EFFECTS OF THERMAL STRESS AND HYPOXIA ON METABOLIC PATTERNS OF TWO CANDIDATE MUSSEL SPECIES FROM CENTRAL TEXAS
Rising temperatures and altered flow regimes in river systems may negatively impact aquatic organisms inhabiting them. Rare mussel species may be at particular risk from thermal stress and hypoxia due to limited range and mobility. We used closed respirometry to test the effects of thermal stress and hypoxia on two candidate species from Central Texas Cyclonaias houstonensis and Cyclonaias petrina, and whether these effects differed between subpopulations. Temperatures ranged from 15 to 36°C. Our main objectives were to determine how metabolic demand, and the ability to meet this metabolic demand, changed as temperatures rose and dissolved oxygen decreased from normoxic to anoxic conditions. Metabolic rates increased linearly with temperature for both species at each location, with C. houstonensis from the Colorado River exhibiting the highest rate of increase. However, neither the ability to regulate, nor the DO threshold below which mussels switched from aerobic to anaerobic respiration changed significantly with temperature. These results suggest that a main effect of rising temperatures is to increase the risk of food limitation, particularly for the C. houstonensis subpopulation in the Colorado River. Sensitivity to hypoxic conditions remained relatively constant with increasing temperatures.
Austin Haney (Primary Presenter/Author), Auburn University, firstname.lastname@example.org;
Brian Helms (Co-Presenter/Co-Author), Troy University, email@example.com;
James Stoeckel (Co-Presenter/Co-Author), Auburn University, firstname.lastname@example.org;