Event starts on 2019.08.07 for 2 days in Makassar
http://msat.fitb.itb.ac.id | https://ifory.id/conf-abstract/JCuqHDYEP
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Corresponding Author
Prayudha Hartanto
Institutions
Geospatial Information Agency
Abstract
Accurate and high-resolution water depth information are important for wide range of coastal research and monitoring. In this case, providing an accurate bathymetric map is a major challenge for remote sensing. This study developed and evaluated a semi-parametric regression to extract depth information using various image datasets (Landsat 8, Sentinel 2A and Worldview 2). We compared the ability of these imageries to map depth information using generalized additive model (GAM). GAM is a semi-parametric generalized linear model which allow for nonlinear relationships between covariates and the target variable. We used the Morotai shallow water area in Indonesia to apply GAM in deriving depth information. We found that higher image spatial resolution results in higher mapping accuracies. This study highlights the potential of selected images and mapping techniques for deriving bathymetric data.
Keywords
bathymetry;SDB;depth;shallow water;GAM;regression model
Topic
Marine Geodesy and Satellite Oceanography
Corresponding Author
Suliskania Nurfitri
Institutions
1) Institute of Oceanography, University of Hamburg, Bundesstrasse 53, D-20146 Hamburg, Germany
2) Department of Oceanography, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia
3) Center for Deep-Sea Research, Indonesian Institute of Science, Jalan Y. Syaranamual Guru-Guru Poka, Ambon 97233, Indonesia
Abstract
The Arafura Sea is a relatively shallow water basin (less than 200 m) which is subjected to monsoonal winds and affected by the Banda Sea circulation. During the southeast monsoon (May to September) there is evidence of upwelling in this region which is indicated by the cooler SST (Sea Surface Temperature) and elevated chlorophyll concentration, especially at the coast of Papua (northern Arafura Sea). In order to address the origin of the upwelled waters masses, a numerical study using Lagrangian particles was utilized. The model was run backward in time to trace the trajectory of the particles arriving at the northern Arafura Sea, particularly in the upper 50 meters. Each particle was traced backward for three months with the arrival date August 31, 2014, as it is representative for an upwelling month. By this experiment we can identify the origin of the particles on June 1, including their depth, which arrive in the northern Arafura Sea. The daily velocity fields of the 3-D model HAMSOM (HAMburg Shelf Ocean Model) application to the Banda and Arafura Sea for 2014 were used to force the Lagrangian particle-tracking experiment. In general, 76.5% (62.3%) of particles arriving in 2.5 m (22.5 m) depth, originated from the upper 50 m of the Ceram and Banda Sea. In addition, particles originating from the depth interval 50-100 m contribute 19.6% (26.8%) to the number of particles arriving in 2.5 m (22.5 m) depth. On the other hand, for particles arriving in 47.5 meter depth 46% are originating from the upper 50 m of the southeastern Arafura Sea and 43% from a depth below 100 m of the eastern Banda Sea.
Keywords
Arafura Sea; Upwelling; Lagrangian study; Backward trajectory
Topic
Coastal and Ocean Dynamics
Corresponding Author
Dudy Wijaya
Institutions
a) Geodesy Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Indonesia
* wijaya.dudy[at]gmail.com
b) Division for Vertical Control Network, Geospatial Information Agency (BIG), Indonesia
Abstract
A new ocean tide model for the Indonesian Sea has been estimated by assimilating TOPEX+JASON (27 years), ENVISAT (8 years), GFO-1 (8 years), and 100 coastal gauge stations (2-5 years) data into a barotropic hydrodynamic model. The new model consists of more than 25 tidal constituents, with a spatial resolution of about 2.5-. The respond method was employed to estimate the amplitudes and phases of about 280 tidal constituents. Only constituents whose amplitudes are larger than 1 cm are added to construct the new model. According to comparisons with another 40 coastal tide gauge stations and collinear residual reduction test, the new model provides a better performance compared to global ocean models, in particular around shallow waters and coastal areas. This advantage is due to the following reasons: (i) fine-scale along-track tidal analysis of multi-mission altimetry and coastal tide gauge data and (ii) optimal estimates of friction velocity and the decorrelation length in the hydodynamical equations.
Keywords
Altimetry; tide gauge; hydrodynamic model; shallow waters
Topic
Marine Geodesy and Satellite Oceanography
Corresponding Author
Ahmad Sirojudin Munir
Institutions
a) Physics Department, Faculty of Mathematics and Natural Sciences, Mulawarman University
Jl. Barong Tongkok, Gn. Kelua, Samarinda Ulu, Samarinda, East Borneo, 75242, Indonesia
*avatarraz[at]gmail.com
b) Mathematics Department, Faculty of Mathematics and Natural Sciences, Mulawarman University
Jl. Barong Tongkok, Gn. Kelua, Samarinda Ulu, Samarinda, East Borneo, 75242, Indonesia
Abstract
In the Makassar Strait, upwelling occurred by wind-driven current and complexity of bottom topography. Analysis of upwelling phenomena could be determined by salinity, temperature dan three-dimensional current value which happened on a year as a climatology change. Regional Ocean Modelling System (ROMS) is a terrain following three-dimensional model to calculate numerical value which need stability for long-duration simulation. The model has been simulated for 1 years from 1 January 2017 to 31 December 2017 and verified by tidal data. Horizontal Boundary Condition which contain u-v velocities, salinity and temperature, is a climatology data from GLBa0.08 HYCOM. While Vertical Boundary used as atmospheric forcing is a data from ERA-INTERIM ECMWF. The verification use RMSE and RRE methods, showed good result between model and observation data with RMSE=0.1454 meter, and RRE=6.5806%. The result was analysed from 12 sampling points, 6 points on the outflow of the Makassar Strait which generated upwelling and the 6 others on the canal that connect to the Flores Sea and Java Sea. Model giving good result on January, indicate average w-velocity is 9.1183 m/day
Keywords
Analytical Model; Makassar Strait Outflow; Upwelling; Ocean Temperature Circulation;
Topic
Coastal and Ocean Dynamics
Corresponding Author
Faruq Khadami
Institutions
1 Ocean College, Zhejiang University, Zhoushan 316021, China
2 Institut für Geowissenschaften, Christian-Albrechts Universität zu Kiel, 24118 Kiel, Germany
3 Key laboratory of submarine Geosciences, Second Institute of Oceanography, Minister of Natural Resources, Hangzhou 310012, China
4 Helmholtz Center for Ocean Research Kiel GEOMAR, Kiel 24118, Germany
5 Department of Oceanography, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
*e-mail: chenxg83[at]zju.edu.cn
Abstract
Main text: The Lutao hydrothermal field is an intertidal arc-volcanic system located at offshore southeast Taiwan, hosting a Zhudanqu (ZDQ) vent and a Huwaichi (HWC) spring. The totally depleted Mg, moderately enriched chloride and H+ with respect to seawater indicated that the ZDQ endmember was solely derived from the brine phase resulted from low-degree subcritical phase separation. The vapor phase comprised the endmember for the HWC vent fluids. The temperature and pressure of the phase separation were estimated as ~ 150 oC and ~ 5 bar, respectively. The water/rock ratio was calculated as about 2. The Lutao hydrothermal system was slightly affected by semi-diurnal tides, either by tidal loading, or tidal currents, or a joint effort of both. The active circulation period of the Lutao system was about 3 h according to the time delay of its response to tides. Freshwater was almost absent in the HWC vent fluids at normal conditions. The typhoon Fung-wong that attacked the island on Sep 21st, 2014, however, imported freshwater into the vent fluids with a percentage of ~ 16%. Both the ZDQ and the HWC endmembers were a little changed after the typhoon event, suggesting a cooling of the reaction zone. Presumably, the seawater was cooled by the tropical storm by 2-5 oC which consequently quenched the reaction zone and declined the degree of phase separation. After the typhoon passing by, the hydrothermal system began to recover, evidenced by increasing percentages of the HWC endmember and decreasing freshwater contributions. The flux of the HWC endmember was estimated as ~ 500 L h-1 based on these observations. This study, for the first time, reports a shallow-depth hydrothermal system that was cooled by a tropical storm and affected by tides.
