| dc.description.abstract | The purpose of this study was to analyze the water quality of Toba Lake based on the physics-chemical properties of the waters, the phytoplankton community, and the relationship between the physico-chemical factors of the water and the phytoplankton community according to space and time. This research was conducted during two seasons, Dry season (April, May, July) and Rainy season (October, November and December), and was conducted at four stations, namely around the floating net cage area, around the pier, around the agricultural area, and the control area near the waterfall. Data analysis was performed using the SAS 913 program and the Duncan Multiple Range Test (DMRT). The results of the analysis of water physics-chemical factors by space and time showed the quality of the waters in each station is still relatively good, except for floating net cages that have lower oxygen solubility.Data on chemical physics factors that affect phytoplankton in the waters of Lake Toba based on space, namely the temperature factor is in the range of 26.41 °C - 26.70 °C, light penetration in the range of 3.44 m - 5.10 m, degree of acidity (pH) in the range of 7.89 – 8.27, oxygen solubility (DO) in the range of 4 mg/L- 6.79 mg/L, biochemical oxygen requirements (BOD5) in the range of 0.69 mg/L - 0.95 mg/L, conductivity is in the range of 97.39 μS/cm - 164.59 μS/cm, total dissolved solids (TDS) are in the range of 91.48 mg/L - 98.1 1 mg/L, total nitrate is in the range of 2.14 mg/L - 3.95 mg/L, phosphate content (PO4) is in the range of 0.009 mg/L - 0.013 mg/L. While based on time that is the temperature factor is in the range of 26.21 °C - 26.90 °C, light penetration in the range of 3.28 m - 5.23 m, acidity (pH) in the range of 7.44 – 8.55, oxygen solubility (DO) in the range of 5.77 mg/L - 6.36 mg/L, biochemical oxygen requirements (BOD5) in the range of 0.26 mg/L - 1.63 mg/L, conductivity is in the range of 160.52 μS/cm - 168.41 μS/cm, total dissolved solids (TDS) are in the range of 46.62 mg/L - 109.9 19 mg/L, total nitrate is in the range of 1.89 mg/L - 3.73 mg/L, phosphate content (PO4) is in the range of 0.011 mg/L - 0.81 mg/L. There are 36 phytoplankton found in the waters of Lake Toba which are classified into 23 families, 15 orders, 5 classes and 3 phyla. The dominant types of phytoplankton according to space and time are Staurastrum sp and Gloeotila sp. Based on data obtained from the diversity index and phytoplankton uniformity, the water quality of Lake Toba is still good, with a diversity index value greater than 3, while the uniformity index tends to be above 0.9. Types of phytoplankton that are included as indicators of organic pollution in Lake Toba are Oscillatoria sp., Navicula sp., Nitzschia sp., Synedra sp., Stigeoclonium sp., Closterium sp and Melosira sp. Water physico-chemical factors that significantly affect the amount of phytoplankton according to space and time are total nitrate and light with a contribution value of 32.7%. The results of this study are expected to be important information in the management of waters in the Lake Toba region, in order to preserve nature. | en_US |
| dc.description.abstract | Tujuan dari penelitian ini adalah untuk menganalisis kualitas perairan Danau Toba berdasarkan sifat fisika-kimia perairan, komunitas fitoplankton, dan hubungan antara faktor fisika-kimia air dengan komunitas fitoplankton. Penelitian ini dilakukan selama dua musim yaitu musim kemarau (April, Mei, Juli) dan musim hujan (Oktober, November dan Desember) dan dilakukan pada empat stasiun yakni sekitar area keramba jaring apung, sekitar dermaga, sekitar area pertanian, dan area kontrol dekat air terjun. Analisis data dilakukan dengan menggunakan program SAS 913 dan Uji Duncan Multiple Range Test (DMRT). Hasil analisis faktor fisika-kimia air menurut ruang dan waktu menunjukkan kualitas perairan di masing-masing stasiun masih tergolong baik, kecuali keramba jaring apung yang memiliki kelarutan oksigen lebih rendah. Data faktor fisika kimia yang mempengaruhi fitoplankton diperairan Danau Toba berdasarkan ruang yaitu faktor suhu berada pada kisaran 26,41°C - 26,70°C, penetrasi cahaya pada kisaran 3,44 m - 5,10 m, derajat keasaman (pH) pada kisaran 7,89 – 8,27, kelarutan oksigen (DO) pada kisaran 4 mg/L- 6,79 mg/L, kebutuhan oksigen biokimia (BOD5) pada kisaran 0,69 mg/L - 0,95 mg/L, konduktivitas berada pada kisaran 97,39 μS/cm - 164,59 μS/cm, total padatan terlarut (TDS) berada pada kisaran 91,48 mg/L - 98,11 mg/L, total nitrat berada pada kisaran 2,14 mg/L - 3,95 mg/L, kandungan fosfat (PO4) berada pada kisaran 0,009 mg/L - 0,013 mg/L. Sedangkan berdasarkan waktu yaitu faktor suhu berada pada kisaran 26,21°C - 26,90°C, penetrasi cahaya pada kisaran 3,28 m - 5,23 m, derajat keasaman (pH) pada kisaran 7,44 – 8,55, kelarutan oksigen (DO) pada kisaran 5,77 mg/L - 6,36 mg/L, kebutuhan oksigen biokimia (BOD5) pada kisaran 0,26 mg/L - 1,63 mg/L, konduktivitas berada pada kisaran 160,52 μS/cm - 168,41 μS/cm, total padatan terlarut (TDS) berada pada kisaran 46,62 mg/L - 109,19 mg/L, total nitrat berada pada kisaran 1,89 mg/L - 3,73 mg/L, kandungan fosfat (PO4) berada pada kisaran 0,011 mg/L - 0,81 mg/L. Terdapat 36 fitoplankton yang ditemukan di perairan Danau Toba yang diklasifikasikan menjadi 23 famili, 15 ordo, 5 kelas dan 3 filum. Jenis fitoplankton yang dominan adalah Staurastrum sp dan Gloeotila sp. Berdasarkan data yang diperoleh dari indeks keanekaragaman dan keseragaman fitoplankton, kualitas perairan Danau Toba masih baik, dengan nilai indeks keanekaragaman lebih besar dari 3, sedangkan indeks keseragaman cenderung berada di atas 0,9. Jenis fitoplankton yang termasuk sebagai indikator pencemaran organik di Danau Toba adalah Oscillatoria sp., Navicula sp., Nitzschia sp., Synedra sp., Stigeoclonium sp., Closterium sp dan Melosira sp. Faktor fisika-kimia perairan yang berpengaruh nyata terhadap jumlah fitoplankton menurut ruang dan waktu adalah total nitrat dan penetrasi cahaya nilai kontribusi sebesar 32,7%. Hasil penelitian ini diharapkan dapat menjadi informasi penting dalam pengelolaan perairan di wilayah danau Toba, demi menjaga kelestarian alam. | en_US |
