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Jérôme OLLIER

Spatial distribution and composition of marine litter on sandy beaches along the Indian... - 0 views

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    Marine litter in coastal areas can bring economic, social, and environmental damage, especially the loss of aesthetic value of a tourist site. Therefore, research on the composition of marine litter to identify its sources is important for planning strategic action to minimize the problem. This study analyzed beach litter composition on five beaches (Kondangmerak, Balekambang, Ungapan, Ngudel, and Goa Cina) along the Indian Ocean coastline in the eastern part of the south Java region, Indonesia. All the beaches are known as the famous touristic beaches of Malang City, and receive many visitors, especially during the holiday season. Beach litter composition was obtained by collecting different types of litter in a 5 x 5 m square transect. Five square transects were placed along the beach strandline at each beach, and intervals of 20 m separated each transect. In each transect, the litter was collected and counted based on its category (plastic, paper, rubber, fabric, processed wood, metal, glass, ceramic, and hazardous items) and size (0.5-2.5cm, 2.5-5cm, 5-10 cm, and > 10 cm). There was a statistically significant variation in the number of litters among the sizes (p 10 cm was found least on all beaches (< 15%), while the other three size categories were found in similar numbers (in the range of 20% to 50%). Plastic was the dominating type of litter on all beaches. Based on the Clean Coastal Index, all beaches were considered dirty to extremely dirty. All litter on the beaches was the product of tourism activities, and littering habits play a significant role as the source of marine litter in the study areas. Since this is the first study on the marine litter composition in the eastern part of south Java, the results of this study can be used as a baseline for future studies to prevent marine debris pollution and to
Jérôme OLLIER

Sex and Size Influence the Spatiotemporal Distribution of White Sharks, With Implicatio... - 0 views

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    Human activities in the oceans increase the extinction risk of marine megafauna. Interventions require an understanding of movement patterns and the spatiotemporal overlap with threats. We analysed the movement patterns of 33 white sharks (Carcharodon carcharias) satellite-tagged in South Africa between 2012 and 2014 to investigate the influence of size, sex and season on movement patterns and the spatial and temporal overlap with longline and gillnet fisheries and marine protected areas (MPAs). We used a hidden Markov model to identify 'resident' and 'transient' movement states and investigate the effect of covariates on the transition probabilities between states. A model with sex, total length and season had the most support. Tagged sharks were more likely to be in a resident state near the coast and a transient state away from the coast, while the probability of finding a shark in the transient state increased with size. White sharks moved across vast areas of the southwest Indian Ocean, emphasising the need for a regional management plan. White sharks overlapped with longline and gillnet fisheries within 25% of South Africa's Exclusive Economic Zone and spent 15% of their time exposed to these fisheries during the study period. The demersal shark longline fishery had the highest relative spatial and temporal overlap, followed by the pelagic longline fishery and the KwaZulu-Natal (KZN) shark nets and drumlines. However, the KZN shark nets and drumlines reported the highest white shark catches, emphasising the need to combine shark movement and fishing effort with reliable catch records to assess risks to shark populations accurately. White shark exposure to shark nets and drumlines, by movement state, sex and maturity status, corresponded with the catch composition of the fishery, providing support for a meaningful exposure risk estimate. White sharks spent significantly more time in MPAs than expected by chance, likely due to increased prey abundance
Jérôme OLLIER

Sex and size influence the spatiotemporal distribution of white sharks, with implicatio... - 0 views

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    Human activities in the oceans increase the extinction risk of marine megafauna. Interventions require an understanding of movement patterns and the spatiotemporal overlap with threats. We analysed the movement patterns of 33 white sharks (Carcharodon carcharias) satellite-tagged in South Africa between 2012 and 2014 to investigate the influence of size, sex and season on movement patterns and the spatial and temporal overlap with longline and gillnet fisheries and marine protected areas (MPAs). We used a hidden Markov model to identify 'resident' and 'transient' movement states and investigate the effect of covariates on the transition probabilities between states. A model with sex, total length and season had the most support. Tagged sharks were more likely to be in a resident state near the coast and a transient state away from the coast, while the probability of finding a shark in the transient state increased with size. White sharks moved across vast areas of the southwest Indian Ocean, emphasising the need for a regional management plan. White sharks overlapped with longline and gillnet fisheries within 25% of South Africa's Exclusive Economic Zone and spent 15% of their time exposed to these fisheries during the study period. The demersal shark longline fishery had the highest relative spatial and temporal overlap, followed by the pelagic longline fishery and the KwaZulu-Natal (KZN) shark nets and drumlines. However, the KZN shark nets and drumlines reported the highest white shark catches, emphasising the need to combine shark movement and fishing effort with reliable catch records to assess risks to shark populations accurately. White shark exposure to shark nets and drumlines, by movement state, sex and maturity status, corresponded with the catch composition of the fishery, providing support for a meaningful exposure risk estimate. White sharks spent significantly more time in MPAs than expected by chance, likely due to increased prey abundance
Jérôme OLLIER

Potential Plastic Accumulation Zones in the Indian Coastal Seas - @FrontMarineSci - 0 views

