Banda Sea Research Articles

Changes in pH associated with temperature and salinity in the Banda Sea

Changes in pH can impact the biogeochemical processes of the ocean. Several variables, like temperature and salinity, can influence pH levels. This research aims to determine the relationship between pH, temperature, and the salinity of the Banda Sea. The Banda Sea lies in the path of The Indonesian Throughflow (ITF), so temperature and salinity dynamics occur. Research is carried out in the Banda Sea in July 2022 at 5 (five) stations with multiple levels of depth. The measured parameter is the pH clicking using a pH meter, while the temperature and salinity using the Conductivity Temperature Depth (CTD). The results obtained are the pH of the waters ranging from 7.3-7.8 with an average of 7.55. The temperature went from 4.76-27.34°C with an average water temperature of 16.98°C, where the lowest temperature was at 1000 meters. Salinity ranged from 33.19-34.98 PSU with an average of 34.46 PSU. pH and temperature were correlated at 0.892, meaning that temperature significantly affects changes in pH in the waters of the Banda Sea. The correlation between pH and salinity was 0.314, which means that salinity also involves changes in pH in the Banda Sea.

Nitrate and phosphate profiles in the Banda Sea during the northwest monsoon

The Banda Sea (BS) is subjected to monsoonal winds that affected upwelled rich nutrient waters and primary production. However, nutrient characteristic in the region is less constrained. Here, we examine nitrate and phosphate profiles in the Banda Sea from data collected during the northwest monsoon. Waters along the surface density (σθ ) < 22 were dominated by less saline originating from western Indonesia (i. e., Java Sea), accompanied by Indonesian throughflow water Banda (23.0-25.0σθ ) and Banda water (26.5-27.0σθ ), respectively. Surface water was accompanied by low nitrite+nitrate () and phosphate (), meanwhile, the average and concentrations in the upper 500 m were slightly higher in the western part than those in the eastern part suggesting additional sources from upwelled waters. Furthermore, the average nitrite+nitrate to phosphate ratio (N:P ratio) was 11.2:1, indicating nitrogen is a limiting factor for the growth of primary producers, and other sources may play a more dominant role. Two distinct layers in the euphotic zone within different sources and mechanisms namely the nutrient-depleted layer and nutrient-repleted layer were observed. Overall, the result of this study can only be seen as a starting point toward a comprehensive and holistic understanding of the nutrient biogeochemistry of the Indonesia Seas.

Effects of High‐Frequency Flow Variability on the Pathways of the Indonesian Throughflow

AbstractPrevious studies have shown the presence of strong mesoscale eddy activities in the Indonesian Seas and their influence on the transport and water mass properties of the Indonesian Throughflow (ITF), a mean flow from the Pacific Ocean to the Indian Ocean through the Indonesian Archipelago. This study explores the effects of these eddy activities, or high‐frequency flow variability (HFFV), on residence time and pathway of the ITF by conducting Lagrangian particle tracking experiments using a velocity field from an eddy‐resolving ocean general circulation model. Particles are released at key locations in the western and eastern routes of the ITF and tracked both backward and forward in time. To assess the effects of flow variability that has a time scale longer than a day but shorter than a month, the definition of HFFV in this study, we conduct parallel experiments using daily and monthly averaged velocity fields. Particle trajectories reveal the contrasting circulation characteristics of the Sulawesi and Banda Seas. HFFV in the Sulawesi Sea (in the western route) is high, causing water to circulate longer over a broader area. The longer residence time in the Sulawesi Sea helps the upwelling of the inflowing Pacific waters, especially the intermediate water masses, to rise above 300 m at the Makassar Strait, and also has the potential to allow mixing processes to modify the water mass properties of the ITF. In contrast, HFFV is much lower in the Banda Sea and has minimal effects on the ITF.

