Penggunaan Makrozoobentos Dalam Penilaian Kualitas Perairan Sungai Inlet Danau Maninjau, Sumatera Barat

Abstract

Danau Maninjau yang terletak di Provinsi Sumatera Barat telah ditetapkan sebagai salah satu danau prioritas nasional diantara 15 danau lainnya. Kondisi kualitas air Danau Maninjau salah satunya dipengaruhi oleh kondisi kualitas air dari sungai-sungai yang bermuara di danau tersebut. Penelitian ini bertujuan untuk mengetahui kondisi kualitas air sungai inlet Danau Maninjau dengan menggunakan bioindikator makrozoobentos. Penelitian dilakukan pada bulan Juni dan Agustus 2019 di empat sungai inlet Danau Maninjau yang meliputi Sungai Koto Kaciak, Kurambik, Kularian, dan Ranggeh Bayur. Pengambilan sampel makrozoobentos dilakukan di segmen hulu, tengah, dan hilir dengan menggunakan kick net pada substrat berbatu dan berpasir, serta pengeruk Ekman pada substrat berlumpur. Berdasarkan hasil penelitian, ditemukan makrozoobentos di keempat sungai inlet dengan kisaran 5-25 famili dan 4-10 ordo yang tergolong ke dalam delapan kelas meliputi Insekta, Clitellata, Malacostraca, Bivalvia, Gastropoda, Polychaeta, Hirudinea, dan Turbellaria. Hasil analisis korelasi Spearman antara metrik biologi dengan Water Quality Index (WQI)  menunjukkan bahwa metrik SIGNAL, EPT, dan LQI memiliki korelasi yang sangat kuat dengan nilai r > 0,7 (p<0,01). Metrik SIGNAL dengan korelasi tertinggi (r = 0,752) menunjukkan kondisi perairan sungai inlet Danau Maninjau  yang tercemar ringan hingga berat. Metrik SIGNAL, EPT, dan LQI dapat diaplikasikan untuk melengkapi penilaian parameter fisik kimiawi perairan sungai inlet Danau Maninjau. ABSTRACTLake Maninjau which is located in West Sumatra Province has been designated as one of the national priority lakes among 15 other lakes. Water quality conditions of Lake Maninjau is influenced by the condition of the water quality of the streams that flow into the lake. The present study aimed to determine the condition of the water quality of the inlet stream of Lake Maninjau by using macrozoobenthos as bioindicators. This study was conducted in June and August 2019 in four inlet streams of Lake Maninjau including the Koto Kaciak, Kurambik, Kularian, and Ranggeh Bayur streams. A sampling of macrozoobenthos was carried out in the upstream, middle, and downstream using Surber nets on rocky and sandy substrates, and Ekman Grab on muddy substrates. Based on the results of this study, macrozoobenthos were found in the four inlet streams with a range of 5-25 families and 4-10 orders and classified into eight classes including Insects, Clitellata, Malacostraca, Bivalvia, Gastropods, Polychaeta, Hirudinea, and Turbellaria. The results of the Spearman correlation analysis between biological metrics and the Water Quality Index (WQI) show that the SIGNAL, EPT, and LQI metrics have a very strong correlation with r values > 0.7 (p < 0.01). The SIGNAL metric has the highest correlation (r = 0.752) indicates the inlet streams of Lake Maninjau which are lightly to heavily polluted. Metrics of macrozoobenthos communities such as SIGNAL, EPT, and LQI can be applied to complete the assessment of the physicochemical parameters of inlet streams of Lake Maninjau