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Subways play an important role in supporting travel needs, yet whether the benefits of subway expansion can justify the substantial investments remains a much-debated question. Existing studies have arbitrarily defined the catchment area of a subway station using walking distance and have disproportionately focused on commuting trips, potentially underestimating broader subway effects. To address these limitations, this study employed the distance-band approach to accurately define the treatment area of subway stations while incorporating both local and network effects. Based on longitudinal mobile signaling data, we used the difference-in-differences approach to estimate the average treatment effects of 32 new subway stations on different types of home-based travels in Beijing, China. We found that the opening of new subway stations has led to significant increases in subway usage, trip duration, and trip distance within a 2000-m radius, and that commuting trips have been more affected than home-based non-commuting trips, except during the COVID-19 pandemic. Moreover, the new subway stations also enhanced the connectivity of the city-wide network, influencing the travel behavior of residents in the vicinity of existing subway stations. We further found that subway expansion is particularly beneficial for women, younger residents, and residents of low-rent neighborhoods. According to these findings, planning new subway stations in Beijing and other densely populated megacities requires an integrated approach that considers the relationships between the existing transport network and diverse travel demand. • Subway expansion significantly influences travel behavior within a 2000-m radius. • Commuting trips are more affected by subway expansion than non-commuting trips. • The connectivity levels of existing stations improve unevenly following subway expansion. • Subway expansion brings greater benefits for women, younger residents, and residents of low-rent neighborhoods. [ABSTRACT FROM AUTHOR]

• A method is devised to enable the quantitative assessment of precipitation precision among GCMs. • GCP6 demonstrates benefits in simulating precipitation probability, correlation, extreme values, and spatial variability. • Significant variations in the precision of precipitation simulations are evident across models, especially the CP6 models. • The top-ten models are selected for providing suitable rainfall simulations in the Hanjiang River Basin. To effectively compare and analyze daily precipitation modeling capabilities across different CMIP6 datasets, our study introduces a novel method to compare daily precipitation models across CMIP6 datasets in the Hanjiang River Basin (HRB). We quantify indicators such as precipitation distribution, temporal correlation, wet-dry detection, extreme value error, and spatio-temporal variability, enabling a comprehensive rating of precipitation accuracy. It has been found that while both CMIP6(CP6) and NEX-GDDP-CMIP6 (GCP6) models show similar simulation accuracy, GCP6 excels in several aspects like distribution, temporal correlation, extreme value simulation, and spatial variability, yet lags in wet-dry detection and temporal change. Notably, using the comprehensive rating score (CRS) analysis, significant differences in precipitation simulation accuracy exist between models, particularly CP6, with variations of up to 0.22 (51.2%) between the highest and lowest scores. Among the top ten models, GCP6 occupies four positions such as MRI-ESM2-0, GFDL-CM4, MPI-ESM1-2-HR, and TaiESM1, while CP6 holds the remaining six like CanESM5, EC-Earth3-Veg, MPI-ESM1-2-HR, GFDL-CM4, MRI-ESM2-0, and IPSL-CM6A-LR. These findings not only offer a clear understanding of the simulation performance of CMIP6 datasets across various precipitation characteristics, but also quantitatively compare the modeling capabilities of different models for watershed precipitation through CRS. This aids climate adaptation research, hydrological forecasting, and flood management in the basin. [ABSTRACT FROM AUTHOR]