A preliminary magnetic anomaly study of the Nieuwerkerk Seamount, Banda Sea, Indonesia

The Nieuwerkerk seamount has been identified in the Banda Sea since the 1930s by Dutch researchers through the Snellius Expedition. However, the physical description of the seamount and its relation to the surrounding seafloor features has not been discussed due to the lack of geophysical data in the area. This study addresses those issues by examining the shipboard magnetic anomalies acquired during the Jalacitra II-2022 “Banda” Expedition. The result indicates two possible magmatic flows, with the reduced-to-equator magnetic anomaly of around -120 nT and -30 nT at the main and secondary summits, respectively. No magnetic anomaly is identified at the ridge east of the seamount, indicating the absence of structure or magmatic rocks. An extreme magnetic anomaly contrast of up to 145 nT is indicated at the southern foot of the seamount, striking ENE-WSW. These magnetic discontinuities are possibly depicting strike-slip faults, which are also found at the three other smaller seamounts southwest of Nieuwerkerk. These preliminary physical descriptions are key to opening up a discussion on the structure and activities of the Nieuwerkerk seamount and its relationship with the surrounding seafloor features.

Quaternary Seabed Sediment Characteristics as an indication of VMS-mineral deposits at the South Banda Basin and its surroundings, Indonesia

The South Banda back-arc basin is a morphotectonic environment that is part of the South Banda Basin, characterized by a flat morphology with depths ranging from 5000m to 6000m. The purpose of this paper is to analyze and relate morphometric aspects to the Quaternary seabed sediment deposits deposited in an active tectonic basin in the Banda Sea area, including information on the type of sediment and its distribution as well as its relation to volcanic hosted-massive sulfide (VHMS) or volcanogenic massive sulfide (VMS) mineral deposits. The seabed lithofacies in the Banda Arc area were deposited in several morphotectonic environments. The types of deposits that are deposited are pelagic, and hemipelagic deposits including turbidite and volcanic origin deposits. Volcanic deposits consist of gravel, sand, muddy sand, and silt which are classified very poorly to moderately well sorted. The grain composition is volcanic lithic, feldspar, augite, hypersthene, and enstatite which are commonly found in volcanic arcs and troughs. Groups of volcanic grains composed of pyroxene andesite, pumice, and tuffite or siliceous gravel, distributed in the northern and the middle of the volcanic arc area are interpreted to originate from the Banda volcanic complex and the Seram-Gorong islands.

The characteristics of submarine landslide sediments in Eastern Indonesia with study case in Kai Archipelago Waters and Surrounding Area

We review the characteristics of submarine landslide sediments as this phenomenon was observed during geological and geophysics systematic mapping in Eastern Indonesia especially surrounding Kai Archipelago using Geomarin 3 owned by the Ministry of Energy and Mineral Resources and operated by the Marine Geological Institute of Indonesia (MGI). In this survey was encountered seafloor sediment characteristics interpreted as submarine landslide products of a seismically active area. The landslide sediments were characterized by mixed up of gravel, sand, silt and clay fractions with percentages between 5.91 - 15.85, 60.1 - 72.68, 9.42 - 22.40 and 4.06 - 8.97 respectively. The seafloor where the landslide sediments were deposited is a slope with sea depths ranging from 200 up to 700 meters and spread offshore at the south, east and north of Kai Archipelago. Seismicity in this area is related to intense earthquakes that occurred in the subduction zone of the Banda Sea.

