Distribution Patterns Research Articles

Modeling ecological differentiation in the distribution patterns of two subspecies of the Greek Tortoise, Testudo graeca (Reptilia: Testudinidae) in Iran

This study investigates ecological niche differentiation between Testudo graeca zarudnyi and T. g. buxtoni in Iran. Using Species Distribution Modeling (SDM), we analyzed 20 environmental layers derived from bioclimatic and elevation data available through WorldClim to assess the ecological niches of these two subspecies. Occurrence records were gathered from literature, the Global Biodiversity Information Facility (GBIF), and fieldwork. The selected variables for T. g. buxtoni and T. g. zarudnyi included temperature and precipitation variables to highlight their distinct ecological requirements. MaxEnt software was employed to estimate suitable areas of occurrence, achieving AUC values of 0.845 for T. g. buxtoni and 0.706 for T. g. zarudnyi, indicating good model accuracy. Our results highlighted that precipitation in the wettest quarter (BIO16) significantly influences T. g. buxtoni, whereas isothermality (BIO3) is crucial for T. g. zarudnyi. The suitable habitat areas were estimated at approximately 160,000 km² for T. g. buxtoni and approximately 330,000 km² for T. g. zarudnyi only within Iran. Statistical analyses confirmed significant ecological niche differentiation between the two subspecies.

Similarities in distribution pattern between acute multiple osteoporotic vertebral compression fractures and vertebral fractures cascades

BackgroudOsteoporotic vertebral compression fractures (OVCF) cascades (OVCFcs) repeatedly cause vertebral compression to involve multiple vertebra. This study aimed to introduce an accelerated form of OVCFcs: acute multiple OVCF (amOVCF).MethodsOVCF patients with multiple vertebral augmentations in a spine center between June 2016 and October 2020 were retrospectively studied. Demographics, spine trauma, anatomical distribution, and distribution pattern of OVCF in OVCFcs and amOVCF were summarized and compared.Results429 patients with multiple vertebral augmentations in 1164 vertebra were included. There were 210 OVCFcs accumulating 622 OVCF and 219 amOVCF simultaneously involving 542 vertebra. The OVCFcs progressed at 0.48 fractures and 0.56 vertebra per year. Both OVCFcs and amOVCF demonstrated asymmetrical bimodal distribution in spine and most frequently involved L1. The incidence of adjacent OVCF was 40.14% in amOVCF with 2 OVCF and 84.72% in amOVCF with ≥ 3 OVCF, and the distribution pattern of OVCF was not significantly different between amOVCF and OVCFcs. The female/male ratio was 5.56 in OVCFcs and not different from that of 4.34 in amOVCF. The age of females (73.41 ± 8.08 and 76.29 ± 8.25 years old) but not males (77.20 ± 10.13 and 79.75 ± 10.21 years old) was significantly increased from initial to last OVCF in OVCFcs. amOVCF had similar age (72.26 ± 10.09 years old) as OVCFcs at initial OVCF (73.99 ± 8.51 years old) and were significantly younger than OVCFcs at last OVCF (76.82 ± 8.64 years old). 54.29% in OVCFcs and 48.4% in amOVCF reported no evident trauma, and the ratio of apparent spine trauma was higher in amOVCF (43.38%) than in OVCFcs (28.54%).ConclusionsamOVCF are accelerated form of OVCFcs showing similar anatomical distribution and distribution pattern of OVCF in spine. Both amOVCF and OVCFcs cause multiple fragility fractures without significant spine trauma.

Fish fauna of the Upper Grande River basin: checklist and distribution patterns

ABSTRACT The Neotropical region exhibits a remarkable diversity of freshwater fish, with the Upper Grande River in the La Plata basin emerging as a significant yet underexplored hotspot. However, this region is confronted with escalating threats from human activities, such as hydroelectric damming and urbanization, which jeopardize its ichthyofauna. This research conducted a comprehensive inventory of the ichthyofauna in the Upper Grande River, covering diverse environments and sub-basins. Fish sampling at 185 sites revealed over 94 species, indicating a high richness and abundance of migratory fish, as well as the presence of two endangered species. While the study provides valuable insights into fish species richness and distribution, accumulation curves suggest the need for additional sampling efforts. The presence of non-native species, especially in the Aiuruoca and Grande sub-basins, raises conservation concerns. The study underscores the Upper Grande River’s critical role as an area for fish diversity, emphasizing the necessity for ongoing monitoring, conservation efforts, and additional sampling to fully uncover the extent of its ichthyofauna.

