: Angelica Joy G. Yu and Felix M. Salas
Freshwater algae are a diverse group of organisms which impart important functions in the ecosystem pertaining to water quality. Cultured freshwater algae were used to determine the effects of nitrogen in different levels on the pigment composition, chlorophyll a, chlorophyll b and total carotenoids. A three-month study of some physico-chemical properties of Palhi River as well as pigment content of freshwater algae was conducted to find correlations on the different parameters with that of the pigment concentration.
Results of the study showed a strong positive correlation between chlorophyll a and nitrogen level, yet a weak correlation chlorophyll b and total carotenoids on cultured freshwater algae. Both pH (6.06-6.92) and total dissolved solids (249-397ppm) of Palhi river are within the standard limits set by DENR, WHO and USEPA. However, the average total suspended solids (63.0 ppm) and total nitrogen (10.3 ppm) exceeded that of the tolerable limits set by national and international standards. The pigment composition of the freshwater algae showed a strong negative correlation with the nitrogen level in Palhi River which could be attributed to the dynamics, biodiversity and complexities of the river system.
Keywords: culture, DENR, Palhi river, pigment, US EPA, water quality, WHO