International Symposium on Eastern Indonesia Marine Ecosystems

Editors Agus Setiawan, Iis Triyulianti, Charlie Ester de Fretes, Muhammad Zain Tuakia, Sem Likumahua, Faisal Hamzah, Corry Yanti Manullang, Dewi Seswita Zilda, Abdul Wahab Radjab, Muhammad Fadli, Rafidha Dh. Ahmad Opier, Ahmad Romdon. Preface The evaluation of the First Symposium on Banda Sea Ecosystem (ISBSE) held by the Research Center for Deep Sea (then under the Indonesian Institute of Sciences-LIPI) in 2017 indicated the need to expand the geographic coverage area of the symposium. As the follow up, in 2022, the Research Center organized the International Symposium on Eastern Indonesia Marine Ecosystems (ISEIME), with the objective is to gather all marine scientists and observers to meet and share their knowledge and recent information regarding marine ecosystems in eastern Indonesia and the country in general. ISEIME is one of various international conferences that organized by the Indonesian National Research and Innovation Agency-BRIN to focus on topics such as Oceanography and Climate Change; Marine Ecosystems, Biodiversity and Ecology; Marine Monitoring and Management; Marine Pollution; and Marine Geosciences. The event took place on the 24th of November 2022.Human health problems due to the pandemic of COVID-19 in Indonesia has decreased recently, yet in some parts of the country still show slight increase cases. To this end, we decided to conduct the ISEIME 2022 virtually using the zoom platform, which was remotely organized from Ambon, eastern Indonesia. The symposium was commenced by a report from the chairman of ISEIME and subsequently followed by a welcoming-remarks by the Head of Research Center for Deep Sea, Intan Suci Nurhati, Ph.D. In the first session, two keynote speakers (Prof. Ocky Karna Radjasa and Prof. Dwi Listyo Rahayu from BRIN) were given 30-40 minutes to present their talks and followed by a 30 minutes Q&A. Three invited speakers, Prof. Stevan Steinke, Prof. Wiedong Yu and Prof. Madya Dr. Tuan Nurul Sabiqah Tuan Anuar delivered their talks during the second session. In the parallel session, 30 speakers were divided into five different rooms according to the topics and they were given 15 minutes each to deliver their presentations, followed by 5 minutes Q&A.The event has gained a great success due to hard work from the collaboration between the local committee in Ambon, Bali and Jakarta. We would like to thank BRIN International Conference Event Organizer who had taken part in providing time and financial support during the event. Special acknowledgement to all speakers who contribute in the event by imparting their knowledge during the talks and discussions, and also their willingness to participate and contribute in the future marine research in Indonesia. We would also like to extend our sincere thanks to all authors who contribute their findings through their written papers, and for their significant thoughts and ideas in discussions during their presentations. Finally, we give a great appreciation and many thanks to reviewers who have voluntarily participated and contributed not only in judging papers, but also in providing constructive comments and suggestions for authors to improve their manuscripts.ISEIME chairmanSem LikumahuaList of ISEIME Committee is available in this Pdf.

Nieuwerkerk - Emperor of China (NEC) Seamounts (Banda Sea): A multibeam seafloor imagery analysis

A new multibeam dataset of Nieuwerkerk and Emperor of China (NEC) seamounts was acquired during the Jalacitra 2-2022 ”Banda” Expedition in the Banda Sea region. This study discusses a morphometric analysis of the seamounts based on a high-resolution bathymetry digital elevation model (DEM) and describes the morphometric features, namely: slope, profile curvature, and aspect. Morphological results indicate that the Nieuwerkerk seamount has an area of 2,416 km2 with a maximum peak elevation of approximately 3,460 m above the seabed and 357 m below the water surface. In the southwest of the Nieuwerkerk seamount, two new seamounts were discovered, which are still unnamed and seem morphologically connected to the Nieuwerkerk seamount. Each of the seamounts covers an area of 148 km2 and 220 km2, respectively, with a maximum peak elevation of approximately 2,338 m and 2,053 m above the seabed. Additionally, both seamounts have an elevation of 1,878 m and 2,017 m below the sea surface. Meanwhile, the Emperor of China seamount is located southwest of the three formerly mentioned seamounts, with the maximum peak seats at 2,165 m below the sea surface. Seamount C is located in the west of the surveyed area and it covers an area of 95.6 km2 with an elevation of 1,834 m above the seabed. The results of regression analysis indicate that all of the features could be used for the morphological classification.

