Natural Resources, School of


First Advisor

Jamilynn B. Poletto

Date of this Version

Spring 4-24-2020


Engel, A. D. 2020. In Hot Water: Influence of multiple stressors on thermal tolerance of Fathead Minnows Pimephales promelas. University of Nebraska, Lincoln.


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Natural Resource Sciences, Under the Supervision of Professor Jamilynn Poletto. Lincoln, Nebraska: May 2020

Copyright 2020 Alexander D. Engel


Freshwater aquatic systems around the globe are often subjected to physical, biological, and chemical alterations to support societal needs. The Great Plains contains one of the largest agricultural industries in North America, but its productivity has ecological repercussions for adjacent freshwater ecosystems. Specifically, the dependency on surface water irrigation and application of chemical treatments has altered the thermal and chemical composition of freshwater ecosystems throughout the region. Stressors such as elevated temperatures, altered flow regimes, increased contaminant loads affect the physiology and behavior of fishes and can lead to long-term population effects. We examined thermal tolerance of Fathead minnows Pimephales promelas in two experiments, 1) after exposure to atrazine and 2) after an acute thermal stressor. Understanding the thermal dynamics of Fathead minnows and the influence of multiple stressors on thermal tolerance will provide insights into how changing environmental conditions will affect native fish populations. Furthermore, we hope this knowledge will allow managers to more effectively concentrate conservation efforts.

Advisor: Jamilynn B. Poletto