Keywords
Hydrothermal system; Tide; Typhoon;
Topic
Coastal and Ocean Dynamics
Corresponding Author
Idris Mandang
Institutions
a) Department of Geophysics, Faculty of Mathematics and Natural Sciences Mulawarman University
* idris[at]fmipa.unmul.ac.id
Abstract
El Nino Southern Oscillation (ENSO) has been related to climate anomalies throughout the world including East Kalimantan-Indonesia. Extreme rainfall is one of climate anomalies that related by ENSO. This research was analysis extreme rainfall and relationship with ENSO in East Kalimantan. The data set in this research start from 1986 to 2012 but some of stations only have data set from 1993-2012 and 1999-2012. The Correlation analysis and Gumbel are methods that use in this research. Gumbel is distribution method that can be used to predicted flood and the other disaster. Two, five, ten, twenty five, fifty and one hundred years return period for extreme monthly rainfall maximum can be found using the Gumbel Method. The largest rainfall values of two years return period obtained from sta-24 (535,07 mm), five years from sta-2 (788,84 mm), ten years from sta-7 (986,84 mm), twenty five years from sta-2 (1321,65mm), fifty years from sta-2 (1570,00 mm), and one hundred years from sta-2 (1816,51 mm). For the correlation analysis, most of stations were found positive correlation between Monthly rainfall and Southern Oscillation Index. The highest of coefficient correlation is 0,4 (21,4% from all of station). The other stations have correlation coefficient 0,3 (21,4%), 0,2 (32,1%) and less than 0,2 only 21% from all of stations. The result shows that generally rainfall in East Kalimantan related by ENSO.
Keywords
Extreme Rainfall, ENSO, SOI, Gumbel Method, Correlation Analysis.
Topic
Coastal and Ocean Dynamics
Corresponding Author
Zetsaona Sihotang
Institutions
a) Earth Science Department, Faculty of Earth Science and Technology, Bandung Institute of Technology
Jalan Ganesa No 10, Bandung, 40132, Indonesia
*zetsaona.sihotang[at]students.itb.ac.id
b) Hydro-Atmosphere Environment Research Group, Physical Oceanography and Computational Modeling Laboratory, Program Study of Physics, Faculty of Mathematics and Natural Sciences, Mulawarman University
Jalan Barong Tongkok No 04, Samarinda, 75123, Indonesia
Abstract
The Eastern Indonesian Waters are quite a complex area where this region is traversed by Indonesian Throughflow (ITF) that carries water masses from the Pacific Ocean to the Indian Ocean. The water mass movements have an influence on the condition of the waters in this region, which is the Sea Surface Temperature (SST). The SST has an important role that can control weather and climate. This study aims to analyze the phenomena that occur in the distribution of SST in the Halmahera and Banda Seas. The data used for this research is ten years of SST data (1995-2014) in the Halmahera and Banda Seas. The EOF (Empirical Orthogonal Function) method based on the EVP (Eigen Value Problem) applied to the SST data which produces three main components, that is EOF mode and PC mode respectively. The spatial pattern (EOF modes) shows that SST in the Halmahera and Banda Sea regions, while the temporal pattern (PC modes) shows the cycle of phenomena affecting the SST in these regions. The first mode produces 86.66% variance meaning that the monsoon cycle dominantly affecting SST distribution in the Halmahera and Banda Seas. Whereas in the second mode (6.16%) and the third mode (2.13%) indicating a local cycle and shows that the ENSO cycle has a weakly influence on the SST distribution in the study area. It is also has been clarified by the correlation value between ONI (Oceanic Nino Index) and SST is about -0.245.
Keywords
SST; Halmahera and Banda Sea; ENSO; EOF
Topic
Coastal and Ocean Dynamics
Corresponding Author
Wiwin Windupranata
Institutions
1Research Group of Coastal, Ocean and Maritime Engineering, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung
2Center for Earthquake Science and Technology, Research Center for Disaster Mitigation, Institut Teknologi Bandung
3Research Laboratory of Hydrography, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung
4Study Program of Geodesy and Geomatics Engineering, , Faculty of Earth Sciences and Technology, Institut Teknologi Bandung
Abstract
The Southern Coast of West Java Province in the Java Islands is one of prone and exposed area to tsunami hazard. It has about 428 kilometers coastline length, covering 5 administrational regencies (i.e. Sukabumi, Cianjur, Garut, Tasikmalaya, and Pangandaran). It is a strategic area that support many economic activities including tourism, fisheries, electricity power plants, agricultures, markets as well as social factors such as coastal villages, schools and other public facilities. The existence of this strategic area is threatened by the potential for a tsunami disaster mainly from megathrust along the Southern Coast of Java Island. On 2006, a tsunami earthquake of M7.7 occurred off Pangandaran Regency with tsunami height of 5-8 meters and inundated about 500 meters along southern coast of West and Central Java Province. The tsunami caused more than 600 casualties and damage to buildings, public facilities and insfrastructure. Yet, the Indonesia National Earthquake Source and Hazard Map suggest a bigger threat of a plausible M8.7 – M9.2 megathrust earthquake off Java island. This research aims to analyze and map potential areas affected by the tsunami in the South Coast of West Java Province based on numerical modelling carried out with Cornell Multi-grid Coupled Tsunami Model (COMCOT) v1.7 based on the several megathrust earthquake scenarios in southern off West Java. The results of tsunami modelling show that the highest impact is generated in the Sunda Straits & West Java - Central Java Megathrust Scenarios with highest tsunami inundation and the fastest travel time occurred in Cianjur Regency with 26,7 meters height and estimated arrival time of tsunami wave approximately 10 minutes after the mainshock, while the farthest inundation distance is estimated in Sukabumi Regency about 5.8 kilometers from the coast due to existence of river. As an impact of tsunami in socio-economic aspect, Pelabuhan Ratu District in Sukabumi would be the most vulnerable due to high economic activities and number of inhabitants.
