Search Results (295)

Geothermal energy is a critical low-carbon resource in the global carbon neutrality transition, but expanding exploitation has raised growing concerns over geothermal fluid quality degradation and fluoride-related public health risks in the tectonically active coastal region of Guangdong, South China. However, the hydrochemical mechanisms governing fluoride enrichment remain poorly constrained, and conventional qualitative analytical approaches cannot quantitatively disentangle the superimposed effects of multiple subsurface geochemical processes. Based on 20 geothermal groundwater samples, this study integrates hydrochemical characterization, stable hydrogen and oxygen isotope tracing, and positive matrix factorization (PMF) modeling to quantitatively identify dominant hydrochemical processes and decipher the genetic mechanism of fluoride enrichment. The results demonstrate that the geothermal groundwaters belong to Cl–Na hydrochemical facies, with temperatures ranging from 60 °C to 96 °C and total dissolved solids (TDSs) varying from 560 mg/L to 9862 mg/L. Water–rock interaction dominates hydrochemical evolution: congruent dissolution of halite and other evaporite minerals serves as the primary source of bulk salinity, while bidirectional cation exchange on clay mineral surfaces substantially modifies the ionic assemblage. Stable isotope compositions (δD: −47.2‰ to −39.0‰; δ¹⁸O: −7.3‰ to −5.2‰) confirm a dominant meteoric recharge origin, with notable positive ¹⁸O shifts in multiple samples reflecting prolonged deep water–rock interaction with silicate host rocks. Recharge elevations are estimated at 239~682 m, delineating the northwestern medium–low mountain zone as the primary recharge area. Fluoride concentrations (2~13 mg/L) universally exceed the drinking water standard, and their enrichment is governed by a coupled geochemical feedback mechanism: hydrolytic weathering of fluor-bearing silicates releases structural fluoride, while widespread calcite precipitation scavenges aqueous Ca²⁺, weakens the common-ion effect, and promotes fluorite dissolution. The PMF model quantitatively resolves three geochemically meaningful controlling factors with clear process implications. These findings advance the mechanistic understanding of fluoride geochemistry in coastal granitic geothermal systems within the western Pacific tectonic belt, and provide a robust scientific basis for sustainable geothermal resource development and public health risk management. Full article

Marine pollution in the Philippine archipelago poses increasing threats to biodiversity, ecosystem services, and human health due to rapid urbanization, population growth, and inadequate waste management. As a core region of the Coral Triangle, the Philippines is particularly vulnerable to pollutants transported across interconnected marine ecosystems. This review synthesizes current knowledge on the occurrence, sources, analytical approaches, risk assessment, and knowledge gaps associated with conventional and emerging major marine pollutants, including oil, heavy metals, polycyclic aromatic hydrocarbons, persistent organic pollutants, pharmaceuticals and personal care products, per- and polyfluoroalkyl substances, plastics, and additional stressors such as nutrients, pathogens, and shipping-related contaminants. Available evidence indicates widespread contamination of coastal waters, sediments, and marine biota, with pollution hotspots commonly associated with urbanized coastlines, river systems, industrial zones, shipping routes, aquaculture areas, and tourism centers. Emerging pollutants such as plastics and microplastics are increasingly detected even in remote environments, highlighting limitations in current monitoring and management frameworks. However, significant gaps remain in long-term monitoring, standardized methodologies, human health risk assessment, and interdisciplinary integration. This review emphasizes the need for harmonized monitoring programs, improved waste management infrastructure, strengthened regulatory enforcement, expanded analytical capacity, and integrated science-based policies to support sustainable marine management and ocean governance in the Philippines. Full article

The ecological status of the two nautical mile (2 nm) coastal waters of Bulgaria (BG) and Romania (RO) is evaluated in terms of eutrophication, focusing on various environmental and chemical indicators related to nutrient enrichment and its effects. Applying the Blue2 Modelling Framework (Blue2MF) Black Sea model, we simulate diverse combinations of nitrogen (N) and phosphorus (P) reduction. By integrating atmospheric and marine conditions, hydrology and environmental dynamics, the model provides a comprehensive framework for analysing the impact of external pressures on the marine environment and can be used to set regional sustainability goals. Each scenario is assessed with respect to environmental impact, such as enhanced water quality and potential alterations in phytoplankton communities. Furthermore, we establish integrated nutrient criteria for eutrophication control, concentrating on the management of both N and P inputs while maintaining the current ratio between them. The model results indicate that a 20% reduction in both N and P from European Union (EU) rivers would result in about a 24% decrease in N within the BG and RO 2 nm coastal waters, whilst sustaining the N:P ratio across various spatial scales—from river inputs to coastal and offshore zones. This approach is valuable for assessing the potential impacts of different nutrient reduction strategies, aiding the effective management of marine ecosystems to address eutrophication challenges. Full article

Charybdis (Gonioneptunus) bimaculata (Miers, 1886), C. (Charybdis) japonica (A. Milne-Edwards, 1861), and C. (Charybdis) miles (De Haan, 1835) are dominant target species harvested by small-scale artisanal fisheries in the coastal waters of China. Characterizing their spatial distribution and interannual population variability is critical for sustainable crustacean stock conservation. Previous investigations of these three Charybdis congeners have been limited to short-duration, single-season, or geographically restricted descriptive surveys, with no systematic cross-species comparison of seasonal habitat use. This has created major knowledge gaps regarding their long-term spatiotemporal dynamics and ecological niche partitioning. We conducted standardized bottom-trawl surveys aboard research vessels across the southern Yellow Sea and East China Sea from 2018 to 2021 to quantify numerical abundance and biomass of the three congeneric crabs. Two species distribution modeling frameworks—Generalized Additive Models (GAMs) and Boosted Regression Trees (BRTs)—were implemented to generate fine-resolution seasonal habitat suitability maps for each species. We identified minimum thermal thresholds for species presence: bottom water temperature > 8 °C for C. bimaculata and >10 °C for C. miles. Core aggregation zones of C. bimaculata and C. japonica occurred in waters adjacent to the Yangtze River Estuary (32–34° N), whereas C. miles predominated in offshore habitats of the southern East China Sea (27–31° N). In this study, C. bimaculata favors shallow seas with warm bottom water and euryhaline conditions, C. japonica prefers low-salinity coastal waters with cold bottom water, and C. miles thrives in deep, high-salinity offshore waters with eurythermal tolerance. The findings of this study can contribute to the sustainable fisheries management and conservation of these species. Full article

The construction of the Hainan Free Trade Port (FTP) is guided by the core philosophy of “ecological priority and green development.” To meet the practical requirements of building a “Green and Beautiful FTP,” this study constructed a kernel Normalized Difference Vegetation Index (kNDVI) dataset using Landsat series satellite imagery. By integrating methods including the Mann–Kendall (MK) trend test, Hurst exponent, and coefficient of variation (CV), an in-depth analysis was conducted on the spatiotemporal evolution characteristics and trends of growing-season vegetation in Hainan Island from 1994 to 2023. Additionally, the Extreme Gradient Boosting (XGBoost) model and the SHapley Additive exPlanations (SHAP) interpretation method were employed to quantitatively unravel the driving mechanisms of climatic factors and human activities on kNDVI variations. The results indicate that: (1) Over the past three decades, the overall kNDVI of Hainan Island has exhibited a significant upward trend, characterized spatially by an evolution pattern of “stable recovery in the central region and localized degradation along the coast.” (2) The vegetation evolution demonstrates strong persistence and is highly consistent with community stability. The high stability in the central mountainous areas stems from a superior natural background and strict ecological protection; the transition zone is jointly influenced by vegetation types and anthropogenic management; meanwhile the coastal areas exhibit significant degradation characteristics driven by high-intensity human disturbances. (3) The analysis of driving mechanisms reveals a complex control logic of “topographical foundation—human reshaping—extreme climate triggering.” Static topographical factors, such as elevation and slope, occupy an absolute dominant position; human activities, represented by rubber plantation expansion and urbanization, exert a bidirectional reshaping effect characterized by “inland greening and coastal suppression”; furthermore, extreme drought and high temperatures in the later stages of the study demonstrated a significant pulse-like impact, exacerbating the risks of short-term climatic stress. This study clarifies the core patterns of vegetation evolution in Hainan Island, validates the effectiveness of ecological policies, and provides a quantitative scientific basis for ecological conservation and sustainable development in tropical island regions. Full article