Optimal vaccination policy to prevent endemicity: a stochastic model

We examine here the effects of recurrent vaccination and waning immunity on the establishment of an endemic equilibrium in a population. An individual-based model that incorporates memory effects for transmission rate during infection and subsequent immunity is introduced, considering stochasticity at the individual level. By letting the population size going to infinity, we derive a set of equations describing the large scale behavior of the epidemic. The analysis of the model’s equilibria reveals a criterion for the existence of an endemic equilibrium, which depends on the rate of immunity loss and the distribution of time between booster doses. The outcome of a vaccination policy in this context is influenced by the efficiency of the vaccine in blocking transmissions and the distribution pattern of booster doses within the population. Strategies with evenly spaced booster shots at the individual level prove to be more effective in preventing disease spread compared to irregularly spaced boosters, as longer intervals without vaccination increase susceptibility and facilitate more efficient disease transmission. We provide an expression for the critical fraction of the population required to adhere to the vaccination policy in order to eradicate the disease, that resembles a well-known threshold for preventing an outbreak with an imperfect vaccine. We also investigate the consequences of unequal vaccine access in a population and prove that, under reasonable assumptions, fair vaccine allocation is the optimal strategy to prevent endemicity.

Improving agricultural spraying with multi-rotor drones: a technical study on operational parameter optimization

Drones play a key role in enhancing nutrient management efficiency under climate change scenarios by enabling precise and adaptable spray applications. Current aerial spray application research is primarily focused on examining the influence of drone spraying parameters viz., flight height, travel speed, rotor configuration, droplet size, payload, spray pressure, spray discharge and wind velocity on spray droplet deposition characteristics. The present study aimed to study and optimize the effect of spray height, operating pressure, nozzle spacing and spray nozzle mounting configuration on spray discharge rate, spray width, spray distribution pattern, spray uniformity and spray liquid loss. A spray patternator of 5.0 m x 5.0 m was developed per Bureau of Indian Standards (BIS) standard to study the spray volume distribution pattern of boom and hex nozzle configuration. Initially, drone spray operational parameters viz., spray discharge rate (Lm−1), operating pressure (kg cm−2) and spray angle (°) were measured using digital nozzle tester, digital pressure gauge and digital protractor, respectively, in the laboratory. Then optimized the nozzle spacing for boom configuration attachment to drone sprayer and recorded best spray uniformity at 0.6 m nozzle spacing. The drone sprayer hovered at three different heights, viz., 1.0, 2.0 and 3.0 m from the top of the patternator and spray operating pressure was maintained at 4.0 kg cm−2 in outdoor condition. Single pass distribution pattern and one-direction application distribution pattern method used for optimizing height of spray, operating pressure and nozzle mounting confirmation from the results of discharge rate, spray angle, effective spray width, spray liquid loss and spray distribution uniformity. Results showed that, the better spray uniformity distribution was found when the drone sprayer hover height was increased from the top of the patternator (2.0 m). More round spray droplet vertex pattern was generated during the 1.0 m hover height compared to the 2.0 and 3.0 m hover heights due to the direct impact of downwash airflow generated by the rotors. Finally it was concluded that, the good spray volume distribution was found at 2.0 m height of spray with standard hexa nozzle configuration arrangement as compared to the boom spray nozzle arrangement.

Spall: accurate and robust unveiling cellular landscapes from spatially resolved transcriptomics data using a decomposition network

Recent developments in spatially resolved transcriptomics (SRT) enable the characterization of spatial structures for different tissues. Many decomposition methods have been proposed to depict the cellular distribution within tissues. However, existing computational methods struggle to balance spatial continuity in cell distribution with the preservation of cell-specific characteristics. To address this, we propose Spall, a novel decomposition network that integrates scRNA-seq data with SRT data to accurately infer cell type proportions. Spall introduced the GATv2 module, featuring a flexible dynamic attention mechanism to capture relationships between spots. This improves the identification of cellular distribution patterns in spatial analysis. Additionally, Spall incorporates skip connections to address the loss of cell-specific information, thereby enhancing the prediction capability for rare cell types. Experimental results show that Spall outperforms the state-of-the-art methods in reconstructing cell distribution patterns on multiple datasets. Notably, Spall reveals tumor heterogeneity in human pancreatic ductal adenocarcinoma samples and delineates complex tissue structures, such as the laminar organization of the mouse cerebral cortex and the mouse cerebellum. These findings highlight the ability of Spall to provide reliable low-dimensional embeddings for downstream analyses, offering new opportunities for deciphering tissue structures.

