Language：English   Publishing type：Research paper (scientific journal)   Publisher：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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Language：English   Publishing type：Research paper (scientific journal)   Publisher：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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Other Link： https://www.researchgate.net/publication/377759995_Ontogenetic_shifts_in_Symbiodiniaceae_assemblages_within_cultured_Acropora_humilis_across_hatchery_rearing_and_post-transplantation_phases

Publishing type：Research paper (scientific journal)   Publisher：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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Language：English   Publisher：Science of the Total Environment  

In recent years, significant efforts have been dedicated to measuring and comprehending the impact of microplastics (MPs) in the ocean. Despite harmonization guidelines for MPs research, discrepancies persist in the applied methodologies and future challenges, mostly for the smaller fractions (< 100 μm). Whether intentional or accidental, ingesting plastic particles by zooplankton can lead to incorporating this pollutant into aquatic food chains. Therefore, zooplankton can serve as a suitable proxy tool for assessing the presence of plastic particles in ocean waters. However, reliable information is essential for conducting experimental laboratory studies on the impact of MPs ingestion by zooplankton organisms. Using zooplankton as a research tool for MPs offers numerous advantages, including similar sampling methodologies and study techniques as MPs and particle data integration over space and time. The scientific community can gain novel perspectives by merging zooplankton studies with MPs research. This review explores key aspects of using zooplankton as a tool for MPs research in water samples, encompassing various views such as particles ingestion in natural environments, particle quantification in zooplankton samples (past and future), ecotoxicological and toxicology model studies. By leveraging the potential of zooplankton research, advancements can be made in developing innovative techniques for MPs analysis.

DOI： 10.1016/j.scitotenv.2023.167329

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PeerJ  

The density and diversity of Symbiodiniaceae associated with corals can be influenced by seasonal changes . This study provided the first annual investigation of Symbiodiniaceae density and diversity associated with Acropora humilis and Pocillopora cf. damicornis corals in the Gulf of Thailand using both zooxanthellae cell count and next-generation sequencing (ITS-1, ITS-2 regions) techniques, respectively. The results from this study indicated that zooxanthellae cell densities in both coral species differ significantly. The number of zooxanthellae was negatively correlated with the physical environment variable (light intensity). The diversity within A. humilis consisted of two genera, Cladocopium (Cspc_C3: 56.39%, C3w: 33.62%, C93type1: 4.42% and Cspf: 3.59%) and a small amount of Durusdinium (D1: 1.03%) whereas P. cf. damicornis was found to be 100% associated with Durusdinium (D1: 95.58%, D6: 1.01% and D10: 2.7%) suggesting that each coral species may select their appropriate genus/species of Symbiodiniaceae in response to local environmental stressors. The results of this study provided some information on the coral-Symbiodiniaceae relationship between seasons, which may be applied to predict the potential adaptation of corals in localized reef environments.

File： Jandangetal2022.pdf

DOI： 10.7717/peerj.13114

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：FRONTIERS MEDIA SA  

As seawater temperature rises, repeated thermal bleaching events have negatively affected the reefs of the Andaman Sea for over decades. Studies on the coral-associated microbial diversity of prokaryotes and microbial eukaryotes (microbiome) in healthy and bleached corals are important to better understand the coral holobionts that involved augmented resistance to stresses, and this information remains limited in the Andaman Sea of Thailand. The present study thereby described the microbiomes of healthy (unbleached) and bleached colonies of four prevalent corals, Acropora humilis, Platygyra sp., Pocillopora damicornis, and Porites lutea, along with the surrounding seawater and sediments, that were collected during a 2016 thermal bleaching event, using 16S and 18S rRNA genes next-generation sequencing (NGS). Both prokaryotic and eukaryotic microbes showed isolated community profiles among sample types (corals, sediment, and seawater) [analysis of similarities (ANOSIM): p = 0.038 for prokaryotes, p < 0.001 for microbial eukaryotes] and among coral genera (ANOSIM: p < 0.001 for prokaryotes and microbial eukaryotes). In bleached state corals, we found differences in microbial compositions from the healthy state corals. Prevalent differences shared among bleached coral genera (shared in at least three coral genera) included a loss of reported coral-beneficial microbes, such as Pseudomonadales, Alteromonadales, and Symbiodinium; meanwhile an increase of putative coral-pathogenic Malassezia and Aspergillus. This difference could affect carbon and nitrogen availability for coral growth, reflective of a healthy or bleached state. Our findings in part supported previously microbial dysbiosis knowledge of thermal bleaching coral microbiomes around South East Asia marine geography, and together ongoing efforts are to support the understanding and management of microbial diversity to reduce the negative impacts to corals in massive thermal bleaching events.

