Search Results (143)

Mangrove ecosystems along the Pacific coast of Panama are increasingly exposed to anthropogenic pressures such as urban expansion and deforestation. These habitats provide resources for orchid bees (tribe Euglossini), yet information on their assemblages in mangrove environments remains limited. In this study, we documented the diversity and composition of orchid bee communities in mangrove–forest edges from two coastal areas with contrasting levels of human disturbance: Panama Bay and Chame Bay. Orchid bee sampling was carried out during two independent periods: from April to July 2022 at three sites in Panama Bay, and from December 2022 to January 2023 at one site in Panama Bay and one site in Chame Bay, using McPhail traps baited with eucalyptus oil and distributed across multiple zones within each site. A total of 427 individuals representing 14 species and three genera were recorded. Observed species richness and abundance were lower at the more urbanized mangrove sites, where collections were dominated by a few widespread species, particularly Eulaema nigrita. Multivariate analyses revealed differences in community composition between sites. These patterns suggest associations between anthropogenic context and orchid bee assemblage structure in mangrove edges, although longer-term and multi-method studies are required to evaluate temporal consistency and underlying mechanisms. This study provides baseline information to support future monitoring of orchid bee communities in tropical coastal ecosystems. Full article

Ocean winds and waves play a vital role in maritime navigation safety, offshore operations, and coastal zone dynamics. Although both factors have been widely studied individually, the joint characterization of wind and wave events remains limited in the North Indian Ocean. This study, utilizing ERA5 reanalysis data from 1980 to 2022, statistically analyzed the distribution and variation patterns of both wind speed and significant wave height, investigating the occurrence, affected area proportion, frequency, and intensity of SBLWEs. To understand the cause of Strong Breeze and Large Wave Events (SBLWEs), their connections with other phenomena, such as tropical cyclones, were also explored. The results show that regions with strong breezes and large waves are mainly concentrated in the central and western Arabian Sea near Africa and the central and western Bay of Bengal. Monthly averages indicate that wind and wave intensity are much higher during the summer monsoon than in other seasons, with high intensity, probability, and extensive affected areas of SBLWEs. The occurrence probability of SBLWEs is highest in the central and western Arabian Sea (up to ~40%), and the highest probability in the Bay of Bengal is about 20% near the eastern coast of Sri Lanka. The peak period of SBLWEs occurs from June to August, with the largest affected area in July, reaching almost 25%. Over the past 40 years, the number of SBLWEs has shown an increasing trend, with an average of 0.7 events annually. The intensity distribution of SBLWEs resembles that of wind speed and wave height, with the highest intensity areas concentrated in the Bay of Bengal, affected by tropical cyclones. This study can serve as a scientific reference for maritime route planning and offshore operations, helping to reduce the negative impacts of large wind and wave events and enhance navigation safety. Full article

Construction projects on tropical islands face a high incidence of safety accidents due to complex environmental conditions, construction technologies, and varying levels of worker safety awareness. Traditional risk analysis frameworks, constrained by narrow analytical perspectives, struggle to account for the escalating uncertainties and safety perturbations inherent in tropical island construction processes. To address this gap, and to improve upon both Health Safety and Environment Management System (HSE) and Bayesian Networks (BN) methods, an IHIB model for construction safety risk analysis of tropical island buildings was established. The Improve Health Safety and Environment Management System (IHSE) method constructs an indicator system from six dimensions: institutional, health, organizational, safety, environmental, and emergency response factors. The Improved Bayesian network (IBN)method, by introducing fuzzy set theory and an improved similarity aggregation method, more accurately infers the influencing factors and the most probable causal chains for construction safety on tropical islands. Taking the Sanya Haitang Bay construction project as a case study, the IHIB analysis model reveals that high temperatures and strong winds are the decisive factors influencing construction safety risks on tropical islands. The findings contribute to proactive risk prevention and mitigation, offering practical guidance for enhancing construction safety management on tropical islands. Full article

