Kelimpahan dan Struktur Komunitas Plankton di Sungai Pasir dari Kabupaten Kulon Progo (Yogyakarta) hingga Purworejo (Jawa Tengah)

Abstract

The Abundance and Community Structure of Plankton in the Pasir River from Kulon Progo Regency (Yogyakarta) to Purworejo Regency (Central Java). The spatial and temporal variations of environment and anthropogenic activities have resulted in changes in theThe Abundance and Community Structure of Plankton in the Pasir River from Kulon Progo Regency (Yogyakarta) to Purworejo Regency (Central Java). The spatial and temporal variations of environment and anthropogenic activities have resulted in changes in the physical and chemical conditions of the waters. These changes thereby affect the abundance and structure community of the plankton in the aquatic environment. This study aims to determine plankton's abundance and structure community in the Pasir River that flows from Kulon Progo Regency, Yogyakarta, to Purworejo Regency, Central Java. The research was conducted in the Pasir River from December 2019 to January 2020. The samplings were carried out using a purposive sampling method at five sampling stations, and the samples were collected from the predetermined four sampling points in each station. Water quality parameters including temperature, salinity, current velocity, pH, organic matter contents, nitrate and phosphate concentrations were also measured as supporting data. The plankton data were analyzed to determine the abundance, diversity, and dominance indexes. The results showed that the average plankton density was 3,002 individuals/L, with the highest density occurring at Station 5 (4,152 individuals/L). The average diversity index was 1.11 (medium category), and the average dominance index was 0.03 (low category). The lowest abundance and diversity index were found at Station 4 due to the high concentrations of nitrate and phosphate because the location was close to residential areas. The dominant phytoplanktons were the Chlorophyceae and Bacillariophyceae classes, while the zooplanktons were Maxillopoda and Branchiopoda.