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The responses of Sargassum thunbergii germlings to high temperature, low salinity, desiccation, combined
thermal and osmotic stress (35 ºC combined with 12 psu), anthracene, and eutrophication were examined. Probit
regression analysis results showed that the median lethal time (LT50) values of high temperature decreased with the
increase in temperature. The 24 h median lethal temperature was 36.9 ºC. For salinity treatment, the LT50 value of fresh
water was 47.6 h. Survival rates of germlings were over 60% when germlings were exposed to salinities ranging from 27
psu to 7 psu at a time interval of 108 h post-treatment. The LT50 values of desiccation and combined thermal and osmotic
stress (35 ºC combined with 12 psu) were 7.0 h and 9.8 h, respectively. Anovas showed that germlings were inhibited by
high concentrations of anthracene (5 mg L–1 and 10 mg L–1) with low survival rates of below 50% and low relative growth
rates of below 1% after 25 days of culture; however, low concentrations (0.01-1 mg L–1) had no significant effects. In
addition, neither severe eutrophication nor disproportionality of N/P showed any significant effect on the survival and
growth of germlings. Of the environmental stresses tested, possible occurrence of high temperature of 40 ºC and
combined thermal and osmotic stress directly impacted the survival of germlings, suggesting that the deterioration of S.
thunbergii bed may be related more to increasing extreme climatic events.