RESPONSE OF SEA SURFACE TEMPERATURE (SST) AND CHLOROPHYLL-A ON MADDEN JULIAN OSCILLATION (MJO) IN INDONESIAN SEAS

Madden-Julian Oscillation (MJO) is a large-scale phenomenon that occurs in equatorial area, parti-cularly Indonesia. This research aimed to investigate the MJO propagation process and studied the correlation between MJO and sea surface temperature (SST) and chlorophyll-a. Sea variables (SST and chlorophyll-a) and atmosphere variables (outgoing longwave radiation/OLR, 1,5 km wind, and surface wind) were band-pass filtered for 20-100 days period. Spectral density from OLR and 1,5 km wind (2003-2012) shows that the MJO period was dominantly occurred for 40–50 days. Average pro-pagation of  MJO velocity resulted from the atmospheric variable analysis by Hovmöller diagram was 4,7 m/s. Cross correlation between SST and OLR in South Java and Banda Sea results a strong corre-lation during MJO active phase, where MJO took  place first and was then followed by the decreasing SST along the equatorial region. Increasing chlorophyll-a concentration occured at some areas du-ring MJO active phase with relatively short phase delay. During the MJO active phase, fluctuation of wind velocity generates variation over mixed layer depth and triggers upwelling /entrainment. Nutri-ent was upwelled to the water surface and hence increase phytoplankton production and chlorophyll-a concentration. Keywords: Madden Julian Oscillation, OLR, sea surface temperature, surface chlorophyll-

MANGROVE SEDIMENT ACCUMULATION RATE IN TANJUNG BATU, KEPULAUAN DERAWAN, EAST BORNEO

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.The sustainability of mangrove ecosystems is an important aspect because it is related to the decreasing or addition of sediment accumulation such as abrasion and accretion processes. Mangroves in Tanjung Batu have decreased since 2001-2010 due to community activities such as logging, clearing land for ponds and oil palm plantations. This study aims to estimate of mangrove sediment accumulation rate in Tanjung Batu. The study was conducted in February-July 2018. Sampling was carried out at 3 stations including identification of mangrove species, measurement of diameter at breast height (DBH) and sediment corring used stainless pipes. Sediment samples were cut based on intervals 5 cm (depth 0-15 cm), and intervals 2 cm (depth 48-50 cm) used as supported Pb-210 (Stations 1 and 3). Station 5 is cut at intervals of 4, 6 and 8 cm (depths 1-50 cm). Samples analysis using alpha spectrometer to determine radioisotope Pb-210. Determination of sediment age and sediment accumulation rate using the Constant Rates of Supply (CRS) model. The results showed that the rate of sediment accumulation in the last 20 years (1998-2018) ranged 0.09-0.20 g cm-2 years-1. The highest accumulation rate at Station 1 which is location with the oldest age and mangrove density in DBH > 5 cm, while the lowest accumulation rate is at Station 5 which has the youngest sediment age and mangroves in DBH < 5 cm

SEDIMENT ACCUMULATION PROFILE IN MANGROVE RESTORATION AREA OF LEMBAR BAY-LOMBOK ISLAND

Mangrove restoration is really needed for restoring its ecosystem functions, so that it could be able to support fisheries activity and to protect coastal by extreme weather. In addition, mangrove is able to accumulate sediment that important in protecting the coastal area from sea level rise. Therefore,  the aim of this study is to investigate sediment accumulation rate in mangrove area during post restoration. Sampling location were divided into three different stations based on estimated restoration ages, such as ≥ 15  years old (Station 1), 4 - 10 years old (Station 2) and 2 - 8 years old (Station 3). Sediment cores were carried out by inserting 7.6 cm diameter and 100 cm length of polyvinyl chloride pipes. Sedimentation rate is measured by using Pb-210 radionuclide analysis. The results show that the sediment accumulation rate in the last 20th years from all station ranges from 0.17 to 0.42 g/cm2/year. The highest accumulation rate is found at oldest year old station while the lowest accumulation rate is found at younger year old station of mangrove restoration area. Restoration process is clearly able to recover the mangrove’s role in trapping sediment in coastal region. Keywords: sediment accumulation, mangrove restoration, Lembar Bay-                   Lombok Island