Keywords
Tsunami, Megathrust Earthquake, Southern Coast, West Java Province
Topic
Coastal Degradation and Coastal Hazard
Corresponding Author
Widhya Nugroho Satrioajie
Institutions
1 Aquaculture and Fisheries Group, Wageningen University and Research, De Elst 1 6700 AH Wageningen, The Netherlands
2 Research Centre for Deep Sea, Indonesian Institute of Sciences, Jl. Y. Syaranamual Guru-guru Poka –Ambon 97233, Indonesia
3 Department of Ecosystem Studies NIOZ Royal Netherlands Institute for Sea Research Landsdiep 4 1797 SZ t Horntje (Texel), The Netherlands
4 Conservation International Indonesia, Jalan Pejaten Barat No. 16 A Kemang, Jakarta 12550, Indonesia
5 Institute for Marine Resources and Ecosystem Studies, Haringkade 1 1976 CP IJmuiden, The Netherlands
Abstract
The use of anchored fish aggregation devices (FADs) in Indonesian tuna fisheries is facing large challenges. There are two main problems: limited documentation on FAD deployment, and limited compliance by fishers in reporting FADs. Consequently, managing FADs is at present virtually impossible due to inaccurate and inconsistent data that may lead to unsustainable fisheries. In this research, we assess the distribution and densities of FADs in two main areas adjacent to North Sulawesi, Molucca and Celebes Sea based on four data sources. Logbooks of FAD locations from medium purse seine, handline and pole-and-line fishers were used to estimate total numbers and densities; transect surveys were used to check the density estimates; and port authority data were used to compare with the spatial distribution of the logbooks. The latter were not used since they were deemed unreliable. Interviews with fishers gave information on methods of deployment and minimum distances between FADs. We examine the strategies of FAD deployment based on relative influence of various operational and environmental factors. Reconstruction of the total number FADs based on an analysis of the reported and observed minimum distances between FADs (mean and standard deviation 7.2±1.54km, min=3.7km) to remove duplicates ended up with 962 FADs of which 673 in the Molucca Sea and 289 in the Celebes Sea. In particular, the estimate from the Celebes Sea represents most likely only a fraction of the FADs deployed as port authority data show deployment of FADs further from the shore. We show that FAD deployment in North Sulawesi is driven more by operational factors than environmental factors.
Keywords
fish aggregation device, minimum distances, FADs density
Topic
Marine Resources, Conversation and ICZM
Corresponding Author
Ahmad Bahar
Institutions
Fakultas Ilmu Kelautan dan Perikanan, Universitas Hasanuddin
Abstract
Marine tourism activities managed by the community in Tasiwalie Village develop naturally without any management intervention or correct management arrangements. As a result, at the height of the visit, such as on Saturday and Sunday, marine tourism activities and the condition of the region were very chaotic. This study aims to organize marine tourism activity spaces in Tasiwalie Village, Pinrang Regency. This study uses primary and secondary data. The data collection method uses a survey and focus group discussion (FGD) method for participatory mapping. The results of the study obtained the tourist area divided into 4 spaces or zones, namely the coastal recreation zone (42 Ha), bathing and swimming (327.6 Ha), diving and snorkeling (531.6 Ha), as well as boating and banana boats (482.9 Ha).
Keywords
Space management, marine tourism, Pinrang Regency
Topic
Marine Resources, Conversation and ICZM
Corresponding Author
Andri Irawan
Institutions
a) Research Center for Deep Sea – Indonesian Institute of Sciences (P2LD-LIPI), Ambon, Maluku, Indonesia
*andri.irawan[at]lipi.go.id
b) Research Center for Oceanography - Indonesian Institute of Sciences (P2O-LIPI), Jakarta, Indonesia
Abstract
Ambon Bay is located on Ambon Island, which most of the area is within the Ambon City, the capital of Maluku Province. Coastal ecosystems such as coral reefs, mangroves, and seagrass beds still exist on this bay. However, as a coastal ecosystem in a crowded city, the potential of degradation for these ecosystems is very large. Over the past five years, many changes have taken place in this bay. In the land section, the construction of housing and large buildings such as shopping centers has occurred. In addition, on the coast, there has been a construction of new docks and several locations have been reclaimed. Therefore, in 2016 there was a re-observation of the seagrass conditions at all transect locations of 2011, to see the changes that have occurred in seagrass beds in Ambon Bay over the past five years. The results will be compared to the satellite imagery of each location. Overall, the condition of seagrass beds in Ambon Bay in 2016 has decreased from the initial observation in 2011. Of the seven research locations, only one location (Halong) has an increase in its conditions, with seagrass canopy cover rise by almost twofold from previous data (24.29% rise to 50.00%). Four locations experienced a decline in conditions, from a slight decrease in Waiheru and Lateri (25.00% down to 20.91% and 47.14% down to 30.00% respectively) to a sharp decrease in Tanjung Tiram and Passo (65.67% down to 39.33% and 48.33% down to 16.25% respectively). The remaining two locations (Tantui and Hative) were in worse condition because they were damaged by the reclamation project. From 2011 and 2016 satellite image comparison, almost all locations show changes in their land use, with more building built near and on the coastal area, except in Halong. This indicates that seagrass condition negatively affected by coastal development.
Keywords
Seagrass, Decline, Coastal development, Pressure, Reclamation
Topic
Coastal Degradation and Coastal Hazard
Corresponding Author
Juventus W.R Ginting
Institutions
Experimental Station for Coastal Engineering Ministry of Public Works and Housing
Abstract
Revetment Sistem Panel Serbaguna (SPS) or Schematic System Precast (SPS) Revetment is latest innovation of SPS technology. It that has been applied for various area of civil engineering such as bridge, dams and irrigation channel. For this upgrading, SPS has been tested in Hydraulic Laboratory of Experimental Station for Coastal Engineering Ministry of Public Works and Housing as revetment. SPS is tested with 14 scenarios of various wave steepness and water depth to determine the wave run-up characteristic. All hydraulic performance of SPS for each scenario is recorded with video camera. Using image processing technique, we calculate the wave run-up height for each scenario. From all scenarios, the wave run-up only happen in scenarios with water depth of 0.65 m while the rest only experience wave overtopping. Comparing to the classical Iribarren Number graph, relative wave run-up height on SPS revetment is higher than other type of revetment such as Riprap Arhens, Riprap Gunbak, Batu Pecah, Qudripod, Dolos and Tetrapod but below Sisi Miring. For Sisi Miring Revetment, the maximum relative wave run-up height (Ru/H_m0) is 2.5 for Iribarren Number (Ir) = 2.5 as for SPS revetment, it is approximately 2.4 for Ir = 11.
