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TIDAL HARMONIC ANALYSIS AND PREDICTION TO SUPPORT EARLY WARNING FOR COASTAL FLOODING
Full text linkThe Indonesian Maritime Continent (IMC) is the largest archipelago that vulnerable to climate change especially sea level rise. Some coastal areas frequently experience coastal flooding affecting the activities and infrastructures. Thus, an accurate tide prediction in this region plays a pivotal role in providing the early warning, mitigation, and adaptation to frequent coastal flooding. BMKG, through the Center for Marine Meteorology has done undertaken efforts to provide an accurate tidal prediction information by developing the tidal information system call the Indonesian Tidal Information System (INATIS). Tidal harmonic analysis (THA) using the least-square method was applied to sea level data from 49 Marine Automatic Weather System (MAWS) stations collected between 2020-2021 to generate tidal predictions for the period of 2022-2023. Accuracy was assessed based on Mean Absolute Error (MAE) and the Mean Absolute Percentage Error (MAPE). MAWS stations with prediction accuracy above 80% visualized on publicly accessible online platform of the BMKG website using the open-source Looker Studio. Verification of the tidal predictions showed an average prediction accuracy of 93.21% with a MAE of 0.11 m. The high accuracy of INATIS demonstrates its potential as a reference for coastal flood early warning systems
POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) IN INDRAMAYU COASTAL, WEST JAVA: DISTRIBUTION, SOURCE, AND ECOLOGICAL RISK ASSESSMENT
Full text linkPAH pollutants from anthropogenic activities were released into Indramayu Coast and could potentially have negative effects on the environment. This study aimed to determine the distribution, source, and ecological risks of PAHs in the area. Seawater and sediment samples were collected and stored in glass bottles at 4 °C and then further processed in the laboratory. The samples were extracted with dichloromethane and n-hexane and then fractionated using a silica gel column, and finally injected into a Gas Chromatography-Mass Spectrometer (GCMS). The distribution of PAH compounds was detected in all sampling stations in varying amounts. PAH with low molecular weight (two to three rings) was predominant in seawater samples, while high molecular weight (four rings) was predominant in sediments. In addition, by using the molecular diagnostic ratio, the PAH source in Indramayu Coast was detected to be pyrogenic and petrogenic processes that come from anthropogenic activities. Exposure to PAH concentrations in this study posed a lower risk to sediment-dwelling organisms. However, further awareness and periodic monitoring are required to detect carcinogenic PAHs
PENGARUH INTRUSI AIR LAUT DAN HUBUNGANNYA TERHADAP TUTUPAN LAHAN TERBANGUN DI KECAMATAN PASAR MANNA DAN SEKITARNYA, KOTA MANNA, PROVINSI BENGKULU
Full text linkPerubahan penggunaan lahan pada daerah pesisir akibat adanya peningkatan aktivitas manusia yang meningkat dalam beberapa dekade terakhir menyebabkan pencemaran air tanah. Intrusi air laut merupakan salah satu bentuk pencemaran air tanah yang diakibatkan oleh masuknya air laut di bawah permukaan tanah melalui akuifer. Peningkatan jumlah bangunan berupa rumah masyarakat akan menyebabkan over-pumping sehingga muka air tanah menurun dan menyebabkan air laut masuk kedalam air tanah. Penelitian dilakukan di daerah pesisir Pantai Pasar Bawah, Kecamatan Pasar Bawah, Kota Manna. Tujuan dari penelitian mengidentifikasi pengaruh aktivitas antropogenik khususnya tutupan lahan terbangun terhadap intrusi air laut. Data yang digunakan adalah data primer berupa sampel air sumur yang kemudian dianalisis untuk mendapatkan nilai salinitas, DHL (daya hantar listrik), dan TDS (Total dissolved solids) serta data sekunder berupa data citra satelit yaitu Landsat 8 OLI/TIRS yang diekstraksi untuk mengetahui nilai tutupan lahan terbangun dengan menggunakan indeks Normalized Difference Built-Up Index (NDBI). Hasil penelitian menunjukkan pada daerah dengan indeks tutupan lahan terbangun tinggi akan berpengaruh terhadap peningkatan nilai salinitas, DHL (daya hantar listrik), dan TDS (Total dissolved solids). Berdasarkan hasil analisis titik pengamatan 9 yang berada di area indeks tutupan lahan terbangun tinggi memiliki tingkat salinitas tertinggi yaitu 42.6 ppm, begitupun dengan nilai DHL yaitu 281μS/cm dan nilai TDS dengan nilai 100,1 mg/l. Sebaliknya pada daerah penelitian 5 yang berada di indeks tutupan lahan terbangun rendah memiliki nilai salinitas terendah yaitu 17.3 ppm, begitupun dengan nilai DHL yaitu 115 μS/cm dan nilai TDS dengan nilai 45 mg/l
ZOOPLANKTON DISTRIBUTION FROM BACKSCATTER DATA OF ADCP INSTRUMENT IN WEST SUMATRA WATERS
Full text linkAcoustic Doppler Current Profiler (ADCP) conventionally used to monitor ocean current profiles and potentially detect zooplankton distribution remains largely unexplored. Zooplankton are key consumers in the marine food chain, therefore understanding their distribution is critical. This study aims to map the distribution of zooplankton in West Sumatra waters using ADCP backscatter data. Data analyzed encompass ocean current measurements, backscatter, and conductivity-temperature-depth (CTD) profiles collected from March 1 to 3, 2017. Raw ADCP digital counts were converted into mean volume backscattering strength (MVBS) in dB using sonar equations, proportional to zooplankton biomass. The conversion process involved corrections for sound attenuation due to distance and water absorption, ADCP transducer angle correction, and noise