Tag Archives: Phytoplankton

Water Quality and Phytoplankton as Indicators of Pollution in Ibuya River (Published)

Ibuya River runs across the Old Oyo National Park and there is paucity of information on the limnology of the river. In order to assess the status of the river, phytoplankton and water quality were examined during the study period of September 2012 to February 2014 at four sampling stations. A total of 45 species of phytoplankton belonging to four families were identified. The most representative family in terms of species richness was Bacillariophyceae (25 species), followed by Chlorophyceae (9 species) and Euglenophyceae (8 species) and the least dominant is Cyanophyceae with 3 species. Water temperature was 24.73 ± 0.21°C, pH was 7.57 ± 0.04 and dissolved oxygen (DO) was 4.43 ± 0.15 mg/L, conductivity was 140.83 ± 5.60 µS/cm, TDS was 98.11 ± 3.80 m/L. Cadmium (Cd), Lead (Pb) and Phosphate (PO₄) exceeded the permissible limits for surface water (0.003, 0.01 and 3.5 mg/L) respectively. The water quality and phytoplankton species composition of the river showed that allochthonous input from activities within and outside the park has subjected the ecosystem to pollution pressure.

Keywords: Anthropogenic Activities, Ibuya River, Phytoplankton, Water Quality, pollution indicators

Study on the Chemical and Biological Status of Malwatu Oya Basin, Anuradhapura in Sri Lanka. (Published)

Water pollution is a serious problem to the entire world. It threatens the health and wellbeing of humans, plants, and animals. With the advancement of communications and trade due to industrialization, accidental and purposive waste dumping, and uncontrolled use of water sources have contributed to the problem of water pollution in both surface water and the ground water. This study was mainly concerned with the evaluation of water quality of Malwathu Oya and its four basin tanks in the dry zone of Sri Lanka namely Nuwara wewa, Tissa wewa, Nachchaduwa wewa and Mahakanadarawe wewa in the Anuradhapura district using some selected water quality parameters. Malwathu Oya has been using as a source of drinking water for Anuradhapura. Eutrophication through the process of nutrient enrichment of stagnant waters due to urbanization & chemical added agricultural practices has been considered as the significant cause for water pollution in these areas. They cause algal blooms and release of toxic substances from species like cyanobacteria. Low Secchi Depth value and high chlorophyll a concentration indicate eutrophic nature of the Nuwarawewa and Tissawewa Lakes in dry periods. Malwathu oya too showed reasonably high Chlorophyll content during the same period. High nutrient loading was observed through the growth of phytoplankton species. Cylindrospermopsis raciborskii was the most dominant species recorded in the present study and Microcystis aeruginosa, Microcystis incerta, Pediastrum duplex. Merismo pediatenuissima, Melosira granulate and Diatomaelongata were also recorded from Nuwarawewa and Tissawewa during the study period. With respect to Physical and chemical parameters, very high turbidity, high nitrogen compounds ( Ammoinia, Nitrate, Nitrite), phosphate, total suspended solids, dissolved oxygen, chemical oxygen demand, biological oxygen demand were recorded in Nuwarawewa and Tissawewa due to the influence of human activities such as recreational , dumping wastes and agricultural practices. However data indicate that Nachchaduwa and Mahakandarawa lakes are well protected from above threats. At the same time Malwathuoya stream also showed the same kind of pollution pattern causing more critical situations for water treatment and water quality aspects. Therefore, an effective Lake Management and Lake monitoring programmes with integrated catchment management have to be adopted and it is a prior necessity in planning of the management practices of the catchments to get first hand information through this kind of research on these lakes.

Keywords: Coliforms, Eutrophication, Malwathuoya River Basin, Phytoplankton, Urbanization, Water Quality


In the present experiment, phytoplankton belonging to 41 species under 23 genera was observed from Teetha wetland ecosystem during the period of investigation from June 2011 to May 2013. Results revealed that, Bacillariophyceae was found to be the dominant group of phytoplankton (39.13 %) followed by Chlorococcales and Cyanophyceae each with (21.74 %), desmids (13.04 %) and Euglenoids (4.35 %). Teetha Lake is found to be rich in phytoplankton diversity and hence productive. Summer period marked an increase in phytoplankton density. Physicochemical factors like Temperature, pH, Sulphate, Potassium, Nitrate nitrogen, Ammonical nitrogen and Silica were found to be the important factors influencing the growth of phytoplankton and they exhibited significant positive correlation with total phytoplankton. Based on Nygaard’s trophic state indices the wetland is said to be oligotrophic. Inter-relationship of various physicochemical factors and their role with seasonal dynamics of phytoplankton is here by discussed.

Keywords: Correlation, Diversity, Physicochemical factors, Phytoplankton, Wetland