Keywords
wave run-up, imaging analysis, Iribarren Number, non dimensional wave run-up height
Topic
Ocean Engineering and Technology
Corresponding Author
Suyadi .
Institutions
Lembaga Ilmu Pengetahuan Indonesia
Abstract
Weda Bay is one of mega-biodiversity spots in Indonesia, for example it is one of the largest mangrove habitat in North Maluku. However, data and information of mangrove vegetation and its ecosystem services particularly carbon stocks are lacking. Mangroves were sampled using transects in five sites of mangroves across Weda Bay. The transects extended from seaward to landward to cover all vegetation variation. Environmental data (water and substrate) were collected using Conductivity Temperature and Depth (CTD), Dissolved Oxygen (DO) meter, and sediment core. The objective is to identify characteristics of mangrove vegetation, environment, and it ecosystem services in term of aboveground carbon stocks. The study found 17 species of mangrove and the dominant species was Rhizophora apiculata, followed by Bruguiera gymnorrhiza. The importance index of those species were high (Importance index > 45) in the four sites (Yevi, Imam, Halmahera, and Bori-Bori), but Rhizophora Stylosa was important species in Dadawe site (Importance index: 58). The density of mangrove tree was 987 stem ha-1 and sapling was 1,470 stem ha-1. Substrate of mangrove did not vary significantly with distance from the seaward which mainly dominated by mud and clay (3.9 - 63 µm). Mean water temperature in the mangrove area was 29.3℃, salinity 34.1 psu, mean water suspension was 46 mg l-1, mean dissolved oxygen was 3.2 mg l-1, and water current was 10 m s-1. Aboveground carbon stocks were considerable (mean 154 Mg C ha-1, maximum 425 Mg C ha-1). Change in aboveground carbon stocks over the distance from the seaward edge to landward edge was not significantly different. The study also observed mangrove deforestation, exploitation (fire wood), and plastic pollution in all study sites. These data indicate that the environment (water and substrate) of Weda Bay is suitable for mangroves. However, this ecosystem faced some threats such as mangrove deforestation, wood exploitation, and pollution. It can be estimate that mangrove deforestation generates emissions up to 1,546,599 Mg CO2e ha-1 or equivalent with the loss of carbon market price up to US$ 108 million ha-1. These values exclude belowground carbon stocks and other function and services of mangroves. Better mangrove management e.g. reducing deforestation and pollution are required to protect the functions and ecosystem services of mangroves.
Keywords
mangrove vegetation, mangrove environment, carbon stocks, Weda Bay
Topic
Coastal and Ocean Dynamics
Corresponding Author
Agustinus Anung WIDODO
Institutions
1Center for Fisheries Research-Indonesia
2CSIRO-Australia
3Research Institute for Marine Fisheries-Indonesia
Abstract
Abstract With the primary aim of addressing information gaps on the scale and operations of Indonesia-s FAD based tuna fisheries, to aid improved fisheries management, an Indonesia - Australia research collaboration conducted a study during Nov 2013 – Dec 2015 at four key fishing ports in eastern Indonesia and western Indonesia. The full outputs from this study, involving an enumeration program with skipper interviews, biological sampling and direct observations are to be published as final report and subsequent papers. Presented here are preliminary results from research at two ports in eastern Indonesia - Kendari (SE Sulawesi) and Sorong (West Papua). All tuna FADs in Indonesian waters are anchored and are of 3 main float types: steel pontoon (ponton), bamboo with bungalow (rakit), and polystyrene block (gabus). Subsurface attractors are biodegradable materials and most commonly palm branches (nipa and coconut), and do not include netting materials. Tuna fisheries based in Kendari and Sorong include the fishing gears hand-line/troll-line (HL/TR), pole and line (PL), and purse seine (PS) and fishing areas include the Indonesian Fishing Management Areas 713, 714, 715, 716, and 717. Estimating the total number of FADs in these FMAs is difficult because of the current lack of effective systems of FAD registration and monitoring, and also because of the desire of fishing companies and vessel skippers to keep FAD position information confidential. Estimates range from several hundred to several thousand FADs. From 484 fishing trips surveyed, the average number of fishing days in trips of PL and HL/TL vessels in Kendari was 3 days and 7 days respectively, and 6 days for PL vessels in Sorong. Vessels visited up to 7 FADs in a single trip and the level of success in fishing events on FADs within a fishing trip (FAD Success Rate; FSR) varied across the fleets. In Kendari, HL/TR and PL vessels had a FSR of 64.9% and 65.9% respectively. The FSR of PL vessels in Sorong was 84.9%. The average catch rates (per trip) of HL/TL vessels in Kendari in 2013, 2014, and 2015 were 1077 kg, 1273 kg and 980 kg respectively. PL vessels in Kendari had average trip catch rates of 1593 kg (in 2013), 2490 kg (in 2014), and 4260 kg (in 2015). The average catch landings by PL vessels in Sorong in 2013, 2014, and 2015 were 6515 kg, 11,633 kg, and 13,569 kg per vessel per trip respectively. The estimated catch rate range for PS vessels based in Sorong during 14 months (Nov 2013-Dec 2014) was between 7,700 – 12,932 tonnes/set/vessel. Catch compositions included 18 species for HL/TL, 9 species for PL, and 7 species for PS. Skipjack tuna (SKJ) were the dominant species, 73% by volume, in catches of PL in Kendari and PS vessels in Sorong 76% and 81% of total catch respectively but only made up 41% of HL/TL landings and 38% of PL landings in Kendari. Yellowfin tuna (YFT) made up the largest proportion (47%) of HL/TL catches in Kendari, compared to SKJ (41%). A large proporti
Keywords
Characteristics of tuna fisheries, associated with anchored FADs, west Pacific, Indonesian archipelago
Topic
Marine Resources, Conversation and ICZM
Corresponding Author
Dayu Wiyati Purnaningtyas
Institutions
a Oceanography Division, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Indonesia
b Microbial Biotechnology School of Life Sciences and Technology, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Indonesia
c Research Center for Oceanography, Indonesian Institute of Science, Indonesia
d Biochemistry Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Indonesia
*contact author: yanti[at]chem.itb.ac.id
Abstract
S-Acyltransferase gene (pat) encodes a protein acyltransferase (PAT) acting as an enzyme catalyzing an acyl chain transfer to the molecular acceptor, mono- or di-acylglycerol, in the biosynthesis of triacylglycerol (TAG). So far, pat from tropical marine microalgae has yet been explored. We identified an microalgae isolate based on physical morphology and genetic marker of 18S rDNA. Finally, we characterized pat from reverse transcription of total RNA of the isolate, cloned the pat to pGemT and expressed in E. coli TOP10. The results showed that isolate obtained from Maluku water was green spherical in shape with a cell diameter of 2-10 µm. A 1644-bp nucleotide fragment of 18S rDNA was obtained and showed 99% nucleotide sequence similarity with that of Chlorella vulgaris (GenBank no. KF574391.1). The microalgae isolate was identified as Chlorella vulgaris CBI. Reverse transcription product from the total Chlorella vulgaris CBI RNA was a 600 bp nucleotide. The first 300 bp nucleotide was unidentified, but starting from nucleotide no. 301 to the end has 51% identity with pat fragment of Chlorella variabilis (GenBank no. XP_005849764.1). A 77-amino acid residues deduced was identify as the first N-terminus of PAT (domain transporter protein). This pat fragment of Chlorella vulgaris CBI was useful for starting point to find the whole pat seqeunce.
