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

Abstract

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 ∼15 000 μatm (1 atm = 101.325 kPa) or ∼200 000 μatm caused an elevation in hemolymph Ca2+. Exposure to ∼200 000 μatm resulted in a decrease in hemolymph Cl−, and exposure to ∼15 000 μatm caused an increase in hemolymph Na+, whereas ∼200 000 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.