Evaluation of the Efficiency of the Algae Chroccoccus turgidus and Calothrix fusca in Absorbing Phosphate and Nitrite from Water

Abstract

Abstract This study was conducted in the Department of Life Sciences, College of Sciences, Tikrit University, using two species of algae from the Division Cyanophycophyta, isolated, purified, and identified from freshwater spring water in Sulaymaniyah Governorate, namely Chroccoccus turgidus and Calothrix fusca. They were activated by re-cultivating them several times using liquid and solid algae culture media prepared in the laboratory. The study included estimating the effect of the following factors on the efficiency of the algae (C. turgidus and C. fusca) in reducing the concentrations of phosphate (µg/L) and nitrate (µg/L): growth period (0, 7, 14), temperature (20, 24.5, and 30 °C), light intensity (400 and 1960 Lux), type of culture medium (Chu-10 and BG-11), and pH (8 and 8.5). The results were as follows: C. turgidus recorded the lowest concentrations of phosphate and nitrate, 3.47 and 0.516 µg/L, respectively. Cyanobacteria algae reduced the concentrations of phosphate and nitrate with the progression of the experimental time by 11.49% and 18.59%, respectively. The high temperature of 30 °C reduced the concentration of phosphate by 9.56%. Increasing the light intensity to 1960 Lux resulted in the lowest average concentration of phosphate, which was 3.396 µg/L. The Chu-10 medium contributed to a significant reduction in the concentrations of phosphate and nitrate by 16.37% and 12.72%, respectively. Raising the pH value from 8 to 8.5 reduced the concentrations of phosphate and nitrate by 10.45% and 7.89%, respectively.