Keywords
marine microalgae, Chlorella vulgaris CBI, enzyme, S-Acyltransferase
Topic
Marine Resources, Conversation and ICZM
Corresponding Author
NUR AINI MD NOR
Institutions
¹ Centre of Studies for Surveying Science and Geomatics, UiTM Shah Alam, Malaysia
² Oceanography Study Program, Faculty of Earth Science and Technology, Institute Technology of Bandung, Indonesia
Abstract
Kuala Terengganu is one of the areas which were subjected to critical erosion in Malaysia. It is believed that human activities became one of the causes of this incident. Kuala Terengganu is location of Sultan Mahmud Airport. In January 2008, the Malaysia government approved to upgrade the airport included improvement to the terminal and runway extension. The construction is located near the coast, therefore it is necessary to monitor the coast of Kuala Terengganu. This study focuses on the shoreline change detection along the Kuala Terengganu during ten years period between 2007 until 2017 using LANDSAT Images. Digital Shoreline Analysis System (DSAS) is an extension for the ArcGis was used to identify and measure erosion (shoreline retreat) and accretion (shoreline advance) along the coast. From the analysis, the action will take better information disclosure and state government can take action to reduce the erosion. Environmental impact assessment benefits occur in many guises such as improved project design and improved decision making.
Keywords
DSAS, LANDSAT, Shoreline change, Erosion, Accretion
Topic
Coastal and Ocean Dynamics
Corresponding Author
Indah Kartika
Institutions
Hasanuddin University
Abstract
This research was conducted on March 2019 in Barrang Caddi Island, Spermonde Archipelago. The acquisition of Sentinel-2A satellite imagery was on February 24, 2019. DOS method (Dark Object Substraction) was used to atmospheric correction , water column correction using Lyzenga algorithm with values of ki / kj = 0.679844349 and a = -0,39554029. Image classification analysis using IsoData and K-Means unsupervised classification method. Gound truthing using the UPT (Underwater Photo Transect) method. Basic information on spectral values is obtained from Sentinel-2A satellites using band 2 with 490nm, band 3 with 560nm, band 4 with 665nm, and band 8 with 842nm. The results show that there are 4 dominant objects including live coral, rubble, algae, sand and seagrass. The highest spectral reflectance can be detected by green band (560nm) with IsoData and K-Means classifications. Unsupervised classification using IsoData method has capability to detect live coral and while the K-Means method is capable to explore the seagrass.
Keywords
Sentinel-2A, isodata, k-means, spectral, Spermonde
Topic
Marine Geodesy and Satellite Oceanography
Corresponding Author
Tesla Kadar Dzikiro
Institutions
(a,b,c)Sekolah Tinggi Meteorologi Klimatologi dan Geofisika, Mailing address1, email address1
(d)Pusat Meteorologi Maritim, Badan Meteorologi Klimatologi dan Geofisika, Jl Angkasa 1 No.2 Kemayoran, Jakarta 10720
(e)Pusat Penelitian dan Pengembangan Sumber Daya Laut dan Pesisir, Gedung Balitbang KP, JalanPasir Putih I, Ancol Timur, Jakarta 14430, Indonesia
Abstract
Ocean currents have a big role in the marine world. Conventional techniques of measuring ocean currents have spatial and time limitations. High Frequency Radar technology can overcome these obstacles as an alternative to solving solutions effectively and efficiently. The hydrodynamic model is used to predict sea surface currents, such as in Indonesia, known as Ina flows from BMKG and Ina OFS from Pusriskel. The aim of this study is to find out the accuracy of the Ina flows and Ina OFS hydrodynamic models in predicting sea surface currents against high frequency radar observations in Labuan Bajo Waters. The data used are output from Ina flows, Ina OFS and HF Radar in Labuan Bajo in February 2019. The method used to determine accuracy is by correlation coefficient, Root Mean Square Error, and eyeball method for spatial correlation. In general, the results of these tests indicate that Ina-flows has a higher value of accuracy and correlation in two points of the waters of Labuan Bajo with a value of around 0.5 to 0.6, while the error of sea surface currents direction is around 30 degrees to 60 degrees.
Keywords
Sea surface currents, High frequency radar, Hydrodynamic models, Ina flows, Ina OFS
Topic
Ocean Engineering and Technology
Corresponding Author
Muhammad Riza
Institutions
1) Department of Oceanography, Bandung Institute of Technology, Indonesia
2) Program Study of Physics, Faculty of Mathematic and Natural Sciences, Mulawarman University, Samarinda, Indonesia
Abstract
Variations of volume transport in the Halmahera Sea are strongly influenced by the El Nino Southern Oscillation (ENSO). Based on the ENSO Index at Nino 3.4, in 2011 La Nina event took place with a strength of -1.4, while in 2015 El Nino occurred with a strength of +2.6. This paper discusses the variation of transport volume caused by the ENSO phenomenon based on the results of the Regional Ocean Model System (ROMS). On the Halmahera Sea at a latitude of 0.3(^circ)S with a width of 67 km and a depth of up to 300 m, net volume transport always moves southward. The largest volume transport in La Nina 2011 occurred in September-October, which was -8.9 Sv. Meanwhile, in El Nino 2015 the largest volume transport occurred in July-August, which was equal to -4.9 Sv. The cross correlation coefficient between volume transport and SOI in 2011 and 2015 respectively was r = 0.55 and r = 0.61, where these results indicate a strong relationship.