This study investigates the spatiotemporal dynamics of Land Use/Land Cover (LULC) along precipitation gradients across Türkiye by integrating high-resolution satellite-based precipitation datasets (CHIRPS, TerraClimate, and TRMM) with the European Space Agency (ESA) WorldCover (10 m) product and multi-sensor Normalized Difference Vegetation Index (NDVI) composites (Landsat, MODIS, Sentinel-2). Türkiye’s heterogeneous climate, characterized by a sharp contrast between humid coastal belts and semi-arid interiors, serves as a natural laboratory to assess ecosystem responses to moisture availability. The results reveal a systematic and non-linear transformation of LULC classes as precipitation increases. In low-rainfall zones (200–400 mm), agricultural activities and bare surfaces predominate, reflecting human-induced land management in water-constrained environments. A critical ecological threshold was identified between 400 mm and 700 mm, where grassland areas expand rapidly, becoming the dominant class. Beyond the 900 mm isohyet, forest cover exhibits a sharp increase, approaching nearly 100% dominance in regions exceeding 1200 mm, effectively displacing other LULC categories. Comparative analysis of precipitation products shows that while all datasets capture the “coastal-wet/inland-dry” pattern, TRMM tends to overestimate winter precipitation (exceeding 100 mm), whereas CHIRPS and TerraClimate provide more conservative estimates (75–80 mm). Overlay analyses between seasonal NDVI and precipitation confirm a pronounced “time-lag effect” in vegetation phenology. Despite peak precipitation occurring in winter (~75 mm), NDVI reaches its minimum (~0.03) due to thermal limitations and dormancy. Conversely, vegetation greenness peaks during the dry summer months (NDVI ~0.14 to 0.40), utilizing antecedent soil moisture stored during the spring recharge. High-resolution Sentinel-2 data proved superior in delineating micro-topographic vegetation responses compared to Landsat and MODIS. These findings provide a scientific baseline for sustainable land management and climate adaptation strategies, highlighting that precipitation thresholds are the primary determinants of Türkiye’s ecological boundaries. Full article

Tourism development in coastal Mediterranean regions has posed a significant pressure on water local resources, particularly the extensive use of water-intensive recreational infrastructures. This study investigates the spatial distribution and water consumption of public and private swimming pools in the Kassandra peninsula, Halkidiki, Greece. Using Geographic Information Systems (GIS) and high-resolution satellite imagery from 2016 and 2024, the research quantified changes in pool density and estimated associated water losses from evaporation and filter backwashing. Our findings reveal a significant increase in swimming pools and related water demand, intensifying water scarcity during the tourist season. Growth was particularly strong among small private and tourism-related pools, which increased by 192.4% overall and by more than 400% in some districts. This trend reflects a shift from mass hotel-based tourism toward decentralized and flexible tourism models. Furthermore, cartographic outputs and thematic mapping highlight spatial concentrations of water consumption near environmentally sensitive coastal zones. The applied geospatial approach identifies interactions between tourism infrastructure and vulnerable ecosystems, offering an integrated geographic perspective on environmental pressures in coastal areas. Our results emphasize the urgent need for sustainable water management policies, including water reuse practices and strategies to improve the resilience of tourism-dependent regions under climate stress. Full article

