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PARTISI KIMIAWI Cu DAN Fe PADA SEDIMEN PERMUKAAN DI PESISIR TIMUR DAN BARAT SUMATRA UTARA Dewy Septiyanti Yolanda; Tri Prartono; Alan Frendy Koropitan; Mohammad Tri Hartanto; Lestari; Muhamad Riza Kurnia Lubis
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 11 No. 2 (2019): Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Mobilitas (termasuk proses desorpsi-absorpsi) logam berat dalam sedimen bervariasi yang bergantung pada asosiasinya pada komponen mineral dan non-mineral sedimen yang dapat juga mengindikasikan pada sumber alami dan non-alami. Penelitian ini bertujuan mengungkap kemungkinan sumber logam berat Cu dan Fe berdasarkan fraksinasi dan total logam. Lokasi penelitian terdiri dari 11 titik yang terbagi menjadi tiga bagian pesisir timur, pesisir barat, dan Pulau Nias, Sumatera Utara. Fraksi geokimia diperoleh berdasarkan prosedur ektraksi bertingkat SEP BCR (Sequential Extraction Process Bureau Commune de Reference of the European Commission) dalam empat fase yaitu: Fraksi terlarutkan asam, fraksi tereduksi, fraksi oksidasi, dan fraksi residual. Total logam diperoleh berdasarkan metode USEPA 3050B. Pengukuran logam dilakukan dengan menggunakan spektrofotometri serapan atom (SSA). Hasil penelitian menunjukkan bahwa kegiatan antropogenik diduga menyumbang logam Fe dalam sedimen yang ditunjukkan oleh konsentrasi non residu (5,55-203,15 mg/kg) yang lebih tinggi dibandingkan fraksi residu (4,89-21,47 mg/kg). Berbanding terbalik dengan logam Cu yang asosiasi tertinggi adalah fraksi residu (2,24-8,85 mg/kg). Logam berat dalam sedimen mendapat kontribusi dari sumber alami dan antropogenik, logam Cu diduga bersumber lebih banyak secara alami dan logam Fe diduga bersumber lebih dominan dari aktifitas manusia (antropogenik) baik sekitar wilayah pesisir maupun kemungkinan berasal dari daratan.

LAJU AKUMULASI SEDIMEN MANGROVE DI TANJUNG BATU, KEPULAUAN DERAWAN KALIMANTAN TIMUR Intan Sari Dewi; Tri Prartono; Ali Arman; Alan Frendy Koropitan
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 12 No. 2 (2020): Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jitkt.v12i2.28427

Keberlangsungan ekosistem mangrove merupakan aspek penting karena berkaitan dengan pengurangan atau penambahan akumulasi sedimen seperti proses abrasi dan akresi. Mangrove di pesisir Tanjung Batu telah mengalami penurunan sejak 2001-2010 yang disebabkan oleh aktivitas masyarakat seperti penebangan pohon, pembukaan lahan untuk tambak dan perkebunan kelapa sawit. Penelitian ini bertujuan mengestimasi laju akumulasi sedimen mangrove di Tanjung Batu. Penelitian dilakukan pada bulan Februari-Juli 2018. Pengambilan sampel dilakukan pada 3 stasiun meliputi identifikasi jenis mangrove, pengukuran Diameter at Breast Height (DBH) mangrove dan pengambilan sedimen corring menggunakan pipa stainless. Sampel sedimen dipotong berdasarkan interval 5 cm (kedalaman 0-15 cm), dan interval 2 cm (kedalaman 48-50 cm) yang digunakan sebagai Pb-210 supported (Stasiun 1 dan 3). Stasiun 5 dipotong dengan interval 4, 6 dan 8 cm (kedalaman 1-50 cm). Analisis sampel menggunakan alpha spektrometer dengan radioisotop Pb-210. Penentuan umur sedimen dan laju akumulasi sedimen menggunakan model Constant Rates of Supply (CRS). Hasil menunjukkan bahwa laju akumulasi sedimen selama 20 tahun terakhir (1998-2018) berkisar 0,09-0,20 g cm-2 tahun-1. Laju akumulasi tertinggi adalah Stasiun 1 yang merupakan lokasi dengan umur sedimen paling tua dan didominasi mangrove dengan DBH > 5 cm, sedangkan laju akumulasi terendah adalah Stasiun 5 yang memiliki umur sedimen paling muda dan didominasi mangrove dengan DBH < 5 cm.