This study investigates spatial and seasonal variation in the assemblages of benthic microgastropods (snails < 5–10 mm in length) within a poorly studied tropical bay. As these organisms are abundant, diverse and relatively easy to sample, with well-established taxonomy, they may prove a highly suitable group for ecological studies in such areas. Sediment samples were collected from three river basins in Camamu Bay, Brazil, during the wet and dry seasons. A total of 132 microgastropod species was recorded, demonstrating high diversity. The most abundant species were Eulithidium affine, Bittiolum varium, Cerithium atratum, Vitta virginea and Schwartziella bryerea. The least abundant species were Tenaturris gemma, Turbinella laevigata, Petaloconchus erectus, Parviturboides interruptus and Vitrinella cupidinensis. Statistical analysis revealed significant seasonal and spatial differences in diversity and assemblage composition, which correlated with environmental gradients. The results suggest that microgastropods are a suitable component of the biota for ecological and applied studies in marine sediments, particularly in remote tropical locations where full macrofaunal analysis may be challenging. Whilst further testing across impact gradients is needed, this approach offers a practical solution for ecological investigations in remote regions with limited taxonomic expertise and highlights microgastropods as a useful indicator taxon for impact biomonitoring in tropical marine sediments. Full article

Cartagena Bay, a coastal estuary in northern Colombia, receives significant sediment inputs from the Canal del Dique, an artificial channel with average discharge rates of 55 m³/s during the dry season and 250 m³/s during the rainy season. This study presents the variability of turbidity in Cartagena Bay for 21 years (2002–2022) using MODIS satellite imagery. Turbidity series were determined by using a remote sensing empirical algorithm developed for Cartagena Bay in 2024. In the present study, this algorithm was validated using MODIS data, demonstrating an adequate performance (R² = 0.88, RMSE = 3.1, MAPE = 29.5%). Spatial and temporal turbidity patterns were analyzed for three representative months: February (dry season), July (low precipitation), and November (high rainfall). The role of the El Niño–Southern Oscillation (ENSO) on the dynamics of the Canal del Dique discharge and turbidity levels was studied through anomaly analysis and Fourier Transform Analysis (FTA). Results highlight a marked spatial variability in turbidity, with the highest turbidity levels observed near the canal mouth from April to September. FTA revealed a dominant annual cycle in turbidity and discharge, with additional semi-annual and multi-year periodicities linked to the rainfall periods and ENSO. Turbidity variability appears primarily driven by seasonal and local hydrodynamic processes, with a long-term increasing trend in turbidity. This approach can be applied to other tropical estuaries under strong fluvial influence. Full article

Agricultural facilities in tropical regions such as Hainan China face dual challenges from summer typhoons and occasional winter cold waves. Traditional greenhouses are generally constructed at a low height to resist typhoons, which hinders mechanized operations, while the use of insect-proof screens compromises thermal insulation. To resolve these contradictions, this study designs a typhoon-resistant multi-span greenhouse with an elevatable roof. Its core innovation lies in adopting a mechatronic steel cable system to achieve synchronized elevation of single-span roof surfaces. During daily operations, the roof is elevated to facilitate mechanized field operations; during typhoons or cold waves, the roof is lowered to the ground, reducing wind load impact and improving thermal insulation performance. The greenhouse’s elevating system incorporates multiple safety functions, including bidirectional self-locking and overload protection. Structural calculations using PKPM 2010 software show that under two working conditions—roof elevated (basic wind pressure of 0.45 kN/m²) and roof lowered (basic wind pressure of 1.30 kN/m²)—all indicators meet the requirements of relevant codes. Compared with an ordinary circular-arch greenhouse of the same size and under the same loads, the steel consumption of the standard single-span frame (6 m span, 4 m bay width) of the Elevating Greenhouse is only 67.38 kg, a 35% reduction compared with 103.58 kg for the ordinary greenhouse, significantly reducing construction costs. This study provides an innovative, safe, and economical technical solution for protected agriculture in tropical regions. Full article

