Judul: Eksplorasi Potensi Bakteri Aktinomiset dan Kaitannya dengan Kondisi Lingkungan Sedimen di Ekosistem Lamun Pulau Pari.
Abstrak: Bakteri aktinomiset menyumbang 50% senyawa antibiotik yang ada hingga saat ini. Tujuan penelitian ini mengeksplorasi potensi metabolit sekunder yang dimiliki bakteri aktinomiset dan kaitannya dengan kondisi lingkungan sedimen di ekosistem lamun Pulau Pari, Kepulauan Seribu. Isolat aktinomiset diisolasi dan diremajakan menggunakan media ISP 2, dan didapatkan 5 isolat. Uji antibakteri menunjukkan hanya satu isolat (B22b) yang memiliki aktivitas antibakteri terhadap seluruh bakteri uji (Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, dan Staphylococcus aureus), dan diduga termasuk senyawa antibakteri spektrum luas. Aktivitas selulase hanya dimiliki oleh 4 isolat aktinomiset. Analisis sidik ragam (ANOVA) menunjukkan bahwa kerapatan jenis lamun Enhalus acoroides dan Thalassia hemprichii berpengaruh nyata terhadap aktivitas selulase. Aktivitas ini berhubungan dengan peran aktinomiset sebagai dekomposer di ekosistem. Karakteristik kimia sedimen dapat dipengaruhi oleh proses dekomposisi selulosa oleh aktinomiset.
Keyword: aktinomiset, aktivitas antibakteri, aktivitas selulase, kerapatan jenis lamun

Judul: Potensi Bakteri Endofit Lamun Enhalus acoroides sebagai Penghasil Senyawa Antibakteri dari Perairan Pulau Tidung, Kepulauan Seribu
Abstrak: Lamun Enhalus acoroides telah banyak diteliti memiliki kandungan senyawa aktif yang dapat diaplikasikan sebagai antibakteri dan antioksidan serta antifouling. Isolasi mikroorganisme endofit merupakan salah satu cara dalam memperoleh senyawa bioaktif pada tanaman lamun. Hasil isolasi bakteri endofit lamun menggunakan media Zobell 2216E diperoleh 19 isolat. Pengujian antagonis dengan metode difusi agar (double layer) terhadap bakteri patogen dan pembentuk biofilm didapatkan 17 isolat berpotensi. Pengujian tersebut menghasilkan 3 isolat potensial yang selanjutnya dilakukan ekstraksi metabolit sekunder bakteri menggunakan pelarut metanol dan etanol dengan konsentrasi 20 mg/ml. Pengujian ekstrak metabolit sekunder bakteri menggunakan pelarut metanol didapatkan satu isolat berpotensi sedangkan pelarut etanol didapatkan tiga isolat berpotensi. Kemampuan penghambatan ekstrak metabolit sekunder bakteri terhadap bakteri target memiliki aktivitas yang tergolong lemah. Identifikasi terhadap tiga isolat potensial tersebut menunjukkan kecocokan dengan genus Salinicoccus dan Moraxella.
Keyword: antagonisme, antibakteri, bakteri endofit lamun, ekstraksi, fisiologis

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
Keyword: