KEANEKARAGAMAN MAKROZOOBENTOS DI DANAU TOBA KECAMATAN BALIGE KABUPATEN TOBA

Abstrak

Macrobenthic diversity is an important indicator of aquatic ecosystems. This study aimed to determine the diversity, uniformity, dominance, and physical and chemical parameters in the waters of Lake Toba, Balige District, at three different research stations: Station I, Pelabuhan Mulia Raja Napitupulu, Balige, Station II, Tambunan Sunset Beach, and Station III, Lumban Pea Village. This study was conducted from June to August. Sampling was conducted using a purposive sampling method with an Ekman Grab tool, with three replicates at each station. The parameters observed included the diversity index, uniformity index, and macrobenthic dominance index. The physical parameters measured were temperature, light intensity, brightness, and current velocity, while the chemical parameters observed included pH, dissolved oxygen (DO), and biological oxygen demand (BOD). The research results showed that 172 macrobenthic individuals were found, consisting of 8 species: Pilsbryoconcha exilis, Astarte borealis, Pila ampullace, Thiara riqueti, Melanoides plicaria, Crocothemis servilia, Cherax pulverulentus, and Tubifex tubifex. The species with the largest number of individuals was Pila ampullace with 36 individuals, while the species with the smallest number was Crocothemis servilia with 5 individuals. The macrobenthic diversity index was categorized as high (H'=1.9), the evenness index was categorized as medium (E=0.90), and the dominance index was categorized as low (C=0.17). Light intensity ranged from 1275 to 1686 lux. Water clarity was measured between 5.3 and 6.5 meters. Current velocities ranged from 0.20 to 0.40 m/s. The pH remained stable at 7 at all three stations. DO concentrations ranged from 6.4 mg/L to 7.2 mg/L, while BOD ranged from 5.3 mg/L to 5.7 mg/L.