Effects of Temperature and pH on the Growth of Sargassum linearifolium and S. podacanthum in Potassium-Fortified Inland Saline Water

This study tested the effects of temperature and pH on water quality and the growth of Sargassum linearifolium and S. podacanthum in potassium-fortified Inland Saline Water (ISW) of Western Australia (WA), at two levels of pH (low pH range of 5.5-6.5 and ambient pH 7.0-8.2) and two levels of temperature (high temperature 26-27°C and ambient room temperature of 20-22°C) in triplicate for 42 days. The pH of ISW in WA varies from 3.9 to 9.1, whereas the temperature is from 6.1-28.1°C. The results showed that the high temperature initiated the mortalities of the both Sargassum species from the first 14 days of culture period. The high temperature also resulted in a reduction of dried weight and ash content of these two species of Sargassum by the end of the trial. S. linearifolium temperature tolerant threshold was larger than S. podacanthum. Since the day 14, the S. linearifolium biomass and specific growth rate were higher than S. podacanthum at both temperature levels under ambient pH. Higher crude protein in S. linearifolium than S. podacanthum was also recorded at high temperature. Ambient pH and ambient temperature resulted in higher biomass and higher specific growth rate than low pH and high temperature in both species, which is recommended for Sargassum spp. growth.