SEDIMENT ACCUMULATION PROFILE IN MANGROVE RESTORATION AREA OF LEMBAR BAY-LOMBOK ISLAND

<p><em>Mangrove restoration is really needed for restoring its ecosystem functions, so that it could be able to support fisheries activity and to protect coastal by extreme weather. In addition, mangrove is able to accumulate sediment that important in protecting the coastal area from sea level rise. Therefore,  the aim of this study is to investigate sediment accumulation rate in mangrove area during post restoration</em><em>.</em><em> Sampling location were divided into three different stations based on estimated restoration ages, such as </em><em>≥ 15 </em><em> years old (Station 1), 4</em><em> </em><em>-</em><em> </em><em>10 years old (Station 2) and 2</em><em> </em><em>-</em><em> </em><em>8 years old (Station 3).</em><em> </em><em>Sediment cores </em><em>were </em><em>carried out</em><em> </em><em>by inserting 7.6 cm diameter</em><em> and 100 cm length of</em><em> </em><em>polyvinyl chloride</em><em> pipes. </em><em>Sedimentation rate is measured by using Pb-210 radionuclide analysis</em><em>. The result</em><em>s</em><em> </em><em>show that</em><em> </em><em>the sediment accumulation rate in the last 20^th years from all station </em><em>ranges from 0.17 to 0.42 g/cm²/year. The highest accumulation rate is found at oldest year old station while the lowest accumulation rate is found at younger year old station of mangrove restoration area. Restoration process is clearly able to recover the mangrove’s role in trapping sediment in coastal region.</em></p><p><em> </em></p><p><strong>Keywords</strong>:<em> sediment accumulation, mangrove restoration, Lembar Bay-                   </em><em>Lombok Island </em></p

PARTISI KIMIAWI Cu DAN Fe PADA SEDIMEN PERMUKAAN DI PESISIR TIMUR DAN BARAT SUMATRA UTARA

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.Mobility (including desorption-absorption) of heavy metals in sediments varies depending on the chemical properties of sedimentary minerals in which the metals are associated and hence possibly differentiate their origin (natural and anthropogenic). This study aims to reveal on Cu and Fe of origin based on their chemical fractionation and total concentration. The study location consisted of 11 points clustered into three parts i.e the east coast, west coast, and Nias Island of North Sumatra. The geochemical fraction was obtained based on the SEP BCR (Sequential Extraction Process Bureau Reference of the European Commission) multilevel procedure in four phases: acid dissolved fraction, reduced fraction, oxidation fraction, and residual fraction. The total metal determination was based on the USEPA 3050B method. Metal concentration determination were carried out using atomic absorption spectrophotometry (AAS). The results showed that anthropogenic activities suspected of contributing Fe metal to sediment were higher indicated by non-residual concentrations (5.55-203.15 mg/kg) than the residual fraction (4.89-21.47 mg/kg). In contrast to Cu, the highest association in the sediment is the residual fraction (2.24-8.85 mg/kg). These metal apparently were derived from both natural and anthropogenic sources. Heavy metals in sediments have contributed from natural and anthropogenic sources, Cu is thought to have more natural sources and Fe is thought to originate predominantly from human activities both around the coast and possibly from the land

Study of Heavy Metal Distribution and Hydrodynamic Simulation in Green Mussel Culture Net, Cilincing Water - Jakarta Bay

This study aimed to investigate the heavy metals distribution in the surrounding 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, the Princeton Ocean Model was applied, and the model design was developed based on a scenario of an open canal in the eastern and western sides, while the center canal was placed with net 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

Study of Heavy Metal Distribution and Hydrodynamic Simulation in Green Mussel Culture Net, Cilincing Water - Jakarta Bay

This study aimed to investigate the heavy metals distribution in the surrounding 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, the Princeton Ocean Model was applied, and the model design was developed based on a scenario of an open canal in the eastern and western sides, while the center canal was placed with net 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

Three-Dimensional Simulation of Tidal Current in Lampung Bay: Diagnostic Numerical Experiments

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 bottomp.41-50 : ilus. ; 30 c

THREE-DIMENSIONAL SIMULATION OF TIDAL CURRENT IN LAMPUNG BAY: DIAGNOSTIC NUMERICAL EXPERIMENTS

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