Physiological effects of shortand 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 (pCO₂) 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 ~ 15000 μatm (1 atm =101.325 kPa) or ~200000 μatm caused an elevation in hemolymph Ca²⁺. Exposure to ~ 200000 μatm resulted in a decrease in hemolymph Cl−, and exposure to ~ 15000 μatm caused an increase in hemolymph Na⁺, whereas ~ 200000 μatm caused a decrease. Exposure to elevated pCO₂ 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 pCO₂ for both experiments. This study shows that elevated pCO₂ had limited impacts on the physiological responses of adult freshwater mussels.