Kelimpahan dan Keanekaragaman Fitoplankton di Perairan Danau Toba Desa Paropo Kecamatan Silahisabungan Kabupaten Dairi Provinsi Sumatera Utara

Abstract

Paropo Village is one of the villages located in Silahisabung District, Dairi Regency, North Sumatra Province. The water area of Paropo Village has been utilized for various fishery and non-fishery activities including fishing grounds, floating net cage cultivation and water transportation ports. This study aims to determine the community structure of phytoplankton and the level of water quality using the saprobic method in the waters of Lake Toba, Paropo Village, Silahisabung District, Dairi Regency, North Sumatra Province. This research was conducted in June-July 2022. Determining the location of the sample used a purposive random sampling method at 3 observation stations. Collection of phytoplankton using plankton net. The results of the study found that there were 12 species with 6 classes. The total abundance of phytoplankton at station I was 2035 cells/liter consisting of 9 species. At station II there were 2880 cells/liter consisting of 10 species. At station III there were 1700 cells/liter consisting of 9 species. The diversity value at each station shows that all stations are included in moderate diversity with a value at station I that is 2.242, station II that is 2.321, station III that is 2.288. Based on the saprobic index, the phytoplankton in Lake Toba, Paropo Village, Silahisabung District, Dairi Regency, North Sumatra Province is grouped into Oligo/mesosaprobic with a value of 1.94 and is classified as very lightly polluted. The Principal Component Analysis results show that temperature and phosphate negative correlate with the diversity of phytoplankton with values of 0.898 and 0.155. The relationship between brightness, pH, DO, N-total and current velocity has a negative correlation with the diversity of phytoplankton with a value of -0.961, -0.275, -0.510, -0.841, -0.994.