Publications by authors named "Voranop Viyakarn"

In this study, environmental microplastic samples (>30 μm) were collected from surface seawater and the water column, characterized, and used to assess ecological risks. The influence of mesh selectivity on ecological risks was also evaluated through subsampling. Results show that surface microplastic concentrations (>30 μm) range from 92 to 3306 pieces/m along Japan's southwest coast, with significant increases at Stas.

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Research on microplastics must be harmonized. Therefore, we thoroughly evaluated in the Association of Southeast Asian Nations (ASEAN) region, addressing challenges and priorities in protocol harmonization and microplastics research promotion. Of the 615 papers searched by the Web of Science, 164 were used for this systematic review.

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Article Synopsis
  • Coral polyps consist of three parts: surface mucus, tissue, and skeleton, which can accumulate microplastics (MPs) to different extents, but research on this is limited.
  • In a study of four coral species from Si Chang Island, P. cf. damicornis showed the highest MP accumulation, especially in its skeleton, with fragments being the most common type.
  • The most frequent colors found were black, white, and blue, with nylon and polyethylene terephthalate (PET) being the major polymer types identified; this study highlights the importance of understanding MP accumulation patterns in corals globally.
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In this study, microplastic concentrations in the southeastern coastal regions of Japan were measured along the northward ocean current at seven stations from Okinawa to Tokai region. Concentrations ranged from 0.014 to 0.

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Microplastics (MPs) and plastic additive chemicals are emerging pollutants of great concerns around the world. Open dumping sites can be important sources of those pollutants in emerging countries, but little is known about their occurrence, distribution, transport pathway, and remediation approach. This study aimed to obtain the comprehensive dataset on plastic pollution in an open dumping site in Thailand, including (1) the polymer types and organic/inorganic plastic additives in plastic garbage, (2) horizontal distribution of MPs and plastic additives in the surface soil, (3) the effects of soil-capping treatment, and (4) the vertical transport.

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Hydrocarbon contamination, including contamination with polycyclic aromatic hydrocarbons (PAHs), is a major concern in Antarctica due to the toxicity, recalcitrance and persistence of these compounds. Under the Antarctic Treaty, nonindigenous species are not permitted for use in bioremediation at polluted sites in the Antarctic region. In this study, three bacterial consortia (C13, C15, and C23) were isolated from Antarctic soils for phenanthrene degradation.

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Microplastics could be ingested by many organisms, including zooplankton, involving bioaccumulation and biomagnification mechanisms a cross food webs. The information about microplastic ingestion by zooplankton keeps increasing worldwide. However, it is still limited for particle sizes under 300 μm (small microplastics, SMPs) and in areas such as Southeast Asia, which is considered one of the hotspots for plastic debris.

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We reported on microbial communities isolated from 18 seawater samples affected by oil spills in Rayong province, Thailand, using the V3-V4 region of 16S rRNA gene sequencing.

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Article Synopsis
  • Southeast Asian countries contribute significantly to ocean plastic waste, with a study conducted on Si Chang Island revealing microplastic (MP) pollution levels ranging from 0.02 to 42.46 particles per meter across different seasons.
  • Seasonal factors like precipitation, wind, and currents from monsoons significantly influence the abundance and distribution of MPs, highlighting a notable pattern of environmental impact.
  • The study proposes that UV exposure in dry seasons and heavy rains in wet seasons contribute to the generation and dispersal of MPs, posing a threat to coral reef ecosystems and suggesting that increased monitoring of microplastics is essential in these vulnerable areas.
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Marine debris comprising single-use plastic products (SUPs) is ubiquitous in Asian coastal waters, but there is little information on the types of polymers and the concentrations of plastic additives such waste products contain. In this study, 413 SUPs randomly collected from 4 Asian countries between 2020 and 2021 were analyzed to obtain specific polymer and organic additive profiles. Polyethylene (PE), coupled with external polymers, was prominent in the inside of the SUPs, whereas polypropylene (PP) and polyethylene terephthalate (PET) were prevalent in both the insides and outsides of the SUPs.

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  • This study investigates how seasonal changes affect the density and diversity of Symbiodiniaceae (zooxanthellae) associated with coral species in the Gulf of Thailand.
  • It finds that zooxanthellae cell densities vary significantly between coral species and are negatively correlated with light intensity.
  • Two coral species showed different preferences for specific genera of Symbiodiniaceae, indicating that they may choose their symbionts based on local environmental conditions, which could help in understanding coral adaptations.
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Southeast Asia is considered to have some of the highest levels of marine plastic pollution in the world. It is therefore vitally important to increase our understanding of the impacts and risks of plastic pollution to marine ecosystems and the essential services they provide to support the development of mitigation measures in the region. An interdisciplinary, international network of experts (Australia, Indonesia, Ireland, Malaysia, the Philippines, Singapore, Thailand, the United Kingdom, and Vietnam) set a research agenda for marine plastic pollution in the region, synthesizing current knowledge and highlighting areas for further research in Southeast Asia.

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Improved access to field survey infrastructure throughout South-East Asia has allowed for a greater intensity of biodiversity surveys than ever before. The rocky bottoms and coral reef habitats across the region have been shown to support some of the highest sea slug biodiversity on the planet, with ever increasing records. During the past ten years, intensive SCUBA surveys have been carried out at Koh Tao, in the Gulf of Thailand, which have yielded remarkable findings in sea slug biology and ecology.

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Article Synopsis
  • Coral bacterial communities, or microbiota, are crucial for the growth and health of coral larvae, affecting processes like nitrogen fixation and antibiotic production.
  • This study is the first to explore the bacterial makeup of Acropora humilis larvae in Thailand, analyzing samples from various developmental stages using 16S rRNA gene sequencing.
  • The research found distinct shifts in bacterial populations at different stages of larval development, highlighting microbial selection and providing early insights into the symbiotic relationships between bacteria and coral larvae.
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A novel bacterium, designated strain ANT13_2, was isolated from a phenanthrene-degrading consortium enriched from a soil sample collected near the Great Wall Station located in the southwestern area of King George Island, Antarctica. Following a polyphasic taxonomic study, a novel species belonging to the genus was described. The strain was a Gram-stain-positive bacterium that exhibited a rod-coccus growth cycle.

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The discovery of multi-species synchronous spawning of scleractinian corals on the Great Barrier Reef in the 1980s stimulated an extraordinary effort to document spawning times in other parts of the globe. Unfortunately, most of these data remain unpublished which limits our understanding of regional and global reproductive patterns. The Coral Spawning Database (CSD) collates much of these disparate data into a single place.

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An interlaboratory comparison exercise was conducted to assess the consistency of microplastic quantification across several laboratories. The test samples were prepared by mixing one liter seawater free of plastics, microplastics made from polypropylene, high- and low-density polyethylene, and artificial particles in two plastic bottles, and analyzed concurrently in 12 experienced laboratories around the world. The minimum requirements to quantify microplastics were examined by comparing actual numbers of microplastics in these sample bottles with numbers measured in each laboratory.

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Corals are sensitive to minute changes in their environments, and their continued existence is substantially threatened by the increasing number of destructive anthropogenic activities and unprecedented rates of climate change. Although cryopreservation has been successfully to preserve mammalian gametes for decades, coral cryopreservation was attempted for the first time less than 15 years ago, and freezing protocols exist for only a handful of coral species. The present study developed a cryopreservation protocol for the sperm of the common Indo-Pacific reef-builder Acropora humilis.

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In this study, the ultrastructure of the oocytes of 6 types of scleractinian corals was observed by transmission electron microscopy (TEM). Moreover, histological and ultrastructural analyses were performed to improve our understanding of the organelles involved in coral oocyte formation. In all 6 stony coral species, the microvilli were tubular and directly grew from the surface of the oocyte membrane; yolk bodies, lipid granules, and cortical alveoli accounted for most of the volume inside the oocytes, suggesting that they are associated with energy storage and buoyancy.

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Gorgonian corals are slowly declining due to human interaction and environmental impacts. Cryopreservation of gorgonian corals is an ex-situ method of conservation, ensuring future reproduction. The present study assessed the vitrification properties of cryoprotectant (CPT) mixtures using the cryotop, cryoloop and open pulled straw (OPS) cryopereservation methods prior to experimentation on gorgonian (Junceella juncea) oocytes.

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The lipid phase transition (LPT) from the fluid liquid crystalline phase to the more rigid gel structure phase that occurs upon exposure to low temperatures can affect physical structure and function of cellular membranes. This study set out to investigate the membrane phase behavior of oocytes of three gorgonian corals; Junceela fragilis, J. juncea and Ellisella robusta,at different developmental stages after exposure to reduced temperatures.

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