Constraining the processes that fractionate barium isotopes is essential for utilising barium isotope ratios as environmental tracers. Barium concentration measurements from soils, rivers, and estuaries demonstrate that adsorption–desorption reactions significantly influence the distribution of fluid–mobile barium at the Earth's surface, potentially driving isotopic fractionation. To quantify the direction and magnitude of isotopic fractionation resulting from these reactions, a riverine and an estuarine series of batch experiments were conducted using environmentally important adsorbent minerals and surface waters. Himalayan river sediment and water samples were used to validate the experimental results. Adsorption–desorption reactions were found to be rapid, relative to the average transit time of sediment and water in catchments, and largely reversible. The direction and magnitude of isotopic fractionation in the riverine experiment series were consistent with the riverine field samples (preferential adsorption of the lighter isotopes). The reaction rate, reversibility, and magnitude of isotopic fractionation were found to depend primarily on the mineral. Experiments performed with iron oxyhydroxides (goethite and ferrihydrite) resulted in a greater degree of fractionation compared to clay minerals (kaolinite and montmorillonite). Estuarine experiments, designed to simulate sediment passage through a salinity gradient, demonstrated a high degree of reversibility, with 77% to 94% of adsorbed barium desorbed upon the addition of seawater to freshwater-equilibrated clay minerals. The results of the estuarine experiments suggest that barium isotope ratios measured in marine paleo-archives (e.g. , corals) will reflect both the adsorbed and dissolved freshwater barium inputs to the ocean. The combined findings of this study indicate that the chemical and isotopic behaviour of barium differs from more conventional group 1 and 2 metal isotope systems due to a significant proportion of barium released from bedrock dissolution partitioning to mineral surfaces, rapid reaction rates between fluid–mobile phases, and a high degree of reaction reversibility. Consequently, riverine barium isotope ratios are likely to provide unique insights into the complex array of terrestrial weathering and erosion processes that sustain life on Earth. [ABSTRACT FROM AUTHOR]

[Display omitted] • Introducing new combined models of MC-MCE-CA, MC-MLP-CA, MC-SW-CA and MC-LR-CA for the development of land use methodology, with emphasizing the nature and principles of them for modeling of land use changes studies. • Comparing the capabilities of the new models with the traditional CA-Markov model in terms of the overall accuracy of the models and the basis of their implementation in land use change studies. • Monitoring and modeling of land use changes from the areas of industrial and agricultural activities in a long time range of about half a century (1989-2037). Land use change is one of the most significant environmental issues in many countries and is the main reason for ecosystem changes. This issue is one of the most important environmental crises in Iran due to the lack of planning and inappropriate human use of the natural environment. Many parts of Iran, especially the Urmia Lake basin, are involved in challenging land use changes. The trend of land use changes extracted from Landsat images in the Urmia lake basin with overall accuracy and Kappa coefficient of more than 85 % and 80 % respectively shows that during the 32-year period (1989–2021) agricultural lands, built-up lands and barren lands respectively 3330.83 km2, 466.86 km2 and 5325.8 km2 have increased in area. On the other hand, the areas of vegetation and water bodies decreased by 6625.79 km2 and 2497.7 km2, respectively. The current trend of land use changes in Urmia basin based on all models of Markov chain-Multi Criteria Evolution-Cellular Automata (MC-MCE-CA), Markov Chain-Multilayer Perceptron-Cellular Automata (MC-MLP-CA), Markov Chain-Sim Weight-Cellular Automata (MC-SW-CA), Markov Chain–Logistic Regression-Cellular Automata (MC-LR-CA) indicate the continuation of changes until 2037. Meanwhile, based on the most accurate models such as MC-MLP-CA and MC-LR-CA models, agricultural lands will increase by 1436.60 km2 and 1258.33 km2, built-up lands by 75.23 km2 and 65.52 km2, and barren lands by 808.94 km2 and 856.90 km2 respectively. Also, the vegetation lands will be reduced by 1890.64 km2 and 1755.31 km2 and water bodies by 430.13 km2 and 425.44 km2. In general, the results showed that MC-MLP-CA, MC-LR-CA, MC-SW-CA, MC-MCE-CA models with Overall Kappa 89.89, 87.09, 84.52 % and 84.84 and Percent of Correctness 93.65, 93.09, 91.52 and 91.77 respectively, with higher accuracy than the CA-Markov model (Overall Kappa = 81.49 % and Percent of Correctness = 87.49 %) are more effective for land use changes modeling. [ABSTRACT FROM AUTHOR]