Evolution of population distribution and its influencing factors in the poverty-stricken mountainous region of Southwest China from 2000 to 2020

Understanding the characteristics and determinants of population distribution is essential for formulating effective policies and strategies, especially in the poverty-stricken mountainous regions. This study investigates the characteristics, evolution (2000–2020), and influencing factors of population distribution in the Liangshan Yi ethnic region, a representative poverty-stricken mountainous region in Southwest China. The results reveal that: (1) Over the past two decades, the spatial pattern of population distribution has remained stable. However, the balance of population distribution has improved, as indicated by the decreasing size of the standard deviation ellipse, reflecting a more even population spread. (2) The population distribution demonstrates significant clustering in town centers, with strong positive correlations, as reflected in Moran’s I index values of 0.732, 0.708, 0.620, 0.556, and 0.554 for the years 2000, 2005, 2010, 2015, and 2020, respectively. (3) The vertical zonation pattern and the differentiation characteristics in slope and aspect play a significant role in population distribution. Over time, these factors have played an increasingly significant role in shaping the evolution of population distribution. The interaction between natural factors and vegetation is pivotal in the spatiotemporal patterns of population distribution. These factors have directly and indirectly contributed to the persistence of poverty in these mountainous areas by limiting accessibility, resource availability, and economic opportunities. The study’s results provide valuable insights for enhancing population distribution strategies in impoverished mountainous regions and informing policy-making.

Ancient gene introgression promotes biodiversity of Nymphaea nouchali in Hainan under environmental changes

AbstractHybridization is common in the plant kingdom. Under the influence of global climate change, an increasing number of hybrid species have experienced significant shifts from the geographical distribution of their parents, making it more difficult to detect ancient gene flows. Nymphaea nouchali is a rare aquatic flower native to Hainan Province. Owing to habitat destruction and human interference, the natural range of N. nouchali has gradually reduced to the point of extinction. To explore how hybrid populations form using RAD‐seq with population genetic analysis, it is shown that there are heterozygous deletions and inbreeding in N. nouchali and a number of ancestral components in Nymphaea lotus, low of genetic differentiation, and little gene flow between N. nouchali and N. lotus, and ancient introgression between ancestors may have been more frequent than gene exchange after the origin of the species. Accordingly, the ancient N. nouchali genotypes were gradually infiltrated by N. lotus genes and their forms changed in Hainan. Potential distribution pattern analysis also predicted the possible distribution of N. lotus in Hainan. This lays a foundation for exploring the natural genetic mechanisms of Nymphaea species formation and evolution.

Global Gridded Crop Production Dataset at 10 km Resolution from 2010 to 2020

The global gridded crop production dataset at 10 km resolution from 2010 to 2020 (GGCP10) for maize, wheat, rice, and soybean was developed to address limitations of existing datasets characterized by coarse resolution and discontinuous time spans. GGCP10 was generated using a series of adaptively trained data-driven crop production spatial estimation models integrating multiple data sources, including statistical data, gridded production data, agroclimatic indicator data, agronomic indicator data, global land surface satellite products, and ground data. These models were trained based on agroecological zones to accurately estimate crop production in different agricultural regions. The estimates were then calibrated with regional statistics for consistency. Cross-validation results demonstrated the models’ performance. GGCP10’s accuracy and reliability were evaluated using gridded, survey, and statistical data. This dataset reveals spatiotemporal distribution patterns of global crop production and contributes to understanding mechanisms driving changes in crop production. GGCP10 provides crucial data support for research on global food security and sustainable agricultural development.

