Initially, we set out to test modifications in fish behavior in response to increased doses of caffeine. We soon found out that there are dramatic changes to the water chemistry with the addition of caffeine that prompted a switch in the experimental design. The presence of caffeine in the aquarium’s environment resulted in an increase of ammonia to lethal levels, accompanied by an increase of nitrites. In addition, a biofilm-like substance appeared on the inside of the aquarium’s glass. We cultured the organisms from the biofilm, as well as from the water in the aquarium. Both locations appeared to contain bacteria of the genus Pseudomonas. The caffeinated aquariums showed considerably larger amounts of bacterial colonies compare to the control aquariums. We hypothesize that the increased ammonia concentrations in the caffeinated aquariums are correlated with the metabolic activity of the Pseudomonas bacteria, making the caffeinated environment toxic for aquatic life.

Faculty Mentor: Alexey Nikitin, Biology


Adrienne presented at the Michigan Academy of Sciences, Arts, and Letters March 26, 2010 in Grand Rapids, MI.

Page last modified March 24, 2014