Physiological responses of Grateloupia turuturu and Chondrus ocellatus to nano-plastics.

The objective of this study is to investigate the effect of nano-plastics (NPs) on the growth, photosynthesis, oxidative stress and antioxidant enzymes in Grateloupia turuturu and Chondrus ocellatus. Difference of surface characteristics between G. turuturu and C. ocellatus may affect adherence of plastics to their surface. The seaweed samples were cultivated at 5 different NP concentrations (0, 20, 200, 2000, 20000 ng/L) for 21 days. The accumulation of nano-plastics on surface of C. ocellatus was higher than that of G. turuturu. The highest concentration of NPs (20000 ng/L) inhibited the growth and photosynthesis activity of C. ocellatus. At the same concentrations, oxidative stress was caused with increase of antioxidant enzyme activities. G. turuturu was not affected by NPs at all tested concentrations. Based on these results, toxic effects of nano-plastics may be species specific. Toxicity is dependent on the capacity of macroalgae to accumulate nano-plastics on their surface.