Salinity-induced oxidative stress and regulation of antioxidant defense system in the marine macroalga Ulva prolifera

► Hyposalinity and hypersalinity caused a significant decrease in GRG and Fv/Fm. ► Oxidative damage occurred was more severe at 60‰ than at 10‰. ► Alterations in antioxidant defense system aren't consistent between 60‰ and 10‰.