DOI： 10.3389/fmars.2022.763421

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Language：English   Publisher：MDPI  

In this study, coral disease was first reported in the coral hatchery in Thailand. Disease were usually found on corals aged two to five years old during the months of November to December of each year. To identify bacterial strains, culture-based methods for strain isolation and molecular techniques of the 16S rRNA gene analysis were used. The resuts showed that the dominant genera of bacteria in diseased corals were Vibrio spp. (comprising 41.01% of the isolates). The occurrence of the disease in the coral hatchery can have a significant effect on the health and survival of juvenile corals before being transplanted to natural reefs for restoration.

DOI： 10.3390/d14010018

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A symbiosis of bacterial community (sometimes called microbiota) play essential roles in developmental life cycle and health of coral, starting since a larva. For examples, coral bacterial holobionts function nitrogen fixation, carbon supply, sulfur cycling and antibiotic production. Yet, a study of the dynamic of bacteria associated coral larvae development is complicated owning to a vast diversity and culturable difficulty of bacteria; hence this type of study remains unexplored for Acropora humilis larvae in Thai sea. This study represented the first to utilize 16S rRNA gene sequencing to describe the timely bacterial compositions during successfully cultured and reared A. humilis larval transformation in aquaculture (gametes were collected from Sattahip Bay, Chonburi province, Thailand), from gamete spawning (0 h) and fertilization stage (1 h), to embryonic cleavage (8 h), round cell development (28, 39 and 41 h), and planula formation (48 h). The sequencing results as estimated by Good's coverage at genus level covered 99.65 ± 0.24&#37; of total bacteria. While core phyla of bacteria were observed (Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes), changes in bacterial population structures and differential predominant core bacterial orders were denoted for each larval developmental stage, from fertilization to embryonic cleavage and subsequently from the embryonic cleavage to round cell development (P = 0.007). For instances, Pseudoalteromonas and Oceanospirillales were found prevalent at 8 h, and Rhizobiales were at 48 h. The bacterial population structures from the round cell stage, particularly at 41 h, showed gradual drift towards those of the planula formation stage, suggesting microbial selection. Overall, this study provides preliminary insights into the dynamics of bacterial community and their potentially functional association (estimated from the bacterial compositions) during the developmental embryonic A. humilis in a cultivation system in Southeast Asia region.

DOI： 10.1038/s41598-021-91379-w

Language：English   Publishing type：Research paper (scientific journal)  

Global warming has caused elevated seawater temperature and coral bleaching, including events on shallow reefs in the upper Gulf of Thailand (uGoT). Previous studies have reported an association between loss of zooxanthellae and coral bleaching. However, studies on the microbial diversity of prokaryotes and eukaryotes (microbiome) as coral holobionts are also important and this information is still limited in the uGoT. To address this shortcoming, this report provided baseline information on the prokaryotic (bacteria and archaea) and eukaryotic microbes of healthy and bleached colonies of four prevalent corals Acropora humilis, Acropora millepora, Platygyra sinensis, and Porites lutea and surrounding seawater and sediments, using 16S and 18S rRNA gene next-generation sequencing. Both prokaryotic and eukaryotic microbes showed isolated community profiles among sample types (corals, sediment, and seawater) (ANOSIM: P < 0.001, R = 0.51 for prokaryotic profiles and P < 0.001, R = 0.985 for eukaryotic microbe profiles). Among coral species, P. sinensis showed the most diverse prokaryotic community compared with the others (ANOSIM: P < 0.001, R = 0.636), and P. lutea showed the most diverse eukaryotic microbes (P = 0.014, R = 0.346). Healthy and bleached corals had some different microbiomes in species and their prevalences. For instance, the significant increase of Alphaproteobacteria in P. sinensis resulted in reduced prokaryotic community evenness and altered potential metabolic profiles (i.e., increased amino acid metabolism and genetic information processing and transcription, but decreased prokaryotic functions in cell motility, signaling, and transduction). For eukaryotic microbes, the loss of the algal Symbiodinium (colloquially known as zooxanthellae) in bleached corals such as P. lutea resulted in increased Chromista and Protista and, hence, clearly distinct eukaryotic microbe (including fungi) communities in healthy vs. bleached colonies of corals. Bleached corals were enriched in bacterial pathogens (e.g., Acinetobacter, Helicobacter, Malassesia, and Aspergillus) and decreased coral-beneficial prokaryotic and eukaryotic microbes (e.g., Rhizobiales & nbsp;and Symbiodinium). Additionally, this study identified microbiome species in bleached P. lutea that might help bleaching recovery (e.g., high abundance of Rhizobiales, Oceanospirillales, Flavobacteriales, and Alteromonadales). Overall, our coral-associated microbiome analyses identified altered diversity patterns of bacteria, archaea, fungi, and eukaryotic microbes between healthy and bleached coral species that are prevalent in the uGoT. This knowledge supports our ongoing efforts to manipulate microbial diversity as a means of reducing the negative impacts of thermal bleaching events in corals inhabiting the uGoT.