This study examines the influence of gateway seaports on inland ports within a river port system, focusing on the Yangtze River port system as a case study. The research initially employs a fixed-effects panel model to confirm the overall positive impact of Shanghai Port on Yangtze River inland ports. Subsequently, using Panel data model with individual-specific slopes, this study reveal that Shanghai Port positively affects each inland port, but the magnitude of this impact varies significantly. The research further employs a panel threshold regression model to dissect the mechanisms through which Shanghai Port influences inland ports in terms of geographical, operational, and economic distances. In terms of geographical distance, the influence of Shanghai Port on the throughput of Yangtze inland ports diminishes as the navigational distance increases. Notably, inland ports located downstream on the Yangtze River are the first and most impacted, marking the downstream area as an early influencer in the port regionalization process. As to operational distance, Shanghai Port exerts a stronger influence on inland ports with higher throughput levels, as opposed to those with lower throughput. With respect to economic distance, inland ports in cities with higher economic development are found to be less influenced by Shanghai Port compared to those in less economically developed regions. This nuanced understanding provides invaluable insights into the interconnectedness of major gateway ports and their inland counterparts. • Investigates the mechanism of how gateway seaports influence inland ports within a river port system. • Employs a panel model with fixed effects to confirm the overall positive impact of Shanghai Port on Yangtze River inland ports. • Constructs a Panel data model with individual-specific slopes to specifically examine the influence of Shanghai Port on each inland port. • Uses a panel threshold regression model to examine the influence mechanisms of Shanghai Port on inland ports. [ABSTRACT FROM AUTHOR]

• The concentration of phthalates in the Yellow River is higher. • DMP, DEP, and DiBP were the most frequently encountered components. • Control of construction land release and lake pollution sources is critical. • DNOP and DiBP demonstrate low to moderate risk concentrations. Phthalate esters (PAEs), recognized as endocrine disruptors, are released into the environment during usage, thereby exerting adverse ecological effects. This study investigates the occurrence, sources, and risk assessment of PAEs in surface water obtained from 36 sampling points within the Yellow River and Yangtze River basins. The total concentration of PAEs in the Yellow River spans from 124.5 to 836.5 ng/L, with Dimethyl phthalate (DMP) (75.4 ± 102.7 ng/L) and Diisobutyl phthalate (DiBP) (263.4 ± 103.1 ng/L) emerging as the predominant types. Concentrations exhibit a pattern of upstream (512.9 ± 202.1 ng/L) > midstream (344.5 ± 135.3 ng/L) > downstream (177.8 ± 46.7 ng/L). In the Yangtze River, the total concentration ranges from 81.9 to 441.6 ng/L, with DMP (46.1 ± 23.4 ng/L), Diethyl phthalate (DEP) (93.3 ± 45.2 ng/L), and DiBP (174.2 ± 67.6 ng/L) as the primary components. Concentration levels follow a midstream (324.8 ± 107.3 ng/L) > upstream (200.8 ± 51.8 ng/L) > downstream (165.8 ± 71.6 ng/L) pattern. Attention should be directed towards the moderate ecological risks of DiBP in the upstream of HH, and both the upstream and midstream of CJ need consideration for the moderate ecological risks associated with Di-n-octyl phthalate (DNOP). Conversely, in other regions, the associated risk with PAEs is either low or negligible. The main source of PAEs in Yellow River is attributed to the release of construction land, while in the Yangtze River Basin, it stems from the accumulation of pollutants in lakes and forests discharged into the river. These findings are instrumental for pinpointing sources of PAEs pollution and formulating control strategies in the Yellow and Yangtze Rivers, providing valuable insights for global PAEs research in other major rivers. [Display omitted] [ABSTRACT FROM AUTHOR]

