Judul: Aktivitas Aktual Bakteri Nitrifikasi pada Sistem Resirkulasi Budidaya Kepiting Bakau Scylla serrata dengan Warna Dinding Wadah yang Berbeda.
Abstrak: Perbaikan kualitas air dalam kegiatan akuakultur dapat dilakukan dengan bakteri nitrifikasi. Nitrifikasi merupakan proses oksidasi senyawa amonium menjadi nitrit dan nitrat. Penelitian ini bertujuan untuk menentukan warna dinding wadah terbaik dalam perbaikan kualitas air melalui aktivitas bakteri nitrifikasi pada media budidaya kepiting bakau Scylla serrata menggunakan sistem resirkulasi. Kepiting bakau dengan bobot 52.6±7.2 g dipelihara pada wadah berukuran (60×40×40) cm selama 45 hari dengan tingkat pemberian pakan 5 % per hari sebanyak dua kali sehari. Penelitian dilakukan dengan dua perlakuan dan tiga ulangan, yaitu dinding wadah berwarna gelap (intensitas cahaya 40-100 lux) dan dinding wadah berwarna terang (310-380 lux). Hasil penelitian menunjukkan bahwa kinerja produksi kepiting bakau terbaik terdapat pada perlakuan wadah gelap, yaitu tingkat kelangsungan hidup 30.00±6.00 % dan laju pertumbuhan spesifik 0.44±0.02 % per hari. Kinerja bakteri nitrifikasi terbaik terdapat pada wadah terang, yaitu kelimpahan bakteri 4.40±0.14 (107 CFU mL-1) pada hari ke-0, 4.92±0.18 (107 CFU mL-1) pada hari ke-21, dan 5.44±0.18 (107 CFU mL-1) pada hari ke-42, aktivitas oksidasi amonium 89.51-98.81 % dengan aktivitas pembentukan nitrit 50.85-87.20 %, serta aktivitas pengurangan nitrat sebesar 6.40-47.31 %. Jenis bakteri nitrifikasi didominasi oleh kelompok bakteri Pseudomonas sp. 12 isolat, Bacillus sp. 6 isolat, dan Acinetobacter sp. 6 isolat. Hasil dari penelitian ini menunjukkan bahwa dinding wadah terang dengan intensitas cahaya 310-380 lux dapat digunakan untuk perbaikan kualitas air melalui kinerja bakteri nitrifikasi.
Keyword: aktivitas bakteri, identifikasi bakteri, kualitas air, nitrifikasi, Scylla serrata

Judul: Profil Respon Fisiologis dan Kinerja Produksi Kepiting Bakau Scylla serrata pada Wadah Terang – Gelap dalam Sistem Resirkulasi
Abstrak: Kepiting bakau Scylla serrata merupakan salah satu komoditas budidaya yang menjadi ciri khas umum Indonesia, dan memiliki permintaan yang tinggi. Teknik manipulasi lingkungan dapat dilakukan untuk kenyamanan kepiting dari intensitas cahaya yang berlebih maupun gangguan dari luar yang akan mempengaruhi kelangsungan hidup dan pertumbuhan kepiting bakau. Kepiting Bakau berasal dari nelayan Pasuruan Jawa Timur berukuran bobot awal 46,6 + 1,1 g yang dipelihara didalam wadah box berukuran (60×40×30 cm3) dalam sistem resirkulasi selama 42 hari dengan pemberian pakan ikan rucah secara restricted 5% sebanyak dua kali sehari. Penelitian ini bertujuan untuk menganalisa sintasan profil respon stress dan pertumbuhan yang terbaik dalam pemeliharaan benih kepiting bakau Scylla serrata dalam wadah gelap dan terang dengan sistem resirkulasi. Penelitian dilakukan dengan 2 perlakuan dan 3 ulangan yaitu: wadah terang (A) dan wadah gelap (B). Hasil penelitian menunjukan wadah gelap merupakan kondisi wadah optimum untuk benih Kepiting Bakau ditunjukkan oleh kelangsungan hidup tertinggi yaitu 30±6%, laju pertumbuhan spesifik yaitu 0.44±0.02%/hari, kadar sel hemosit 2,47±0.04%, kada glukosa darah 41.76±0.11, dan rasio konversi pakan 6.38±0.27
Keyword: biomassa, kepiting bakau, tingkat konsumsi oksigen, total perhitungan sel hemosit

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