Search Results (20,539)

Vegetation water content, characterized by vapor pressure deficit (VPD) and vegetation optical depth (VOD), can represent vegetation health in terrestrial ecosystems. In this study, using remote sensing Ku-band VOD and VPD, the spatiotemporal distribution assessment, Mann-Kendall trend analysis, seasonal trend decomposition, and correlation analysis and significance testing were conducted to investigate the spatiotemporal distribution patterns, seasonal variations and correlations of VPD and VOD across China from 2000 to 2016. And the correlation between climate factors (temperature and precipitation) with VOD and VPD was discussed. The results show the following: (1) The annual mean VPD in China predominantly ranged from 0 to 4 KPa, while the annual mean VOD were centered around 0 to 2 during 2000–2016. Spatially, the VOD peaked at 1–2 in southwest China. VPD have significant seasonal variations across China, with high VPD in the summer. (2) The VPD and VOD in most regions of China fluctuated and showed an upward trend from 2000 to 2016, with significantly increased VPD in northwest and southwest China. (3) On a monthly scale, regions where VOD positively correlated with VPD accounted for 89.69% of the total area of China. The proportion of areas with a significant positive correlation was 82.96%. The proportion of areas with a negative correlation was 10.31%, and the proportion of areas with a significant negative correlation was 5.41%. Annual VOD and VPD exhibited a positive correlation of 61.28% of China’s total territory. Among these, the area exhibiting a significant positive correlation made up 6.15%. The area demonstrating a negative correlation amounted to 38.72%, and the area with a significant negative correlation constituted 2.22%. This study can contribute to understanding vegetation water content dynamics across China, which is crucial for ecosystem sustainability in China. Full article

Monitoring bottom dissolved oxygen (DO) is crucial for understanding hypoxia, a threat to marine ecosystems and fisheries. However, traditional observations are limited in spatiotemporal coverage, while numerical models consume tremendous computing resources. This study develops an interpretable machine learning framework to simulate the bottom DO distribution on the East China Sea (ECS) shelf and explore its potential driving mechanisms. By integrating remote sensing, in situ observations, and numerical model outputs, the framework generates high-resolution (4 km) DO estimates from 1998 to 2024. Validation against independent datasets confirms the improved accuracy and spatial resolution, with an RMSE below 1 mg/L. The results reveal a persistent decline in DO, strongly linked to rising sea surface temperature (SST), underscoring the role of surface warming in bottom water deoxygenation. Model interpretability further identifies the SST and bathymetry as key factors. This framework provides a robust tool for assessing bottom DO trends, hypoxia, and their ecological impacts, supporting future monitoring and management of the ECS shelf. Full article

From 2020 to 2022, hydrological extremes such as severe floods and droughts occurred successively in Jiujiang city, Poyang Lake Basin, posing a threat to regional water quality safety. The chlorophyll-a (Chl-a) concentration is a key indicator of river eutrophication. Until now, there has been a lack of empirical research exploring the Chl-a trend in inland water in Jiujiang in the context of hydrological extremes. In this study, Sentinel-2 satellite remote sensing data sourced from the Google Earth Engine (GEE) cloud platform, along with hourly water quality data collected from monitoring stations in Jiujiang city, Jiangxi Province, China, are utilized to develop a quantitative inversion model for the Chl-a concentration. The Chl-a concentrations for various inland water types were estimated for each quarter from 2020 to 2022, and the spatiotemporal distribution was analyzed. The main findings are as follows: (1) the quantitative inversion model for the Chl-a concentration was validated via in situ measurements, with a coefficient of determination of 0.563; (2) the spatial estimates of the Chl-a concentration revealed a slight increasing trend, increasing by 0.1193 μg/L from 2020 to 2022, closely aligning with the monitoring-station data; (3) an extreme drought in 2022 led to less water in inland water bodies, and consequently, the Chl-a concentration displayed a significant upward trend, especially in Poyang Lake, where the mean Chl-a concentration increased by approximately 1 μg/L from Q1 to Q2 in 2022. These findings revealed the seasonal changes in the Chl-a concentrations in inland waters in the context of extreme hydrological events, thus providing valuable information for the sustainable management of water quality in Jiujiang city. Full article

