The waters of Thailand are associated with some of the most severe cases of envenomation from jellyfish in Asia, often attributed to the extensive marine recreational tourism industry it supports. The western Gulf of Thailand in particular has been shown to host among the highest abundances of box jellyfish, while also being home to some of the highest marine recreational tourism, such as along the Koh Samui archipelago. Here we utilise aspects of the same tourism industry to develop a deeper understanding of stinging jellyfish population dynamics, by combining citizen science at the island of Koh Tao, with dedicated in-situ surveys and remote sensing data. Our analyses of 170 box jellyfish sightings and 81 blooms of Pelagia sp. across a six-year period revealed a strong seasonal trend, with both groups being most abundant between July and December. Decision tree analysis of the complete observation dataset and multiple environmental variables revealed a combination of precipitation and lunar cycle to be the strongest predictors of the assessed stinging jellyfish at Koh Tao. Furthermore, blooms of Pelagia sp. were associated with extensive medusivory by a large diversity of predators, including reef building corals. These observations add to the growing literature showing that scleractinian corals are readily able to ingest larger prey items, either by solitary or protocooperative feeding strategies. Meanwhile, no consumption of box jellyfish medusae was recorded during the study. These findings may allow for improved tourism management practices while also supporting a wider biogeographic assessment of stinging jellyfish in south-east Asia.
The emergence of a novel coronavirus strain triggered a global health crisis, impacting both health and economies worldwide, including Thailand since 2019. While prior research hinted at connections between environmental factors and rising COVID-19 cases, these links remained inconclusive. This study investigated indoor and outdoor (I/O) ratios and explored potential correlations between fine particulate matter (PM2.5), meteorological conditions, and the case fatality rate (CFR%) of COVID-19 in Bangkok and its metropolitan area from January to December 2021. In Spearman’s Rank correlation analysis, the results found that CFR% exhibited a positive correlation with relative humidity (RH) (r=0.187) and a negative correlation with PM2.5 (r=-0.190) and wind speed (WS) (r=-0.039). The generalized additive model (GAM) indicated that RH, PM2.5, temperature, and WS adversely affect the CFR% of COVID-19. Consistent relationships between PM2.5, RH, and WS were observed in both Spearman’s Rank correlation and the GAM model. This study underscored the complexity of understanding pandemic dynamics across seasons, I/O ratios, and the influence of lag days. By presenting the results, they may serve as a valuable reference for planning interventions during future pandemics.
Using background values from different geological areas can lead to misinterpretation of ecological risk levels; therefore, selecting appropriate environmental background values is critical. We compared results from various sources and utilized empirical soil background values from parent materials. This study focused on soil properties and the presence of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) along the two highest traffic density highways in Thailand. The findings showed that out of 40 collected roadside soil surface samples, organic matter was significantly related to all heavy metals, except As. Fine-textured soils were the controlling factor for Fe, As, Cu, and Zn concentrations. Positive correlations among the concentrations of Cd, Cr, Cu, Pb, and Zn suggested these metals likely share common origins, primarily from traffic-related sources. Evaluation of the geoaccumulation index (Igeo), the enrichment factor (EF), and the contamination factor (CF) highlights Zn as particularly influenced by human activities. The potential ecological risk index (PERI) revealed low to moderate risks along both highways, while the pollution load index (PLI) indicated varying pollution levels between the two highways. Variations in heavy metal concentrations and ecological risks between the two highways stemed from traffic-related factors and differing environmental conditions. Implementing effective traffic management plans and zoning regulations is crucial for preserving soil resources and safeguarding environmental health. This study suggested that for areas with similar soil formation backgrounds, our background values can serve as proxies for ecological risk evaluation in other studies.
The soil bacterial community is critical for understanding biological processes in soils and is used for agricultural soil management. The understanding of microorganisms and ecology in different soil groups classified based on soil properties (e.g., minerals, soil texture, location, nitrogen, phosphorus, organic carbon and pH, among others), is limited. To suggest soil management strategies using bacterial data, we classified soils into four groups based on physical–chemical characteristics and elucidated their relationships with soil nutrient characteristics and the bacterial community in agricultural fields in Saraburi Province, Thailand. Results show that soil groups with high bacterial diversity had positive correlations with total Kjeldahl nitrogen and available phosphorus but were negatively affected by total organic carbon and pH levels. Dominant bacterial genera included Lactobacillus , Phascolarctobacterium , Prevotella , Clostridium , Gaiellales and Blautia . Significant key biomarkers were found ( p < 0.05). Nutrient-rich soil groups (high available P, acidic pH) were found with genus Agromyces , while low nutrient soil groups (low available P, basic pH) were found with Hydrogenispora , Ignavibacterium and Bauldia . Based on co-occurrence networks, organic degrading bacteria functioned with other bacteria at high degrees of interconnections, suggesting organic amendment, biostimulation and biodegradation using nutrient-rich organic substrates could be used for agricultural soil improvements.