Seasonal response of coccolithophores and its potential to reconstruct paleomonsoon in the eastern Indonesian seas: an overview

Coccolithophore is a group of marine calcifying phytoplankton and its living distribution is sensitive to ecological change within the photic zone. Their coccoliths contribute majorly to the marine sediments and have become a reliable proxy in paleoceanography and paleoclimatology. The upper hydrology of the eastern Indonesian seas has been strongly influenced by seasonal climate change, the Australian-Indonesian monsoon. We review and discuss the result of previous studies on the response of living coccolithophore to seasonal change and the significance of their coccoliths as a proxy for reconstructing past dynamic of monsoon in the region. Coccolithophores abundance, species assemblages and coccolith malformation change in respond to the shift of photic environment condition modulated by reversing monsoon with particular responds across the region. Coccoliths variations in the marine sediment core archives from off southwest Sumba, eastern Banda Sea and Halmahera Sea show an insignificant control of glacial-interglacial climate variability to paleoproducitivity. Primary productivity based on the relative abundance of Florisphaera profunda has contributed to reconstruction of the past dynamic of Australian-Indonesian monsoon. However, more extensive and continuous observation of coccolithophores and their relationship with the photic environment in the eastern Indonesian seas is necessary for a better understanding of their response to monsoon dynamics in the present, past and future.

KARAKTERISTIK FISIS TELUK AMBON MENGGUNAKAN PEMODELAN HIDRODINAMIKA 3 DIMENSI

Outer Ambon Bay (TAL) and Inner Ambon Bay (TAD) are part of Ambon Bay, which are semi-enclosed waters bounded by a narrow threshold. The characteristics of TAL are strongly influenced by the condition of the Banda Sea waters. Physical characteristics in the Banda Sea are influenced by the phenomenon of upwelling during the southeast season which brings water masses with high salinity and low temperature into the TAL. The condition of Ambon Bay is also influenced by the density gradient and tidal upwelling phenomenon. A 3-dimensional hydrodynamic modeling simulation was conducted to see the tidal upwelling phenomenon that affects the physical dynamics in Ambon Bay. The model simulation time was adjusted to the southeast season, namely June 1 - October 31, 2015. Comparison of simulated tidal elevation values with observation data showed a Root Mean Square Error (RMSE) value of 0.11 m with a correlation coefficient of 94.3%. The distribution of water temperature from the model simulation shows the same value as the satellite image data, which is 26°C.

Indonesian chitons of the genera Belknapchiton Sirenko, Saito et Schwabe, 2022 and Leptochiton Gray, 1847(Mollusca: Polyplacophora: Leptochitonidae)

On the basis of the collections of the R/V Vityaz in the Banda Sea, Indonesia, a review of the chiton fauna of the genera Belknapchiton and Leptochiton was carried out. Leptochiton commandorensis , until now known only from the northern Pacific near the Commander Islands, is here added to the four known Indonesian deep sea species. This species turned out to be with juveniles in the pallial groove. A scanning electron microscope study of the collected specimens of B. giganteus made a corrected, supplemented description of this rare species possible. The age variability of the valves shape and shell sculpture of the two collected species was studied. Particular attention is paid to the age variability of the number of micraesthetes on the tegmentum grains and the position of the mucro.

Deformation Signals at Mud Volcano in Kambing Island Detected by L-band InSAR

Abstract – Mud volcanoes are generated by fluid and solid material extrusion from their mud reservoir and are predominantly found at convergent plate margins. Kambing Island is a small island in Eastern Timor, Indonesia, where the Australian continental plate collides with the Banda Sea plate. The previous geological study identified active mud volcano on this island, but it is still unclear whether and to what extent they are active. In this work, we attempt to detect surface deformation due to the mud volcanoes activism in Kambing island using the Advanced Land Observing Satellite/ Phased Array Type L-band Synthetic Aperture Radar (ALOS/PALSAR) Interferometry Synthetic Aperture Radar (InSAR). The ALOS/PALSAR datasets consist of 12 ascending and 5 descending Synthetic Aperture Radar (SAR) data from 2006 to 2011. Although the results indicate surface deformation signals are hardly detected in the interferogram pairs due to lost coherence and atmospheric noise, we could highlight the episodic occurrence of surface deformation signals between April and November 2008 reaches 6.4 cm moving away from the satellite line of sight. In the future, to back up our findings, further field surveys or long-term InSAR are needed. Keywords: mud volcano, InSAR, deformation.