Global Warming and Landscape Fragmentation Drive the Adaptive Distribution of Phyllostachys edulis in China

Global warming and landscape fragmentation significantly affect the spatial distribution pattern of bamboo forests. This study used high-resolution data and an optimized MaxEnt model to predict the distribution of Phyllostachys edulis in China under current and future climatic conditions in three climate scenarios (SSP126, SSP370, SSP585), and analyzed its land use landscape fragmentation using landscape indices. The results indicate that Phyllostachys edulis currently has potentially suitable habitats majorly distributed in East China, Southwest China, and Central South China. The precipitation of the driest month (BIO14) and the precipitation seasonality (BIO15) are the key environmental factors affecting the distribution of Phyllostachys edulis. In the next three scenarios, the adaptive distribution area of Phyllostachys edulis is generally expanding. With an increase in CO2 concentration, the adaptive distribution of Phyllostachys edulis in the 2050s migrates towards the southeast direction, and in the 2070s, the suitable habitat of Phyllostachys edulis migrates northward. In the suitable habitat area of Phyllostachys edulis, cropland and forests are the main land use types. With the passage of time, the proportion of forest area in the landscape pattern of the high-suitability area for Phyllostachys edulis continues to increase. Under SSP370 and SSP585 scenarios, the cropland in the Phyllostachys edulis high-suitability area gradually becomes fragmented, leading to a decrease in the distribution of cropland. In addition, it is expected that the landscape of high-suitability areas will become more fragmented and the quality of the landscape will decline in the future. This research provides a scientific basis for understanding the response of Phyllostachys edulis to climate change, and also provides theoretical guidance and data support for the management and planning of bamboo forest ecosystems, which will help in managing bamboo forest resources rationally and balancing carbon sequestration and biodiversity conservation.

Histomorphometry of Gastrointestinal Tract Mucosae of Sonali and Indigenous Chickens in Bangladesh

The study was conducted to provide a histomorphmetric comparison between the mucosa of the gastrointestinal tract (GUT) and the distribution pattern of gutassociated lymphoid tissue (GALT) in two types of chickens in Bangladesh: Sonali and Indigenous chickens. The study included 20 male Sonali and indigenous chickens aged 10 to 11 weeks, divided evenly into two groups of 10 chickens each. Following humane slaughter, various segments of the GUT were collected for histomorphometric analysis with hematoxylin and eosin staining. The histological investigation revealed that the epithelial lining and mucosal layer of the esophagus were thicker in the Sonali than in the Indigenous chickens. Nonetheless, the Indigenous chickens had a bigger number of lymphocytes. Indigenous chickens had thicker lining epithelium in the proventriculus, whereas Sonali chickens had thicker mucosa. Indigenous chickens showed greater lymphocyte populations than Sonali. Indigenous chickens exhibited taller duodenal and jejunal villi, but Sonali chickens had taller ileal villi. The Sonali possessed wider duodenal and jejunal villi, while Indigenous chickens had wider ileal villi. Because of their scavenging activity, Indigenous people have greater lymphocyte populations in the small intestine. The Sonali possessed the most lymphatic nodules in Meckel's diverticulum, as well as a higher crypt depth and lymphocyte density. Indigenous chickens had thicker mucosa and Lieberkühn crypts in the caecum, whereas Sonali had a greater lymphocyte count. Indigenous chickens showed larger lymphatic nodules and crypts in the cecal tonsil, whereas Sonali had thicker mucosa, deeper crypts, and a higher lymphocyte population in the colon. Lymphocytes were found scattered throughout the tissues of Sonali and Indigenous chickens. The cells were primarily detected within the lamina propria. Further research with other types of chickens could be undertaken to measure lymphocytes, intraepithelial lymphocytes, and lymphatic nodules. J. of Sci. and Tech. Res. 6(1): 33-44, 2024

Measurement and optimization paths of the multidimensional development levels of counties in the Yellow River Basin: based on the sustainable livelihoods framework