Khaya ivorensis (K. ivorensis), one of the most valuable tropical hardwood species indigenous to West and Central Africa, has been classified as a threatened tree species. However, information on its remaining population and distribution are limited. We mapped the current K. ivorensis spatial distribution, modelled the spatial autocorrelation and estimated its economic value using volume estimation and market pricing. The study was conducted in Odigbo and Irele local government areas (LGA), Ondo State, Nigeria. Spatially, localities of 97 K. ivorensis were identified across the study area and can be added into a wide range of datasets from local to global inventories. Large trees in diameter and height were statistically clustered in the north of Odigbo and assumed to relate with forest reserve management. Estimated median tree volumes were 0.39 m3 and 0.31 m3 in accordance with the allometric volume function and specific volume function, respectively. The economic values of wood varied approximately from US$111,208 to US$72,081. Findings from this study are a valuable resource for conserving this species and other threatened tree species.
The complexity of the relationships among multiple ecosystem services (ES) is not fully understood. This could be because of the difficulty in assessing ES relationships, in general, and particularly, an uneven study of geographical distribution and the relationships among ES demand remains under-researched. Yet, understanding relationships among multiple ES can support policy and management decisions, from problem definition to interventions. This novel research focused on addressing some of the challenges, presenting relationships among ES demand undertaken in Omo Biosphere Reserve (OBR), Nigeria, to improve understanding and extend the geographical coverage of ES relationship studies. In this study, primary data were obtained using a questionnaire survey administered to 302 individuals in OBR. Multinomial regression, correlation and factor analysis were used to identify key ES, explain the influence of sociodemographic attributes on ES preferences and identify the trade-offs, synergies and bundles of ES demand, respectively. The results showed that there were 18 key ES demanded with more preference for provisioning ES such as crops than other ES. Few sociodemographic attributes were identified to influence people's preferences for ES. Furthermore, major trade-offs occurred between provisioning ES with synergies observed among provisioning, regulating and cultural ES. Of the six bundles identified, the first three bundles explained 53% of the total variance which involved environmental, health and basic needs. Our findings not only provide valuable information that could help achieve a well-managed landscape but also support decision-making process and management strategies that could potentially strengthen rural livelihoods.
In aquaculture systems, insufficient nutrients impede shrimp growth while excessive amounts of nutrient inputs lead to environmental degradation and unnecessary high investment. A study of in-out nutrient budgets in an intensive Litopenaeus vannamei farm was conducted in this work to measure the amount of nitrogen (N) and phosphorus (P) input and output from the system. The feed conversion ratio (FCR) was obtained to determine the level of nutrient input performance. Between September and December 2017, monthly water and sediment samples were taken within one crop cycle. Nutrient concentrations in sediment and water increased over 90 days. The total nitrogen concentration in the pond water and effluents were in accordance with wastewater quality control for aquaculture; however, the total phosphorus concentration failed to meet the water quality control from the water input through the end of the crop cycle. The nutrient budget model showed that the input/output contained 107.8 kg N and 178.4 kg P. Most of the N input came from shrimp diets (80%) while most of the P came from fertilizer (57%). Both N (46%) and P (54%) mainly deposited in the sediment as an output process. The FCR of this farm is 2.0. Based on the 1.8 FCR scenario, this farm could reduce 147 kg of feed in total, which accounts for 9.04 kg N and 2.21 kg P reduction. The farmer could save $1027 USD crop − 1 ($1 USD = 32.7 baht), as well as reducing uneaten food at the bottom of the pond. This study offers a simple and straightforward model that can practically reduce environmental impacts and increase the profitability of farms.
