First case in Japan of neriifolin detection in a patient with coconut crab (Birgus latro) poisoning.

From urban heat island to thermal resilience: Lessons from low-cost microclimate monitoring in a small tropical island

Multi-media occurrence, risk assessment, and island-specific management implications of emerging contaminants in Hainan Island, China

Recent developments in rapidly developing archipelagic nations like Indonesia have led to encroachment on remote islands and an increase in pollution, particularly from microplastics. Due to their remoteness and limited resources, there is a need for versatile bioindicators for microplastics. It has been hypothesized that ascidians can serve as effective bioindicators because of their filter-feeding mechanism. Although research on microplastics in ascidians has been conducted in temperate waters, information regarding this issue in tropical environments remains limited. This study evaluated the ascidian community represented by the species Botrylloides crystallinus, Clavelina moluccensis, Didemnoides patella, and Leptoclinides reticulatus, sampled from four tropical islands with distances of 17.48-117.62km from the main islands. Microplastic contents varied significantly according to differences in species (p = 0.001) and islands (p = 0.001). These ascidian species can serve as proxies for fiber and transparent microplastics. For microplastics less than 300µm, the order of the ascidian species in terms of microplastic accumulation was as follows: D. patella > L. reticulatus > C. moluccensis > B. crystallinus. The polymer analysis revealed that polyethylene terephthalate (PET) is especially prevalent in C. moluccensis, D. patella, and L. reticulatus. In contrast, the polymer composition in B. crystallinus was predominantly polypropylene (PP) (67%), followed by PET (33%). As efficient filter-feeders and being widely distributed, ascidians present fundamental opportunities for the versatile, reliable, and low-cost environmental monitoring of microplastics, in particular, tropical remote islands.

Land-use transition (LUT), a pivotal vector for anthropogenic intervention in the carbon cycle, profoundly influences the formation and evolution of regional carbon emission patterns. This study focuses on Hainan, China's sole tropical island, and establishes a model accounting for carbon emissions associated with LUT based on related remote-sensing data, socioeconomic statistics, and energy consumption-related data between 2000 and 2025. We combine spatial autocorrelation analysis, an extended logarithmic mean Divisia index decomposition model, and the Tapio decoupling model to systematically elucidate the spatiotemporal features of LUT-associated carbon emissions, their driving factors, and their decoupling relation with economic growth. Notably, Hainan Province features an LUT involving decreasing and increasing proportions of carbon-sink land and carbon-source land, respectively, with construction land expansion being the primary transition mode driving carbon emission growth. The associated carbon emission response features a spatial differentiation pattern of high values concentrated in the north and west and low values localized in the south and east. In addition, carbon sources and sinks demonstrate considerable spatial agglomeration. Economic output is the core driver promoting carbon emission growth, with improvements in land-use efficiency and energy intensity being critical for carbon emission mitigation. During the examined period, the correlation between LUT-associated carbon emissions and economic growth evolves from weak to strong decoupling, demonstrating the remarkable efficacy of peak carbon and carbon neutrality goals in guiding emission reduction-focused LUT. Overall, this research provides a scientific basis for coordinating LUT and low-carbon development in the Hainan Free Trade Port initiative.

Residues, influencing factors, and health risk assessment of phthalate esters (PAEs) in major crops from a tropical island in China.

Occurrence, seasonal variability, and ecological risk of emerging contaminants in estuarine and nearshore waters around Hainan Island, China.

Coastal erosion is a significant driver of global mangrove loss, yet its net effect on carbon stocks remains poorly understood. This uncertainty arises from sampling limitations and the potential for inland migration and accretion to offset losses. In this study, we estimated the total ecosystem carbon stocks (TECS) of mangroves undergoing erosion and accretion on a tropical island along the Amazon coast. The carbon balance was quantified over a 38-year period by combining field sampling with remote sensing. We found pronounced spatial variability in mangrove TECS (250–1373 Mg C ha⁻¹), closely linked to forest structure, soil properties, and coastal hydrodynamics. Results revealed an accentuated net decline of 55–77 % in TECS between 1985 and 2023, with an estimated loss of approximately 2500 Mg C. These losses are driven by an asymmetry in the carbon balance, highlighting that newly mangrove stands cannot fully compensate for the carbon lost from mature forests characterized by high biomass and organic-rich soils. Ultimately, our results reinforce the importance of local studies to improve large-scale estimates of carbon stocks and other ecosystem services provided by mangrove forests. • Coastal dynamics drive major shifts in Amazon mangroves carbon stocks. • Total Ecosystem Carbon Stocks varied widely (250–1373 Mg C ha⁻¹) across sites. • High carbon stocks were linked to peat layers in Rhizophora -dominated mangroves. • Changes on mangrove extant revealed a high decline in TECS, ∼ 2400 Mg C loss. • Results highlight the importance of localized processes in carbon assessments.

