Effect of Copper on the Germling Growth of Brown Macroalga Sargassum horneri

Abstract

Recently, a great interest has been observed in using marine species for coastal environmental impact assessment. Embryos of brown macroalga, Sargassum horneri, distributed throughout the northwest Pacific coast, appear be a promising marine indicator for such assessments. This study identified the effects of copper (Cu–EDTA) on the germling growth of S. horneri. Following exposure to various copper concentrations for 21 days, the germination rate, specific growth rate, and final thallus area of S. horneri germlings were measured. The germination of the embryo was completely inhibited when exposed to 10 µg/L, and the no observed effect concentration (NOEC) for germination was estimated as 5 µg/L. Since the incubation period was longer for lower copper concentrations, growth inhibition could be clearly observed and was deduced to be a chronic toxicity effect. The median effective concentration (EC₅₀) and NOEC for the final thallus area were 0.50 and 0.16 µg/L, respectively. The results demonstrated that the embryos of S. horneri are more sensitive to copper than other seaweeds, further suggesting that its growth patterns can effectively be utilized to assess coastal environmental impacts.