Optimizing Plankton Growth and Diversity in Biofloc Systems through Silica Supplementation

Biofloc is a fish cultivation system that relies on a collection of microorganisms, such as bacteria, protozoa, and microalgae, that live in the form of flocs or clumps. This study aims to determine the effect of varying silica concentrations on plankton abundance and diversity index in biofloc systems. Conducted from February to March 2024, the research employed a Completely Randomized Design (CRD) method with four treatments (0 ppm, 15 ppm, 20 ppm, and 25 ppm) and three replications each. The parameters observed were phytoplankton abundance, zooplankton abundance, and diversity index. Observation of plankton abundance using a 10 x 10 magnification microscope using SRC (Sedgewick Rafter-counting Cell) with a volume of 1 ml and diversity index using the Shannon Wierner method. The results of this research are that the addition of a silica concentration of 15 ppm is the best concentration with a phytoplankton abundance value of 450,729 cells/L, a zooplankton abundance of 827,778 cells/L and a diversity index of 2,662.