The Effects of Salinity, Nitrogen, and Phosphorus on Survival and Weight Gain of Gracilaria sp.

Abstract

Gracilaria is a genus of red marine algae, it is also an economically significant species of macroalgae. The aim of this study is try to use algae itself to reduce organic and inorganic pollution in the aquatic environment to achieve the effect of water quality improvement. Macroalgae is a kind of plant resource that can be utilized to obtain the growth a of food resource in nature, and thus address the problem of resource degradation and depletion brought by the increase in population, food safety, food security etc. This study used different concentrations in the solution, for salinity nitrogen, and phosphorus in culture of Gracilaria. In order to find the most suitable condition and nutrient profile, the growth rate, survival rate and ultimately weight gain of Gracilaria were evaluated in this study. In 20 ppt of salinity, the growth rate of Gracilaria was higher than that of 10 ppt and 30 ppt saliniy. However, in 30 ppt salinity, Gracilaria survival rate was higher than that observed at 10 ppt and 20 ppt. The concentrations of nitrogen and phosphorus did not significantly influence the growth rate orsurvival rates. The concentrations of all treatments of nitrogen and phosphorus were reduced in presence of Gracilaria during the culture period, so it can be concluded that Gracilaria has the ability to remove nitrogen and phosphorus from the water in which it is growing and thus reduce eutrophication and improve the water quality.