In the context of rapid urbanization and extreme climate change globally, balancing ecological resources and economic development for land spatial planning has become one of the pressing issues that need to be addressed. This study proposes a composite model to construct a spatial ecological security pattern. It identifies restoration areas with different risk levels based on the spatial distribution of land use, offering suggestions for optimizing spatial configuration. Focusing on the central Shaanxi region of the Yellow River Basin in China, ecological sources are identified by integrating ecological factors, and ecological corridors and restoration zones are extracted using the minimum cumulative resistance difference and circuit theory. The results indicate significant improvements in ecological quality and desertification in the study area from 2000 to 2020. Currently, the core area covers 51,649.71 km², accounting for 62.18% of all landscape types; the total ecological source area covers 31,304.88 km², representing 18.84% of the entire area. These ecological source areas are mainly distributed in the northern Loess Plateau and the southern mountainous regions. The area has 26 important ecological corridors, identifying 16 ecological pinch points and 12 ecological barriers, presenting an ecological security pattern characterized by a grid-like structure in the northern region and a dispersed pattern in the southern region. Additionally, 273.72 km² of ecological restoration priority areas and 197.98 square kilometers of ecological restoration encouragement areas are proposed as key planning regions for ecological environmental protection. This study provides references for optimizing spatial configuration to promote the sustainable development of urban and rural living environments in the Yellow River Basin. Full article

Against the backdrop of the newly constructed urban rail transit network and the ongoing urbanization of strip-shaped cities, this study investigates the distribution and evolution of commercial points of interest (POIs) in the central urban area of Lanzhou. The research analyzes data from three distinct years (2016, 2018, and 2020) to observe the temporal changes in commercial entities before and after the establishment of metro stations. Stable explanatory variables influencing the distribution and evolution of commercial POIs are identified, including rail transit passenger flow, demographic characteristics of the working and residential populations surrounding stations, as well as building and road densities in their vicinity. Through statistical analysis and model construction, these influencing factors are systematically evaluated to establish a relatively stable linear regression equation that quantifies the weights assigned to each factor. This study enhances our understanding of how urban rail transit impacts urban vitality within belt-shaped cities while elucidating its positive role in shaping development patterns unique to such areas. It clarifies the relationship between changes in urban vitality and spatial configuration, thereby providing valuable insights for urban planners and decision-makers. Furthermore, this research can serve as a reference model for other strip-shaped cities seeking to optimize their distribution of urban vitality through the effective utilization of urban rail transit systems. Full article

According to statistics from the United Nations Environment Program (UNEP), the construction industry accounts for approximately 30% to 40% of global energy consumption and greenhouse gas emissions, making it a major source of carbon emissions. As a critical component of urban construction, residential buildings are characterized by their large scale and significant potential for carbon reduction. Building on this context, this study utilizes diversified geospatial data and applies the life-cycle stage framework for residential buildings alongside the emission factor method to calculate total carbon emissions during the material production, construction, and operation phases. It systematically analyzes the distribution characteristics and spatial evolution trends of life-cycle carbon emissions for urban residential buildings. The findings reveal that 63.06% of the cumulative carbon emissions from residential buildings in Xi’an originate from the operation phase, underscoring the importance of optimizing carbon emissions in this phase as a critical priority for future reductions. Additionally, the spatial distribution of residential building carbon emissions exhibits significant clustering, with an increasingly pronounced expansion pattern. Over time, the direction of expansion has shifted from a northeast–southwest orientation to a northwest–southeast trajectory and continues to extend toward peripheral areas. Economic growth, increased urbanization, and the intensive consumption of specific building materials are identified as significant drivers of residential carbon emissions, while population growth and improvements in material utilization efficiency help mitigate emissions to some extent. This study offers valuable insights to support the green development of China’s construction industry and to advance energy-saving and carbon-reduction strategies. Full article

Retinal Müller glial cells (RMG) play a crucial role in retinal neuroinflammation, including autoimmune uveitis. Increasing evidence supports their function as active modulators of immune responses and potential atypical antigen-presenting cells (APCs). To further investigate this hypothesis, we conducted a differential proteome analysis of primary equine RMG from healthy controls and horses with equine recurrent uveitis (ERU), a spontaneous model of autoimmune uveitis. This analysis identified 310 proteins with differential abundance. Among these, the Major Histocompatibility Complex (MHC) class II and the enzyme Arginase 1 (ARG1) were significantly enriched in RMG from uveitis-affected horses, whereas Mannose Receptor C-type 2 (MRC2) and its interactor Thrombospondin 1 (THBS1) were more abundant in healthy RMG. The detection of MHC class II in equine RMG, consistent with previous studies, validates the robustness of our approach. Furthermore, the identification of ARG1 and MRC2, together with THBS1, provides new insights into the immunomodulatory and antigen-presenting properties of RMG. Immunohistochemical analyses confirmed the proteomic findings and revealed the spatial distribution of ARG1 and MRC2. ARG1 and MRC2 are thus markers for RMG in the neuroinflammatory or physiological milieu and highlight potential differences in the immune function of RMG, particularly in antigen presentation. Full article

