Abundance and composition of phytoplankton communities in middle stream of Citanduy river, West Java

The relationship between phytoplankton composition and environmental conditions in their habitat provides an important role for their as an assessment of the status and quality of river waters and the management of these waters. The aim of this research was studied of composition and abundance of phytoplankton communities in Citanduy River, particularly in middle stream. The study has conducted in April, July, and October 2018. The study location consists of 4 stations. The research has measured the abundance index, diversity index, and dominance index of plankton. The physic-chemical waters parameters which was measured consist of temperature, pH, DO, depth, transparency, nitrite, ammoniac, nitrate, total phosphate, and chlorophyll-a. Phytoplankton of Citanduy River consists of 4 classes. The abundance index of phytoplankton was around 2,578-7,366 cells/L; diversity index of phytoplankton is around 0.48-2.57, while the highest dominance index was Pediastrum sp with 0.56. Based on multiple regression analysis, the abundance of phytoplankton in April was influenced by nitrates and temperature. The abundance of phytoplankton in July is influenced by nitrite and ammonia. Meanwhile, in October, phosphate and oxygen parameters affect the abundance of phytoplankton. The Citanduy River is still in the stable category because the water quality is still in a sufficient condition for aquatic biota, especially phytoplankton. The ammonium and total phosphate of BBWS station in October were higher than standard. The high concentration of nitrogen and phosphorus nutrients is the results from the surrounding land for rice fields, plantations, fish farming, and waste disposal. (paper)