Acid volatile sulphide (AVS), one of the most reactive phases in sediments, is a crucial link in explaining a dynamic biogeochemical cycle in a marine ecosystem. Research gaps exist in describing the spatial variation of AVS and interconnections with sediment covariates in the Eastern Upper Gulf of Thailand. Measurements of AVS and auxiliary parameters followed the standard protocol. A comparison of ordinary kriging (OK), cokriging (CK), and regression kriging (RK) performance was evaluated based on the mean absolute error (MAE) and root mean square error (RMSE). The concentrations of AVS ranged from 0.003 to 0.349 mg g−1 sediment dry weight. Most parameters contained short range spatial dependency except for oxidation–reduction potential (ORP) and pH. The AVS tended to be both linearly and non-linearly related to ORP and readily oxidisable organic matter (ROM). The RK model, using inputs from the tree-based model, was the most robust of the three kriging methods. It is suggested that nonlinear interactions should be taken into account when predicting AVS concentration, and it is expected that this will further increase the model accuracy. This study helps establish a platform for ecological health and sediment quality guidelines.
Degradation and destruction of mangrove forests in many regions have resulted in the alteration of carbon cycling. Objectives of this study were established to answer the question regarding how much soil organic carbon (SOC) is stored in wetland soils in part of the upper northeastern Gulf of Thailand and to what extent SOC is related to organic matter (OM). A total of 29 soil samples were collected in October 2015. Soil physiochemical analyses followed the standard protocol. Spatial distributions were estimated by a kriging method. Linear regression and coefficient were used to determine the suitable conversion factor for mangrove soils. The results showed that surface soil (0–5 cm) contained higher SOC content as compared to subsurface soil (5–10 cm). Considering a depth of 10 cm, this area had a high potential to sequester carbon with a mean ± standard deviation of5.59±2.24%. The spatial variability of OM and SOC revealed that organic matter and carbon decreased with the distance from upstream areas toward the gulf. Based on the assumption that OM is 50% SOC, the conversion factor of 2 is recommended for more accuracy rather than the conventional factor of 1.724.
Given the complexity and heterogeneity of mangrove conservation landscape, research gaps still exists to quantify sulfate and total sulfide and their relationships with sediment properties and environmental covariates. Thirty-two sediment samples in the top layers (0-10 cm) were analyzed to assess biochemical properties, sulfate and total sulfide contents. With an average±SD value of 0.62±0.36 mg/g, the total sulfide content from the study site was high compared to the southern part of Thailand. The distribution of sulfate content exhibited high values in nearby land area which gradually reduced in seaward discharges/runoff, whereas high concentrations of total sulfide were highlighted around the center of the study site and vertically accumulated in the top few centimeters of soil and decreased with depth. The most pronounced factor affecting the amount of sulfate and total sulfide content was organic matter, while pH, organic carbon, potassium, salinity, and sediment-mangrove conditions correlated with sulfate and sulfide at different levels. Total sulfides concentration can be considered as indicator of over nutrient-rich sediments for assessing environmental quality perhaps the die-back of mangroves. Concerns about high total sulfide concentrations across mangrove conservation areas should receive more attention, in particular the reduction of OM from the anthropogenic source.
The protection of water, land, and air resources has profound implications for the sustainability of ecosystem services provided to societies that are embedded within economies, global systems, and socio-cultural and political contexts. This study assessed preferences for provisioning, regulating, and supporting ecosystem services, specifically, climate regulation (carbon sequestration), nutrient control (water quality), and agricultural and forest productivity, and the willingness to pay for protection of these ecosystem services by residents in the Suwannee River Basin of Florida, as assessed through a household mail survey and choice experiment. A conditional logit model was used to evaluate preferences and marginal willingness to pay (MWTP) under different scenarios. Survey respondents identified nutrient control (water quality) as the most important service, while agricultural and forestry production was somewhat important, and climate regulation/carbon sequestration was the least important. Respondents expressed the highest level of trust in local government agencies to implement ecosystem service protection programs, and welcomed the implementation of such programs anywhere in the basin, but not close to their home. The average MWTP was extremely low (<$2/household/year) when compared to other studies, and suggests that respondents have many competing interests for their discretionary spending in relation to environmental amenities.
The objective of this study was to develop and implement a Reduce-Reuse-Recycle (RRR) communication strategy through environmental camp as a comprehensive communication tool to promote the RRR concept to elementary school students. Various activities from five learning bases including the folding milk carton game, waste separation relay, recycling relay, quiz game, and drawing were conducted in the learning environment with enjoyment. One hundred nine students at Koh Si Chang School attended an environmental camp. The results indicated that the environmental camp program statistically significantly increased posttest score from 12.47 to 14.13. However, to achieve sustainable solid waste management, environmental education and communication programs should include continuous participatory action research which links all stakeholders.