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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. • Adherence capacity of nano-plastics was significantly higher on Chondrus ocellatus than Grateloupia turuturu. • In Chondrus ocellatus, oxidative stress and antioxidant enzyme activities was enhanced at 20000 ng/L. • Growth, photosynthesis, oxidative stress and antioxidant enzymes of G. turuturu were not affected by nano-plastics. • Toxicity of nano-plastics are species specific, dependent on adherence capacity. [ABSTRACT FROM AUTHOR]

Abstract: λ-Carrageenan from Chondrus ocellatus was degraded by microwave. The changes in intrinsic viscosity [η] during degradation were investigated. Based on the concept that the random scission of glycosidic linkage basically obeys first-order kinetics, [η] for each short-term microwave process could be obtained. The degradation rate coefficient (k n ) of kinetics equation describing the microwave degradation of λ-carrageenan on different conditions was determined. The results demonstrated that changes of external pressure play a most important role in degradation of λ-carrageenan for same short-term microwave process. The susceptibility to degradation is also related to molecular size and concentration of λ-carrageenan. But at higher stress, the relationship between k n and [η] n deviates first-order kinetics. [Copyright &y& Elsevier]