Percampuran Turbulen Di Tenggara Samudera Hindia Saat Siklon Tropis Marcus Menggunakan Data ARGO Float Muhammad Hafidz Ibnu Khaldun; Yuli Naulita; Alan Frendy Koropitan
Journal of Marine and Aquatic Sciences Vol 6 No 2 (2020)
Publisher : Fakultas Kelautan dan Perikanan Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/jmas.2020.v06.i02.p17

Tropical cyclones are a phenomenon that occurs because of the interaction between oceans and atmospheric circulation. The southeastern Indian Ocean is one of the areas that has a high activity of tropical cyclones. Tropical cyclones that cross waters can result in mixing of water masses. The mixing process produces water mass entrainment between lower and upper layers which decreases temperature in the upper layer. The purpose of this study was to estimate the strength of turbulent mixing caused by tropical cyclones using Argo Float data. The result of this study shows the turbulent mixing caused by tropical cyclones was very strong in the surface layer. Turbulent mixing is not found before the cyclone and increases when the cyclone occurs. The increase in turbulent mixing was recorded at a depth of 50 m which had an energy dissipation value ranging from 6.86x10-8 - 1.93x10-4 W/Kg and a turbulent mixing value with a range of 1.0x10-3 - 2.51x10-1 m2 s-1. This study concluded that the turbulent mixing in the surface layer is caused by tropical cyclones which is the main factor triggering the increase in the dissipation of kinetic and turbulent energy at the sites.

Pemodelan Pola Arus dan Sebaran Konsentrasi Tembaga (Cu) Terlarut di Teluk Jakarta Harpasis S Sanusi; Alan F Koropitan; Haeruddin Haeruddin; Andis K Nugraha
ILMU KELAUTAN: Indonesian Journal of Marine Sciences Vol 10, No 3 (2005): Jurnal Ilmu Kelautan
Publisher : Marine Science Department Diponegoro University

Penelitian ini dilakukan untuk mempelajari pola arus dan sebaran konsentrasi logam berat tembaga (Cu) terlarut di Teluk Jakarta, DKI Jakarta, dengan menggunakan model gabungan hidrodinamika-transpor konsentrasi Cu terlarut. Solusi numerik yang digunakan dalam penelitian ini adalah pendekatan numerik beda hingga eksplisit Upstream. Hasil verifikasi menunjukkan kemiripan antara hasil model dengan data lapangan. Secara umum, saat pasang arus pasut masuk ke dalam teluk dari mulut teluk bagian timur menuju daerah pantai teluk Jakartadan akhirnya keluar melalui mulut teluk bagian barat. Demikian sebaliknya saat surut arus pasut masuk ke dalam teluk dari mulut teluk bagian barat dan keluar melalui mulut teluk bagian timur. Simulasi dengan pengaruh angin menunjukkan pola yang sama dengan arus pasut saja. Pola sebaran konsentrasi Cu terlarut umumnya mengikuti pola arus yang ada, dengan degradasi penurunan konsentrasi terlihat tinggi pada dekat sumber (muara-muara sungai) kemudian menurun dengan semakin jauhnya dari sumber. Hal ini menunjukkan bahwa peranan adveksi sangat dominan dalam menyebarkan suatu material di suatu perairan.Kata kunci: Teluk Jakarta, model gabungan hidrodinamika-transpor konsentrasi Cu terlarutThis research was done to study flow pattern and heavy metal distribution of dissolved Cu concentration in Jakarta Bay, DKI Jakarta, by using a coupled hydrodynamic-dissolved Cu concentration transport model. Thecoupled model has been solved numerically, which is explicit finite difference of Upstream. Model verification showed a good agreement between model results and field observation. Generally, tidal current inflows from eastern part of mouth-bay and outflows to western part of mouth-bay during flood tide. Reversely, the tidal current inflows from western part of mouth-bay and outflows to eastern part of mouth-bay during ebb tide. The water current still has a similar pattern for wind influence in the simulation. Distribution pattern of dissolved Cu concentration mainly follows the flow pattern, with concentration degradation showed high near source area (mouth of rivers) and decrease as far from the sources. Therefore, the role of advection is more dominant in material distribution in the waters.Key words: Jakarta Bay, coupled hydrodynamic-dissolved Cu concentration transport model