Komposisi dan Kerapatan Jenis Alga di Taman Wisata Perairan Laut Banda di Kabupaten Maluku Tengah

The purpose of this study was to identify the type of algae, calculate the composition, density, diversity index, similarity index, and dominance index, and measure water quality parameters in the waters of the Banda Sea marine tourism park in central Maluku regency. The method used in this study is a line transect method and a quadrant frame measuring 1m x 1m. There are 3 stations used with 5 replications each. The results showed that there were three divisions of algae, namely Chlorophyta, Phaeophyta, and Rhodophyta, with details of the species obtained were Amphiroa fragilissima, Boodlea composita, Boergesenia forbesii, Cladophora, Chaetomorpha crassa., Dictyota dichotoma, Gracilaria edulispuntia, Halimeda macrophyopuntia. tuna, Padina australis, Ulva compressa, Ulva reticullata. and Valonia ventricosa. The Chorophyta division of 66% obtained the highest species composition value, the highest density was obtained by the Amphiroa fragilissima species of 0.205. In addition, the ecological index such as (1) the diversity index was in the medium category with a value range of 1.35-1.97, (2) the similarity index included in the high category with a value range of 0.72-0.86 which indicates that the ecosystem is in a stable condition and the dominance index of the three stations shows a value close to one, namely 0.87-1 which indicates that there is a tendency for one species to dominate. The measurements of water quality parameters such as temperature, salinity, and currents show that they are optimal for algae growth.

Reconstructing the Parameters of Internal Tidal Bores in the Banda Sea from Satellite Remote Sensing Data

This article presents an algorithm for estimating the vertical displacements of isopycn and horizontal current velocities caused by internal tidal borings from their manifestations in the roughness field on satellite images of the Banda Sea. The calculation algorithm is formulated within the framework of the Korteweg-de Vries equation (KdV), augmented with a term taking into account the cylindrical divergence. The coefficients of the KdV equation — quadratic nonlinearity, dispersion and tidal linear internal wave velocity — were calculated using the mean — climatic density profile in the Banda Sea. The leading soliton velocity and wavelength in the rear zone of the internal tidal borings were determined from satellite images. Using the proposed methodology, estimates of the maximum vertical displacement of the pycnocline/maximum amplitude of the leading soliton and the maximum velocity of surface currents induced by the internal tidal borings were obtained. It follows from the analysis of satellite images that the internal tidal borings in the Banda Sea are transformed under the action not only of nonlinearity and dispersion, but also of cylindrical divergence. It is shown in the framework of the knoidal model of internal tidal borings that in the process of evolution the energy of its leading and subsequent waves is attenuated due to the cylindrical divergence. This attenuation is estimated when the leading soliton travels a distance equal to twice the tidal period.

A cause for hope: largely intact coral-reef communities with high reef-fish biomass in a remote Indonesian island group

Context The health of coral reefs is declining rapidly across the world because of anthropogenic impacts. In the mega-diverse Coral Triangle, the consequences of chronic overfishing and human use are worst near coastal population centres. Aims The remote islands and reefs in the centre of the Banda Sea (Indonesia) remain largely unstudied, but their distance from populated areas could provide protection from fishing. Methods We conducted the first visual census surveys of coral-reef communities at the uninhabited Lucipara group in the Banda Sea. Key results Sites showed medium to high coral cover and fish assemblages with high biomass, including abundant large predatory species. All sites exceeded the fish biomass conservation target of 1150 kg ha−1 proposed by McClanahan et al. (2015), by a factor of ~2–10. Benthic cover explained &gt;50% of variance in fish abundance and diversity, with submassive corals, Dendrophyllia spp., and bare rock as key predictors. Conclusions Our results suggested that Lucipara’s reefs are among the healthiest in Indonesia, likely owing to their remoteness. However, this remoteness might also hamper policing against destructive fishing practices, highlighting a conservation gap. Implications Lucipara’s reef communities should be protected in a time of global coral-reef declines.

