Salinity preference of two diatoms and their growth performance in three prepared and two alternative on-farm media sources

Abstract

Salinity and preferred nutrient composition of <i>Chaetoceros affinis</i> and <i>Skeletonema costatum</i> were tested. Salinity was tested at 12, 16, 23, 28, and 32 ppt. Three compositions of nitrogen (N), phosphorus (P), and potassium (K) and two on-farm low-cost alternative media sources, cow urine (CU) and hatchery waste water (HWW), were tested to find the suitable NPK ratio and to determine the efficacy of the on-farm media respectively. <i>Chaetoceros affinis</i> preferred 23 ppt salinity, while <i>Skeletonema costatum</i> preferred both 28 and 32 ppt. Among the NPK treatments, higher cell density was observed in 4:1:1 followed by 4:2:1 ratios. Significant differences in maximum cell density of both species were observed in the NPK treatments while only <i>S. costatum</i> showed significant difference in CU and HWW.