Biomarker Response of Ocean Acidification Induced Hypercapnia on Marine Bivalve Donax cuneatus, Linnaeus 1758

Abstract

The present study reports the investigation of the sub lethal impacts of ocean acidification induced hypercapnia (pH 7.5 and 7.0) and leakage of sub sea bed Carbon Dioxide storage sites (pH 6.5-5.5) on marine bivalve Donax cuneatus, Linnaeus 1758 collected from the Gulf of Mannar province. Fifteen days experiment was carried out in laboratory microcosms in a closely monitored environment. The impacts of Hypercapnia on Biomarker enzymes indicating neurotoxicity (Acetylcholinesterase), oxidative stress (lipid peroxidation and catalase) and phase II biotransformation of xenobiotics (glutathione S transferase, and reduced glutathione) were estimated. The increase in lipid peroxidation and catalase activities suggest hypercapnia induced oxidative stress. The decreasing pH also increased the activity of reduced glutathione and glutathione S transferase which acts as detoxifying enzymes for Hypercapnia induced toxicity however the hypercapnic conditions inhibited the levels of acetylcholine esterase which indicates the polluted environment substantiating stress induced high rate of mortality at low pH levels. The above used biomarkers thus provide a valuable tool for monitoring ocean acidification induced hypercapnic stress at a sublethal level.