Artificial light at night (ALAN) is recognised as an emerging threat to global biodiversity but no technical mitigation strategy can prevent all impacts on ecosystems. Consequently, the most effective measure remains turning-off lights whenever and wherever possible. However, few studies, all carried out in temperate environments, assessed the effectiveness of Part-Night Lighting (PNL) and the benefits that might result from changes in switch-off times. On the tropical Reunion Island, where ALAN is increasing exponentially, we assessed the sensitivity of an endemic bat species ( Mormopterus francoismoutoui ) to light, and the effectiveness of PNL in reducing the potential impacts on this species, depending on the switch-off times implemented. We took advantage of the modification of an existing PNL during a month-long event, consisting in switching off lights two hours earlier than the rest of the year. By carrying out an acoustic monitoring of bat echolocation calls, using a Before-After Control-Impact Paired protocol, we showed that bats were attracted to lit sites, especially at the beginning and end of the night, when the lights were on. When the lights were switched off earlier in the evening, there was no longer any impact on bat activity and rhythm, although a tendency toward greater activity at the end of the night in lit sites persisted in clear weather. This provides important insights, encouraging extensive use of PNL, ideally with even earlier switch-off times, as a promising measure for mitigating ALAN effects on this endemic species whose overall population vulnerability is still unknown. • The endemic tropical bat species Mormopterus francoismoutoui is attracted to lights. • Its activity rhythm includes two activity peaks, at the start and end of the night. • Current part-night lighting schemes fail to mitigate impacts of lights on bats. • Earlier switch-off times prevent lights from affecting early-night activity. • Lights should be turned off earlier in the evening and on later in the morning.

Respiratory tract infections remain a major cause of morbidity, with a disproportionate burden in the Caribbean. We aimed to characterize the seasonality and burden of key respiratory viruses across the Caribbean region of the Kingdom of the Netherlands. We analysed virological detection data from 2018 to 2024 collected across all six islands. Seasonal patterns of rhinovirus, influenza virus, respiratory syncytial viruses (RSV) and human metapneumovirus (hMPV) were modelled using generalized additive models. Associations with climate, tourism, age, and disease severity were assessed. Rhinovirus was most frequently detected. Influenza peaked between November and March (P < 0.001), coinciding with periods of high tourism (e.g., Aruba: OR 8.72; 95% CI: 6.37-12.10). In contrast, RSV peaked between June and December (P < 0.001), closely aligning with the rainy season (e.g., Aruba: OR 6.42; 95% CI: 4.26-9.75). HMPV showed a distinct seasonal peak between November and December (P < 0.001), partially overlapping with both RSV and influenza circulation. Rhinovirus detection was significantly associated with increased disease severity, including oxygen therapy need (OR 2.78; 95% CI: 1.72-4.50) and respiratory distress (OR 2.26; 95% CI: 1.42-3.67). RSV seasonality in the Caribbean differs substantially from that observed in temperate regions such as Europe, indicating that prevention schedules developed for temperate climates may be systematically misaligned with local transmission dynamics. Our region-wide data offer insights to guide locally tailored prevention strategies and underscore the need for climate- and mobility-aware respiratory virus preparedness in tropical island regions.

ABSTRACT Vocalization is an important behavior in amphibian biology. In the tropics, amphibian diversity is high and calling activity can overlap among various species. The acoustic niche partitioning hypothesis could explain how closely related species coexist in sympatry and not compete within the acoustic niche. In this study, using passive acoustic monitoring, we set out to evaluate whether acoustic niche partitioning occurs within three sympatric Pristimantis frog species from the Caribbean for the first time. Prior evidence suggests there is overlap at the spatial and temporal scales in the acoustic niche in these species. Therefore, we evaluated whether acoustic niche partitioning occurs within characteristics of the signal properties of their advertisement calls at the spectral scale. We collected acoustic data at 15 sites across the island of Tobago to gather quantitative measurements on the advertisement calls for these three island endemics. From 237 calls, we found significant differences within the signal properties among the three frog species. Signal properties were also significantly different between each species, suggesting all three avoid each other at this scale. Our results provide additional evidence of acoustic niche partitioning in tropical frogs, and specifically in these three species on this small tropical island for the first time, including one which is currently classified as Data Deficient on the IUCN Red List. Our findings can contribute towards improving the conservation and ecology of tropical anurans and interspecific competition in sympatric species on islands.