• The accuracy of the eDNA method of planktic algae in the Tuojiang River Basin was higher than that of conventional survey methods. • SEM analysis showed algae growth was significantly affected by N/P ratio, and was mainly limited by phosphorus. At the same time, SEM also obtained the causal relationship of each water environment and water quality parameters. • Mantel analysis showed the phytoplankton in TRB water exhibits strong correlations with NH 3 -N, COD, TDS, TN, and TP and all of which were statistically significant relationships. • The factors influencing phytoplankton growth in the TRB were consistent with the observed and monitored data. Tuojiang River Basin is a first-class tributary of the upper reaches of the Yangtze River—which is the longest river in China. As phytoplankton are sensitive indicators of trophic changes in water bodies, characterizing phytoplankton communities and their growth influencing factors in polluted urban rivers can provide new ideas for pollution control. Here, we used direct microscopic count and environmental DNA (eDNA) metabarcoding methods to investigate phytoplankton community structure in Tuojiang River Basin (Chengdu, Sichuan Province, China). The association between phytoplankton community structure and water environmental factors was evaluated by Mantel analysis. Additional environmental monitoring data were used to pinpoint major factors that influenced phytoplankton growth based on structural equation modeling. At the phylum level, the dominant phytoplankton taxa identified by the conventional microscopic method mainly belonged to Bacillariophyta, Chlorophyta , and Cyanophyta , in contrast with Chlorophyta, Dinophyceae , and Bacillariophyta identified by eDNA metabarcoding. In α-diversity analysis, eDNA metabarcoding detected greater species diversity and achieved higher precision than the microscopic method. Phytoplankton growth was largely limited by phosphorus based on the nitrogen-to-phosphorus ratios > 16:1 in all water samples. Redundancy analysis and structural equation modeling also confirmed that the nitrogen-to-phosphorus ratio was the principal factor influencing phytoplankton growth. The results could be useful for implementing comprehensive management of the river basin environment. It is recommended to control the discharge of point- and surface-source pollutants and the concentration of dissolved oxygen in areas with excessive nutrients (e.g., Jianyang–Ziyang). Algae monitoring techniques and removal strategies should be improved in 201 Hospital, Hongrihe Bridge and Colmar Town areas. [Display omitted] [ABSTRACT FROM AUTHOR]

• A coupled metal and metalloid transport model were developed based on improved two-dimensional hydrodynamic water quality model and SWAT model. • The contents and spatial-temporal distribution of arsenic were characterized. • Impacts of hydro-climate, hydropower station and non-point source were explored. • Model helps to quantify and analysis the transport of metalloid pollution. With the increasing severity of arsenic (As) pollution, quantifying the environmental behavior of pollutant based on numerical model has become an important approach to determine the potential impacts and finalize the precise control strategies. Taking the industrial-intensive Jinsha River Basin as typical area, a two-dimensional hydrodynamic water quality model coupled with Soil and Water Assessment Tool (SWAT) model was developed to accurately simulate the watershed-scale distribution and transport of As in the terrestrial and aquatic environment at high spatial and temporal resolution. The effects of hydro-climate change, hydropower station construction and non-point source emissions on As were quantified based on the coupled model. The result indicated that higher As concentration areas mainly centralized in urban districts and concentration slowly decreased from upstream to downstream. Due to the enhanced rainfall, the As concentration was significantly higher during the rainy season than the dry season. Hydro-climate change and the construction of hydropower station not only affected the dissolved As concentration, but also affected the adsorption and desorption of As in sediment. Furthermore, As concentration increased with the input of non-point source pollution, with the maximum increase about 30%, resulting that non-point sources contributed important pollutant impacts to waterways. The coupled model used in pollutant behavior analysis is general with high potential application to predict and mitigate water pollution. [Display omitted] [ABSTRACT FROM AUTHOR]

