Biochemical Response of the Cyclopoida Copepod Apocyclops borneoensis Exposed to Nickel

The use of biomarkers to evaluate the biological effects of pollutants in marine organisms represents a recent tool in biomontoring programs. The cyclopoida copepod Apocyclops borneoensis was exposed to different Ni treatments [0 (control), 10, 100, 1000 μg 1^-1Ni] for 1, 2, 4, 7, 14 days. At each exposure time, acetylchlinesterase (AChE), superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione (GSH) were analyzed. Additionally, lipid peroxidation (LPO) level was measured after a 14-day exposure. The results show that Ni treatment significantly stimulated copepod’s antioxidants SOD, GST and GSH at environmentally relevant concentrations after a certain exposure time. On the other hand, the exposure time significantly affected SOD and GSH. In contrast, Ni exposure significantly decreased LPO level, implying that the factor involved in LPO might not significantly depend on the operations and functions in the antioxidant defense system. In addition, Ni might also be a neurotoxic agent to copepods via changing AChE activity.