Judul: Kinerja Pertumbuhan dan Kualitas Larva Ikan Lele yang Dipelihara dalam Media Bioflok dengan Penambahan Chlorella sp.
Abstrak: Tujuan penelitian ini adalah untuk mengevaluasi kinerja pertumbuhan dan kualitas larva ikan lele (Clarias gariepinus) yang dipelihara dalam media bioflok dengan penambahan Chlorella sp. Larva berumur dua hari setelah menetas (days post hatching, DPH) dengan ukuran panjang 0.66-0.68 cm dipelihara dalam akuarium berukuran 30x30x30 cm yang diisi air sebanyak 10 L dengan kepadatan 20 ekor/L selama 20 hari. Larva yang digunakan berasal dari dua induk yang dipelihara dalam media yang berbeda yaitu media kontrol (dengan pergantian air) dan media bioflok (tanpa pergantian air, dengan penambahan sumber karbon). Larva dari masing-masing induk dipelihara dalam tiga media pemeliharaan yang berbeda, yaitu kontrol (dengan pergantian air dan tanpa penambahan sumber karbon dan Chlorella sp.), media bioflok tanpa penambahan Chlorella sp. (M1) dan media bioflok dengan penambahan Chlorella sp. (M2). Setelah masa pemeliharaan dilakukan uji stres dengan merendam 10 ekor larva dalam air bersalinitas 20 g/L selama satu jam. Hasil penelitian menunjukkan bahwa benih dari induk bioflok yang dipelihara pada media bioflok+Chlorella sp. memberikan hasil terbaik yang ditunjukan dengan tingkat kelangsungan hidup, pertumbuhan panjang mutlak, laju pertumbuhan harian, koefisien keragaman panjang dan uji stres salinitas yang lebih baik (P<0.05) dibandingkan dengan kontrol.
Keyword: bioflok, ikan lele, induk, kualitas, larva, pertumbuhan

Judul: Kinerja Produksi dan Kualitas Benih Ikan Lele yang Dipelihara dalam Sistem Bioflok dengan Penambahan Chlorella sp.
Abstrak: Penelitian ini bertujuan untuk mengevaluasi kinerja produksi dan kualitas benih ikan lele yang dipelihara dalam sistem bioflok dengan penambahan Chlorella sp. Benih ikan lele berumur dua hari setelah menetas (days post hatching, DPH) dengan panjang rata-rata awal 0,70±0,01 cm dan bobot rata-rata awal 3,41±0,01 mg dipelihara selama 14 hari dalam 9 unit kolam terpal berdiameter 3 m dan tinggi 0,7 m dengan kepadatan 20 ekor/L. Benih dipelihara dalam tiga sistem pemeliharaan yang berbeda, yaitu kontrol dengan pergantian air dan tanpa penambahan sumber karbon dan Chlorella sp. (K), sistem bioflok tanpa Chlorella sp. (BF), dan sistem bioflok dengan penambahan Chlorella sp. (BFC). Setelah masa pemeliharaan dilakukan uji stres dan uji tantang. Uji stres dilakukan dengan merendam 30 ekor benih ikan lele yang diambil secara acak dari setiap kolam perlakuan ke dalam air bersalinitas 20 g/L selama satu jam, sedangkan uji tantang dilakukan dengan merendam 30 ekor benih ikan lele yang diambil secara acak dari setiap kolam perlakuan ke dalam air yang telah diberi bakteri Aeromonas hydrophila dengan konsentrasi 2,75×105 CFU/mL. Hasil penelitian menunjukkan bahwa benih ikan lele yang dipelihara dalam sistem bioflok dengan penambahan Chlorella sp. memberikan tingkat kelangsungan hidup, pertumbuhan panjang mutlak, laju pertumbuhan harian, serta tingkat kelangsungan hidup pasca uji stres salinitas dan uji tantang bakteri yang lebih baik (P<0,05) dibandingkan pada perlakuan kontrol.
Keyword: bioflok, ikan lele, kualitas benih, produksi

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