Keanekaragaman Plankton sebagai Indikator Kualitas Air Danau Siais Kabupaten Tapanuli Selatan

Abstract

Background : Plancton has very essential role in waters environmental, both as fundamental of food chain (primary producer) and as one tropic level paramater. Water quality can be assessed by biological analysis using plancton aquatic biota as a bio indicator. The aimed of this research were to know the diversity and abundance of plancton as a bio indicator and its correlations of physical – chemical and biologic the water quality of Siais Lake. Siais lake is the two largest lake in Sumatera, lies in the South Tapanuli Residence with 20 – 25 m deep and about 450 Ha wide. Method : The researched has been done during in November 2010 to March 2011, sample were collected by using plancton net from five stations with Purposive Random Sampling and in every observation station performed three times. Sample were identified in Laboratory PSDAL, Depatement of Biology,Faculty of Mathematic and Natural Science North Sumatera University. Result : The result showed that three were 65 genera from thirteen classes of plancton which including 8 classes of Phytoplancton such as Ascomycetes, Bacillariophyceae, Chlorophyceae, Chrysophyceae, Cyanophyceae, Dinophyceae, Mastigophorea, Xanthophyceae, 5 classes of Zooplancton such as Adenophorea, Branchiopoda, Ciliate, Maxillopoda, and Monogononta. Glenodirium has the highes density index with 6571,429 individu / ml founded in 5th station, and 22 genera has the lowest density index with 40,816 ind/ml was founded in each station. The highest index diversity (h’) was foundeed in 5 th station with 3,414 and the lowest value was founded at the 4th station with 2,321. according to the analysis ait pearson correlation, shiny intensity, pH, DO, organic substrate has the positive correlated to the diversity of plancton, while temperature, transparency, TDS, TSS, BOD5, fosfate, nitrat, E. Coli has the negative correlated to the diversity of plancton.

Latar belakang : Plankton mempunyai peranan yang sangat penting dalam suatu perairan selain sebagai dasar dari rantai makanan juga merupakan salah satu parameter tingkat kesuburan suatu perairan. Kualitas air dapat dinilai melalui studi analisis biologi menggunakan plankton biota akuatik sebagai bioindikator. Tujuan penelitian ini adalah untuk mengetahui keanekaragaman dan kelimpahan plankton sebagai bioindikator kualitas air, danau Siais dan korelasinya terhadap faktor fisika, kimia dan biologi. Danau Siais adalah danau terbesar kedua di Sumatera terletak di Kabupaten Tapanuli Selatan dengan kedalaman 20 – 25 m dan luasnya lebih kurang 450 Ha. Metode : Penelitian ini telah dilaksanakan selama bulan November 2010 sampai Maret 2011. Sampel diambil menggunakan plankton net pada lima stasiun dengan metode Purposive Random Sampling dan tiap stasiun pengamatan dilakukan tiga kali ulangan. Sampel diidentifikasi di Laboratorium PSDAL, Departemen Biologi, Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Sumatera Utara, Medan. Kesimpulan : Hasil penelitian didapatkan 65 genus dari 13 kelas plankton yang terdiri dari 8 kelas phyroplankton yaitu Ascomycetes, Bacillariophyceae, Chlorophyceae, Chrysophyceae, Cyanophyceae, Dinophyceae, Mastigophorea, Xanthophyceae dan 5 kelas Zooplankton yaitu : Adenophorea, Branchiopoda, Ciliate, Maxillopoda, and Monogononta. Nilai kelimpahan tertinggi adalah genus Glenodinium sebesar 6571,429 ind/l ditemukan pada stasiun 5, dan 22 genus dengan nilai kelimpahan terendah sebesar 2,321 pada stasiun 4. Dari hasil analisis korelasi Pearson menunjukkan bahwa intensitas cahaya, pH, DO, substrat organik, mmberikan pengaruh positif terhadap keanekaragaman plankton. Sedangkan suhu, penetrasi cahaya, TDS, TSS, BOD5, COD, Fosfat, Nitrat, E.Coli berpengaru