Traditional species distribution models can identify climatically suitable areas but offer limited guidance for spatially explicit agricultural planning. In this study, we constructed a three-dimensional coupled framework of “suitability prediction–habitat quality filtering–ecological security screening” by integrating BIOMOD2 ensemble modeling, InVEST habitat quality assessment, and ecological security evaluation to identify candidate cultivation zones for Piper nigrum L. in China under climate change. Based on occurrence records and environmental variables, we simulated potential suitable habitats under current and future climate scenarios, identified key climatic drivers, and delineated candidate zones by overlaying habitat quality and ecological security levels. The results show that the current total suitable area for P. nigrum is 87.76 × 10⁴ km², with low-, moderate-, and high-suitability areas accounting for 37.28 × 10⁴ km², 25.12 × 10⁴ km², and 25.36 × 10⁴ km², respectively. Temperature seasonality and winter cold stress were identified as the dominant factors shaping the suitability pattern. Under future climate scenarios, the total suitable area shows an increasing trend, with highly suitable areas expanding toward the coastal regions of South China and the low-latitude hilly zones. After overlaying with habitat quality and ecological security, climatically suitable but ecologically fragile or intensively disturbed areas were effectively excluded, and the current candidate cultivation zones were identified as mainly concentrated in the southern Yunnan–southern Guangxi–Guangdong–Hainan coastal region. This framework enables a transition from identifying climatic suitability to collaborative climate–habitat–ecology screening, providing a scientific basis for sustainable cultivation and germplasm management of P. nigrum, and is transferable to priority cultivation area identification for other tropical cash crops. Full article

Accurate characterization of coastal environments requires high-resolution spatial data and robust analytical workflows which are capable of capturing the complexity of intertidal surfaces and engineered shoreline structures. This study presents a field application of terrestrial and vessel-based LiDAR with AI-assisted point-cloud processing to support coastal mapping and shoreline analysis in a complex tidal flat environment. Field measurements were conducted in a geomorphologically dynamic estuarine system dominated by wide tidal flats and diverse natural and artificial coastal features. A comparative assessment of terrestrial laser scanning (TLS) and vessel-based mobile mapping system (MMS) data revealed distinct platform characteristics: TLS provided long-range, high-fidelity geometric measurements suitable for broad intertidal zones, whereas vessel-based MMS offered rapid and continuous coverage but exhibited range-related limitations in offshore and distal areas. To extract key coastal features, an AI-assisted workflow was implemented in Trimble Business Center (TBC), primarily using the TLS dataset as the input for feature extraction. The vessel-based MMS data were used to evaluate complementary acquisition characteristics, including coverage continuity, scanning range, accessibility, and visualization of coastal features, rather than as direct input for joint TLS–MMS AI classification. A manually curated training dataset consisting of 80 object-level point-clouds—cars, streetlights, powerlines, and fences—was used to train a custom extraction model, while TBC’s built-in AI tools were employed to automatically separate ground surfaces, vegetation, and built structures from the TLS point-cloud. The TLS-based AI-assisted workflow produced a multilayered representation of the TLS data, enabling detailed delineation of intertidal flats, engineered shoreline structures, and adjacent artificial objects. Quantitative evaluation based on comparison with manually annotated ground truth yielded an overall F1-score of approximately 0.87, indicating practical extraction performance for the evaluated object types. The results highlight the complementary strengths of TLS and vessel-based MMS data and the practical applicability of TLS-based AI-assisted point-cloud processing in complex coastal settings. The results indicate that TLS-based AI-assisted point-cloud processing, supported by vessel-based MMS comparison, can provide an operationally useful approach for coastal feature extraction, shoreline monitoring, and coastal infrastructure assessment in complex tidal flat environments. By improving the acquisition, interpretation, and management of high-resolution coastal spatial information, the proposed workflow can support sustainable shoreline monitoring, coastal infrastructure maintenance, and evidence-based coastal environmental management in vulnerable tidal flat environments. Full article

Mangrove forests deliver globally significant climate-mitigation and coastal-protection benefits, yet their resilience to climate extremes remains poorly quantified—a key uncertainty for sustainable coastal management. We reassess the unprecedented 2015–2016 mangrove dieback along ~1000 km of the Gulf of Carpentaria, northern Australia, to determine its driver and whether the collapse was structurally abrupt. Combining a mangrove-extent mask, an 11-year radar backscatter series, satellite precipitation, the modeled sea level, the reanalysis temperature and atmospheric dryness, and an El Niño index, we show that an apparent abrupt radar decline during the event was an artifact of non-vegetated tidal-flat and open-water pixels: once analysis was restricted to mangrove pixels, the signal remained stable throughout. Independent spaceborne lidar confirmed that canopy structure concentrates within the mapped mangrove zones, validating the mask. The dieback coincided with a strong sea-level fall, with anomalies reaching about −15 cm, under near-to-above-average rainfall and low atmospheric dryness, indicating that sea-level fall, not rainfall deficit, was the proximate stressor. These findings advance sustainable, mask-applied satellite monitoring of blue-carbon ecosystems and provide an evidence base for climate-adaptive coastal-resilience planning under intensifying climate variability. Full article