Green asparagus grows in clusters, which can cause overlaps with weeds and immature stems, making it difficult to identify suitable harvest targets and cutting points. Extracting precise stem details in complex spatial arrangements is a challenge. This paper explored the YS3AM (Yolo-SAM-3D-Adaptive-Modeling) method for detecting green asparagus and performing 3D adaptive-section modeling using a depth camera, which could benefit harvesting path planning for selective harvesting robots. Firstly, the model was developed and deployed to extract bounding boxes for individual asparagus stems within clusters. Secondly, the stems inside these bounding boxes were segmented, and binary masks were generated. Thirdly, high-quality depth images were obtained through pixel block completion. Finally, a novel 3D reconstruction method, based on adaptive section modeling and combining the mask and depth data, is proposed. And an evaluation method is introduced to assess modeling accuracy. Experimental validation showed high-performance detection (1095 field images demonstrated, Precision: 98.75%, Recall: 95.46%, F1: 0.97) and robust 3D modeling (103 asparagus stems, average RMSE: length 0.74, depth: 1.105) under varying illumination conditions. The system achieved 22 ms per stem processing speed, enabling real-time operation. The results demonstrated that the 3D model accurately represents the spatial distribution of clustered green asparagus, enabling precise identification of harvest targets and cutting points. This model provided essential spatial pathways for end-effector path planning, thereby fulfilling the operational requirements for efficient green asparagus harvesting robots. Full article

Seed orchards play important roles in supplying good seeds. Miniature orchards have the advantages of reducing management areas, but rapid crown development will decrease light intensity and seed production. Block-rotation cycles within an orchard need to be evaluated to optimize total seed production per unit time and area. The development of tree height and primary branches, as well as spatial light variation over the years after pruning and defoliation manipulation were evaluated in a miniature orchard of Chamaecyparis obtusa (Sieb. et Zucc.) Endl. set on the Pacific side of Japan. Just two years after manipulation, the branches of the upper-crown parts had grown so long that they were touching each other, and the light environments of the lower-crown parts had become drastically darker. Next, based on the crown development and light variation and the relationship between cone production and light intensity, we performed a simulation of total cone production over the years in a hypothetical orchard composed of multiple blocks. Then, the simulated total cone production was compared between the block-rotation cycles, where crown management was performed every three or four years. Compared to the three-year block rotation, the distribution of within-tree cone production for the four-year block rotation was more biased towards only the upper crown, since the lower crown became suddenly darker. It was estimated that cone production for the entire tree and the entire seed orchard would be lower than in the three-year block rotation. The approach and findings of this study will be useful for improving seed orchard management. Full article

The carbon stock in terrestrial ecosystems is closely linked to changes in land use. Understanding how land use alterations affect regional carbon stocks is essential for maintaining the carbon balance of ecosystems. This research leverages land use and driving factor data spanning from 2000 to 2020, utilizing the Patch-generating Land Use Simulation (PLUS) model alongside the InVEST ecosystem services model to examine the temporal and spatial changes in carbon storage across Beijing. Additionally, four future scenes for 2030—urban development, natural development, cropland protection, as well as eco-protection—are explored, with the PLUS and InVEST models employed to emulate dynamic land use changes and the corresponding carbon stock variations. The results show that the following: (1) Between 2000 and 2020, changes in land use resulted in a significant decline in carbon storage, with a total reduction of 1.04 × 10⁷ tons. (2) From 2000 to 2020, agricultural, forest, and grassland areas in Beijing all declined to varying extents, while built-up land expanded by 1292.04 km² (7.88%), with minimal changes observed in water bodies or barren lands. (3) Compared to the carbon storage distribution in 2020, carbon storage in the 2030 urban development scenario decreased by 6.99 × 10⁶ tons, highlighting the impact of rapid urbanization and the expansion of built-up areas on the decline in carbon storage. (4) In the ecological protection scenario, the optimization of land use structure resulted in an increase of 6.01 × 10⁵ tons in carbon storage, indicating that the land use allocation in this scenario contributes to the restoration of carbon storage and enhances the carbon sink capacity of the urban ecosystem. This study provides valuable insights for policymakers in optimizing ecosystem carbon storage from a land use perspective and offers essential guidance for the achievement of the “dual carbon” strategic objectives. Full article