We present a discriminant metric study of stone projectile points (n = 422) from 21 archaeological sites in the Andes of South America (16–37°S). We use comparative datasets critically, since darts may have been smaller than previously thought. We assess the use-life of each point and tie them to reliable chronological sequences, in order to increase the reliability of our data. Our results show that in the Lake Titicaca Basin and northwestern Argentina, bows had replaced spearthrowers by 1780–950 cal BP, prior to the development of complex societies such as Wari and Tiwanaku. South of 29°S, the results suggest that bow technology was transmitted from north to south, since the earliest arrow-sized points at 29°S date to 3000 cal BP and at 37°S, 1800–1000 cal BP. North of 34°S, the continental limit of domesticated plants and animals, there is a gradual abandonment of the spearthrower. South of 34°S in northern Patagonia, both weapon systems coexisted. We suggest that bow and arrow technology was not an independent invention in the southern Andes, but instead, it appeared in new groups via macroregional technological borrowing among Andean herders. [ABSTRACT FROM AUTHOR]

The extent to which archery technology affected social organization in the Andes region of South America remains understudied. To identify the timing and consequences of archery technology in the Lake Titicaca Basin, this analysis examines metric data from 1179 projectile points from the region, 11–1.0 cal. ka. We find that the greatest decrease in projectile point size occurred across the Late/Terminal Archaic and Formative/Tiwanaku period boundaries, 5.0 and 1.5 cal. ka, respectively. We do not find a statistically significant decrease in size during any other transition, including the Terminal Archaic/Formative boundary, which was previously hypothesized to have been the time when archery technology first appeared in the region. These results instead favor the hypothesis that archery technology first entered the region during the Terminal Archaic Period, 5.0–3.5 cal ka. We furthermore observe that this technological transition coincided with the growth of settlements, a surge in the use of exotic goods such as obsidian, a low level of inter-group violence, and incipient agropastoralism—a pattern that intensified during the subsequent Formative period when monumental ceremonial centers emerged. These findings lead us to propose a model for South American archery technology in which its appearance after 5000 years ago contributed to the emergence of new cooperative dynamics that expanded regional exchange networks and community aggregation. [ABSTRACT FROM AUTHOR]

Continuous bedside monitoring of brain tissue oxygen levels is a crucial component in the management of comatose patients suffering from acute brain injury on neurointensive care units. Ensuring sufficient brain oxygenation is recognized as an essential objective within neurocritical care, aimed at safeguarding patients from secondary ischemia. Hypoperfusion in occipital and the posterior watershed regions often remains undetected, as the placement of probes in these areas is challenging. A major concern is that patients would have to lie on the traditionally used implanted bolts due to the occipital entry point of the probes. Therefore, we present a novel technique compatible with magnetic resonance imaging that enables bedside placement of brain tissue oxygen probes without the use of a bolt in these areas. We conducted bedside implantations of Licox brain tissue oxygenation probes through Frazier's point utilizing peripheral venous cannulas on burr holes eliminating the need for bolts. A novel approach was successfully established for the bedside implantation of a Licox brain tissue oxygenation probe for occipital regions. This technical note describes the feasibility of a novel, simple, and straightforward bedside technique for boltless implantation of Licox brain tissue oxygen probes leading to rigid fixation and compatibility with magnetic resonance imaging. [ABSTRACT FROM AUTHOR]

To examine clinical and sociodemographic differences between patients with delusional disorder; with and without diagnoses of an additional severe mental disorder (SMD) or cognitive impairment. Population-based study including all individuals diagnosed with DD between 2005 and 2021 from a large catchment area in Madrid, Spain. Sociodemographic and clinical characteristics and the antipsychotic prescription patterns of the study population was described. Patients were divided into (i) patients with DD and no additional diagnosis of SMD or cognitive impairment (DD group), (ii) patients with DD and a diagnosis of an additional SMD (DD-SMD group), and (iii) patients with DD and cognitive impairment (DD-CI group). Of 1109 patients with a DD diagnosis (62.5 % female), 131 (11.8 %) patients were diagnosed with an additional SMD, and 69 (6.2 %) were diagnosed with cognitive impairment. DD-SMD patients were on average 10 years younger and had longer time between first mental healthcare contact and DD disorder than DD patients. DD-CI patients were on average 10 years older and had a higher proportion of females. Paliperidone (21.9 %) and aripiprazole (20.6 %) were the modal antipsychotic drugs chosen overall. DD-SMD patients were more likely to receive paliperidone and to be prescribed long-acting injectable medication; DD-CI were more likely to receive risperidone or quetiapine; and DD patients were more likely to receive olanzapine. Sociodemographic and clinical characteristics and choice of antipsychotic drug and delivery method for individuals with DD vary based on its comorbidity. [ABSTRACT FROM AUTHOR]