correction. Processing results revealed zooplankton distribution in raw ADCP data ranging from 20 to 160 counts and in MVBS data spanning -140 dB to -40 dB. MVBS values derived from ADCP acoustic signal processing were filtered within the -100 dB to -60 dB range, representing the zooplankton backscatter range. Zooplankton distribution was observed at depths of 0-300 m. Vertical zooplankton distribution was generally high in the 100-200 m layer and decreased at 0-100 m and 200-300 m. This is attributed to the influence of the Equatorial Undercurrent transporting zooplankton biomass from the Indian Ocean to West Sumatra waters at depths of 100-200 m, characterized by high salinity (34.6-35.2 PSU) and cold temperatures (19°-21°C). This study demonstrates the utility of ADCP in observing zooplankton distribution based on their backscatter values and the influence of ocean currents in transporting zooplankton biomass
KARAKTERISTIK ARUS LAUT JAWA PADA MUSIM BARAT DI BEBERAPA KEDALAMAN
Full text linkArus laut merupakan pergerakan massa air secara horizontal yang dapat disebabkan oleh beberapa faktor seperti tiupan angin, perbedaan densitas maupun pasang surut laut. Arus laut merupakan parameter hidro-oseanografi yang dinamis dan mempunyai peran penting dalam transpor nutrien, larva, material, dan lain sebagainya. Tujuan penelitian ini untuk mengetahui karakteristik arus Laut Jawa di beberapa kedalaman. Metode penelitian adalah metode kuantitatif berupa analisis data dan deskriptif. Data yang digunakan diperoleh dari pengukuran arus mengunakan alat Vessel Mounted ADCP (Acoustic Doppler Current Profiler) yang dilakukan pada bulan Desember 2019 dengan menggunakan kapal riset Pusat Riset Oseanografi-Badan Riset dan Inovasi Nasional. Dari hasil pengolahan dan analisa data diperoleh di Laut Jawa kecepatan arus minimal rata-rata nya adalah 0,003 m/s sedangkan kecepatan arus maksimal rata-rata nya adalah 0,393 m/s. Kecepatan arus ter lambat adalah 0.001 m/s terjadi pada kedalaman 30 m sedangkan kecepatan arus tercepat adalah 0,410 m/s terjadi pada kedalaman 35 m. Secara umum arah arus yang terjadi di Laut Jawa pada monsun barat adalah menuju timur laut
SEDIMENT CHARACTERISTICS TO SUPPORT THE REVITALIZATION OF TPPI TUBAN PORT, EAST JAVA, INDONESIA
Full text linkTPPI Tuban Port is located in Tuban Regency, East Java. Geologically, the rocks are composed of reef limestone in the Paciran Formation, which is Pliocene–Early Pleistocene. The importance of complying with jetty capacity standards and water conditions in commercial ports is emphasized as the key to maintaining smooth port operations, making port revitalization a necessity. One of the main aspects to consider is the sedimentation problem, closely related to sediment characteristics. A deep understanding of sediment dynamics is essential for designing effective solutions to ensure the sustainability of port operations. This research aims to determine the distribution pattern of bed load characteristics such as water content, specific gravity, gradation, sediment texture, d50 size of sediment grains, and statistical analysis of bed load sediment in the west and rainy seasons, where the influence of sediment from land is very large. so it is hoped that it can support the port revitalization plan. The methods used include taking sediment samples in the field, testing sediment samples in the laboratory, statistical sediment analysis, and descriptive analysis of bed load characteristics using the Gradistat method. Based on the study results, the water content value ranges from 22.446% to 218.289%, and the specific gravity ranges from 2,100 g/m³ to 2.690 g/cm³. Additionally, the grain size varies from 0.080 mm to 0.900 mm, and the average grain size ranges from 261.1 μm to 2657.5 μm. Sediment sorting is dominated by very poorly sorted materials, with statistical analysis indicating a dominance of the very platykurtic type. The lithological type is predominantly sand
STUDY OF HEAVY METAL LEAD (PB) CONTENT IN THE CORAL REEF ENVIRONMENT OF PANJANG ISLAND, BANTEN
Full text linkRapid industrial expansion in Banten has triggered a surge in pollution, impacting areas like Panjang Island in Banten Bay. Pollution on Panjang Island stems primarily from industrial operations and shipping activities. This study investigates the distribution of lead (Pb) metal concentrations in Panjang Island's coral reef environment, focusing on sediment and surface water. It also examines how seasonal variations, influenced by ocean currents, affect Pb concentration distribution. Data were gathered using purposive sampling, collecting sediment samples, surface water samples, and oceanographic data. Pb levels in both sediments and surface water underwent analysis at the National Research and Innovation Agency (BRIN) laboratory, employing atomic absorption spectrophotometry (AAS). Our findings indicate that during the transitional II season, Pb concentrations in sediment ranged from 4.2 to 17 mg/kg, while the westerly season showed Pb concentrations spanning 3.8 to 23.4 mg/kg. Surface water during these seasons exhibited Pb concentrations varying from 0 to 0.03 mg/l. Notably, at several monitoring stations, surface water Pb concentrations exceeded the threshold set by Regulation No. 22 of 2021, suggesting potential harm to the coral reef ecosystem surrounding Panjang Island. Elevated Pb concentrations were observed during the transitional II season in the island's western part and the westerly season in the eastern part. These disparities appear to be influenced by the direction of ocean currents, highlighting their role in shaping Pb distribution in Panjang Island's waters