Keanekaragaman Makrozoobentos sebagai Indikator KUalitas Perairan Danau Toba Balige Kabupaten Toba Samosir

Abstract

Lake Toba is the largest lake in Southeast Asia, lies in the Northern part of Barisan Mountain Range. The water surface of Lake Toba is 995 m above sea level and about 1129,7 Km2 wide, length 87 Km, and 455 m deep. The water of this lake is used not only for agriculture, drinking water, traditional market but also for quay wall. The people activities along this lake could influence its water quality, because the waste produced by those people activities is thrown to this river directly. The changes of those water qualities in the lake induce the change of macrozoobenthos community. For that reason, it is necessary to observe the Danau Toba water quality based on macrozoobenthos indicator. The aims of the research were to know the diversity of macrozoobenthic as bioindicator in Danau Toba and to determine the Danau Toba quality level in relation to physical-chemical and biologis of the lake. The research was carried out from December 2008 until February 2009 in Danau Toba Balige Toba Samosir. Sampel were collected from four stations by Purposive Random Sampling method. Surber net and Eckmann Grabb were used to taken the sampel. Samples were identified in Laboratory PSDAL, Department of Biology, Faculty of Mathematic and Natural Sciences of North Sumatera University. The result showed that there five classes within ten ordo, 17 family and 21 genera of Macrozoobenthic were found. Elimia sp has the highest density index with 77,77 individu/m2 founded in second station, and Haitia sp in fourth station has the lowest density index with 1,23 individu/m2. The Highest Index Diversity (Hí) was founded at the 4th station with 2,08 and the lowest value was founded at the 1st station with 1,71. According to the analysis of Pearson Correlation, pH, DO, Oxygen Saturation and COD has the positive correlated to the diversity of Macrozoobenthic, while Organic Substrat, Fosfat, Nitrat, BOD5 and Temperature has the negative correlated to the Diversity of Macrozoobenthic.

Danau Toba merupakan danau terbesar di Asia Tenggara, berada di sebelah utara Pegunungan Bukit Barisan. Danau Toba terletak pada ketinggian 995 m di atas permukaan laut, dengan luas 1129,7 km2, panjang 87 km, dan kedalaman 455 m. Air dari danau ini dipergunakan untuk pertanian, air minum, pekan dan sebagai dermaga. Berkembangnya aktivitas masyarakat di sekitar danau dapat berpengaruh terhadap kualitas airnya, karena limbah yang dihasilkan dari kegiatan penduduk tersebut dibuang langsung ke danau. Tujuan dari penelitian ini adalah untuk mengetahui keanekaragaman makrozoobentos sebagai indikator kualitas perairan Danau Toba Balige serta menentukan kualitas perairan Danau Toba berdasarkan sifat fisika-kimia biologi yang dimilikinya. Penelitian ini, telah dilakukan mulai bulan Desember 2008 ñ Februari 2009 sampel diambil dari 4 stasiun penelitian. Titik pengambilan sampel ditentukan dengan metode Purposive Random Sampling. Sampel diambil dengan menggunakan Surber net dan Eckmann Grab kemudian diidentifikasi di Laboratorium PSDAL Departemen Biologi, Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Sumatera Utara, Medan. Dari hasil penelitian didapatkan makrozoobentos yang terdiri dari 5 kelas, 10 ordo, 17 famili dan 21 genus. Nilai kepadatan tertinggi didapatkan dari taksa Elimia sp sebesar 77,77 individu/m2 yang ditemukan pada stasiun II dan terendah dari taksa Haitia sp sebesar 1,23 individu/m2 yang ditemukan pada stasiun IV. Nilai Indeks Keanekaragaman (Hí) makrozoobentos tertinggi didapati pada stasiun IV sebesar 2,08 dan terendah pada stasiun I sebesar 1,71. Dari hasil analisis korelasi Pearson menunjukkan bahwa pH, DO, Kejenuhan Oksigen dan COD berkorelasi positif dengan keanekaragaman makrozoobentos sedangkan Substrat, Fosfat, Nitrat, BOD5 dan Suhu berkorelasi negatif.