• Landsat bands alone may not give adequate quality of LULC mapping in a heterogeneous landscape. • Remote sensing-derived indices and auxiliary data improve the accuracy of LULC mapping. • LULC maps classified under different classification algorithms have shown a significant discrepancy. Land use/land cover (LULC) information is regarded as one of the most important variables in global change studies. Several LULC classification algorithms are available with different levels of accuracy in LULC mapping under different geographical setups. Furthermore, different remote sensing (RS) based indices and auxiliary data have been reported to have contributed to the accuracy of LULC mapping. Hence, the main aim of this study was to compare the different ML algorithms for the LULC mapping and explicitly assess the potential contribution of different RS-derived indices and auxiliary data on classification accuracy in the Upper Tekeze-Atbarah (UTA) river basin in Ethiopia. The overall classifiers evaluation result revealed that random forest (RF) performed best and followed by K-Nearest Neighbour (KNN), Support Vector Machine (SVM), Artificial Neural Network (ANN), Maximum Likelihood Classification (MLC), and Classification and Regression Tree (CART). Compared to RF, the MLC method showed less accuracy by 16.2% (19.7%) in OA (kappa coefficient) respectively, which showed that the currently emerging ML classifiers contributed to an improvement in LULC mapping. The use of RS-derived indices and DEM as predictors together with the Landsat bands improved the overall accuracy and kappa coefficient by 5.5% and 7% respectively. Furthermore, the discrepancy in the classified LULC map from RF and other classifiers was compared at pixel-level and the result showed a considerable disagreement between the LULC maps. For instance, when the LULC map from RF and KNN are compared, only 80.6% of the area has the same LULC condition. This result reflects the potential discrepancy that could exist in LULC maps from different classifiers. The hydrological simulation under each of the classified map also resulted in a considerable difference in the major water balance components. In a conclusion, given the considerable difference in classifier performance and the potential propagation of errors in LULC maps to further applications such as water resources assessment, it is highly recommended to explicitly evaluate the available classifiers. Users should also harness the power of RS indices and auxiliary datasets for improved LULC mapping. [ABSTRACT FROM AUTHOR]

Shangshan is the earliest Neolithic culture discovered in the lower Yangtze region and is significant as one of the origins of rice agriculture worldwide. During the Early Holocene, the Shangshan human groups settled in the river basins of the upper Qiantang region and transitioned from hunter-gatherers to farmers. Little is known about the dominant factors motivating them to settle down and their occupation patterns for adapting to local environments. To address these issues, we applied an ad hoc method by coupling landform classification, geomorphic fieldwork, accessibility analysis, and flood risk assessment. The results of geomorphic and accessibility analyses show that the ancient residents preferred to occupy the edges of the Middle Pleistocene terraces along second- and third-order streams. These locations are mainly situated in the centers of river basins and have height differences of 5–15 m, less than approximately 15-min walking distance from streams, providing them with stable residential spaces and accessible water resources. Within the 10-min territorial scope, there are always some fluvial plains near the terrace edges, indicating that the plain is another critical landform utilized by the residents. The wide plains and a plain-terrace-upland geomorphic assemblage, within 1-h and 2-h scopes, respectively, imply that the residents started to develop agricultural land while they also exploited diverse environments to ensure a plentiful food supply. Furthermore, the hydrologic analysis and assessment reveal that the residents were aware of the potential flood risks: their settlements are located at 30-min walking distance or greater from the high-order streams; most sites are exposed to low flood risks, with average percentages of unflooded territory greater than 67% and 43% in the minor and large flood scenarios, respectively; and each site has sufficient arable land with areas of 5–23 km2 within a 1-h scope, even under the large flood scenario. Overall, these results reveal that the river basins provided favorable living environments, and the residents could flexibly manage the landscapes to ensure stable settlements and food production, thus enabling the appearance and development of a sedentary society and rice agriculture during the early Holocene. Ultimately, the methods used in this study provide an effective approach to exploring the occupation patterns of prehistoric residents in the river basins. [ABSTRACT FROM AUTHOR]

