Metal Toxicity across Different Thallus Sections of the Green Macroalga, Ulva australis

We aimed to identify functional differences between different sections of the thallus Ulva australis and develop tissue-endpoint combinations assess toxicity six metals (i.e., Ag, As, Cd, Cr, Cu, Ni). EC50 values for these in three were obtained multiple endpoints: relative growth rate (RGR), chlorophyll a fluorescence, pigment contents, expression photosynthesis-related gene, rbcL. The responses endpoints varied across respective sections; overall, most toxic Ag Cu. These best evaluating metal toxicity: ETRmax middle toxicity; RGR section As Cd; marginal Cr; Chl b contents Cu; basal Ni. inhibition (0.06 mg∙L−1) all lower than those quality standard wastewater discharge Cu Republic Korea US, pointing suitability U. australis-based risk assessment.