Produktivitas Primer Perairan Danau Toba di Desa Unte Mungkur Kecamatan Muara Kabupaten Tapanuli Utara

Abstract

This research was conducted in the waters of Lake Toba in Unte Mungkur Village, Muara District, North Tapanuli Regency. The purpose of this study was to determine the level of primary productivity and water quality of Lake Toba in Unte Mungkur Village based on the value of the water quality parameters and to determine the abundance and diversity of phytoplankton in these waters. This research was conducted in September-October 2022 with a purposive sampling method to determine the research station. The water quality parameters studied were temperature, brightness, pH, Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), phosphate, nitrate, and chlorophyll-a. From the results of the study obtained the value of primary productivity with the dark bottle-light bottle method was 487.968 mgC/m3/day at station I, 150.144 mgC/m3/day at station II, and 187.68 mgC/m3/ day at station III, station I showed the level of water fertility, namely mesotrophic (moderate water fertility level), while at stations II and III the water fertility level was oligotrophic (low water fertility level). The value of primary productivity with the chlorophyll-a method is 386.561 mgC/m3/day at station I, 267.794 mgC/m3/day at station II, and 344.955 mgC/m3/day at station III, indicating the level of fertility at the three stations is in the mesotrophic category.