The Yellow River Basin (YRB) faces intense man-land conflicts. However, existing studies rarely focus on the comprehensive and multidimensional development levels in the YRB, and there is a lack of refined county-level studies, making it difficult to fully support the implementation of ecological protection and high-quality development strategy in the YRB. Under the Sustainable Livelihoods Framework, the spatial distribution, differences, and correlation characteristics of the multidimensional development levels of counties in the YRB are disclosed. This is achieved by comprehensively utilizing geospatial, socio-economic, and other multi-source data in combination with methods such as the entropy weight method, the Theil index, and spatial analysis. Optimal development paths are proposed with a focus on the development types of counties. The findings are as follows: (1) Counties in the YRB have a low overall multidimensional development level, presenting a spatial distribution pattern of “high in the east and low in the west” overall. In terms of each dimension, the average value ranking of lower reach > middle reach > upper reach is observed in each dimension; the exception is the financial dimension (with the ranking of middle reach > lower reach > upper reach). (2) Differences between counties in the development indices vary across different dimensions. The differences in the multidimensional development indices and in the development indices of each dimension (except for the natural dimension) are mainly attributable to differences between counties within each reach. Differences between reaches are non-significant. (3) The multidimensional development levels of counties in the YRB and their development levels in each dimension show strong spatial correlation. And significant counties are mainly identified as LL-type (clusters of low value areas) and HH-type (clusters of high value areas). (4) Depending on the measurement results and advantageous factors of the county multidimensional development index, counties are classified into four development types: weak development type, single-dimension-led development type, potential coordinated development type, and multidimensional coordinated development type. Based on this classification, targeted optimal development paths are proposed with a focus on the specific characteristics of different development types. The research findings can provide effective scientific support for ecological protection and high-quality development in the YRB.

Thermal Optimalization with CFD Analysis and Real-Time Performance Identification in Briquette Ovens Using Modbus-Based Communication

Briquette ovens that utilize biomass energy frequently face obstacles in achieving consistent heat distribution, resulting in ineffective energy usage and varying product quality. This study tackles these challenges by merging Computational Fluid Dynamics (CFD) analysis, performed with Cradle software, alongside a Modbus-based temperature data acquisition system to significantly boost energy efficiency and temperature regulation. A total of 32 K-type thermocouples were meticulously positioned within the oven to gather real-time temperature data, which was processed through LabVIEW. CFD simulations revealed irregular heat distribution patterns, especially at the rear of the oven. The temperature data obtained via Modbus corroborated these observations, allowing for strategic modifications to enhance heat distribution and minimize energy loss. The system achieved an impressive accuracy rate of 98.89%, with a mere error margin of 1.11%, substantially elevating the oven’s energy efficiency and briquette drying capabilities. This research clearly illustrates that the integration of CFD modeling with real-time data acquisition constitutes a powerful method for optimizing the functionality of industrial heating systems.

Modeling the current and future habitat suitability of clematis tangutica (ranunculaceae) on the qinghai-tibet plateau based on an ensemble method.

This research explores the impact of environmental changes on the distribution of Clematis tangutica, providing theoretical support for its conservation, development, utilization, and early warning monitoring of potential impacts on the ecological environment and local plant communities. An ensemble model in R was used to simulate the suitable habitats of Clematis tangutica on the Tibetan Plateau, integrating climate, topography, and soil variables. Simulations were conducted under three distinct future climate scenarios. The ensemble model exhibited superior performance, as indicated by a true skill statistic of 0.9203, compared to the individual models. Clematis tangutica primarily occupies the eastern Tibetan Plateau, with optimal habitats predominantly located in western Sichuan Province. Regions of inadequate suitability encompass approximately 69.72% of the total area (equivalent to approximately 1743 thousand square kilometers), while highly suitable areas constitute about 5.48% (equivalent to approximately 137 thousand square kilometers). In the future, as the temperature rises on the Qinghai-Tibet Plateau, overall precipitation is expected to increase, though regional differences will exist, particularly the SSP245 scenario in the 2050s, the centroid of Clematis tangutica distribution is projected to shift northwest, potentially providing favorable conditions. The distribution pattern of Clematis tangutica is strongly influenced by fluctuations in temperature and elevation, as these factors directly affect the plant's ability to thrive in specific regions. Changes in these variables may alter its future distribution, particularly under climate change scenarios. There is a tendency for the center of mass of Clematis tangutica to migrate northwest under future climatic conditions.

