Phytoplankton response to differences in light and the addition of phosphorus in Lake Cikaret

Abstract

The composition and abundance of phytoplankton in the waters are strongly influenced by the supply of phosphorus and light intensity. Observations were made to obtain the optimum phosphorus concentration with a certain level of light which caused the high abundance of phytoplankton in Lake Cikaret. A 2 x 2 factorial design was used to see the effect of three levels of phosphorus (0.03 mg/L, 0.09 mg/L, and 0.15 mg/L) and three levels of light (30%, 70%, and 100% luminance) on the abundance and composition of phytoplankton. The parameters observed were the abundance and composition of phytoplankton, dissolved oxygen, pH, temperature, turbidity, light intensity, and total phosphorus. The results showed that the addition of phosphorus in the waters increased the abundance of phytoplankton. The abundance of Chlorophyta was high in the first week, followed by the abundance of Bacillariophyta and Chlorophyta in the second week until the end of the observation. Synedra sp. (Bacillariophyta) tended to be high in abundance at a low light intensity, while Mougeotia sp. (Chlorophyta) tended to be high at all light intensities.