Moored Observations of the Currents and Transports of the Maluku Sea

Abstract The mean circulation and volume budgets in the upper 1200 m of the Maluku Sea are studied using multiyear current meter measurements of four moorings in the Maluku Channel and of one synchronous mooring in the Lifamatola Passage. The measurements show that the mean current in the depth range of 60–450 m is northward toward the Pacific Ocean with a mean transport of 2.07–2.60 Sv (1 Sv ≡ 106 m3 s−1). In the depth range of 450–1200 m, a mean western boundary current (WBC) flows southward through the western Maluku Sea and connects with the southward flow in the Lifamatola Passage. The mean currents in the central-eastern Maluku Channel are found to flow northward at this depth range, suggesting an anticlockwise western intensified gyre circulation in the middle layer of the Maluku Sea. Budget analyses suggest that the mean transport of the intermediate WBC is 1.83–2.25 Sv, which is balanced by three transports: 1) 0.62–0.93 Sv southward transport into the Seram–Banda Seas through the Lifamatola Passage, 2) 0.97–1.01 Sv returning to the western Pacific Ocean through the central-eastern Maluku Channel, and 3) a residual transport surplus, suggested to upwell to the upper layer joining the northward transport into the Pacific Ocean. The dynamics of the intermediate gyre circulation are explained by the potential vorticity (PV) integral constraint of a semienclosed basin. Significance Statement The Indonesian Throughflow plays an important role in the global ocean circulation and climate variations. Existing studies of the Indonesian Throughflow have focused on the upper thermocline currents. Here we identify, using mooring observations, an intermediate western boundary current with the core at 800–1000-m depth in the Maluku Sea, transporting intermediate waters from the Pacific into the Seram–Banda Seas through the Lifamatola Passage. Potential vorticity balance suggests an anticlockwise gyre circulation in the intermediate Maluku Sea, which is evidenced by the mooring and model data. Transport estimates suggest northward countercurrent in the upper Maluku Sea toward the Pacific, supplied by the Lifamatola Passage transport and upwelling from the intermediate layer in the Maluku Sea. Our results suggest the importance of the intermediate Indonesian Throughflow in global ocean circulation and overturn. More extensive investigations of the Indo-Pacific intermediate ocean circulation should be conducted to improve our understanding of global ocean overturn and heat and CO2 storages.

Seasonal variation of some oceanographic parameters in the Arafura Sea – Gulf of Carpentaria

The shallow continental shelf of Arafura Sea-Gulf of Carpentaria borders the Torres Strait in the east and the deep Banda Sea in the west, where the monsoonal winds system controls shelf circulation. This study aims to investigate spatial and temporal variation of shelf circulation, surface temperature (SST), seas surface height (SSH), using the multi-datasets of validated model output and satellite-derived data. The model reproduced well the satellite derived SST and SSH (corr.> 0.98). The northwesterly monsoonal winds are fully developed between December and February (NWM period), but the southeasterly winds are intensified during the southeast monsoon (SEM). During the monsoon breaks, the southeasterly-easterly winds are still dominant. The shelf circulation is coincident with the wind direction. During the NMW period the eastward flows from Banda basin and Timor Sea are dominant, creating a clockwise circulation within the Gulf. In contrast, the westward flow dominates during the SEM period, creating an anti-clockwise circulation in the Gulf. Exchange of water via the Torres Strait is also seen. Spatial pattern of temperature and SSH reveal a dissimilarity between the Gulf and the Arafura Sea (99.9% of explained variance) with dominant periodicity of annual and semi-annual scales.

