Monitoring planktonic cyanobacteria in Lake Maninjau, West Sumatra, Indonesia

Abstract

Harmful Cyanobacterial blooms are global environmental issue. Some efforts have been made to prevent and minimize their occurrence in waters. This study aims to monitor the planktonic Cyanobacteria community and environmental factors that influence their dominance in Lake Maninjau. Samples of Phytoplankton and water quality data were collected in 2001, 2005, 2009, 2014, 2015, 2016, 2018, and 2019. Twenty-four species of planktonic Cyanobacteria which belonged to orders Chroococcales, Oscillatoriales, and Nostococales. Percentage of Cyanobacteria abundance ranged from 2.9% to 95.32%. High percentage of Aphanocapsa (76.21%), Anabaena (33.25%), Chroococcus (86.4%), Microcystis aeruginosa (94.37%), Oscillatoria (50.94%), and Aphanizomenon gracile (72.43%) was recorded in different periods. Cylindrosprmopsis raciborskii was often found in the lake with percentage of abundance not more than 20.75%. Cyanobacteria abundance ranged from 734.2 to 4,180,867 individualL-1. The lowest Cyanobacteria abundance was characterized by low total phosphorus and conductivity. High Cyanobacteria abundance was related to the high levels of TP, concentration, conductivity and low TN/TP ratio. Nutrient, conductivity, and temperature were also the factors that influenced the dominance of Cyanobacterial species in Lake.