Effects of temperature and salinity on the growth and biochemical composition of the brown alga Sargassum fusiforme (Fucales, Phaeophyceae)

Temperature and salinity are well-known environmental factors that affect the growth and biochemical composition of brown algae. In this study, we conducted a culture experiment to test the effects of temperature (10, 15, and 20 °C) and salinity (10, 20, 30, and 40 psu) on specific growth rates (SGR) and five compounds (carbon, nitrogen, chlorophyll (Chl) a , Chl c , and fucoxanthin) of Sargassum fusiforme , an ecologically and commercially important species. The results showed that both temperature and salinity had significant effects on SGR and the tissue contents of carbon and nitrogen. Maximal SGR of 6.04% day −1 was achieved at 20 °C and 30 psu. The highest tissue content of carbon (38.19 ± 1.01%) was obtained at 10 °C and 30 psu, while that of nitrogen (2.78 ± 0.09%) was at 15 °C and 10 psu. Significant positive effects of increased temperature were found on both Chl a and Chl c contents. A significant positive effect of increased salinity was only found on the Chl a content. The Chl a and Chl c contents were maximized at 0.50 ± 0.03 and 0.16 ± 0.03 mg g −1 at 15 °C and 20 psu. In addition, significant positive effect of increased temperature and significant negative effect of increased salinity were detected for the fucoxanthin content; this was at a maximum of 2.62 ± 0.04 mg g −1 at 15 °C and 10 psu. These physiological data provide valuable information related to the enhancement of S. fusiforme composition when in cultivation under controlled conditions.