Biology (B.S.B.)

Document Type and Release Option

Thesis (open access)

Faculty Mentor

Dr. Johanne Lewis


With the predicted increase in global water temperature and acute hypoxic episodes, knowledge of the effects these stressors can have on local aquatic life is extremely valuable. This study thereby quantified the change in metabolic rate in Bluegill sunfish, in response to increased temperature and low dissolved oxygen concentration, by utilizing intermittent flow respirometry. Both maximum metabolic rate (MMR) and resting metabolic rate (RMR) were determined in response to variations in dissolved oxygen content, specifically > 95% O2 and 40% O2. Additionally, three temperature treatment groups were established, with temperatures of 20, 25 and 30°C in order to ascertain the effect of increased temperature on MMR and RMR. This data was then used to calculate aerobic metabolic scope (AMS) and extrapolate the effects these stressors have on energy availability. Decreases in dissolved oxygen content were determined to result in a decrease in AMS, due to the limiting of MMR. Additionally, increases in acclimated temperature, were shown to lead to an increase in AMS, until the optimum temperature for the species was attained, after which AMS decreased. Through this, it was determined that the bluegill sunfish are currently near or in their optimum temperature range in the summer months, leading to an increased urgency for mitigations to global warming. With the expected increases in temperature over the next eight decades, these fish may be pushed out of their optimum temperature range, leaving them more susceptible to the effects of additional stressors such as hypoxia.