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    Plastics account for ~80% of the litter in many marine environments (MORALES-CASELLES et al., 2021) and, a suitable example of a transboundary problem. Several decades of waste mismanagement have made plastics ubiquitous in the global ecosystem and one of the largest growing environmental problems (KERSHAW, 2016). Given the growing evidence of the threats caused by plastics and the projected alarming accumulation in the oceans, environmental managers are urgently pursuing sustainable solutions to reduce plastic. One solution to plastic pollution is identifying the accumulation zones (i.e., hotspots of plastic accumulation). Accumulation zones are also critical for our long-term understanding of the dynamics of plastics in the marine system and identifying vulnerable ecosystems (Lebreton et al., 2017). However, few reports have focused on this aspect of plastic research, particularly from the Indian coast. At the same time, there was a surge in marine plastic publications (80 articles); however, 65% of the study was from beaches. This article addressed this gap by identifying potential plastic accumulation zones along the Indian coast based on published literature. Studies in the field of oil dispersion, plankton connectivity, and marine safety recovery provide an opportunity to understand how oceanographic features may govern the transport of plastic in the ocean (VAN SEBILLE et al., 2020).
Jérôme OLLIER

A Maldives Beach Awash in Bioluminescent Phytoplankton Looks Like an Ocean of Stars - C... - 0 views

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    A Maldives Beach Awash in Bioluminescent Phytoplankton Looks Like an Ocean of Stars.
Jérôme OLLIER

Coupled hydrodynamic and water quality modeling in the coastal waters off Chennai, East... - 0 views

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    Coastal waters are inherently dynamic due to river discharge, industrial effluents, shipping, dredging, waste dumping, and sewage disposal. Population growth in urban cities, climate change and variability, and changes in land-use practices all contribute to pressure on coastal water quality (SKOVSKI et al., 2012; MILLER and HUTCHINS, 2017; KUMAR et al., 2020; Vijay PRAKASH et al., 2021). Anthropogenic activity is evident around these estuaries and coastal and open ocean environments. Hence, it is important to assess the water quality on a regular basis and provide mitigation measures for coastal pollution (YUVARAJ et al., 2018). Improving water quality and variability in coastal waters is necessary and should be prioritized. Observational programs, which are more expensive and time-consuming, aid in understanding the status of water quality and its trends. Many countries have coastal programs that use predictive systems to inform the public and stakeholders about coastal health. Hydrodynamic processes are an integral part of complex surface water systems. The main factor that determines the concentration of pollutants is hydrodynamic transport, which includes advection, dispersion, vertical mixing, and convection (James, 2002). The flow and circulation patterns have a great influence not only on the distribution of temperature, nutrients, and dissolved oxygen (DO) but also on the aggregation and distribution of sediments and pollutants. When a load of pollutants is discharged into coastal waters, it is affected by the fate and transportation processes that change its concentration. Several studies have been conducted to evaluate the coastal water quality spatiotemporally along the east coast of Indian coastal waters using site-specific data and model configuration (PANDA et al., 2006; BHARAHTI et al., 2017; NAIK et al., 2020; MOHANTY et al., 2021). Through numerical modeling and remote sensing, estimation is user-friendly and low-cost in evaluating any water quali
Jérôme OLLIER

On the Beach: killer plastic art at the end of the earth - video - @guardianeco - 0 views

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    On an isolated stretch of Western Australian beach, artist Tim Pearn creates art from colourful washed-up plastic waste
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    On an isolated stretch of Western Australian beach, artist Tim Pearn creates art from colourful washed-up plastic waste
Jérôme OLLIER

On a Remote Island, a Lost Part of the World Is Found - @earthinstitute - 0 views

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    On a remote tropical island in the Indian Ocean lies a geologic enigma. Some 4 million years ago, volcanic eruptions on the seabed piled lava upward almost two miles, until it broke above the waves. Then it kept piling up, to form what is now the craggy, densely vegetated island of Anjouan. Like all islands formed this way (think Hawaii) Anjouan is 100 percent dark volcanic basalt. Except for the part that is not. That part-a mass of pure white quartzite, apparent remains of a river or beach deposit formed on some faraway, long-ago continent-is not supposed to be there.
Jérôme OLLIER

Platform publishes list of ships dismantled worldwide in 2017 - @NGOShipbreaking - 0 views

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    According to new data released today by the NGO Shipbreaking Platform, 835 large ocean-going commercial vessels were sold to the scrap yards in 2017. 543 were broken down - by hand - on the tidal beaches of Bangladesh, India and Pakistan: amounting to 80,3% of all tonnage dismantled globally.
Jérôme OLLIER

Hydrodynamic Drivers and Morphological Responses on Small Coral Islands-The Thoondu Spi... - 0 views

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    Assessing the resilience of islands toward altered ocean climate pressures and providing robust adaptation measures requires an understanding of the interaction between morphological processes and the underlying hydrodynamic drivers. In this sense, this study presents changing sediment volumes on various temporal scales for the fringing reef island Fuvahmulah. Based on three field campaigns, conducted over 2 years, aerial imagery provides information on marine aggregates of the island's beaches. In addition, high resolution climate reanalysis data serves as input into an empirical and a numerical approach. Together, both approaches describe the driving processes behind volumetric seasonal and interannual changes: On the one hand, the empirical method quantifies sediment transport rates for calcareous sediments over the whole time span of the data set by considering wind and swell waves from multiple directions. On the other hand, the numerical method gives insights into the complexity of currents induced by dominant wave components. Combining these methods facilitates hindcasting and predicting morphological changes under varying wave climate, assessing sediment pathways over the whole reef, and describing the seasonal and interannual evolution of the sand spit Thoondu. As a result, this study reveals sediment distribution on different spatio-temporal scales and elucidates their significance in the design of conventional and alternative low-regret coastal adaptation.
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