Keywords
transport volume variation, Halmahera Sea, ENSO, numerical model, ROMS
Topic
Coastal and Ocean Dynamics
Corresponding Author
Alina Blume
Institutions
1. Indonesian Institute of Sciences (LIPI)-R.C for Geotechnology, 2. RWTH Aachen-Geology Department. *Corresponding author sri004[at]lipi.go.id
Abstract
Indonesia is an important site for climate studies, because of it-s located between Indian and Pacific oceans. Climate phenomena which is happened in the Pacific and Indian oceans i.e El Nino Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) influence Indonesian climate. To understand behaviour of climate phenomena and its impact to Indonesian climate it is required paleoclimate data which provide long time series climate data back to hundred till thousands year. Sea surface temperature is one of important climate parameter. Coral Sr/Ca is convinced as coral paleo-thermometer. In this study, the available coral Sr/Ca is used to reconstruct past SST variability (Coral SST). The variability of coral SST from several sites in Indonesia waters is investigated and compared between sites. The coral SST is also correlated with the Nino 3.4 and IOD indices to know how the climate phenomena influence the SST variability. The result shows that the influence of IOD and ENSO difference between sites. Some sites e.g Seribu island coral SST shows that SST is influenced by IOD rather than ENSO, while from Timor coral SST shows that shows that Indian Ocean Dipole (IOD) influences SST and SSS while ENSO only influences SST
Keywords
Sr/Ca, coral, SST
Topic
Coastal and Ocean Dynamics
Corresponding Author
Ignatius Tri Hargiyatno
Institutions
Center for Fisheries Research, Agency for Marine and Fisheries Research and Human Resources, MMAF
Abstract
Handline tuna fisheries in Palabuhanratu have developed since 2004 and categorized as small-scale fisheries. Economic sustainability is one of the objectives of the handline tuna operation. This paper aims to analyze the cost and revenues of tuna fishing resources by using a handline in Palabuhanratu. The results indicate the handline catch rate has increased from the years 2012-2014 with an average 657kg / trip. The investment cost of handline tuna fishing operation is $19,792.86,-, with depreciation charge of $5,525.00,-/year, maintenance cost amount $2,589.29,-/year and operational cost of $16,222,-/year. The revenue from the fishing business is $44,057,-/year. The business profit amount USD $ 301,-/trip or USD $ 7,217,-/year. Based on investment analysis the value of R / C = 1,32, PP = 1,86, NPV = $ 24,528.27,-, B/C = 5,27 and IRR = 119%, where it shows that fishing is profitable, with a relatively quick payback and sustainable.
Keywords
Cost, Revenue, handline, tuna, Palabuhanratu
Topic
Marine Resources, Conversation and ICZM
Corresponding Author
Ahmad Romdon
Institutions
1 Centre of Excellence for Tuna Resources Conservation (CoE TRC), Centre for Deep-Sea Research Indonesian Institute of Sciences (CDSR-LIPI), Jalan Y. Syaranamual, Guru-guru Poka, Ambon Maluku 97233
*ahma077[at]lipi.go.id
2 Yayasan Biodiversitas Indonesia (BIONESIA), Jalan. Tukad Balian No. 121 Denpasar, Bali 80226
Abstract
Conserving tuna stock, biological information of tuna larvae is essential for understanding spawning ground and spawning time. However, morphological identification of larval is difficult and often times questionable. Meanwhile, genetic identification is useful and helpful to confirm the morphological identification result. This study purpose is to confirm a morphological identification result with genetic identification and determine the tuna species exactly. Specimens used in this research were obtained from a survey conducted in the Banda Sea in October 2018. Samples were collected by a bongo net towed obliquely. Morphological identification is to the tribe level, regarding the key features of the meristic and morphometric. Small tissue fragment from each sample was also analysed for genetic purposes using amplification of mitochondrial control region. Phylogenetic analysis was then performed using Neighbour-Joining with 1000 bootstrap replication. Genetic distance between individual sequences calculated using Kimura 2-parameter methods. Sequences of Euthynnus affinis (AP012946), Katsuwonis pelamis (KM094133, KM261666, KM094145, KM605252, KM094135), and Petenia splendida (KJ914664) were generated from GenBank database, and added to the phylogenetic analysis for species comparison. Result of morphological identification is showed that the larvae having 37 to 42 myomeres, preopercular spine developed, moderate in depth, moderate to large head and eyes identified as a tuna larva (Thunnini). However, this morphological data is not supported by genetic result, which indicated that the samples were identified as K. pelamis, E. affinis, and P. splendida. The intraspecific pairwise genetic distance for each species of K. pelamis, E. affinis, and P. splendida is 4.4 %; 0.5 %; and 22.3%, respectively. Meanwhile, the average pairwise genetic distance between the three species ranges from 16.2% to 33.3%.
Keywords
Tuna larva, Morphological identification, Genetic identification
Topic
Marine Resources, Conversation and ICZM
Corresponding Author
Muhammad Rizqy Septyandy
Institutions
Program Study Geophysics
Program Study Geology
Department of Geography
Universitas Indonesia
Abstract
Historically, the Sunda Strait has experienced several tsunamis recorded in the tsunami catalog caused by several geological phenomena. One of the last tsunami events in the Sunda Strait was the tsunami on December 22, 2018. The condition of bathymetry, coastal topography and high rainfall were some of the trigger factors for tsunamis in the Sunda Strait in addition to the eruption of Mount Anak Krakatau. To anticipate a tsunami in the future, a model of the height of tsunami waveforms that arrived at the coast was made. This study focused on producing rapid predictions of tsunami waveforms arriving at the coast using data signals recorded when a tsunami occurs due to landslide sub-marine. The remarkable training speed requires that it can be used to run in real time conditions and can be used as a tsunami early warning system in near-field tsunami events on the west coast of Banten. The proposed method used non-linear relationships by utilizing Sunda Strait bathymetry data, tide gauge signals, and coastal topography along the west coast of Banten, as well as rainfall during the past tsunami. Therefore, it becomes an advantage compared to ordinary inversion analysis that uses linear assumptions. The results of this study indicate that the extreme machine learning method produces more accurate results with a faster time compared to the inversion method in the propagation, tsunami run-up, and inundation zones on the west coast of Banten. In addition, the uncertainty analysis produced by our model proves that this method is robust and reliable, resulting in a model that can be used as a reference for tsunami safety zones by the local government.