Genome Studies in Amaranthus cruentus L. and A. hypochondriacus L. Based on Repeatomic and Cytogenetic Data

Amaranthus cruentus L. and Amaranthus hypochondriacus L. are valuable and promising food crops for multi-purpose use that are distributed worldwide in temperate, subtropical, and tropical zones. However, their karyotypes and genomic relationships still remain insufficiently studied. For the first time, a comparative repeatome analysis of A. cruentus and A. hypochondriacus was performed based on the available NGS data; bioinformatic analyses using RepeatExplorer/TAREAN pipelines; and chromosome FISH mapping of 45S rDNA, 5S rDNA, and the most abundant satellite DNAs. In the repeatomes of these species, interspecific variations in the amount of Ty3/Gypsy and Ty1/Copia retroelements, DNA transposons, ribosomal, and satellite DNA were detected. In the repeatomes of both species, shared satDNAs with high sequence similarity were identified. The chromosome distribution patterns of four effective molecular markers, 45S rDNA, 5S rDNA, AmC4, and AmC9, allowed us to identify all chromosome pairs in the species karyotypes, construct unique karyograms of A. cruentus and A. hypochondriacus, and confirm the close relationship between their genomes. These results are important for comparative karyotypic studies within the genus Amaranthus. Our findings demonstrated that cytogenomic analyses might provide important data on genomic relationships within Amaranthus and increase knowledge on genome organization in these valuable crops.

RETRACTED: Choi et al. Distribution Pattern and Brood Parasitism Characteristics of an Endangered Fish, Pseudopungtungia nigra, in the Geum River Basin, South Korea. Fishes 2022, 7, 321

The journal Fishes retracts the article titled “Distribution Pattern and Brood Parasitism Characteristics of an Endangered Fish, Pseudopungtungia nigra, in the Geum River Basin, South Korea” [...]

Trace element composition of discordant zircon as a reflection of the fluid regime of paleoproterozoic granulite metamorphism (Khapchan terrane, Anabar shield)

New data on the U–Pb age (SHRIMP-II) and anomalous trace element composition (SIMS) of zircon from gneisses of the Khapchan Group of the Khapchan terrane of the Anabar Shield are presented. The gneisses contain igneous zircon with a core whose age is 1971 ± 19 Ma. During the main stage of granulite metamorphism, the igneous zircon cores became enriched in incompatible elements (Ca, Ti, Pb, Sr, Ba) and were surrounded by a new zircon population (black in the CL image). The REE distribution patterns in the recrystallized cores acquired a “bird’s wing” profile atypical for zircon. At the final stage of metamorphism, after the fluid lost its reactivity, a new population of zircon crystallized, less enriched in incompatible elements and with a typical REE patterns for granulite zircon. The horizontal pattern of HREE distribution is consistently repeated, which indicates the co-crystallization of zircon and garnet. The estimated crystallization temperature of the main part of zircon varies in a narrow range of 800–830 °C. All zircon domains in the Weserill diagram with concordia form a single trend with a zero lower intercept and a concordant upper intercept around 1920–1930 Ma. This value corresponds to the age of regional Paleoproterozoic granulite metamorphism. A unique feature of zircon from the Khapchan gneisses is that the zircon cores did not retain the age marks of the protolith, but were completely reset during metamorphism both in terms of the U–Pb system and the trace element composition, which can be explained by the exceptional intensity of the impact of fluid during metamorphism of the granulite facies, superimposed on the rocks of the Khapchan terrane of the Anabar Shield.

Mobile Observation Field Experiment of Atmospheric Vertical Structure and Its Application in Precipitation Forecasts Over the Tibetan Plateau

AbstractWe carried out the first Mobile Field Observation Campaign of Atmospheric Profiles (MFOCAP) in the southeast Tibet and the Three‐River Source Region (TRSR) of the Tibetan Plateau (TP) by adopting two vehicle‐mounted integrated mobile observations (MO) system from July 18 to 30, 2021. Reliable MO data sets of air temperature (Ta), water vapor density (WVD) and relative humidity (RH) with high spatio‐temporal resolution over the TP were obtained and assimilated to improve precipitation forecast using the four‐dimensional variational (4DVAR) data assimilation (DA) method. The results show that Ta, WVD and RH profile data retrieved with the mobile microwave radiometer (MR) are credible over the TP. The atmospheric vertical structure measured by the mobile MR can reproduce the spatio‐temporal evolution characteristics of water vapor transport, temperature stratification and cloud structure. The distribution pattern of 24‐hr accumulated rainfall prediction with Ta profile DA was closer to measurements, and 6–12 hr forecasts for low to moderate rainfall in the central and western regions of Qinghai province were improved significantly. Data assimilation with air temperature retrievals from mobile MR observations were found beneficial for accurate simulation of water vapor transport, convergence and divergence of wind field, and upward motion associated with precipitation events. The finding of this study highlights the value of MR remote sensing observations in improving the rainfall monitoring and forecasts over the TP and downstream regions.