Groundwater is an important resource for domestic, agricultural, and ecological use in the Surat Thani basin, southern Thailand, where increasing demand from agriculture, urbanization, and tourism is placing pressure on aquifer systems. This study investigates groundwater recharge and basin-scale flow dynamics using integrated numerical groundwater modeling, stable isotope analysis, and hydrochemical interpretation. A three-layer MODFLOW model representing floodplain (Qfd), terrace (Qt), and semi-consolidated aquifers was calibrated for 2018–2024 using PEST with pilot-point parameterization. Despite there being only four observation wells, the model achieved excellent agreement between simulated and observed heads (weighted RMSE = 0.0707 m). Simulated groundwater generally flows from western uplands toward the central floodplain and eastern coastal plain, with the Tapee River acting mainly as a gaining stream. Recharge rates range from 1.2 to 77.3 mm/yr (mean 23.7 mm/yr), representing only 1–4% of annual precipitation, while evapotranspiration is the dominant form of water loss. Stable isotope signatures (δ²H, δ¹⁸O) indicate recharge from direct monsoonal rainfall with minimal evaporation. Hydrochemical facies evolve from Ca–HCO₃ recharge waters to mixed facies along downgradient flow paths, reflecting increasing residence time and water–rock interaction. The results identify western and northern upland areas as key recharge zones requiring long-term protection and sustainable groundwater management. Full article

Land use/land cover (LULC) is one of the core driving factors affecting terrestrial ecosystem carbon storage and exacerbating global warming. As an area with the most intense land–sea interactions, China’s coastal zone has experienced drastic LULC transition and carbon storage fluctuations during the rapid urbanization process. Based on the InVEST model, this study analyzes the spatiotemporal dynamics of LULC and carbon storage (CS) in China’s coastal regions from 2000 to 2024, and simulated multi-scenario carbon storage trajectories for 2050 integrating the SSP-RCP scenarios of the Coupled Model Intercomparison Project Phase 6 (CMIP6). Furthermore, the XGBoost-SHAP and generalized additive models (GAMs) were introduced to deeply analyze the nonlinear characteristics and temporal heterogeneity of the driving mechanisms of CS evolution. The results show the following: (1) During the study period, the LULC structure of the coastal region was dominated by cropland and forestland consistently accounting for over 85%, but exhibited a competitive pattern characterized by the continuous expansion of built-up land severely squeezing ecological spaces. (2) The total regional CS showed an overall phased downward trend, accompanied by increasing fragmentation of high carbon sink areas. Notably, as the core carbon pool, the reduction in forest area was the dominant factor causing regional net carbon losses. (3) CS remained relatively stable under SSP1-2.6, representing a sustainable development pathway with low greenhouse gas emissions. In contrast, SSP2-4.5, SSP3-7.0, and SSP5-8.5 exhibited more pronounced declines in carbon storage by 2050, indicating that SSP1-2.6 is the most favorable pathway for maintaining long-term carbon storage stability in China’s coastal regions. (4) The driving mechanism of CS has undergone a profound shift from being dominated by natural ecological baselines to human activities. Land use intensity (LUI) has emerged as the strongest predictor in the model, and the nonlinear impacts of human activities have grown increasingly complex over time. This study highlights the complex impacts of high-intensity human disturbances on the coastal carbon cycle, providing a scientific basis for formulating differentiated carbon management strategies and adaptive spatial land-use planning oriented toward the “Dual Carbon” goals. Full article