Abstract Monin–Obukhov similarity theory (MOST) has long served as the basis for parameterizations of turbulence exchange between the surface and the atmospheric boundary layer in models for weather and climate prediction. Decades of research, however, have illuminated some of the limitations of MOST‐based surface‐layer parameterizations, particularly when MOST's foundational assumptions of flat and horizontally homogeneous terrain are violated. Recent work has leveraged the anisotropy of turbulence as an additional non‐dimensional term to extend and generalize MOST to complex terrain. In this work, we examine the performance of this generalized MOST for the scaling of velocity variances, refit these scalings, and study key characteristics of turbulence anisotropy across the 47 towers in the wide‐ranging National Ecological Observation Network (NEON). NEON in particular covers a diverse selection of ecosystems, from the Arctic circle to tropical islands, and as such expands the previous generalized MOST to vegetated canopies and other environments not examined in previous studies. The work finds that anisotropy‐generalized MOST extends readily to these new environments, with robust performance across seasons over a wide range of canopy and terrain configurations. Results also illuminate velocity variance scaling further across degrees and forms (one‐component/two‐component) of anisotropy, relate the degree of anisotropy to key environmental characteristics, and evaluate scaling differences between canopies and non‐vegetated surfaces across atmospheric conditions, seasons, and the diurnal cycle. Overall, this study expands our understanding of the complexity of turbulence, while paving the way for improved surface‐layer parameterizations.

Island area is widely known to affect taxonomic richness across different trophic levels. However, the impact of island size on taxonomic evenness, which quantifies the species abundance distribution, has yet to be explored, especially in tropical island ecosystems. In this study, twenty representative tropical islands with areas ranging from 2 ha to 406 ha and minimal human disturbance were selected. Then we measured the taxonomic evenness of aboveground plants, belowground soil bacterial and fungal communities, as well as a series of soil properties (i.e. pH, salinity, organic carbon, total nitrogen, total phosphorus, total potassium and carbon/nitrogen ratio). We found that, like the positive area‐richness relationship, the taxonomic evenness of the plant community also increased with island area, indicating more stable plant communities on the larger islands. However, the island area did not affect the taxonomic evenness of soil bacterial and fungal communities. Furthermore, the effects of island area on the taxonomic evenness of the plant and soil bacterial communities were mediated through soil factors (e.g. soil pH and salinity). Together, the contrasting area–evenness relationships among plant and soil microbe groups highlight the importance of dissecting potential mechanisms underlying community dynamics of different organisms.

The village of Aplaya, Puerto Galera, on the Philippines island of Mindoro is renowned for its beach and scuba diving. Despite its reputation as an isolated tropical island paradise, Aplaya is also infamous for sex tourism––a legacy of a colonial and military history. Following imperial rule by the Spanish, the US colonized the Philippines and established military bases which expanded during the Vietnam War along with the rest and recreation (R &amp; R) offerings in the base areas, including go-go bars and sex for hire. When the bases closed in the 1990s the sex clientele transferred from military to tourist, and red-light go-go bars opened up in Aplaya. In my ethnographic work on sex tourism, foreign male sex tourists narrate their desires for a Utopian paradise, a tropical beach that is imagined as uninhabited except for the welcoming natives and sexually available women. They nostalgically recount yearnings for a paradise that, lost in the West, is found in the sultry tropics. Colonial and military histories are elided in these imaginaries about the natural access and excess of the tropics. This cultural landscape of the complex relations of sex and tourism call up Lévi-Strauss’ reverie in Tristes Tropiques or Sad Tropics, of the degradation entailed in temperate and tropical encounters and the desire for a pure tropics. However, male sex tourist’s nostalgic imaginaries in reality are also a story of trysts gone troppo.

Abstract Droughts and hot extremes, individually and in combination, are intensifying, driven by anthropogenic greenhouse gas emissions. However, a globally comparable and cross‐national assessment of the future risks posed by these events remains a critical gap. Our analysis shows that under current policies, leading to ∼2.7°C warming by 2100, 28.5% ± 9.3% of the global population (roughly 2.6 ± 0.9 billion people) may face heightened compound hot‐dry extremes. Based on present‐day per capita emissions, the cumulative lifetime emissions of ∼3.4 average global citizens (or ∼1.2 average US citizens) could expose one individual to these conditions by the end of century. Tropical island nations are expected to experience the most severe increases in compound hot‐dry extremes. More critically, low‐income countries, despite contributing minimally to global emissions, are projected to suffer more frequently than high‐income countries. These findings underscore the urgent need for equity‐focused, immediate policy action to address the socio‐economic disparities exacerbated by climate change.

Occurrence, landscape impact, and risk assessments of pesticides in a major river basin of a tropical island, South China.

