KOMUNITAS PLANKTON DAN KUALITAS AIR OXBOW LAKE BENGAWAN SOLO DI DESA SIDOWARNO KABUPATEN KLATEN

TIRTADANU, , - Drs. Namastra Probosunu M.Si

2013 | Skripsi | MANAJ. SUMBER DAYA PERIKANAN

Pelurusan Sungai menyebabkan terbentuknya oxbow lake sehingga terjadi perubahan kondisi fisik dan kimia perairan yang berpengaruh terhadap biota air, salah satunya yaitu plankton. Tujuan penelitian ini adalah untuk mengetahui struktur komunitas plankton dan kualitas air dan mengetahui hubungan kepadatan plankton dengan kualitas air Oxbow Lake Bengawan Solo. Penelitian dilakukan dari bulan Maret sampai April 2013 di Oxbow Lake Bengawan Solo Desa Sidowarno Kecamatan Wonosari Kabupaten Klaten selama 5 minggu dan pengambilan sampel dilakukan satu kali tiap minggu pada 5 stasiun pengamatan. Sampel plankton diambil menggunakan jaring plankton dengan cara menyaring air sebanyak 50 l dan sampel plankton diawetkan dengan 4% formalin. Pengamatan plankton dilakukan di Laboratorium Ekologi Perairan UGM dengan memasukkan larutan sampel plankton ke dalam Sedgwick Rafter Counting Cell (SR) dan diamati dengan mikroskop perbesaran 10 x 10. Parameter kualitas air yaitu kecerahan, suhu air, oksigen terlarut, karbondioksida bebas dan alkalinitas diukur secara langsung (in-situ) sedangkan TSS, pH, bahan organik, fosfat dan nitrat diukur di laboratorium (ex-situ). Plankton yang ditemukan di Oxbow Lake Bengawan Solo sebanyak 40 genera yang terdiri dari 22 genera dari fitoplankton dan 18 genera dari zooplankton. Fitoplankton yang mendominasi perairan yaitu Synedra sedangkan zooplankton yang mendominasi perairan yaitu Cyclops. Nilai rata-rata kelimpahan plankton di lima stasiun penelitian berkisar antara 60-125 sel/l dan indeks keragaman plankton berkisar antara 1,27-1,74. Kecerahan perairan Oxbow Lake Bengawan Solo berkisar antara 34,55-94,99 cm; suhu air berkisar antara 26,8-28,5 o C; TSS berkisar antara 206,3-385,9 mg/l; pH berkisar antara 6,88-6,92; O2 terlarut berkisar antara 0,826-4,01 mg/l; CO2 bebas berkisar antara 22,04-36,04 mg/l; alkalinitas berkisar antara 81-93,4 mg/l; bahan organik berkisar antara 15,94-26,32 mg/l; fosfat berkisar antara 15,94- 26,32 mg/l dan nitrat berkisar antara 0,1078-0,2968 mg/l. Hasil analisis regresi berganda menunjukkan bahwa TSS, pH, oksigen terlarut, fosfat dan nitrat berkorelasi negatif terhadap kepadatan plankton sedangkan karbondioksida bebas dan bahan organik berkorelasi positif terhadap kepadatan plankton

Channelization of the river cause to the formation of oxbow lake that make the physical and chemical conditions to change and affect to aquatic living organism that are plankton. The objectives of the research were to know plankton community structures and water quality in Oxbow Lake of Bengawan Solo and to determine the relationship between density of plankton with water quality in oxbow lake. The research has been done from March to April 2013 in Oxbow Lake of Bengawan Solo River Desa Sidowarno Kabupaten Klaten and the research has been done for 5 weeks. Samples were taken once a week from five observation stations. Samples of Plankton were taken using plankton nets by filtering 50 l of water with plankton net and samples of plankton were preserved with 4% formalin. Observation of the plankton has been studied in Laboratorium Ekologi Perairan UGM by entering sample of plankton into Sedgwick Rafter Counting Cell (SR) and the sample of plankton were observed by microscope 10x10. Water quality parameters that are brightness, water temperature, dissolved oxygen, free carbondioxide and alkalinity were measured directly while TSS (Total Suspended Solid), pH, organic matter, phosphate and nitrate were measured in the laboratory. Plankton which have been found in Oxbow Lake Bengawan Solo were 40 genus which consist of 22 genus of phytoplankton and 18 genus of zooplankton. Phytoplankton which dominate in oxbow lake are Synedra while zooplankton which dominate in oxbow lake are Cyclops. The average value of the abundance of plankton in the five observation stations ranged between 60-125 cells/l and plankton diversity index ranged between 1,27-1,74. Water transparency in Oxbow Lake of Bengawan Solo ranged between 34,55-94,99 cm; water temperature ranged between 26,8- 28,5 o C; TSS ranged between 206,3-385,9 mg/l, pH ranged between 6.88-6.92; dissolved O2 ranged between 0.826-4.01 mg/l; free CO2 ranged between 22,04-36,04 mg/l, alkalinity ranged between 81-93,4 mg/l; organic matter ranged between 15,94-26,32 mg/l; phosphate ranged between 15,94-26,32 mg/l and nitrate ranged between 0,1078-0,2968 mg/l. Results of multiple regression analysis showed that TSS, pH, dissolved oxygen, phosphate and nitrate negatively correlated to the density of plankton while free CO2 and organic matter positively correlated to the density of plankton

Kata Kunci : indeks keragaman, kepadatan, kualitas air, oxbow lake, plankton