First-order analyses on the role of surface wind in the long-term contraction of the Indo-Pacific warm pool

Due to its high evaporation rate, the Indo-Pacific Warm Pool (IPWP) is one of the most important drivers of Indonesian weather and climate. Previous studies, based on the Sea Surface Temperature (SST) proxy records, suggest that IPWP in the mid-Holocene era (~6000 years ago) underwent a contraction (colder on its east-west perimeter and warmer on its center) compared to today’s condition. In this research, the role of surface wind in contracting the IPWP was analyzed by checking the coherency between changes in SST, wind-stress magnitude, and evaporation. The Climate Community System Model version 4 (CCSM4) simulated these three physical quantities under the pre-Industrial and mid-Holocene scenarios. In these simulations, an anti-phase relation between SST and wind-stress magnitude indicates an important role for a weaker surface wind in warming the SST in the center of the IPWP (South China Sea and Banda Sea), mainly during boreal autumn. However, a weaker surface wind did not seem to have simultaneously suppressed ocean evaporation to warm the SST, as shown by the phase-lag relation in their monthly climatology. On the other hand, colder SSTs on the east-west perimeter of the IPWP (western coast of Sumatra and northern coast of Papua) are unlikely to be associated with changes in the surface wind following a weak correlation between their SST and wind-stress magnitude

Scalloped Hammerhead (Sphyrna lewini) Movement Behavior toward Diver in Banda Waters, Maluku

Shark diving tourism opens opportunities to study shark behavior towards diver. As one of the popular attractions for the marine tourism in Indonesia, shark diving play significant role for the conservation in the eastern part of Indonesia. Banda Sea, as well as Morotai, Derawan, Raja Ampat, Nabire and Teluk Cenderawasih, Bali, Lombok, Komodo, and Gorontalo, is famous for its shark diving attraction. Despite its famous status as a tourism attraction, little is known about the behavior of scalloped hammerhead shark during the interaction with Self-Contained Underwater Breathing Apparatus (SCUBA) diver. The information of scalloped hammerhead shark movement behavior during interaction with SCUBA diver is important for developing ecological assessment, safe diving practice, and shark tourism carrying capacity. This research involves DOV (Diver Operated Video) to record the movement patterns of shark while interacting with SCUBA Diver. Evaluation of approximately 457 photos and 32 videos of the Sphyrna lewini during 14 days of observations has been analyzed during SCUBA diving shows the most common shark agonistic display: pectoral fins depression - apart from other displays such as tail slapping, flank displaying, charging, snout raise, and jaw gapping. It also reveals three (3) new shark agonistic postures which were never been recorded previously: charging, snout raise, and jaw gapping. This study showed that there are consistent behaviors observed while meeting with SCUBA divers and this may be beneficial for development of safety diving management, as well as conservation efforts.

Pathways and destinations of floating marine plastic debris from 10 major rivers in Java and Bali, Indonesia: A Lagrangian particle tracking perspective

Large amounts of plastic discharging from rivers in Java and Bali can potentially pollute many fishing areas in Indonesia. To identify strategies to mitigate this problem, it is important to understand the pathways and destinations of this marine debris. Therefore, the pathways and destinations of debris discharging from 10 major Java and Bali rivers were investigated using a Lagrangian particle tracking model. The amount of floating plastic discharging from each river was determined by the population in each river catchment area, the Mismanaged Plastic Waste ratio, and precipitation. Our study demonstrated that plastic debris pathways in Java and Bali primarily follow surface currents and are secondarily driven by wind toward the Indian Ocean. Around Indonesia, the prevailing monsoonal circulation plays an important role in determining the destination of floating debris. A larger amount of debris was discharged into the seas around Indonesia during the northwest winter monsoon when the precipitation rate was higher, leading to a considerable accumulation of debris in various Indonesian fisheries management areas. The areas most affected were Southern Java, Western Sumatra, and the Banda Sea in descending order. The most effect way of reducing the debris over Southern Java was reducing mismanaged plastic over Yogyakarta, Banten, and Bali provinces or along Progo River.