Primary Productivity of Jakarta Bay in A Changing Environment: Climate Change and Anthropogenic Impacts Vincentius Siregar; Alan F. Koropitan
BIOTROPIA - The Southeast Asian Journal of Tropical Biology Vol. 20 No. 2 (2013)
Publisher : SEAMEO BIOTROP

Jakarta Bay receives direct impact from the rapid development of infrastructure and landbased industries which contributed to the increase in pollution and nutrient, and at the same time facing climate change. This condition influenced growth of chlorophyll- and primary production. To investigate changes of primary production in Jakarta Bay due to anthropogenic and climate change impacts, a field measurement, laboratory experiment and collection of several data sets have been conducted. The study showed that impact of anthropogenic, particularly sediment load from the land to primary production is important. The intensification of primary production occurs in the middle region of Jakarta Bay, while the chlorophyllconcentration is high in the river mouth area. The anthropogenic impact is indicated by the land use change that has increased to 73% during the last ten years. The laboratory experiments by injecting CO in the waters, as a global warming simulation, have shown a decrease in chlorophyll- and primary production. Therefore, the combination of anthropogenic and climate changemay have a double impact on the Jakarta Bay ecosystem.Key words: Primary production, Jakarta Bay, anthropogenic, climate change, impact

THREE-DIMENSIONAL SIMULATION OF TIDAL CURRENT IN LAMPUNG BAY: DIAGNOSTIC NUMERICAL EXPERIMENTS Alan Frendy Koropitan; Safwan Hadi; Ivonne M.Radjawane
International Journal of Remote Sensing and Earth Sciences (IJReSES) Vol 3,(2006)
Publisher : National Institute of Aeronautics and Space of Indonesia (LAPAN)

Princeton Ocean Model (POM) was used to calculate the tidal current in Lampung Bay using diagnostic mode. The model was forced by tidal elevation, which was given along the open boundary using a global ocean tide model-ORITIDE. The computed tidal elevation at St. 1 and St 2 are in a good agreement with the observed data, but the computed tidal current at St 1 at depth 2 m is not good and moderate approximation is showed at depth 10 m. Probably, it was influenced by non-linier effect of coastal geometry and bottom friction because of the position of current meter, mooring closed to the coastline. Generally, the calculated tidal currents in all layers show that the water flows into the bay during flood tide and goes out from the bay during ebb tide. The tidal current becomes strong when passing through the narrow passage of Pahawang Strait. The simulation of residual tidal current with particular emphasis on predominant contituent of M2 shows a strong inflow from the western part of the bay mouth, up to the central part of the bay, then the strong residual current deflects to the southeast and flows out from the eastern part of the bay mouth. This flow pattern is apparent in the upper and lower layer. The other part flows to the bay head and froms an antic lockwise circulation in the small basin region of the bay head. The anticlockwise circulations are showed in the upper layer and disappear in the layer near the bottom. Keywords: POM, diagnostic mode, tidal current, residual current, Lampung Ba.

NUMERICAL CALCULATION FOR THE RESIDUAL TIDAL CURRENT IN BENOA BAY-BALI ISLAND GEDE HENDRAWAN; I WAYAN NUARSA; WAYAN SANDI; - A.F. KOROPITAN; YASUHIRO SUGIMORI
International Journal of Remote Sensing and Earth Sciences (IJReSES) Vol 2(2005)
Publisher : National Institute of Aeronautics and Space of Indonesia (LAPAN)

Princeton Ocean Model (POM) was used to calculate the tidal current and M2-residual current in Benoa Bay using barotropic model (mode 2). The model was forced by tidal elevation, which was given along the open boundary condition using tide data prediction from Hydro-Oceanography Division-Indonesian Navy (DISHIDROS TNI-AL). The computed tidal current and residual current have been compared with both data in Benoa Bay, that are data of the open boundary of Benoa Bay and condition of Benoa Bay after developed a port and reclamation of Serangan Island. The maximum velocity of tidal current for open boundary conditions at flood tide is 0.71 m/sec, whereas at ebb tide is 0.65 m/sec and the maximum velocity after developed a port and reclamation of Serangan Island, at flood tide, is 0.69 m/sec. The simulation of residual current with particular emphasis on predominant constituent of M2 after developed a port and reclamation of Serangan Island shows a strong flow at the western part of Tanjung Benoa and Benoa Harbor and also at bay mouth between Serangan Island and Tanjung Benoa. Maximum velocity of M2-residual current is 0.0585 m/sec by the simulation and showed that the current which was produced forming two eddies in the bay of which one eddy is in the mouth of bay in southern part. The residual current for open boundary condition of bay shows four eddies circulation, one big eddies and the others small. The anticlockwise circulation occurs in the inner part of the bay. Key words: model, simulation, tidal current, residual current