• Temporal correlations exist in the GRACE TWS time series, resulting in the presence of colored noise. • To show the impact of these correlations, we apply autoregressive noise model and variance component estimation model. • Neglecting these correlations leads to underestimation of trend uncertainty, misinterpreting its significance. Temporal correlations are prevalent in most geophysical time series data, leading to what is known as colored noise, which become more apparent in the frequency domain rather than time domain. Neglecting this type of noise in modeling can result in underestimated standard errors for the parameters of the model used to analyze the time series. As a result, statistical tests misinterpret the significance of these parameters, such as the overall trend rate, because the "signal to noise" ratio becomes incorrectly larger than it should be. In this study, we investigate the temporal correlations in the time series data from the Gravity Recovery and Climate Experiment (GRACE) mission. GRACE and its successor mission GRACE Follow-On (GRACE-FO) have been successfully employed to monitor global total water storage anomalies over two decades since its initial launch in 2002. We primarily utilize monthly GRACE mascon (mass concentration) solutions provided by NASA Goddard Space Flight Center (GSFC), examining both regional and global scales. The power spectrum density of the residuals, calculated after applying standard harmonic regression to each mascon time series on Earth's land, reveals an average spectral index of κ = −1. This indicates the predominance of flicker noise, one of the most common forms of colored noise in geodetic time series. Notably, the noise becomes more Brownian (κ < −1) in regions with intense hydrological events, while it tends to be more white noise (κ → 0) in areas with less water circulation compared to other land regions. This observation suggests that unmodelled hydrological events, such as droughts, floods, and ones associated with ice-melting, contribute to the residuals as colored noise in the time series. To account for this noise in our time series modeling, we primarily consider autoregressive (AR) moving average (MA) process, commonly known as ARMA, in addition to the standard variance component estimation for noise amplitudes. We focus on individual mascon blocks in the Türkiye Region and mascon solutions for 24 world's major river basins. Our findings demonstrate that an ARMA(1,1) model is sufficient for describing the noise in these regions. The results underscore the importance of considering colored noise, as it leads to approximately three times larger standard errors for the overall trend rate. This substantially impacts the significance of the trend rates. [ABSTRACT FROM AUTHOR]

Due to the complexity of open-channel networks in which a lengthy procedure is required to understand and analyze their behavior. This paper introduces a methodology for the skeletonization of complex tree-shaped open channel systems. The aim is to aggregate separate branches into one equivalent branch, which has a new skeletonization factor. Three different illustrative examples of river systems using two approaches are analyzed. The software package HEC-RAS is employed to simulate the proposed open channel networks as a one-dimensional steady, gradually varied flow state. Results show that there is a strong correlation between the skeletonization factor required for the equivalent branch and the flow rate of the equivalent branch. The skeletonization factor is also significantly affected by an increase in the ratio of the bed width of each branch canal to that of the main channel in Approach A. The water depth along the main channel has increased more significantly in approach B than in approach A, with average increases of 49.5 %, 29.2 %, and 14.1 % for a number of branches equal to 2, 4, and 6, respectively. Finally, the developed skeletonization concept can be used to represent complex open-channels network models. [ABSTRACT FROM AUTHOR]

