Effect of inorganic and organic fertilizers on growth, survival rate and chlorophyll-a content of green seaweed Caulerpa racemosa

Abstract

This research aimed to determine the effect of inorganic and organic fertilizers on the growth, survival rate, and chlorophyll-a content of Caulerpa racemosa. C. racemosa with an initial weight of 9.71±0.4 g was cultured for 28 days in three different culture media which were seawater without fertilizer (control), medium with inorganic hydroponic nutrient fertilizer (HN), and liquid organic fertilizer (LO). The cultured medium had significant differences in growth rate among treatments. The highest specific growth rate (SGR) of C. racemosa occurred when cultured in the HN medium with a rate of 2.70±0.02% per day, followed by the LO medium (2.07±0.03% per day) while the lowest SGR was in the control which was only 1.65±0.01% per day. In contrast, the three treatments media did not affect the survival rate of C. racemosa. The chlorophyll-a content showed a positive correlation with growth rate, where the highest chlorophyll-a content was observed on the HN medium with a rate of 222.0±4.5 µg per gww), followed by the LO medium (208.6±6.6 µg per gww) and control (121.2±10.2 µg per gww). The HN medium could be used for land-based culturing of C. racemosa at the dosage of 1.5% (ml/L).