Komunitas Makrozoobentos sebagai Bioindikator Kualitas Air di Sungai Batang Serangan-Tangkahan Kabupaten Langkat, Sumatera Utara

Abstract

The research about “The Community of Makrozoobenthic as Bioindicator Water Quality in Batang Serangan-Tangkahan River, Langkat, North Sumatera”, has been done in April to June 2010. Sampling was done three months period, first period in April, the second in May and the third in June. Samples were taken from four observation stations and in every observation stations performed nine times. Sample point was determined by using Purposive Random Sampling method and the samples were taken by using Surber Net. The result showed that there were found 3 classes, 13 Ordo, 31 family and 38 genus of macrozoobenthic. The class of insects is the most makrozoobenthic community that is composed of 9 ordo, 26 Family and 33 Genus and the least was Crustaceae consist of 1 Ordo, 1 Family and 1 Genus is Palaemonetes. The average value of Index Diversity (Hl ) in station 1 (H1 is 2,08), station 3 (H1 is 2,16) and station 4 (H1 is 2,37) showed that the stations are not polluted, while the station 2 ( H1 is 1,67) is lightly polluted. Batang Serangan Tangkahan River has high equitably (E value 0,63 - 0,98 ). Macrozoobenthic communities as bioindicator are Ephemeroptera (Mayflies), Plecoptera (Stoneflies), Trichoptera (Caddisflies and Net spinning caddisflies), Coleoptera (Water penny), Megaloptera (Hellgrammite) and Odonata (Dragonflies nymph and Damselflies nymph). Based on the Biotic Index (BI) Batang Serangan - Tangkahan River relatively clean stream (BI value 10-19). F Test among periods showed that there was no effect of sampling period on macrozoobenthic diversity. F test among stations showed the effect of different stations for diversity of macrozoobenthic, that is between station 2 and 4. Analysis of Pearson correlation that temperature, light intensity, pH, BOD5, COD, nitrate, phosphate, organic substrate have the positive correlation to the diversity of macrozoobenthic, while the flow velocity and DO have the negative correlation.

Penelitian tentang “Komunitas Makrozoobentos Sebagai Bioindikator Kualitas Air di Sungai Batang Serangan - Tangkahan Kabupaten Langkat Sumatera Utara” telah dilakukan pada bulan April sampai dengan Juni 2010. Pengambilan sampel dilakukan 3 periode yaitu periode I bulan April, periode II bulan Mei dan periode III bulan Juni. Sampel diambil dari 4 stasiun pengamatan dan pada setiap stasiun pengamatan dilakukan 9 kali ulangan. Titik pengambilan sampel ditentukan dengan menggunakan metode Purposive Random Sampling dan sampel diambil dengan menggunakan Surber Net. Dari hasil penelitian ditemukan 3 Kelas, 13 Ordo, 31 Famili dan 38 Genus makrozoobentos. Kelas Insekta merupakan komunitas makrozoobentos yang terbanyak yaitu terdiri dari 9 Ordo, 26 Famili, 33 Genus dan yang paling sedikit adalah dari Kelas Crustaceae yang terdiri dari 1 Ordo, 1 Famili dan 1 Genus yaitu Palaemonetes. Nilai rata - rata Indeks Keanekaragaman (H’) menunjukkan bahwa stasiun 1 (H’ sebesar 2,08), stasiun 3 (H’ sebesar 2,16) dan stasiun 4 (H’ sebesar 2,37) tidak tercemar, sedangkan stasiun 2 (H’ sebesar 1,67) tercemar ringan. Berdasarkan Indeks Keseragaman (E) tergolong perairan yang memiliki Indeks Keseragaman tinggi dengan nilai E berkisar : 0,63 - 0,98. Komunitas makrozoobentos sebagai Bioindikator adalah Ephemeroptera (Mayflies), Plecoptera (Stoneflies), Trichoptera (Caddisflies dan Net spinning caddisflies), Coleoptera (Water penny), Megaloptera (Hellgrammite) dan Odonata (Dragonflies nymph dan Damselflies nymph). Berdasarkan Indeks Biotik (IB) tergolong perairan bersih dengan nilai IB berkisar : 10 - 19. Uji F antar periode menunjukkan tidak ada pengaruh periode pengambilan sampel terhadap Indeks Keanekaragaman makrozoobentos. Uji F antar stasiun menunjukkan ada pengaruh perbedaan stasiun terhadap Indeks keanekaragaman makrozoobentos, yaitu antara stasiun 2 dan 4. Dari hasil analisis korelasi Pearson menunjukkan bahwa Suhu, Intensitas Cahaya, pH, BOD5, COD, Nitrat, Fosfat, Substrat Organik berkorelasi positif dengan keanekaragaman makrozoobentos, sedangkan Kecepatan Arus, DO berkorelasi negatif.