The use of aquatic resources for agriculture, trade, and recreation adds stress to water-dwelling organisms. Rapid changes in abiotic conditions, such as warming due to climate change and nutrient loading from agricultural runoff and urban areas, threaten to induce profound alterations to aquatic environments. These changes affect interspecific community interactions and may cause an aquatic resource to lose its functionality that is valuable to humans. Studying organisms such as plankton that form an ecosystem’s foundation is an important step towards understanding the entire food web and predicting how it may or may not be able to respond to a changing environment. One important planktonic species in the Laurentian Great Lakes is the invasive calanoid copepod Eurytemora carolleeae (formerly considered part of the Eurytemora affinis species complex). This study analyzes the metabolic activity of E. carolleeae in Little Sturgeon Bay, WI, USA using two different methods, over a range of temperatures from 9º to 26ºC. Total oxygen consumption was measured directly using a micropulse oxygen probe, and the activity of aerobic metabolic enzymes in the electron transport system (ETS) was quantified using the in vitro reduction of iodonitrotetrazolium chloride (INT). We find that the respiration rate of E. carolleeae increases linearly from 9º to 26ºC. We also find that the copepod’s metabolic enzymes have an Arrhenius activation energy of 11.1 ± 3.7 kJ/mole and experience a thermal maximum between 22º and 26ºC. This thermal limit has implications for the future success of this species, as the combination of warmer temperatures and the disappearance of oxygenated colder-water refuges may limit E. carolleeae’s success in the Green Bay system.
Level of Honors
magna cum laude
Bart De Stasio
Timpe, Alexander, "Comparison of an Electron Transport System (ETS) enzyme-mediated reduction assay and respiration rate of the invasive copepod Eurytemora carolleeae in Green Bay, WI, USA" (2019). Lawrence University Honors Projects. 145.
Available for download on Saturday, May 30, 2020