Keywords
Tsunami, landslide sub-marine, extreme machine learning, Sunda Strait, inundation zone
Topic
Coastal Degradation and Coastal Hazard
Corresponding Author
Faisal Hamzah
Institutions
1Institute for Marine Research and Observation, Ministry of Marine Affairs and Fisheries, Bali, 82251 Indonesia. (faisalhamzah[at]kkp.go.id)
2State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Science, Xiamen University, Xiamen, 361102, China
3First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China
4Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
5Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences
6Qingdao National Laboratory for Marine Science and Technology, and Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, and University of Chinese Academy of Sciences, Beijing, China
7Research Center for Oceanography, Indonesian Institute of Sciences, Jakarta, Indonesia
Abstract
Research on the carbonate system in the tropical regime of the Indonesian Seas is limited and required to understand carbonate dynamics due to the Indonesian throughflow (ITF). Here, we present marine carbonate system along the main routes of the ITF spanned Mindanao-Sulawesi, Sulawesi Sea, Makassar Strait and Lombok Strait during strong 2015 El Niño and transition seasons of October 2017. Along the main routes, dissolved inorganic carbon (DIC) and total alkalinity (TAlk) were shown lower compared to the main outflow passage of the Lombok Strait. Physical and biogeochemical processes in the upper thermocline is dominated by photosynthesis and carbon dioxide (CO2) release to the atmosphere induced by vertical mixing. DIC vs. TAlk relationship shown mixing process occurred in the upper thermocline following the stratified North Pacific waters. In the upper 150 m, freshwater contribution changed the ITF water structures particularly after the Labbani channel to the Lombok Strait. Strong seasonal and spatial variabilities of sea-air exchange along the main routes. The difference between sea and air partial CO2 (ΔpCO2) in the Mindanao-Sulawesi to eastern Sulawesi Sea showed the main inflow act as sink with a slightly source of atmospheric CO2 ranged from -7 to 23 μatm (-0.19-0.72 mmol C m-2 d-1), while the Makassar strait (3.4-128 μatm) and along southern Makassar Strait to the Lombok Strait (51-76 μatm) were act a source within CO2 degassing of 0.09-8.3 and 2.2-6.9 mmol C m-2 d-1, respectively. Estimating potential carbon flux to support the Indian Ocean primary productivity from the Makassar Strait was ~9972 Tg C y-1 whereas 2090 Tg C y-1 exports to the Indian Ocean via the Lombok Strait, while the remained carbon of 7881 Tg C y-1 were transported to the Banda Sea.
Keywords
carbonate system, Indonesian Sea, Indonesian Throughflow
Topic
Coastal and Ocean Dynamics
Corresponding Author
Purwanti Sabrina
Institutions
a) Department of Earth Science, Faculty of Earth Science and Technology, Institute Technology of Bandung, Indonesia
*purwanti22lelly[at]gmail.com
b) Balai Perikanan Budidaya Laut Ambon, Direktorat Jendral Perikanan Budidaya, Ministry of Marine Affairs and Fisheries Republic of Indonesia
Abstract
Abstract. Inner Ambon Bay has been used as a location for fish farming. The mean seasonal of chemical parameters as much as 3,92 – 6,52 ppm for dissolved oxygen, the surface concentration of nitrate and phosphate each one is 0,05 – 0,143 ppm and 0,014 – 0,6 ppm, meanwhile the pH reach 7,95 – 8,44. The mean seasonal of physical parameters about 30,3 – 34,4 ‰ for salinity and the value of surface temperature is 26,5 – 31,5 °C. This research reviews the condition of an ecosystem in Inner Ambon Bay, consist of nutrients, phytoplankton, zooplankton, and detritus (NPZD) concentrations. The input model uses data on temperature and average nitrate concentration from Ambon Marine Aquaculture Center (Balai Perikanan Budidaya Laut Ambon) which is located on 3,63529 °S and 128,2312 °E. Model simulation is carried out for 4 years (2015 – 2018) with a time step of 6 minutes. The model simulation result shows that the mean nutrient concentration is 3,52 – 3,84 mmolC/m3. The verification of nutrient concentration from a model with observation data (nitrate concentration) used a statistics method. The value of RMSE is 0,05 mg/L or 0,5 mmolC/m3, meanwhile correlation is 0,41. The highest nutrient concentration occurred in the east season. It could be influenced by upwelling from Banda Sea that carried high nutrients from the surface.
Keywords
Model; NPZD; Nutrient; Seasonal
Topic
Marine Resources, Conversation and ICZM
Corresponding Author
Susanna Nurdjaman
Institutions
Department of Oceanography, Faculty of Earth Sciences and Technology
Institut Teknologi Bandung
Abstract
Beach is an area where the environment and its coastline are very dynamic, caused by the effects of wind, waves, tides and other factors such as seasonal variations, climate change, sea level rise, human activities and so on. PROSAPA (PROteksi SAbut kelaPA) Project is a coastal protection product that uses plants known as Bioengineering. This product uses coconut fiber waste and is environmentally friendly. The aims PROSAPA Project is to reduce erosion rates, reduce or dampen of the ocean wave and stabilize eroded coastlines by using a combination of deep-rooted plants and biodegradable materials such as coconut fiber. Beside that this project uses coconut fiber which available along the coast and therefore low-cost installation. Plants that have high salt tolerance with deep roots are used to help stabilize the area. This project identified environmentally sustainable approaches to coastal protection, as distinct from traditional -hard- engineering solutions. The project case studies is applied on the southern coast Java Island, particularly at Pangandaran Beach, West Java, Indonesia. Application of this method depends on the oceanographic condition such as wave high and direction, high of erosion, tidal and kind of sediment. Evaluating of monitoring this project after almost one year, this project are potentially applicable at any coastline.
Keywords
Bioengineering, coconut fiber, environmentally coastal protection, PROSAPA, Pangandaran Beach
Topic
Ocean Engineering and Technology
Corresponding Author
Hasti Amrih Rejeki
Institutions
School of Meteorology Climatology and Geophysics, The Agency for Meteorology Climatology and Geophysics of Republic of Indonesia
Jalan Perhubungan I No. 5, Komplek BMKG, Tangerang Selatan 15221, Indonesia
*hastiamrihrejeki[at]gmail.com
Abstract
The Indonesian Maritime Continent is an area of propagation and crossing of Madden Julian Oscillation (MJO) in phases 3, 4, and 5. The active MJO causes the increasing of convective activity and strong winds on the area it passed. In the active phase, the ocean will get a response from MJO activities as the response to strong westerly winds. The depth of the thermocline in the tropics varies from season to season and from year to year. MJO, as the intraseasonal variability is one of the causes for the variations in the depth of the thermocline layer. The objectives of this study are to investigate and properly understanding the equatorial thermocline dynamics related to MJO activity in the Indonesian Maritime Continent. By using the temperature data in 0 - 400 m of depth which obtained from Marine Copernicus, this study will investigate the equatorial thermocline dynamics which are precisely at 5N, 0, and 5S of latitude in the MJO phase 3, 4, and 5 area during the period of 2018. The results showed that the dynamics of the thermocline depth has a response to MJO according to the location of the activity. However, it also decreases the thermocline depth in the northern (southern) equator. The results of this study also show the relation of convective activity in the atmosphere with variations in thermocline depth which will also have an impact on weather conditions in the Indonesian region.