The intertidal sediments of Sanya Haitang Bay, a tropical coast, harbor abundant multicellular magnetotactic prokaryotes (MMPs). Using light and electron microscopy, micromanipulation sorting, and whole-genome amplification, we examined their diversity from morphological, phylogenetic, and ecological perspectives. Two types of MMPs were identified: ellipsoidal (eMMPs) and spherical (sMMPs). Their average abundance was 1.37 × 10³ ind./dm³ in autumn and 0.27 × 10³ ind./dm³ in spring, indicating strong seasonal variation. eMMPs averaged 9.74 × 8.15 µm, consisting of 80–100 cells arranged in layers, whereas sMMPs averaged 5.64 µm in diameter with 40–50 cells organized radially or spirally. Electron microscopy revealed bullet-shaped magnetosomes in both types: those in eMMPs averaged 90.1 × 34.0 nm, while those in sMMPs averaged 97.2 × 36.3 nm. Interestingly, Cu was homogenously detected in the magnetosomes of sMMPs. 16S rRNA gene analysis identified nine OTUs, including three potential new species in the Desulfobacteraceae family within Thermodesulfobacteriota phylum. Of these, two may represent a new genus, and one is affiliated with Candidatus Magnetananas. Global distribution analysis suggests that eMMPs prefer stable, nutrient-rich environments, whereas sMMPs occupy broader ecological niches. Together, these findings expand understanding of tropical MMP diversity and distribution, and the discovery of Cu-containing magnetosomes provides new insight into biomineralization mechanisms. Full article

The present study aimed to evaluate the antifouling efficacy of Piper betle leaf extracts as a bioactive additive for eco-friendly antifouling coatings. The composition of P. betle extract was determined and analyzed. Phytochemical analysis revealed that the ethanol extract of P. betle contained phenolics, tannins, proteins, carbohydrates, and flavonoids, with total phenolic content reaching 260.3 mg GAE/g dry weight and flavonoid content reaching 52.56 mg QE/g dry weight. The antibacterial test results showed that the ethanol extract of P. betle exhibited maximum antibacterial efficacy against E. coli, B. subtilis, S. aureus, and marine bacteria, with inhibition zone diameters of 28.7 ± 0.5, 27.0 ± 1.6, 22.1 ± 0.6, and 35.1 ± 0.5 mm, respectively. Based on the laboratory test results, the ethanol extract of P. betle was chosen to be added to coatings as an antifouling additive. The content of the extract was 0.5, 1.0, and 1.5 wt.%. A field test conducted in tropical seawater (at Nha Trang Bay) demonstrated that incorporating 1 wt.% of P. betle extract into an acrylic copolymer-based coating significantly enhanced its antifouling performance. After nine months of immersion in seawater, this sample maintained an antifouling efficiency of 74%. These findings highlight the potential of P. betle extract as a sustainable alternative to conventional antifouling agents in marine coatings. Full article

Invasive species can alter community composition and ecosystem functioning. In the subtidal rocky shores of Arraial do Cabo Bay, southeastern Brazil, the invasive coral Tubastraea spp. has established populations, raising concerns about long-term impacts on native benthic communities. This study investigates temporal shifts in β-diversity across 44 fixed plots containing Tubastraea spp., monitored over 383 days. Underwater photographic surveys and multivariate analyses identified nine distinct benthic community types, each forming mosaic structures of sessile organisms. Temporal β-diversity analyses revealed that only the group characterized by Tubastraea, crustose calcareous algae and the zoantharian Palythoa caribaeorum showed significant differences between species gains and losses over time, suggesting temporal-scale dependency. Key contributors to community dissimilarity included P. caribaeorum, crustose calcareous algae, turf, the sponge genus Darwinella, and Tubastraea. This study highlights the importance of considering both spatial and temporal heterogeneity when assessing the ecological impact of marine invasive species. Our findings underscore the need for multi-scale monitoring to fully understand the dynamics of tropical subtidal ecosystems under biological invasion. While numerous studies report a correlation between Tubastraea abundance and shifts in ecological diversity, this relationship may be weak, as critical drivers such as the complexity of community organization are rarely accounted for. Full article