Study of Heavy Metal Distribution and Hydrodynamic Simulation in Green Mussel Culture Net, Cilincing Water-Jakarta Bay Koropitan, Alan Frendy; Cordova, Muhammad Reza
Makara Journal of Science Vol. 21, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

This study aimed to investigate the heavy metals distribution inthesurrounding area of green mussel culture net,Cilincing water, Jakarta Bay,and its distribution behavior. The water sampling was carried out during the ebb tide. The heavy metal concentration was then measured by using atomic absorption spectroscopy (AAS). In order to understand the water circulation behavior related to heavy metal distribution in the study area, thePrinceton Ocean Model was applied, and the model design was developed based ona scenario ofanopen canal in theeastern and western sides, while the center canal wasplaced withnet cages in the water column resembling the green mussel culture net. The observed heavy metal distribution showed an intensified concentration in the green mussel culture location. The observed water current also showed a reduced velocity in the location. The modeling approach could explain the water circulation behavior in response to the presence of net units in the water column. In this case, the density of net units for green mussel culture potentially produced shear stress in the water column, which affected the flow pattern and the distribution of heavy metals. Therefore, the existence of green mussel culture nets has a potential to become a trap for pollutant distribution in the water.

Pemodelan hidrodinamika arus pasang surut Teluk Mayalibit Kabupaten Raja Ampat Provinsi Papua Barat Asep Sandra Budiman; Alan F. Koropitan; I Wayan Nurjaya
Depik Vol 3, No 2 (2014): August 2014
Publisher : Faculty of Marine and Fisheries, Universitas Syiah Kuala

Abstract. Mayalibit Bay has an unique topography due to it has only one way long canal , narrow, and devious that connecting to open sea. Study on the water mass dynamics concerning to elevation and tidal current in Mayalibit Bay was conducted by constructing the 2D numerical hydrodynamics model which was simulated for 30 days to describe the pattern of elevation and water current which was resulted from tidal processes. The 2D hydrodynamic equation was employed by finite difference methods. Validation result showed that the model has a good performance and it was relevance to in-situ measurement. The pattern of elevation and water current from many tide periods had been spatially analyzed. Generally, simulation showed that there was a significant difference between the elevation and water currents pattern inside and outside the bay during high and low tides.. Elevation and water current have higher value during highg tide (maximum 0.35 m and 0.2 m/s) than low tide period (maximum 0.14 m and 0.1 m/s ) with the velocity of water current was faster at ebb-tide or low tide. The water current in entry canal has higher value than in any part of the bay which themaximum velocity was varied from 1.6 m/s (flood-tide) to 3.7 m/s (ebb-tide). The direction of current during high tide flows was dominantly to the West-Northwest or enters the bay by following its geometric and to the East-Southeast or exits from the bay during the ebb-tidesKeywords : Tidal; quasi-enclosed waters; numerical models; finite difference Abstrak. Teluk memiliki topografi yang unik karena hanya memiliki satu celah atau jalur panjang, sempit, dan berkelok yang menghubungkannya dengan laut terbuka. Kajian dinamika massa air terkait elevasi dan arus pasang surut di Teluk Mayalibit telah dilakukan dengan membangun sebuah model numerik hidrodinamika 2D yang disimulasi selama 30 hari untuk menggambarkan pola elevasi dan arus akibat pasang surut. Persamaan hidrodinamika 2D diselesaikan dengan metode beda hingga. Hasil validasi menunjukkan bahwa model telah memiliki performa yang cukup baik dan relevan bila diverifikasi dengan hasil pengukuran di lapangan. Pola elevasi dan arus dalam beberapa periode pasang surut dianalisis secara spasial. Hasil simulasi menunjukkan bahwa ada perbedaan yang signifikan antara elevasi dan pola arus di dalam dan di luar teluk selama periode pasang purnama dan pasang perbani. Elevasi dan arus memiliki nilai yang lebih tinggi pada saat pasang purnama (maksimum 0,35 m dan 0,2 m/detik) dibandingkan dengan pada saat pasang perbani (maksimum 0,14 m dan 0,1 m/detik) dengan kecepatan arus yang lebih tinggi pada saat surut. Arus di jalur masuk teluk memiliki nilai yang lebih tinggi dibandingkan bagian manapun di dalam teluk, dimana kecepatan maksimumnya bisa mencapai 1,6 m/detik (pasang) sampai 3,7 m/detik (surut). Arah arus dominan di dalam teluk pada saat pasang adalah Barat - Barat Daya atau masuk ke dalam teluk mengikuti geometrinya dan ke Timur-Tenggara atau ke luar teluk pada saat surut.