DOI： 10.3389/fmars.2021.643962

Language：English   Publishing type：Research paper (scientific journal)  

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. The CSD includes 6178 observations (3085 of which were unpublished) of the time or day of spawning for over 300 scleractinian species in 61 genera from 101 sites in the Indo-Pacific. The goal of the CSD is to provide open access to coral spawning data to accelerate our understanding of coral reproductive biology and to provide a baseline against which to evaluate any future changes in reproductive phenology.

DOI： 10.1038/s41597-020-00793-8

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<jats:p>The emission of greenhouse gases, including high CO2 and other materials, initiates global warming and climate change. Atmospheric CO2 that affects the carbonate system of seawater causes ocean acidification (OA). OA affects marine organisms directly, as well as humans economically and ecologically. Considering the high impact of OA and following the United Nations' Sustainable Development Goals, systematic research and monitoring of OA is necessary in Indonesia, whose seas play an important role in this emerging phenomenon. This review discusses the urgency of OA monitoring systems and suggests carbonate system monitoring, as well as carbon biogeochemistry. OA significantly affects marine production and alters ecosystem services, and it is likely to have an impact on habitats shifting from calcified to non-calcified and reducing benthic complexity. Its effect on calcifying organisms can also be found, i.e., coral calcification and/or dissolution of CaCO3 of calcifying organisms. Acidity (pH), as well as the carbonate system variables of seawater, fluctuate, especially with variations in space and time. Coastal ecosystems that are directly affected by terrestrial input will have carbonate system variables that fluctuate more. The annual rate of decreasing seawater pH, especially over an open and large spatial scale, may indicate OA. Therefore, a monitoring system must be implemented to obtain systematic and comprehensive information on OA. Here, we also introduce a biogeochemical monitoring initiative for OA in Lombok with the established protocols. Improvement of many aspects, including analysis instruments, analysis methods, sample treatment, and sampling frequency will provide new insight into further research and monitoring of OA.</jats:p>

DOI： 10.29037/ajstd.638

Repository Public URL： https://hdl.handle.net/2324/7148409

Language：English   Publishing type：Research paper (scientific journal)  

The effects of pH reduction on the settlement and development of the coral Pocillopora damicornis were investigated. Three different pH treatments (pH = 7.6, 7.9, and 8.1) were used. In addition, water quality (temperature, salinity, total alkalinity) around the study site was monitored. The results showed significant differences in the settlement rates of Pocillopora damicornis larvae between pH treatments (p a parts per thousand currency sign 0.05). A decrease in pH levels caused a strong decline in larval settlement rate. In addition, at pH 7.6 and 7.9, all larvae were unable to complete metamorphosis, and metamorphosis delay was observed. Field monitoring showed low fluctuation of all seawater parameters within 24 hours, and there was no difference between seasons. From this study, a strong negative effect of pH reduction on P. damicornis larvae was observed. Although the function of physiology is still not clearly understood, correlations are likely to exist.

DOI： 10.1007/s12601-015-0043-z

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Language：English   Presentation type：Oral presentation (general)  

Venue：Government Complex   Country：Thailand  

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Karatsu Seaside Hotel  

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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