A B S T R A C TBatang Gadis River, located in Mandailing Natal, faces a severe threat by the increase of human activities along the river. The fish community, as well as other biotas, is exposed to reducing environmental condition. Therefore, the study of fish community in this river is essential to get the most recent condition as a baseline data. The purpose of this research was to determine the species diversity of fish in Batang Gadis River of Mandailing Natal. This research used a descriptive exploratory method by surveying with purposive sampling method to collect samples at four specified stations. This study used a fishing net with a zig-zag pattern of sampling covered the river bank for about 200-300m at each observation station. The collected fish samples were identified at the Biology Laboratory of the University of Muhammadiyah Tapanuli Selatan. This study found ten species of fish from five families. The family with the most significant members was Cyprinidae (6 species), and the other families, Bagridae, Clariidae, Nemachelidae, and Loricariidae, were found with only one species. The species diversity comprised of Rasbora lateristriata, Nemacheilus fasciatus, Mystacoleucus marginatus, Tor tambra, Cyprinus carpio, Clarias bathracus, Rasbora argyrotaenia, Barbonymus gonionotus, Puntius binotatus, Bagrus nemurus, and Pterygoplichthys pardalis. The fish population of Batang Gadis River has diversity index (H') of 1.77 and similarity index (E) of 0.77.

One of the parameters of quality of drinking water that is suitable for consumption is not contaminated by Escherichia coli, Salmonella and Shigella sp. Beside microbiological tests, water quality testing can be carried out molecularly only in few hours, using PCR (Polymerase Chain Reactions) technique. Although PCR is a basic molecular technique, various detection methods can be developed from it. The key to success in making a PCR-based method is inseparable from bioinformatics studies when designing primers that are specific to pathogen target DNA. The purpose of this research was to design pathogen-specific primers and do in silico study of PCR using bioinformatics software to get better planning in developing detection method. DNA sequence templates of E. coli, Salmonella and Shigella were downloaded from NCBI and multiple-aligned using Geneious Prime bioinformatic software. Primers were designed according to conserved region of these pathogens. The primers specificity was checked using Primer BLAST tools in NCBI. The result of this study was a pair of primers that amplify 825 bp fragment of 16S rRNA sequence specific to E. coli, Salmonella and Shigella.

AbstrakBackground: Sungai Batang Gadis merupakan sungai yang sangat penting sebagai penyedia air untuk mendukung kelangsungan hidup dan kegiatan perekonomian utama masyarakat, yaitu pertanian. Disepanjang pinggiran sungai Batang Gadis banyak ditemukan daerah pertanian masyarakat yang memanfaatkan irigasi dari aliran sungai Batang Gadis. Tujuan dari penelitian ini adalah untuk menentukan tingkat pencemaran pestisida di Sungai Batang Gadis Mandailing Natal. Metode : Metode survey digunakan dalam penelitian ini dengan mengambil dua titik sampling yaitu Muara Mais dan Tamiang. Penentuan titik sampling menggunakan Purposive sampling method. Pengambilan sampel air, tanah dan ikan yang diambil dianalisis menggunakan Gas Kromatografi. Hasil : Hasil penelitian menunjukkan residu pestisida hanya ditemukan pada stasiun II (Muara Mais). Residu pestisida yang ditemukan pada air, sedimen tanah dan ikan dari golongan organofosfat yang terdeteksi adalah diazinon, malation, dan klorfirifos sedangkan dari golongan organoklorin aldrin, dieldrin dan endosulfan. Selain residu pestisida juga ditemukan residu pupuk yaitu fosfat, amonia, nitrat, nitrit dan sulfida. Kesimpulan : Residu pestisida pada Sungai Batang Gadis yang ditemukan hannya pada titik lokasi yang ditemukan daerah pertanian disepanjang pinggiran sungai tersebut. Kadar residu pestisida dan juga residu pupuk yang ditemukan masih berada di bawah Batas Maksimal Residu (BMR) pestisida. Konsentrasi residu pestisida organofosfat tersebut yang terbesar terdapat pada tanah, lalu ikan dan terakhir air, sedangkan organoklorin terbesar pada ikan, air kemudian tanah. AbstractBackground: Batang Gadis River is a river that is very important as a water provider to support the survival and main economic activities of the community, namely agriculture. Along the banks of the Batang Gadis river, many community farms are found that utilize irrigation from the Batang Gadis river. The study was conducted to determine the level of pesticide pollution in the Batang Gadis Mandailing Natal river. Methods:The survey method was used in this study by taking 2 sampling point locations. Determination of sampling locations using purposive sampling method. Water, sediment and biota sampling from each study location will be analysized using a Gas Chromatograph (GC) methode. Result: The results showed that pesticide residues were only found at Station II (Muara Mais). Pesticide residues found in water, soil sediments and fish from the organophosphate group detected were diazinon, malation, and chlorphyrifos while those from the organochlorine group were aldrin, dieldrin and endosulfan. In addition to pesticide residues, fertilizer residues are also found, namely phosphate, ammonia, nitrate, nitrite and sulfide. Conclution: Pesticide residues in Batang Gadis River which were found only at the location found by agricultural areas along the river bank. Pesticide residue levels and fertilizer residues found are still below the pesticide Maximum Residue Limit (BMR). Concentrations of these organophosphate pest...

