Combined effects of copper and microplastics on physiological parameters of Tubastrea aurea corals

Microplastics (MPs) have been a serious environmental problem because it can carry pollution like heavy metals and organic pollutants. However, the combined effect of MPs and bivalent copper ion (Cu(II)) on the coral azooxanthellate has been rarely studied. In the present study, the combined effects of PVC and Cu(II) on the physiological responses of Tubastrea aurea were studied. Our results showed that MPs alone enhanced the activity of catalase (CAT), superoxide dismutase (SOD), and reduced glutathione (GSH). The mixture groups had the same effects on the CAT and GSH, which enhanced CAT and GSH activity by 97% and 53% respectively. MPs alone and the combined treatment groups decreased the activity of lipid peroxide (LPO) and the content of metallothionein (MT) by 45% and 20% of the coral Tubastrea aurea. Cu(II) exposure always had negative effect on the physiological parameters of coral, and MPs decreased the toxicity of Cu(II) in the combined groups. This work is the first time to report the combined effects of Cu(II) and microplastics on azooxanthellate coral, which will provide important preliminary data for the following research.