Pemodelan hidrodinamika arus pasang surut Teluk Mayalibit Kabupaten Raja Ampat Provinsi Papua Barat Asep Sandra Budiman; Alan F. Koropitan; I Wayan Nurjaya
Depik Vol 3, No 2 (2014): August 2014
Publisher : Faculty of Marine and Fisheries, Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13170/depik.3.2.1536

Abstract. Mayalibit Bay has an unique topography due to it has only one way long canal , narrow, and devious that connecting to open sea. Study on the water mass dynamics concerning to elevation and tidal current in Mayalibit Bay was conducted by constructing the 2D numerical hydrodynamics model which was simulated for 30 days to describe the pattern of elevation and water current which was resulted from tidal processes. The 2D hydrodynamic equation was employed by finite difference methods. Validation result showed that the model has a good performance and it was relevance to in-situ measurement. The pattern of elevation and water current from many tide periods had been spatially analyzed. Generally, simulation showed that there was a significant difference between the elevation and water currents pattern inside and outside the bay during high and low tides.. Elevation and water current have higher value during highg tide (maximum 0.35 m and 0.2 m/s) than low tide period (maximum 0.14 m and 0.1 m/s ) with the velocity of water current was faster at ebb-tide or low tide. The water current in entry canal has higher value than in any part of the bay which themaximum velocity was varied from 1.6 m/s (flood-tide) to 3.7 m/s (ebb-tide). The direction of current during high tide flows was dominantly to the West-Northwest or enters the bay by following its geometric and to the East-Southeast or exits from the bay during the ebb-tidesKeywords : Tidal; quasi-enclosed waters; numerical models; finite difference Abstrak. Teluk memiliki topografi yang unik karena hanya memiliki satu celah atau jalur panjang, sempit, dan berkelok yang menghubungkannya dengan laut terbuka. Kajian dinamika massa air terkait elevasi dan arus pasang surut di Teluk Mayalibit telah dilakukan dengan membangun sebuah model numerik hidrodinamika 2D yang disimulasi selama 30 hari untuk menggambarkan pola elevasi dan arus akibat pasang surut. Persamaan hidrodinamika 2D diselesaikan dengan metode beda hingga. Hasil validasi menunjukkan bahwa model telah memiliki performa yang cukup baik dan relevan bila diverifikasi dengan hasil pengukuran di lapangan. Pola elevasi dan arus dalam beberapa periode pasang surut dianalisis secara spasial. Hasil simulasi menunjukkan bahwa ada perbedaan yang signifikan antara elevasi dan pola arus di dalam dan di luar teluk selama periode pasang purnama dan pasang perbani. Elevasi dan arus memiliki nilai yang lebih tinggi pada saat pasang purnama (maksimum 0,35 m dan 0,2 m/detik) dibandingkan dengan pada saat pasang perbani (maksimum 0,14 m dan 0,1 m/detik) dengan kecepatan arus yang lebih tinggi pada saat surut. Arus di jalur masuk teluk memiliki nilai yang lebih tinggi dibandingkan bagian manapun di dalam teluk, dimana kecepatan maksimumnya bisa mencapai 1,6 m/detik (pasang) sampai 3,7 m/detik (surut). Arah arus dominan di dalam teluk pada saat pasang adalah Barat - Barat Daya atau masuk ke dalam teluk mengikuti geometrinya dan ke Timur-Tenggara atau ke luar teluk pada saat surut.

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