Reconstructing the geological evolution of small tropical volcanic islands: Insights from the study case of Moorea (French Polynesia)

Abstract The Island Mass Effect (IME) in tropical regions remains understudied, despite its potential to fertilize oligotrophic oceanic gyres and impact on higher trophic levels. Guadeloupe provides an ideal case study of IME due to its diverse nutrient sources, dual exposure to the Caribbean Sea on the western coast and Atlantic Ocean on the eastern coast, and seasonality. Two field campaigns (June 2023, early wet season; January 2024, dry season) assessed macro‐ and micro‐nutrient sources including dissolved iron (DFe) and nitrate (NO 3 − ) and their effects on phytoplankton biomass and composition. Key Fe sources included river outflows influenced by hydrothermalism, weathering, sediment resuspension on the Atlantic shelf, and Saharan dust deposition, with contributions varying seasonally and spatially. Nitrate inputs were mainly linked to anthropogenic river influence, with additional Sargassum contributions in June. On the Atlantic coast, seasonal shifts in DFe and NO 3 − fluxes, associated with river inputs in the dry season and dust and Sargassum in the wet season, did not lead to major changes in phytoplankton assemblages. Diatoms dominated the continental shelf, where NO 3 − and DFe were higher. Marked seasonal changes in phytoplankton occurred only on the Caribbean coast, associated with increased DFe and localized diatom blooms near river outflows in June, although cyanobacteria generally remained the dominant group on this coast. Overall, two distinct IMEs were identified, shaped by contrasting nutrient regimes on each coast. However, offshore nutrient export was minimal and cyanobacteria predominated in offshore oligotrophic waters. These findings enhanced our understanding of IME variability and island‐driven nutrient cycling in tropical systems.

ABSTRACT Aim Tropical Asia's extraordinary plant diversity is thought to be intrinsically linked to its dynamic geological history. However, quantifying the precise evolutionary processes that assembled this diversity across the archipelago remains challenging. A recently proposed biogeographic framework classifies the functional roles of different regions as “radiators,” “incubators,” “corridors” or “accumulators,” offering a useful framework to analyse this complexity. Here, we aim to provide a critical, independent test of this framework using the megadiverse tree genus Syzygium as a model system. Syzygium originated on the Sahul Shelf, contrasting with the Indochinese origin of rattan palms used in the original framework validation. Location Tropical Asia, Pacific Islands and Africa. Methods We analysed the complete chloroplast genome of 200 species of the genus Syzygium and performed phylogenetic analysis to estimate divergence times, ancestral region reconstruction, and estimated diversification and extinction rates. We then analysed the relationship between regional area and the dispersal of species and examined speciation and dispersal patterns in relation to the geographical environment. Results Our comprehensive chloroplast phylogenomic analysis indicates rapid diversification of Syzygium commencing ~12 million years ago, coinciding with shelf collision. Biogeographic reconstructions indicate that while the framework's general principles hold – continental shelf act as “radiators” and isolated islands as “incubators” – the specific geographic roles vary depend on lineage history . Main Conclusions Our study validates the radiator‐incubator model as a general feature of tropical Asian evolution but refines it by demonstrating that historical contingency is key to understanding the assembly of Earth's richest biota. Tropical Asian plant diversity reflects a unique geological history of continental shelf collision and dynamic island geography, offering insights into biodiversity evolution in other geologically active regions worldwide, highlighting the importance of maintaining large, connected natural areas and dispersal corridors for preserving the evolutionary processes that generate Earth's botanical richness.

Background: Sleep problems are prevalent among student populations worldwide. Medical students, facing heavy academic workloads and intense pressure, are particularly susceptible to sleep disorders. While sleep quality among Chinese university students has been consistently declining, research focusing on medical students in tropical island provinces like Hainan remains insufficient. This study aims to address this geographical gap by analyzing the sleep quality status and influencing factors among medical students in Hainan Province. Objective: To investigate the current status of sleep quality and its associated factors among medical students in Hainan Province, providing a scientific basis for developing targeted interventions. Methods: A cross-sectional survey was conducted in April 2024 using purposive sampling to recruit undergraduate students from a medical university in Hainan. The Self-Rating Scale of Sleep (SRSS) developed by Li Jianming was administered, and 551 valid questionnaires were collected anonymously. Data were analyzed using univariate analysis and pairwise comparisons to assess sleep quality and associated factors, with demographic variables as independent variables. Results: Among participants, 40.1% reported sleep problems (31.2% mild, 8.2% moderate, 0.7% severe). The mean total SRSS score was 21.78 ± 5.73. Compared to the national norm, medical students showed significantly higher scores in sleep quality, insufficient arousal, and post-insomnia responses (p < 0.05). Academic major was identified as a significant influencing factor (p = 0.012), with clinical medicine students demonstrating significantly poorer sleep quality than health management majors (p = 0.010). No significant differences were found for gender or academic year. Conclusions: Sleep problems are prominent among medical students in Hainan, with clinical medicine students at higher risk due to academic and professional pressures. Recommendations include optimizing curriculum schedules, strengthening psychological support systems, and developing targeted interventions for clinical majors.