Structure of plankton communities in Cijulang River Pangandaran District, West Java Province, Indonesia

A river is a water ecosystem that plays an important role in the hydrological cycle and functions as a catchment area for the surrounding area. One of the organisms inhabiting river waters is plankton. The purpose of this study was to determine and analyze the structure of the plankton community in the waters of the Cijulang River and to study the relationship between plankton abundance, as well as some physical-chemical parameters of the water. The study was conducted in January, February, and March 2018 on the Cijulang River, at 5 (five) stations with a purposive sampling method. Accordingly, 17 genera were found, from 7 phytoplankton classes consisting of 6 Bacillariophyceae genera, 1 Clorophyceae genera, 2 Cyanophyceae genera, 3 Zygnematophyceae genera, 2 Desmidiaceae genera, 1 Synurophyceae genera, and 2 Fragillariophyceae genera. Also found were 10 genera from 5 classes of zooplankton consisting of 4 genera Maxillopoda, 2 genera Branchiopoda, 1 genera Gastropoda on veliger fase, 1 genera Ostracoda, and 2 genera Copepoda. The abundance of phytoplankton obtained ranges from 11-57 cells / L, while the zooplankton ranges from 8 – 40 ind/L. The diversity index (H ') = 1.397 - 2.275 and dominance index (D) = 0.022 - 0.294. Physical-chemical parameters of the waters, respectively, were 22 °C - 31 °C, light intensity 47.5 cm - 254 cm, salinity 0 ppt - 20 ppt, and dissolved oxygen 6.2 mg / L - 13.4 mg / L. Ammonia concentration 0.03 - 0.08 mg / L. All stations had a phosphate value of less than 0.16 mg / L and a silicate concentration of 0.01 - 0.0581 mg / L.