Abstract
Jatibarang Reservoir is a reservoir built on the Kreo River ± 10 km upstream of the confluence with the Kali Garang river, Changes in water quality conditions due to tourism activities in the Jatibarang reservoir will cause changes in the ecosystem and composition of the plankton community. This study aims to examine the structure of the plankton community at different depths in the Jatibarang reservoir and examine the physical and chemical parameters at different depths in the Jatibarang reservoir. Sampling was carried out at 4 points with a depth of 0m, 1m, 2m, and 3m. Based on the results of the study, we found 34 species of plankton belonging to 6 divisions, namely 12 species of Bacillariophyta, 15 species of Chlorophyta, 1 species of Phyrrophyta, 2 species of Euglenophyta, 1 species of Cyanophyta, and 1 species of Copepoda. The abundance of plankton in all stations and the depth level ranged from 22.081-123.9928 Ind/L, with the highest abundance at 1m depth, namely 246.297-993.681 Ind/L. Based on the diversity index (H'), uniformity index (E), and dominance index (D), the community structure in all stations and the depth level of the Jatibarang reservoir is stable with moderate species diversity, uniformity index is evenly distributed and there is plankton that dominates, namely at a depth of 2m at station 1, the species Ankistrodesmus so. Chlorophyta and Bacillariophyta with species Achnanthes sp, Cymbella sp, and Ankistrodesmus sp are mostly found in the waters of the Jatibarang reservoir. The waters of the Jatibarang reservoir have temperatures ranging from 25-27℃, pH 6-7.5, and brightness 50.5-79.5 cm. Dissolved oxygen 6.9 – 8.25 mg/L. The value of nitrate is 0.163-2.698 mg/L and phosphate is 0.163-2.698 mg/L. The water quality in the Jatibarang reservoir is still within the range to support the life of aquatic organisms.