Physiological effects of short- and long-term exposure to elevated carbon dioxide on a freshwater mussel, Fusconaia flava

Zones of elevated carbon dioxide (CO2) have the potential to deter the movement of fishes. Should CO2 be used as a barrier, non-target organisms, such as freshwater mussels, have the potential to be impacted. In this study, the physiological responses of adult Fusconaia flava exposed to elevated partial pressures of CO2 (pCO(2)) over both short-term (6 h exposure with 6 h recovery) and long-term (4-, 8-, and 32-day exposure) periods were measured. A 6 h exposure to either similar to 15 000 mu atm (1 atm = 101.325 kPa) or similar to 200 000 mu atm caused an elevation in hemolymph Ca2+. Exposure to similar to 200 000 mu atm resulted in a decrease in hemolymph Cl-, and exposure to similar to 15 000 mu atm caused an increase in hemolymph Na+, whereas similar to 200 000 mu atm caused a decrease. Exposure to elevated pCO(2) for long-term periods caused a decrease in hemolymph Mg2+ and an initial increase in hemolymph Ca2+. Body condition and hemolymph glucose were not significantly influenced by elevated pCO(2) for both experiments. This study shows that elevated pCO(2) had limited impacts on the physiological responses of adult freshwater mussels.