Effect of short-term exposure to ocean acidification on antioxidant response in the Patagonian scallop Zygochlamys patagonica (P.P. King, 1832) from the Southwest Atlantic Ocean

Abstract

Ocean acidification (OA) can impair antioxidant responses in bivalves altering their capacity to cope with environmental changes. Here, we analyzed the effects of short-term OA exposure on antioxidant responses of an important commercial Patagonian scallop Zygochlamys patagonica (P.P. King, 1832), considering present pH variability at natural beds of scallops and OA conditions. The scallops were exposed at three levels of pH, (1) high pHT= 8.10 (mean annual pH at the sampling site), (2) medium pHT= 7.80 (minimum value of natural variability recorded at scallops’ bed close to the sampling site) and (3) low pHT= 7.50 (0.30 below medium pH value) for 4 and 17 days of experimental time. Oxidative damage and antioxidants were measured in hemolymph, gill and mantle. Hemolymph did not show signs of oxidative damage thus, antioxidant response induction was not detected under OA exposure. Gills showed antioxidant activation at 4 days under OA which decreased by the end of the experiment, with no signs of oxidative damage. Non-enzymatic antioxidant decreased under OA in the mantle. This study supports previous evidence of bivalves´ capacity to maintain their redox homeostasis under experimental OA conditions and constitutes a cornerstone to continue elucidating this species ‘strategies to cope with environmental changes.