The Effect of Acidification on Trophic Cascades in Freshwater Lakes

Taylor Houston and Emily K. Prince

This study of freshwater ecology seeks to examine how acidification affects the strength of trophic cascades separate from any other factors. Freshwater acidification has known effects on the chemosensory mechanisms of fish, which makes it harder for them to avoid predators, can change their physiology, and can severely limit their food source and survivability to adulthood. Many inland lakes near Lake Michigan are separate from one another, but have similar physical characteristics and biodiversity. Following the population changes in three connected trophic levels of multiple lakes allows us to examine how acidification affects the strength of trophic cascades while controlling for other factors that have already been documented to affect trophic cascades. Specifically, this study looked into the relationship between chlorophyll levels, copepods, and Johnny Darters. The control lake had little evidence of a top-down trophic cascade. In the acidified lake there were much stronger trends among the trophic levels, but they were not the trends we would expect to see in a top-down trophic cascade. Most interesting of all there was a strong negative correlation between Johnny Darters and chlorophyll levels.

• Taylor Houston graduated high school with an IB diploma from Amarillo High School in Amarillo, Texas. She is a senior majoring in psychology with minors in biology and child & family studies. She is a member of Lander Spectrum, the Lander Honors College, and the Psi Chi International Honors Society. After graduation she plans to move back to Texas to be closer to family.