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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., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Jang Kyun Kim reports financial support was provided by National Research Foundation of Korea. Jang Kyun Kim reports financial support was provided by Ministry of Oceans and Fisheries of Korea. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

A major goal of phylogeographic analysis using molecular markers is to understand the ecological and historical variables that influence genetic diversity within a species. Here, we used sequences of the mitochondrial Cox1 gene and nuclear internal transcribed spacer to reconstruct its phylogeography and demographic history of the intertidal red seaweed Chondrus ocellatus over most of its geographical range in the Northwest Pacific. We found three deeply separated lineages A, B and C, which diverged from one another in the early Pliocene-late Miocene (c. 4.5-7.7 Ma). The remarkably deep divergences, both within and between lineages, appear to have resulted from ancient isolations, accelerated by random drift and limited genetic exchange between regions. The disjunct distributions of lineages A and C along the coasts of Japan may reflect divergence during isolation in scattered refugia. The distribution of lineage B, from the South China Sea to the Korean Peninsula, appears to reflect postglacial recolonizations of coastal habitats. These three lineages do not coincide with the three documented morphological formae in C. ocellatus, suggesting that additional cryptic species may exist in this taxon. Our study illustrates the interaction of environmental variability and demographic processes in producing lineage diversification in an intertidal seaweed and highlights the importance of phylogeographic approaches for discovering cryptic marine biodiversity., (© 2015 John Wiley & Sons Ltd.)