While coastal species have been widely studied, active port areas in tropical island regions with intense maritime traffic remain critical, but habitats for cetaceans within the Caribbean have not been thoroughly studied. This study examines the spatial and temporal patterns of habitat use and the characteristics of groups of six cetacean species in the Bay of Fort-de-France in Martinique, an area with heavy marine traffic. Data were collected from 2018 to 2022 through systematic boat-based surveys. We analyzed standardized observations of group occurrence, size, behavior, and depth preference across different subzones of the bay. Our results reveal that Stenella attenuata and Stenella longirostris are the most frequently observed species, exhibiting distinct seasonal patterns, while other species occur more sporadically. Group sizes and behavioral patterns vary significantly across zones and depths. Larger, more interactive groups are generally observed in shallow areas. Several species’ preference for nearshore waters highlights the ecological value of the bay and the potential risks posed by anthropogenic pressures, such as noise, collisions, and habitat degradation. Our findings underscore the importance of considering cetacean habitat use in port management strategies. This study provides essential baseline knowledge to support conservation efforts and the development of mitigation measures that reconcile economic activities with the protection of marine biodiversity. Full article

Live bait fishing, which was initiated around the 1950s on the coast of Dakar for the exploitation of tropical tunas, remains poorly studied. This study aims to examine the ichthyological diversity in Hann Bay and analyze the seasonal variation in species used as live bait. Ten experimental fishing campaigns were conducted between February and November 2023, using a beach seine and a purse seine. Captured individuals were sorted by species, counted, and weighed. Salinity and temperature drive seasonal changes in live bait fish communities in Hann Bay. Beach seine captured 389,171 individuals from 65 species, representing a biomass of 1743 kg. Purse seine yielded 9408 individuals from 62 species, representing a total of 306 kg. Ten species were identified as live bait, ten of which were caught with beach seine (Engraulis encrasicolus dominated) and eight with purse seine (Sardinella maderensis dominated). Eight of the ten live bait species were caught by both purse seine and beach seine. For beach seine, Shannon’s index was higher during the cold season, indicating a better distribution of species abundance. For purse seine, species abundance was lower in the cold season. Pielou’s evenness index indicated a more balanced assemblage in the cold season for beach seine (0.65) and in the warm season for purse seine (0.74). The number and weight of live baits did not vary significantly between seasons. These results may support the sustainable management of coastal small pelagics, whose juveniles are used as live bait. Full article

The world is facing a state of “global boiling,” causing damage to various sectors. Developing pedestrian systems is a key to mitigating it, especially in tropical and humid cities where the climate discourages walking and increases the need for shaded walkways. Recent research shows a lack of data and in-depth studies on the built environment promoting walkability in such climates, creating a research gap this study aims to fill. Using Singapore as a case study, four locations—Marina Bay, Orchard Road, Boat Quay, and Chinatown—were surveyed and analyzed through visual decoding and questionnaires. Results show that natural light is the most frequently observed and important element in pedestrian pathway design in tropical and humid areas. Trees and sidewalks are also important in creating a walk-friendly environment. Green spaces significantly influence the desire to walk, though no clear positive outcomes were found. Additionally, “Other Emotions” negatively affect the decision to walk, suggesting these should be avoided in future pedestrian pathway designs to encourage walking. Full article