This study focuses on a typical chemically contaminated site in the southeastern coastal region of China, investigating the natural attenuation mechanisms of benzene and o-toluidine in groundwater through high-throughput sequencing, physicochemical analyses, and stable isotope techniques. The results demonstrate significant heterogeneity in the spatial distribution and degradation processes of pollutants within the contaminated zones (W27, W28, W31). Environmental factors such as HCO₃⁻, SO₄²⁻, and ORP predominantly influence the microbial community structure and functional distribution. Stable isotope data reveal that δD and δ¹³C enrichment effects are most pronounced in the deep layer (W28_40m), indicating active pollutant degradation, while degradation in the deeper layers of W27 and W31 is constrained by anaerobic conditions and reduced microbial activity. The combined analysis of hydrogen and carbon isotopes elucidates the degradation pathways and dynamic processes of pollutants within the contaminated zones, providing quantitative evidence for natural attenuation mechanisms and scientific support for optimizing site remediation strategies. Full article

To investigate the influence of factors such as tourism, agriculture, and population density on the presence of microplastic (MP) content in aquatic environments and their associated ecological risks, Jingpo Lake, a remote high-mountain lake situated away from urban areas, was selected as the research subject. This study examined the abundance, types, sizes, colors, and polymer compositions of MPs within the water body, fish, and sediments. By considering variables, including fishing practices, agricultural activities, population dynamics, and vegetation cover, an analysis was conducted to unravel the spatial and temporal distribution of MPs concerning human activities, ultimately leading to an assessment of the ecological risks posed by MP pollution. The findings revealed that the average abundance of MPs in the lake’s surface water was recorded as (304.8 ± 170.5) n/m³, while in the sediments, it averaged (162.0 ± 57.45) n/kg. Inside the digestive tracts of fish, the MP abundance was measured at 11.4 ± 5.4 n/ind. The contamination of MPs within the aquatic environment of Jingpo Lake was found to be relatively minimal. Variations in MP loads across time and space were observed, with MPs predominantly falling within the size range of small planktonic organisms (50–1000 μm). Additionally, the prevalent colors of MPs in the water samples were white or transparent, constituting approximately 55.65% of the entire MP composition. Subsequently, they were black, red, and blue. This colors distribution were consistent across MPs extracted from fish and sediment samples. The chemical compositions of the MPs predominantly comprised PE (31.83%) and PS (25.48%), followed by PP (17.56%), PA (11.84%), PET (6.71%), EVA (4.56%), and PC (2.03%). Regarding the seasonal aspect, MP concentrations were highest during summer (46.68%), followed by spring (36.75%) and autumn (16.56%). The spatial distribution of MPs within Jingpo Lake’s water body, fish, and sediments was notably influenced by human activities, as confirmed by Pearson correlation coefficients. A strong association was observed between MP levels and water quality indicators such as ammonium nitrogen (NH₄-N), total phosphorus (TP), and chlorophyll-a (Chla), suggesting that human-related pollution contributed significantly to MP contamination. The diversity assessment of MP pollutants exhibited the highest variability in chemical composition (1.23 to 1.79) using the Shannon–Wiener Index. Subsequently, the diversity of colors ranged from 0.59 to 1.54, shape diversity from 0.78 to 1.30, seasonal diversity from 0.83 to 1.10, and size diversity from 0.44 to 1.01. The assessment results of ecological risk highlighted that the risk categories for MPs within the surface water, fish, and sediments of Jingpo Lake were categorized as I for the PHI and PLI and as “Minor” for the PERI. These relatively low-risk values were attributed to the predominantly low toxicity of the distributed MPs within the Jingpo Lake basin. Moreover, the results of the risk assessment were found to be interconnected with the distribution of the local population and agricultural activities around the sampling sections. Usage patterns of coastal land and population density were recognized as influential factors affecting MP loads within the water body, sediments, fish, and other components of the lake ecosystem. Full article