The purpose of this study is to find out the river water quality in terms of the spread of heavy metals found from the gold mining in Batang Gadis Mandailing Natal River and to determine the effect of heavy metal distribution on river flow from the gold mining of aquatic biota on the Batang Gadis Mandailing Natal River. This research uses descriptive exploratory method by conducting a survey first. Determination of sampling sites using purposive sampling method at the two stations that are determined. Sampling of water and sediments from each location. Water samples were taken as much as 500 mL, samples of sediment were taken at a depth of 10-15 cm from the base surface as much as 100-200 g (Mann, 1978). Examples of water biota are randomly taken at each station as much as 50-100 g, then put together into a composite sample for further analysis in the laboratory. Water quality is measured insitu include temperature, brightness, turbidity, depth, current speed, pH, DO, CO2. While the COD sample, BOD was taken to the laboratory to be analyzed by preservation using ice at a temperature of around 4 oC before observing in the UMTS biology laboratory. Data obtained, then analyzed descriptively. The results of this study are the levels of heavy metals found in the two Batang Gadis River observation stations that are equally good in water, sediment and those found in fish, namely Hg <0,0008, Cd <0,003 and Pb <0,005. Metal levels found are still below the threshold value, but need to be aware of the accumulation of these metals. The histological observations of crisp fish gills at the Bustak mine station are found to experience edema and necrosis which are strongly suspected to be caused by pollution of heavy metals found in the Batang Gadis River. The histological observations of crisp fish liver at the Bustak mine station are found to experience necrosis which is allegedly caused by heavy metal pollution found on the Batang Gadis River

Kemampuan berpikir tingkat tinggi adalah kemampuan yang mencakup tiga aspek yaitu analisis, evaluasi dan penciptaan sesuai dengan implementasi kurikulum 2013. Berdasarkan pengamatan pra-penelitian yang dilakukan di SMAN 2 Koto XI Tarusan diperoleh bahwa instrumen yang digunakan oleh guru masih pada level kognitif C1-C3 dengan persentase C1 56%, C2 40%, dan C3 4%, sedangkan untuk tuntutan kemampuan berpikir level siswa yang lebih tinggi harus mampu berpikir pada level kognitif C4-C6. Penelitian ini bertujuan untuk menghasilkan instrumen penilaian kemampuan berpikir tingkat tinggi tentang materi sistem pencernaan dengan menggunakan model 4D models. Subjek penelitian dua orang dosen biologi FMIPA UNP sebagai validator dengan rata-rata hasil validasi instrumen penilaian sebesar 78,82% dengan kriteria cukup valid. Ini menunjukkan instrumen penilaian kemampuan berpikir tingkat tinggi tentang materi sistem pencernaan cukup valid dikembangkan dari segi materi, konstruksi, bahasa serta tingkat kognitif instrumen penilaian kemampuan berpikir tingkat tinggi sehingga dapat digunakan untuk mengukur kemampuan berpikir tingkat tinggi peserta didik tentang materi sistem pencernaan.