Judul: Fermentasi bakteri pelarut fosfat (Pseidomonas sp. ) dan penambat nitrogen (Alcaligenes sp.) untuk pupuk mikroba
Abstrak: Penggunaan pupuk mikroba merupakan alternatif untuk menggantikan pupuk kimia. Pseudomonoas sp. dan Alcaligenes sp. berpotensi sebagai pupuk mikroba pelarut fosfat dan penambat nitrogen.Produksi bakteri diawali dengan optimasi pH dan nutrien. Optimasi pH dilakukan pada kisaran pH 5.5 hingga 7.5. Optimasi nutrien dilakukan pada media King's B dengan penggantian sumber nitrogen dan sumber karbon. Sumber nitrogen pada media King's B diganti dengan hidrosilat kedelai sedangkan sumber karbon divariasikan dengan gliserol, manitol, sukrosa, dan glukosa. Kultivasi bakteri diamati dengan hitungan cawan dan mengukur pH.
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Judul: Karakterisasi Bakteri Pelarut Fosfat Dan Penambat Nitrogen Dari Area Penambangan Batuan Kapur.
Abstrak: Fosfat (P) dan nitrogen (N) adalah makronutrien yang dibutuhkan oleh tumbuhan. Tanaman dapat memanfaatkan fosfat dalam bentuk terlarut (Pi, H2PO4 - atau HPO4 2-) dan nitrogen dalam bentuk anorganik (NO3 - dan NH4 +). Ketersediaan hara, termasuk P dan N di tanah marginal, seperti tanah bekas penambangan batuan kapur, sangatlah terbatas bagi tanaman. Pemupukan menggunakan pupuk kimia, seperti urea, amonium sulfat, dan TSP, dilakukan sebagai salah satu alternatif untuk meningkatkan kandungan hara makro tersebut di dalam tanah. Namun pemakaian yang berlebihan menimbulkan pengaruh kurang baik bagi tanaman dan lingkungan. Agens hayati dari kelompok bakteri plant growth promoting rhizobacteria (PGPR) diharapkan dapat mengurangi pemakainan pupuk kimia. Penelitian ini bertujuan untuk mengisolasi dan mengkarakterisasi bakteri pelarut P yang dapat menambat N dari tanah sekitar penambangan batuan kapur. Sampel tanah diambil dari sekitar penambangan batuan kapur PT Indocement, Palimanan, Cirebon. Bakteri pelarut P dari sampel tanah diisolasi pada media Pikovskaya dengan metode pengenceran serial. Isolat pelarut P yang memiliki kemampuan menambat N diseleksi pada media N-free bromthymol blue (NfB). Tingkat kemampuan bakteri dalam melarutkan P secara kualitatif ditentukan berdasarkan nilai indeks pelarutan P (IP). Empat isolat (GPA2.1, GPA2.2, GPC1.7 dan GPC3.7) dipilih berdasarkan nilai IP, kriteria pertumbuhannya pada media selektif, hipersensitivitas terhadap daun tembakau, dan kestabilan pertumbuhannya. Isolat terpilih dianalisis kemampuannya dalam melarutkan P dengan metode kolorimetri dan kemampunnya dalam menambat nitrogen diukur dengan metode Acetylene Reduction Assay. Identifikasi secara morfologi dilakukan dengan pewarnaan Gram, sedangkan secara molekuler dilakukan berdasarkan gen 16s rRNA. Sebanyak 22 isolat bakteri yang mampu melarutkan P dan menambat N berhasil diisolasi. Sembilan dari 22 isolat tidak menimbulkan gejala hipersensitif terhadap daun tembakau. Uji kuantitatif pelarutan P menunjukkan bahwa isolat bakteri GPA1.7 dapat melarutkan P tertinggi dalam media Pikovskaya cair (450 mg/L) pada inkubasi hari ke-5 dan 6, sedangkan isolat bakteri GPC3.7 memiliki aktivitas penambatan N tertinggi (0.291 ppm/jam). Isolat GPA2.1, GPA2.2, dan GPC3.7 merupakan bakteri Gram negatif sedangkan isolat GPC1.7 merupakan bakteri Gram positif. Identifikasi berdasarkan gen 16S rRNA menunjukkan bahwa isolat GPA2.1 berkerabat dekat dengan Pseudomonas oryzihabitans dan Pseudomonas psychrotolerans, sedangkan GPA2.2, GPC1.7 dan GPC3.7 masingmasing berkerabat dekat dengan Stenotrophomonas maltophilia, Bacillus megaterium, dan Acinetobacter baumannii. Isolat bakteri pelarut P dan penambat N yang didapatkan selanjutnya dapat dimanfaatkan untuk memperbaiki kesuburan tanah pada area bekas tambang batuan kapur.
Keyword: bakteri pelarut P, bakteri penambat N, tanah batuan kapur, 16S rRNA

Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite