記述言語：英語   出版者・発行元：Science of the Total Environment  

Individual coral polyps contain three distinct components—the surface mucus layer, tissue, and skeleton; each component may exhibit varying extent of microplastic (MP) accumulation and serve as a short- or long-term repository for these pollutants. However, the literature on MP accumulation in wild corals, particularly with respect to the different components, is limited. In this study, we investigated the adhesion and accumulation of MPs in four coral species, including both large (Lobophyllia sp. and Platygyra sinensis) and small (Pocillopora cf. damicornis and Porites lutea) polyp corals collected from Si Chang Island in the upper Gulf of Thailand. The results revealed that MP accumulation varied significantly among the four coral species and their components. Specifically, P. cf. damicornis exhibited the highest degree of accumulation (2.28 ± 0.34 particles g−1 w.w.) [Tukey's honestly significant difference (HSD) test, p < 0.05], particularly in their skeleton (52.63 %) and with a notable presence of high-density MPs (Fisher's extract test, p < 0.05). The most common MP morphotype was fragment, accounting for 75.29 % of the total MPs found in the coral. Notably, the majority of MPs were black, white, or blue, accounting for 36.20 %, 15.52 %, and 11.49 % of the samples, respectively. The predominant size range of MP particles was 101–200 μm. Nylon, polyacetylene, and polyethylene terephthalate (PET) were the prevalent polymer types, accounting for 20.11 %, 14.37 %, and 9.77 % of the identified samples, respectively. In the large polyp corals, while MP shapes, colors, and sizes exhibited consistent patterns, remarkable differences were noted in the polymer types across the three components. The findings of this study improve the understanding of MP accumulation and its fate in coral reef ecosystems, underscoring the need for further investigation into MP-accumulation patterns in reef-building corals worldwide.

DOI： 10.1016/j.scitotenv.2024.176210

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Science of the Total Environment  

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. This study aimed to characterize the size, shape, and polymer types of the SMPs ingested by the copepod Centropages furcatus in Si Chang Island (upper Gulf of Thailand). The study spans offshore and coastal waters, with data collected across wet, intermediate, and dry seasons. Using a semi-automated technique for micro-FTIR (Fourier-transform infrared) scanning spectroscopy for particle analysis, we found ingested SMPs in all samples. A total of 750 individuals of the calanoid Centropages furcatus were analyzed, finding 309 plastic particles and an average ingestion value of 0.41 ± 0.13 particles ind−1, one of the highest recorded values. All the particles were fragments, with a predominant size under 50 μm, and polymer types as Polypropylene (PP, 71 %), followed by Ethylene-Propylene-Diene-Monomer (EPDM, 16 %) and Polyethylene (PE, 7 %). Up to 470.2 particles m−3 were estimated to be retained by this calanoid species and potentially available for trophic transfer. The effect of rainfall on SMPs ingestion was inconclusive, with a non-significant observed tendency to higher ingestion values near the coastal area than offshore area, suggesting a decrease in particle exposure due to the runoff effect. Nevertheless, future studies should increase the frequency of surveys to arrive at better conclusions.

DOI： 10.1016/j.scitotenv.2024.172837

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Science of the Total Environment  

Southeast Asian countries are recognized as significant contributors to the discharge of abundant plastic waste into the ocean. In this study, we conducted neuston net surveys on Si Chang Island of the Gulf of Thailand, a coral reef conservation area, to determine the presence of microplastic (MP) pollution. The survey, conducted during the wet (southwesterly monsoon), transition, and dry seasons (northeasterly monsoon), revealed that the MP abundance was in the range of 0.02–42.46 particles m−3. The precipitation, wind, and current direction induced by monsoons influenced the abundance and distribution of MP, presenting a significant seasonality. The cluster analysis for colors and polymer types of MPs suggested that the origin of plastic particles is diverse. Based on our results, a proposal for the generation, sources, and pathways for MPs in the Gulf of Thailand is presented: 1) plastic wastes exposed to strong UV light during the dry season get fragmented around the river, and 2) heavy rains wash away the particles during the wet season. This proposal is applicable to tropical regions, including the Gulf of Thailand. Therefore, this paper concluded that ocean currents induced by monsoons and the unique climate, resulting in the generation of MPs on land, increase MP presence and distribution in the ocean surrounding Southeast Asia countries. Furthermore, coral reef ecosystems can be particularly threatened by MPs in these areas. So, an increase in MP monitoring on coral ecosystems from Thailand and the world is highly recommended.

DOI： 10.1016/j.scitotenv.2024.170787

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Frontiers in Marine Science  

Coral reefs have been declining worldwide due to multiple threats. Various approaches for coral restoration have been employed to increase coral populations. Sexual propagation is a crucial technique that can enhance the genetic diversity of coral offspring, thereby increasing coral reef resilience in the face of a changing environment. However, the effectiveness of using sexually reared corals for transplantation depends on many factors, including the biological traits of the coral and the physical environment. This study investigated the relationship between Acropora humilis and Symbiodiniaceae during the ontogenetic stages of the coral in ex-situ conditions and after transplantation to a natural reef. Coral sexual propagation techniques were conducted to produce experimental coral colonies. The fertilization rates of coral gametes averaged 98.48 ± 0.34%. However, the survival rate of juvenile corals gradually declined to 45.96 ± 1.31% at 18 months old under hatchery conditions and to 20% after transplantation to a natural reef. Acropora humilis associated with Symbiodiniaceae lineages belonging to three genera: Symbiodinium, Cladocopium, and Durusdinium. Reared juvenile corals developed a more specific and stable association with particular Symbiodiniaceae under hatchery conditions, whereas after transplantation, corals tended to contain a higher diversity of Symbiodiniaceae lineages. These results indicate that a shift in Symbiodiniaceae composition can provide long-term benefits to corals during their ontogenetic cycle and when the environment changes.

DOI： 10.3389/fmars.2024.1138021

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その他リンク： https://www.researchgate.net/publication/377759995_Ontogenetic_shifts_in_Symbiodiniaceae_assemblages_within_cultured_Acropora_humilis_across_hatchery_rearing_and_post-transplantation_phases

掲載種別：研究論文（学術雑誌）   出版者・発行元：Regional Studies in Marine Science  

Researchers have made a significant effort to reveal plastic pollution's presence and consequences worldwide; however, there are no standard methods to evaluate the level of microplastic pollution. In this context, pollution index assessment in the marine environments contributes to showing a criteria of pollutants. Therefore, the pollution load index (PLI), the polymer risk index (H), and the pollution risk index (PRI) were estimated based on the MPs abundance and polymer-type information in situ for five areas around Japan's sea. According to H values, the contamination due to MPs presented low to moderate pollution levels in each area. Whereas the PRI classified the pollution levels from low (offshore) to very high (coast). Based on MPs' predicted concentrations for 2030 and 2060, the PRI is expected to increase, reaching a very high-pollution level even for offshore areas. The results of this study emphasize the importance of action to prevent additional plastic pollution and the importance of continued monitoring of the MPs in the environment.

DOI： 10.1016/j.rsma.2023.103287

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開催年月日： 2024年4月

記述言語：英語   会議種別：口頭発表（一般）  

国名：タイ王国  

開催年月日： 2023年6月

記述言語：英語   会議種別：シンポジウム・ワークショップ パネル（公募）  

国名：シンガポール共和国  

開催年月日： 2023年5月

記述言語：英語   会議種別：シンポジウム・ワークショップ パネル（公募）  

国名：日本国  

記述言語：英語  

国名：その他  

記述言語：その他  

国名：その他  

Microplastic in the marine environment and potential effect to human health

The content is about plastic pollution research with the collaboration between Japan and Thailand.

A lecture on coral reef and coastal ecosystem conservation. https://www.egat.co.th/egattoday/egattoday/index.php?option=com_k2&view=item&id=19918:02082565-fuel02