Bacterial Community Structure and Environmental Driving Factors in the Surface Sediments of Six Mangrove Sites from Guangxi, China

Mangroves, as blue carbon reservoirs, provide a unique habitat for supporting a variety of microorganisms. Among these, bacteria play crucial roles in the biogeochemical processes of mangrove sediments. However, little is known about their community composition, spatial distribution patterns, and environmental driving factors, particularly across the large geographical scales of mangrove wetlands. In this study, the composition and spatial distribution of the bacterial community structure and its response to fifteen physicochemical parameters (including temperature, pH, salinity, moisture, clay, silt, sand, organic carbon (OC), total nitrogen (TN), total phosphorus (TP), inorganic phosphorus (IP), organic phosphorus (OP), δ13C, δ15N, and carbon/nitrogen ratio (C/N ratio)) were characterized in 32 sampling locations of six different mangrove habitats from Guangxi, China, applying 16S rRNA gene high-throughput sequencing technology and correlation analysis. Our results indicated that the spatial distribution patterns in bacterial communities were significantly different among the six different mangrove sites, as evidenced by NMDS (non-metric multidimensional scaling), ANOSIM (analysis of similarity), and LDA (linear discriminant analysis) analysis. Composition analysis of bacterial communities showed that overall, Chloroflexi (8.3–31.6%), Proteobacteria (13.6–30.1%), Bacteroidota (5.0–24.6%), and Desulfobacterota (3.8–24.0%) were the most abundant bacterial phyla in the mangrove surface sediments. Redundancy analysis (RDA) further highlighted that salinity, δ13C, temperature, δ15N, and silt were the most critical environmental variables influencing the composition of bacterial communities across the whole mangrove samples. Notably, Chloroflexi, one of the most abundant bacterial phyla in the mangrove wetlands, displayed a significantly positive correlation with OC and a negative correlation with δ13C, suggesting its essential role in the degradation of terrestrial-derived organic carbon. These findings support the current understanding of the roles of the bacterial communities and their interactions with environmental factors in diverse mangrove ecosystems.

Spatial Distribution and Mechanisms of Groundwater Hardness in the Plain Area of Tangshan City, China

Groundwater resources play a critical role in meeting the agricultural, industrial, and domestic water demands of Tangshan, a key industrial city in China. However, with the acceleration of urbanization and the overextraction of groundwater, issues related to groundwater quality have become increasingly apparent. Notably, groundwater hardness has steadily increased over the years, posing risks to human health and elevating industrial water treatment costs. This study analyzed the spatial distribution characteristics and causes of groundwater hardness using 214 groundwater quality samples collected in 2022 from the plain area of Tangshan City, employing inverse distance weighting (IDW), Gibbs diagrams, ion ratios, mineral saturation indices, and Pearson correlation analysis. The results indicate that, in horizontal distribution, high-hardness groundwater is predominantly concentrated in the southern coastal plain area, with hardness gradually decreasing from south to north. Vertically, shallow groundwater in the coastal plain exhibits significantly higher hardness than deep groundwater, with a non-compliance rate of 94.12%, while deep groundwater hardness remains markedly lower. Mid-depth groundwater (60–300 m) in the alluvial plain exhibits elevated hardness, primarily attributed to mineral dissolution and agricultural irrigation return flow. The spatial distribution pattern of groundwater hardness across the study area is predominantly governed by hydrogeochemical processes and hydrochemical environmental factors, with cation exchange adsorption and evaporation–concentration processes identified as the dominant influences. The analysis of ion sources indicates that Ca2+ and Mg2+, the primary contributors to groundwater hardness in the area, are mainly derived from the weathering and dissolution of carbonate minerals, sulfate minerals, and cation exchange processes. Therefore, an in-depth investigation into the spatial distribution and driving factors of groundwater hardness in Tangshan can provide a scientific basis for regional water resource management, pollution control, and water quality optimization. Such research also supports the development of sustainable groundwater management and optimization strategies.