Growth of Sargassum boveanum (Fucales, Phaeophyta) under variations of temperature, photoperiod and irradiance in laboratory conditions

Sargassum is one of the main sources of alginate, the substance with many commercial uses. The species Sargassum boveanum is an edible algae and study of effect of environmental factors on its growth is a step towards is culture. Therefore, growth of Sargassum boveanum under various temperature, irradiance and photoperiod was studied over 6 weeks under laboratory condition. The macroalgae was collected from coasts of Lengeh in June 2011. For each treatment, the algae were inoculated into 20 liters of water aquariums with diameters of 60×30×40 cm. The suspension method used for culture of algae. .The culture conducted at 4700 lux for irradiance, 25Co for temperature ,35PPT for salinity and 12:12 hour (light: dark) photoperiod. The treatments were: temperature (15, 20 and 25oC), photoperiod (12:12, 14:10 and 16:8, light: dark, respectively) and photon irradiances (4700, 5700, 6700 lux). All treatments (tanks) were carried out in triplicates. The length and weight of the thalli were measured on 7, 14, 21, 28, 35 and 42 days. The results of this study showed significant differences on growth of S. boveanum between treatments. Maximum relative growth rate was obtained at 12:12 hour photoperiod (% 4/32), 25Co (% 2.68) and 4700 lux (% 4.32) that proved to be suitable for indoor culture. We recommend spring as the best season for mariculture this alga.