Abstract. This paper presents an analytical study on surface wave attenuation in mangrove forest using analytical model developed by Massel et.al. (1999). The energy dissipation in the frequency domain is determined by treating the mangrove forest as a random media with certain characteristics using the geometry of mangrove trunks and their locations. Initial nonlinear governing equations are linearized using the concept of minimalization in the stochastic sense and interactions between mangrove trunks and roots have been introduced through the modification of the drag coefficients. To see the effectiveness of the mangrove forest in attenuating wave energy the analytical model was applied to two types of mangrove forest i.e. Rhizophora and Ceriops forests. The resulting rate of wave energy attenuation depends strongly on the density of the mangrove forest, and on diameter of mangrove roots and trunks. More effective wave energy attenuation is shown by Rhizophora.

Earthworms as ecosystem engineers can modify the quality of vermibed assembled from mixed soil with organic material in a vermireactor. Various in shapes of the vermireactor are used to produce a vermicast for biofertilizer in agriculture. The objective of this research was to study the vermicast production and its quality produced from a variety of vermireactor shapes. Earthworm (Pheretima sp.) which was applied to the vermireactor consists of: with- and without of earthworms. Three shapes of the vermireactor, namely cylinder, square, and rectangular has been tested. Compost of Chromolaena odorata pruning mixed with soil was used as vermibed. The vermicast process ran until 28 days. The results showed that vermireactor with earthworms which were successfully converted to vermicast was about 49.24% from the vermibed volume, however, no vermicast formed was found from vermireactor without earthworms. The difference in vermicast produced from different vermireactor shapes was not significant. The value of pH, total-N, and C/N ratio among the vermicast was different. The number of the morphological character of bacteria colonies in the vermicast produced from the square vermireactor was the highest, while from cylinder vermireactor was the lowest. We concluded that the quality of vermicast from earthworm (Pheretima sp.) activity was determined by the shape of the vermireactor.

Teluk Kendari merupakan urat nadi perekonomian penting di Kota Kendari. Sedimentasi menjadi isu utama yang dapat mempengaruhi luasan Teluk Kendari termasuk aktivitas yang berlangsung di kawasan tersebut. Sedimentasi yang tinggi dapat ditunjukkan dari tingginya nilai Total Suspended Solid (TSS) di suatu perairan, sehingga perlu dilakukan pemantauan TSS secara periodik di Teluk Kendari untuk mendukung upaya penanganan sedimentasi. Penelitian ini bertujuan untuk mengetahui algoritma penduga materi TSS pada citra Sentinel-2 yang paling tepat untuk diterapkan untuk pemantauan TSS di Teluk Kendari. Algoritma penduga TSS yang digunakan dalam penelitian ini meliputi algoritma Laili (2015), Parwati (2014), Guzman & Santaella (2009), Liu (2017) dan algoritma yang dihasilkan dari persamaan regresi linier.  Evaluasi algoritma dilakukan dengan membandingkan hasil pengukuran TSS in situ menggunakan metode gravimetri dengan hasil ekstraksi TSS dari citra Sentinel-2. Hasil evaluasi menunjukkan bahwa algoritma terbaik untuk menduga TSS pada citra Sentinel-2 di Teluk Kendari adalah algoritma regresi linier. Algoritma regresi linier diperoleh dari korelasi terbaik antara reflektansi citra Sentinel-2 dengan hasil pengukuran TSS in situ. Hasil analisis menunjukkan bahwa TSS di Teluk Kendari berkorelasi baik dengan band 4 sebagai band merah pada citra Sentinel-2. Persamaan regresi linier yang diperoleh yaitu TSS=10707(band 4)+646,3. Hasil evaluasi pendugaan konsentrasi TSS dengan menggunakan algoritma regresi linier memenuhi syarat NMAE dan R2 dengan nilai masing-masing 11,09% dan 0.58.

Penelitian ini terletak di Kabupaten Muna Provinsi Sulawesi Tenggara. Kabupaten Muna merupakan daratan karst yang berkembang cukup baik terutama di bagian timur pulau Muna. Morfologi karst yang tersusun atas batugamping memiliki daya tarik tersendiri baik di bidang pertambangan maupun bidang pariwisata. Pemanfaatan batugamping dalam industri pertambangan memberikan ancaman kerusakan Kawasan karst secara langsung. Oleh sebab itu pemahaman Kawasan Karst sebagai salah satu aset pengembangan geowisata dan pelestarian lingkungan menjadi hal yang mesti diperhatikan. Analisis terhadap keragaman morfologi dan potensi  geowisata menjadi hal yang sangat penting dalam menjawab hal tersebut. Penelitian ini bertujuan untuk melakukan analisis terhadap morfologi yang berkembang dan berpotensi untuk dikembangkan sebagai geowisata. Metode yang digunakan berupa observasi lapangan dan deskripsi kualitatif terhadap jenis litologi batuan dan jenis morfologinya. Jenis batuan yang ditemukan di lapangan yaitu batugamping Packstone, Weckestone dan Crystalline. Morfologi yang berkembang antara lain cliff, notch, sactk, stump, hasil endapan organisme, natural arch, danau air asin, gua, dan perbukitan bergelombang. Beberapa morfologi tersebut telah dikembangkan sebagai lokasi geowisata, tetapi masih banyak lokasi lain yang berpotensi untuk terus dikembangkan. Keberagaman morfologi karst dan unik yang terdapat di Pulau Muna memiliki potensi yang cukup besar untuk dikembangkan sebagai bagian dari geowisata Sulawesi tenggara.

This research aims to examine the relationship between hydrothermal alteration and mineralization (ore mineralogy) in the study area and geological structures in the deformation mechanism. The hydrothermal alteration was determined based on petrographic analysis, and ore mineralogy which was determined based on the ore microscopic analysis. The deformation mechanism is determined by paleo stress analysis using win-tensor, and the direction of principal stress on joints/veins and faults is calculated by the right-dihedron method. Hydrothermal alteration includes silicification, argillic, propylitic, and phyllic alterations; and ore mineralogy consists of stibnite, cinnabar, pyrite, chalcopyrite, sphalerite, covellite, hematite, and arsenopyrite at metamorphic rocks. The geological structure developed in the study area consists of shear fractures and Wumbubangka right Normal-slip Fault, which is accompanied by Wumbubangka right-slip lag fault and Wumbubangka reverse-slip fault formed in a simple shear mechanism. Crenulation, micro-folds, and porphyroblastic are also recognized in thin sections. The Wumbubangka right normal-slip fault, considered a syn-mineralization structure, formed the transpressional and transtensional geologic structures, forming the quartz vein parallel to and crosscutting the foliation. The correlation between surface geological structures and microstructures indicates that tectonic regimes have controlled the alteration and gold mineralization in the study area.