| Popis: |
Each data chapter within this dissertation, while distinct in the stressor/combination of stressors, species under examination, and the purpose of the research effort, contributes to the unified objective of the dissertation: answering critical questions regarding the physiological effects of various environmental stressors on freshwater species. Results from data Chapter 2 indicate that adult Daphnia magna are more sensitive to lead exposure when co-exposed to percent air saturation approaching lethal levels of hypoxia. Moreover, increased hypoxia under control (no lead) conditions induced increased hemoglobin protein and mRNA expression, regardless of isoform transcript and typically in a dose-dependent manner for the latter. In Chapter 3 the maximum sustained swimming speeds (Ucrit) of several fish species of greatest conservation need at different temperatures (15, 22.5, and 30 °C) is assessed, providing valuable insights for site-specific calculations of culvert water velocities (Vf). Additional physiological endpoints of relevance to overall swimming performance were also measured, including maximum burst swimming (Umax), aerobic scope and cost of transport (COT). In Chapter 4 ammonia toxicity at different salinities to juvenile Macrobrachium rosenbergii is determined and real-time metabolic assessments as an effective detection method for perturbations in systems such as recirculating aquaculture systems is conducted. Although these chapters address distinct research topics, they collectively demonstrate the pivotal role of physiology in addressing complex issues related to human activity and environmental impacts. The dissertation's findings contribute novel information emphasizing the importance of understanding physiological responses in mitigating the impacts of anthropogenic activities on freshwater ecosystems. |
