Keanekaragaman Makrozoobenthos di Sungai Tanjung Pura, Kabupaten Langkat, Sumatera Utara

Abstract

The Tanjung Pura River, Langkat Regency, North Sumatra, is an aquatic ecosystem experiencing anthropogenic pressure from livestock farming activities, former sand dredging, and domestic waste. This study aims to analyze the diversity of macrozoobenthos and its relationship with the physico-chemical parameters of the river water. Sampling was conducted at three stations with different activity characteristics (Station 1: livestock area; Station 2: former sand dredging site; Station 3: domestic waste) from January to March 2025. Macrozoobenthos were collected using a Surber net (30×30 cm) and identified in the laboratory, while physico-chemical parameters (temperature, light penetration, flow rate, substrate organic content, pH, DO, BOD₅, nitrate, phosphate, and oxygen saturation) were measured in-situ and in the laboratory. The results showed 21 genera of macrozoobenthos belonging to 3 classes (Crustacea, Insecta, and Gastropoda). Station 2 had the highest diversity (H'= 2.43; moderate category), followed by Station 3 (H'= 2.60; moderate category) and Station 1 (H'= 1.64; low category). The evenness index (E) at all stations was high (0.79–0.87), indicating an even distribution of individuals. Pearson correlation analysis showed that temperature, current velocity, substrate organic content, and nitrate had a very strong positive correlation with macrozoobenthos diversity, while pH and BOD₅ had a very strong negative correlation. DO and oxygen saturation parameters showed a moderately positive correlation, while phosphate showed a weakly positive correlation. Based on these findings, it is concluded that the water quality of the Tanjung Pura River is still fairly good but shows mild to moderate ecological pressure, especially at stations affected by domestic activities. Water quality management should focus on controlling organic matter and pH and BOD₅ parameters to maintain the sustainability of the macrozoobenthos community. Further research with a longer time frame and additional stations is recommended for more comprehensive ecological monitoring.