Trophic Status and Phytoplankton Community Structure of Four Small Lakes in Ciliwung Watershed, Indonesia

Abstract

Small lakes are critical freshwater resources to support the quality of human life. Small lakes in the watershed are becoming threatened ecosystems because of increasing land-use changes and anthropogenic activity. We determine the trophic status, phytoplankton community, and environmental factors in Lake Telaga Warna, Lake Cikaret, Lake Sunter, and Lake Cincin. The data was collected from primary and secondary data in 2000, 2007, 2008, 2016, and 2021. There are two groups of lakes based on water quality and trophic status. Lake Telaga Warna and Lake Cikaret, located at the upper and middle watershed, are eutrophic characterized by lower nutrient temperature, pH, conductivity, and Total Dissolved Solids (TDS). Lake Sunter and Lake Cincin, located at lower watersheds, are hypereutrophic characterized by higher nutrients, temperature, pH, conductivity, and TDS. Cyanobacteria dominance was recorded in Lake Telaga Warna and Lake Sunter, where Microcystis aeruginosa; Cylindrospermosis raciborskii; and Planktotrhix agardhii are the dominant species. Hypereutrophic status in Lake Sunter was characterized by the bloom of Planktothrix agardhii with total abundance (1,038x103 individualL-1 x 103), chlorophyll-a (431 µgL-1), low diversity index and species richness index. Cyanobacteria dominance in Lake Telaga Warna was under phosphorous limitation, while Cyanobacteria bloom in Lake Sunter was under nitrogen limitation.