Using interferometric synthetic aperture radar (InSAR) to observe slow ground deformation can be challenging due to many sources of error, with tropospheric phase delay and unwrapping errors being the most significant. While analytical methods, weather models, and data exist to mitigate tropospheric error, most of these techniques are unsuitable for all InSAR applications (e.g., complex tropospheric mixing in the tropics) or are deficient in spatial or temporal resolution. Likewise, there are methods for removing the unwrapping error, but they cannot resolve the true phase when there is a high prevalence (>40%) of unwrapping error in a set of interferograms. Applying tropospheric delay removal techniques is unnecessary for C-band Sentinel-1 InSAR time series studies, and the effect of unwrapping error can be minimized if the full dataset is utilized. We demonstrate that using interferograms with long temporal baselines (800 days to 1600 days) but very short perpendicular baselines (<5 m) (LTSPB) can lower the velocity detection threshold to 2 mm y⁻¹ to 3 mm y⁻¹ for long-term coherent permanent scatterers. The LTSPB interferograms can measure slow deformation rates because the expected differential phases are larger than those of small baselines and potentially exceed the typical noise amplitude while also reducing the sensitivity of the time series estimation to the noise sources. The method takes advantage of the Sentinel-1 mission length (2016 to present), which, for most regions, can yield up to 300 interferograms that meet the LTSPB baseline criteria. We demonstrate that low velocity detection can be achieved by comparing the expected LTSPB differential phase measurements to synthetic tests and tropospheric delay from the Global Navigation Satellite System. We then characterize the slow (~3 mm/y) ground deformation of the Socorro Magma Body, New Mexico, and the Tampa Bay Area using LTSPB InSAR analysis. The method we describe has implications for simplifying the InSAR time series processing chain and enhancing the velocity detection threshold. Full article

Abundant large organic aggregates, which form mucous webs up to a few decimeters in length, have been observed in Baía de Todos os Santos (BTS), northeastern Brazil. This communication presents preliminary results from field (February 2015) and laboratory (June 2015) experiments that aimed to determine preliminary values for respiration and near-maximum photosynthesis and the impact of macroaggregates on respiration rates. The experiments included the determination of respiration in controls, with the mechanical removal and addition of macroaggregates. The field experiment during a flood tide presented the lowest respiration rate (−7.0 ± 0.7 µM L⁻¹ d⁻¹), average net primary production (8.9 ± 4.5 µM L⁻¹ d⁻¹), and gross primary production (16.0 ± 10 µM L⁻¹ d⁻¹), with a ratio of gross primary production to respiration of 2.3. The control experiments during an ebb tide showed a mean respiration rate of 8.7 ± 2.3 µM L⁻¹ d⁻¹, whereas, after macroaggregate removal, this was 9.5 ± 4.5 µM L⁻¹ d⁻¹. In the laboratory experiments, the control sample respiration rate of 18.4 ± 1.4 µM L⁻¹ d⁻¹ was slightly increased to 20.6 ± 0.1 µM L⁻¹ d⁻¹ after aggregate removal. The addition of aggregates to the control sample increased the respiration rate by approximately 3-fold, to 56.5 ± 4.8 µM L⁻¹ d⁻¹. These results indicate that macroaggregates could have an important role in pelagic and benthic respiration, as well as in the whole bay’s metabolism. Full article

This study examines the evolution, structure, and dynamic and thermodynamic mechanisms of a Mediterranean tropical-like cyclone (TLC), or medicane (from Mediterranean–Hurricane), that occurred in the central Mediterranean region from 15 to 19 September 2020. This event is considered an extreme meteorological phenomenon, particularly impacting the Greek area and affecting the country’s economic and social structures. It is one of the most significant recorded Mediterranean cyclone phenomena in the broader Mediterranean region. The synoptic and dynamic environment, as well as the thermodynamic structure of this atmospheric disturbance, were analyzed using thermodynamic parameters. The system’s development can be described through three distinct phases, characterized by its symmetrical structure and warm core, as illustrated in the phase space diagrams and further supported by dynamical analysis. During the first phase, on 15 September, the structure of the upper tropospheric layers began to strengthen the parent barometric low, which had been in the Sirte Bay region since 13 September. The influence of upper-level dynamical processes was responsible for the reconstruction of the weakened barometric low. In the second phase, during the formation of the Mediterranean cyclone, low-level diabatic processes determined the evolution of the surface cyclone without significant support from upper-tropospheric baroclinic processes. Therefore, in this phase, the system is characterized as barotropic. In the third phase, the system remained barotropic but showed a continuous weakening tendency as the sea surface pressure steadily increased. This comprehensive analysis highlights the intricate processes involved in the development and evolution of Mediterranean cyclones with tropical characteristics. Full article