The Addition of Seaweed Extract (Sargassum sp) as Fertilizer on Culture Media on The Total Density of Skeletonema costatum Cells

Abstract

Microalgae Skeletonema costatum is a natural food that contains nutrients needed for aquaculture. Seaweed contains several nutrients and has body regulatory substances, namely auxin, gibberellin and cytokinin which are useful for increasing the growth of microalgae cells, including S. costatum. The study aims to examine the addition of Sargassum sp. on culture media on cell density of S. costatum. The benefit of this study is to obtain scientific information regarding the addition of Sargassum sp., thus, it can be a natural fertilizer that can be used in the economical cultivation of S. costatum. This study consisted of 5 treatments, namely the concentration of Sargassum sp. extract in media (control) 0 mg/500 mL, 25 mg/500 mL, 50 mg/500 mL, 75 mg/500 mL and a concentration of 100 mg/500 mL, these treatments were repeated three times. S. costatum cell density was checked every 6 hours. The results showed that the use of extracts of Sargassum sp. 100 mg/500 mL had the highest cell density of S. costatum (2.08×107 cells/mL), followed by 75 mg/500 mL (2.00×107 cells/mL), 50 mg/500 mL (1.99×107 cells/mL, 25 mg/500 mL (1.97×107 cells/mL), and 0 mg/500 mL (1.05×107 cells/mL).