Keywords
Indonesian Maritime Continent; Madden Julian Oscillation; Equatorial Thermocline Dynamics
Topic
Coastal and Ocean Dynamics
Corresponding Author
Ismail Abdul Jabbar
Institutions
a) Study Program of Oceanography, Faculty of Earth Sciences and Technology, Bandung Institute of Technology
b) Research Group of Oceanography, Faculty of Earth Sciences and Technology, Bandung Institute of Technology
*) Jl. Ganesha 10, Bandung 40132, Indonesia
Abstract
Extreme wave height analysis has been conducted in Natuna Sea, Indonesia, using 25 years (1991-2015) Significant Wave Heights (SWHs) data from WAVEWATCH 3 (WW3) with spatial resolution of 1/8o. The Natuna Sea is geographically connected to the South China Sea (SCS) and is often crossed by massive storms (cyclones) with wind speeds greater than 30 m/s. These storms may have contributed to the existences of high waves in the SCS, which propagate as swell waves to the Natuna sea and could led to extreme waves in this region. Extreme value analysis has been done by classifying the extreme events of SWHs using Peak-Over Threshold (POT) method with a fixed threshold level at quantile 0.93 and a minimum time separation of 48 hours between two successive extreme events. Furthermore, the Generalized Pareto Distribution (GPD) has been applied to estimate return values of the extreme SWHs for several return periods. The shape and scale parameters of the GPD have been estimated by Maximum Likelihood Estimation (MLE) method. The characteristics of extreme SWHs in the Natuna Sea have been explained by maximum and seasonal distribution plots. Maximum value of extreme SWHs in the SCS can reach 13 m and around 3-5 m in the Natuna Sea. The seasonal distributions of extreme waves indicate that the occurrences of extreme waves in the SCS during Northeasterly Winter Monsoon (NWM) are higher than those during Southwesterly Summer Monsoon (SSM) although the tropical cyclones in the SCS are more likely to happen during SSM. The seasonal mean and maxima of extreme SWHs in the Natuna Sea are also high during the NWM and low during the SSM. To examine effects of swell waves from the SCS and also the future extreme waves in the Natuna Sea, we have analysed the characteristics and calculated the return values of extreme waves in front and behind of Natuna Island, which the former faces directly to the SCS. There are 172 (331) extreme waves happen from 1991-2015 in the front (behind) of Natuna Island and mainly from northeast (southwest). Most of them are around 2-3.5 (0.5-1.5) m with mean period of 7-9 (3-5) s. Moreover, the return values in the front (behind) of the Natuna Island show that there are possibilities of extreme waves with values 4.70, 4.87, and 4.96 (2.08, 2.20, and 2.27) m for return periods of 25, 50, and 75-year, successively.
Keywords
Natuna Sea; Peak-Over Threshold; Generalized Pareto Distribution; extreme waves; return values
Topic
Coastal Degradation and Coastal Hazard
Corresponding Author
Selfrida Missmar Horhoruw
Institutions
(a) Center of Excellence on Resource Conservation of Tuna,
(b) Research Center for Deep Sea-Indonesian Institute of Sciences (LIPI)
(c) Department of Marine Science and Technology, Bogor University
Abstract
Banda Sea waters is the potential area for fisheries, especially for Tuna. Banda eddy and the relationship to chlorophyll-a were studied using the output of ocean circulation model INDESO (Infrastructure Development of Space Oceanography) configuration from 2008-2011 during normal (June-August 2008) and ENSO (El Nino/ June- August 2009 and La Nina/ June-August 2010). The model result showing two clockwise eddies in the northern part of Banda sea and three counterclockwise eddies in the southern part of Banda Sea. The eddy counterclockwise was found from 20 m depth and causing upwelling along the island arc on the western edge of Banda sea. Eddy counterclockwise in the southern of Banda Sea cause the downwelling. The presence of these 5 eddies is thought to be an important factoring in maintaining water balance system in the Banda Sea as long as southeast monsoon period. In the surface, higher vorticity of the eddy was found in the northern of southwest Maluku Island. The presence of this eddy is thought to have a strong influence on nutrient loss on the surface. Our research shows that during the La Nina period, the eddies vorticity increased causing low surface chlorophyll in the surface the Banda Sea.
Keywords
Banda Eddy, ENSO, chlorophyll-a, upwelling, downwelling, INDESO
Topic
Coastal and Ocean Dynamics
Corresponding Author
Ejria Saleh
Institutions
Borneo Marine Research Institute, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah, MALAYSIA;
Abstract
Semporna is one of the most significant areas in the Malaysian Coral Triangle. This area is known as Semporna Priority Conservation Area (SPCA) and the first Marine Spatial Plan in Malaysia. The shallow water areas within its islands are identified for mariculture activities, fishing sites and tourists destination. One part of the area is Tando Bulong Strait located between Semporna and Bum Bum Island. The excellent natural environment and high marine biodiversity are related to water circulation. The objectives of this study are to determine water current pattern and wave impacts along the strait using numerical modeling. Field surveys of bathymetry, deployment of two Acoustic Doppler Current Profilers (ADCP) for water level and current measurements were done from 1 to 30 August 2017. During this field trip, assessment of current coastal community activities along the strait was also carried out. The field data (water current and water level) were needed for validation and verification of the Delft3D modelling software. The waves, current speed, and direction were analysed and presented on different tidal cycles and seasonal monsoon. Results indicate that tidal cycles and seasonal monsoon play a major role in water exchange of the Strait. The current speed along the coastline is about 0.3 m/s but increase up to 0.37 m/s along the Strait. The model predicted that flood tide current speed during the northeast monsoon flows southwards and increase between 0.6 m/s and 1 m/s at the middle of the Strait south. The wave height during this monsoon is approximately 0.65 m in the north and decreases down to 0.3 m inside the strait. The water circulation is important for the mariculture (seaweed farming), fish cages and marine pollution management. The findings will hopefully lead to a better understanding of the dynamic of the Tando Bulong Strait and improve the future prediction state of the Semporna area.
Keywords
Current pattern, waves, monsoon, Tando Bulong Strait, Semporna
Topic
Coastal and Ocean Dynamics
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