The exploration level of the Bogda Mountain front belt is relatively low, and the research on hydrocarbon accumulation is limited, resulting in unclear sources of discovered oil. To further investigate the geochemical characteristics and sources of crude oil in the Bogda Mountain front belt, this study conducted geochemical experimental analysis and oil–source correlations on crude oil and hydrocarbon source rock samples from the Permian Lucaogou Formation in the Yongfeng sub-sag and surrounding areas of the Bogda Mountain front belt. By using gas chromatography–mass spectrometry technology, the geochemical characteristics of saturated hydrocarbons and aromatic compounds were analyzed. Combined with stable carbon isotopes of saturated hydrocarbons and aromatic hydrocarbons, the organic matter source, maturity, and sedimentary environment were determined. The research results indicate that the crude oil from Well Xyd 1 exhibits mature characteristics, and the source material was deposited in a reducing to weakly oxidizing, weakly reducing environment. The source rocks of the Lucaogou Formation in Well Xyd 1 were formed in a reducing, semi-saline–saline sedimentary environment, while those from the Gjg and Dhs outcrops developed in a weakly oxidizing–weakly reducing, non-high-salinity, weakly stratified sedimentary environment. Carbon isotope, terpane, and isoalkane characteristics confirm a significant genetic relationship between the crude oil from Well Xyd 1 and the local Luzhaogou Formation source rocks. The source rocks of the Luzhaogou Formation in the Yongfeng sub-sag exhibit strong heterogeneity, with significant differences in sedimentary environments and parent materials in their spatial distribution. Maturity analysis indicates that the Luzhaogou Formation source rocks in Well Xyd 1 have reached a mature stage, whereas those from the Gjg and Dhs outcrops are at a relatively low maturity level. Full article

This study investigates the impacts of climate change on snake behavior and distribution in Taiwan by analyzing roadkill data from the Taiwan Roadkill Observation Network (TaiRON). Focusing on data from 2012 to 2019, the analysis reveals temporal and spatial changes in snake roadkill patterns, shedding light on the ecological effects of a warming climate. From 2012 to 2019, the number of snake roadkill events exhibited a rising trend, particularly during peak activity months from May to October, which accounted for over 70% of annual cases. However, a notable increase was observed in January, traditionally a low-activity period, with roadkill numbers rising 14.9-fold and proportions increasing nearly 6-fold over the study period. This shift suggests that warmer winters are extending the active period for snakes, potentially altering their seasonal behaviors. Spatially, snake roadkill numbers showed a northward and upward migration, reflecting a response to rising temperatures and habitat shifts to higher-altitude regions. These migratory trends, while adaptive, expose snakes to heightened roadkill risks in newly occupied habitats. The findings underscore the potential of roadkill data as a robust ecological monitoring tool for understanding species responses to climate change. By integrating citizen science with ecological and spatial analyses, this research highlights the critical role of environmental changes in driving snake activity and distribution shifts. This study emphasizes the need for climate-adaptive conservation strategies, including road design improvements and biodiversity-focused policies, to mitigate roadkill risks and safeguard snake populations. These insights contribute to broader efforts in ecological conservation and the formulation of evidence-based policies to address the impacts of climate change on cold-blooded animals. Full article

This study presents a numerical methodology for analyzing hydroacoustic noise generation and its propagation in a homogeneous domain using Lighthill’s analogy, the finite volume method, and hybrid-Higdon boundary conditions. The approach consists of three key steps: performing an eddy-resolving Large Eddy Simulation to capture the unsteady fluid dynamics, extracting the turbulent field to compute the acoustic source term via Lighthill’s analogy, and solving a homogeneous wave equation to propagate the noise in an open domain. The methodology is applied to a turbulent plane channel flow, simulating the acoustic field for a fluid with water-like density at a Mach number of 0.1. The results reveal the spatial distribution of the acoustic pressure, highlighting the dominant noise sources and their spectral characteristics. The acoustic domain extends beyond the turbulent region, enabling the study of pressure propagation outside the flow. The findings demonstrate that noise generation is strongly linked to turbulent structures near the walls, with significant acoustic radiation occurring in the low-wavenumber range. This framework provides a powerful tool for modeling noise propagation in marine and industrial applications, offering insights into turbulence-induced sound in underwater environments. Future work could extend the approach to more complex geometries, higher Reynolds numbers, and heterogeneous domains, further advancing its applicability to real-world acoustic challenges. Full article