Coastal zones are facing rising exposure to climate-related hazards alongside intensifying human pressures, which highlights the need for robust tools to assess vulnerability. This study uses a GIS-based Coastal Vulnerability Index (CVI) to quantify and map relative vulnerability along ~13 km of shoreline in Al Hoceima Bay (northern Morocco). The proposed CVI integrates eight geological and physical indicators, including geomorphology, shoreline erosion and accretion rates, coastal slope, elevation, natural habitats, relative sea-level rise, significant wave height, and tidal range. Spatial analyses were performed using remote sensing data, historical records, field measurements, and Geographic Information Systems (GIS). The analysis reveals that 37% of the shoreline is categorized as high vulnerability, 44% is moderate, and 19% is low. Highly vulnerable sectors are primarily associated with low elevations, gentle coastal slopes, sandy beach systems, limited natural habitat protection, and proximity to river mouths. These findings demonstrate that the applied CVI provides a rapid and cost-effective framework for identifying priority areas for coastal management and climate adaptation. The proposed approach offers valuable decision-support insights for sustainable coastal planning in Al Hoceima Bay and other Mediterranean coastal environments characterized by limited data availability. Full article

Seawater intrusion presents a significant risk to coastal aquifers, particularly in low-lying locations where groundwater resources are intensively exploited. This study assesses the vulnerability of the Keta Strip aquifer in Southeastern Ghana to seawater intrusion using the GALDIT model; a widely applied index-based approach that evaluates seawater intrusion risk based on six key hydrogeological indicators: groundwater occurrence (G), aquifer hydraulic conductivity (A), groundwater level above sea level (L), distance from the shoreline (D), impact of existing intrusion (I), and aquifer thickness (T). These parameters were analyzed using data from 105 monitoring wells within a Geographic Information System (GIS) environment. The resulting vulnerability index was spatially grouped into four categories: low, moderate, high, and very high vulnerability. Results indicate that very high and high vulnerability regions are predominantly clustered along the coastal margins and central portions of the study area, driven mainly by low hydraulic gradients, proximity to the shoreline, and high hydraulic conductivity. Moderate vulnerability zones dominate inland areas, while low vulnerability zones are limited and confined to northern sections. Sensitivity analysis reveals that hydraulic head (L) and distance from shoreline (D) are the most influential parameters, whereas TDS exhibits relatively low contribution to overall vulnerability. The findings highlight the critical role of hydrogeological controls and anthropogenic pressures in shaping seawater intrusion risk and provide a scientific basis for sustainable groundwater management in the Keta Strip and similar coastal environments. Full article

Diadromous fish provide key ecological and socio-economic services in European Atlantic catchments, yet their marine phase remains poorly understood and weakly integrated into management. Involving nine partners from Portugal, Spain, France and Ireland, the DiadSea Interreg Atlantic Area initiative aims to fill these critical knowledge gaps on the marine and estuarine phases and to translate this information into coordinated conservation and fisheries management tools. To do so, the project combines historical and newly collected fishery-dependent and -independent data (landings, by-catch, cooperative surveys with commercial and recreational fishers) with advanced microchemical, genetic and environmental DNA (eDNA) analyses to characterize marine distributions, mixing areas and connectivity for shads, Atlantic salmon, sea trout, European eel, sea lamprey and other diadromous species. It also includes innovative case studies on lamprey tagging and intestinal metabarcoding, coastal habitat suitability mapping for shads using river plumes and environmental variables, and joint otolith microchemistry–genomics approaches to reassess European eel panmixia and maternal origin at the Atlantic scale. Species distribution models under present and future climate scenarios, specifically RCP4.5 and RCP8.5, are used to identify priority marine areas for conservation, zones of high temporal turnover and key interfaces ensuring longitudinal (river–sea) and latitudinal connectivity, which will feed into an updated interactive web Atlas of diadromous species. In parallel, DiadSea establishes a transnational observatory of stakeholders to harmonize legislation, co-develop adaptive fisheries management plans and produce climate-aware policy guidelines, while capacity-building actions include an origin-labeling scheme for sustainably harvested diadromous fish, educational games and a comic book to raise awareness among younger generations and the wider public. Together, these work packages will deliver the first integrated, marine-focused, evidence-based and decision-support framework for diadromous fishes in the North-Eastern Atlantic, strengthening conservation, sustainable fisheries and stakeholder engagement under ongoing climate change. Full article