The study aims to develop an analytical framework for assessing cycling infrastructure from adolescents' safety perspectives, facilitating the prioritisation of areas based on effectiveness and existing conditions. Through an online survey (n = 323), we explored the perceived safety of Australian adolescents with different types of cycling lanes. The majority of survey participants prefer physically separated or protected cycleways. However, only 8.8% of the adolescent population in Greater Sydney has continuous cycleways to their catchment high-schools through these types of cycleways. Our study found a larger number of adolescents (28.1%) have access to nearby parks via safe cycleways. Although this difference appears to be due to the greater number of parks available, it could potentially contribute to significantly higher rates of recreational cycling participation in Sydney. This study also introduces an evaluation metric that combines the composite cycleway connectivity index, adolescent population density, and home-to-school distances to assist high-level selection and prioritisation of future infrastructure projects aimed at promoting active school travel. • A framework to assess cycling infrastructure from adolescents' safety perspective, aiding investment prioritisation. • Most adolescents prefer separate or protected cycleways, but limited access exists in Greater Sydney, Australia. • An evaluation metric for assessing adolescent cycling infrastructure was introduced at the school catchment area level. [ABSTRACT FROM AUTHOR]

Groundwater Storage (GWS) is an important component of the water cycle and a vital resource for supplying water to millions of people as well as sustaining domestic and economic activities, especially in arid and semi-arid regions such as Africa. This study aims to estimate and analyze the recent groundwater changes (ΔGW) for 11 major African basins in light of climate changes and global warming utilizing the data from the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) from January 2003 to December 2021. We proposed a new gap-filling technique to calculate the missing months between GRACE and GRACE-FO missions for the continuous estimation of groundwater changes. Then, we establish a new framework to analyze and investigated the climate parameters that could affect groundwater changes using Empirical Orthogonal Function (EOF) technique. Our analysis reveals that the new gap-filling technique is significantly consistent with the TWS time-series based on the trend line analysis. The lowest GPCC drought index value occurs in the lower Nile basin by approximately −0.93, while the highest occurs in the middle of Africa in Congo basin by approximately −0.02. The precipitation rate is mostly concentrated in mid-Africa while North and South Africa shows a weak rate. Meanwhile, according to the analysis of dependent climate parameters, climate change has had a negative impact on groundwater. However, the long-term effect on the groundwater does not clearly appear because most of Africa is located within semi-arid and arid regions. The effect of rain on groundwater was evident through EOF analysis, which shows GWS EOF Mode-2 (36.28%) and precipitation EOF Mode-1 (78.34%) were found to be in significant agreement in spatio-temporal domains. [ABSTRACT FROM AUTHOR]

The article describes image processing, where a comparison of selected image segmentation algorithms for counting the number of objects in an image was performed. The comparison was performed on a real example of photographic images, taken under everyday conditions. The results obtained were verified for correctness and accuracy, for which purpose the Jaccard index was used. The comparison was performed using a proprietary tool implemented in Python. [ABSTRACT FROM AUTHOR]

The present work describes the taxonomic and paleobiogeographic study of two fossil woods related to extant Aspidosperma. The silicified specimens come from the fossil localities of Santa Ana (30°54′S, 57°55′W) and Concordia (31°19′S, 57°59′W), Entre Ríos Province, Argentina, belonging to the El Palmar Formation (Late Pleistocene). This unit represents the sedimentary body of the upper fluvial terrace generated by the Uruguay River in its middle basin in eastern Argentina. The anatomical features that distinguish the woods are growth rings delimited by axial parenchyma and fibers, semi-ring to-diffuse-porous woods; mainly solitary vessels; simple perforation plates; alternate, bordered, and vestured intervessel pits; scarce paratracheal and diffuse apotracheal axial parenchyma; homocellular, and uniseriate to-triseriate rays; non-septate fibers. Climate reconstruction modelled at the regional scale (Ecological Niche Modeling) revealed variations in macroecological diversity patterns of the nearest living relatives (Aspidosperma australe and A. polyneuron) over the last ca. 130,000 years. Optically stimulated luminescence dating of sediments from the upper part of the El Palmar Formation in the type area reveals that the unit spans from the Last Interglacial period (warm substage, MIS marine isotope stage 5a), to the penultimate interglacial (MIS 7). This period was characterized by warmer and wetter conditions than those observed today. The eco-anatomical characteristics of the fossil record reflect this type of environment. The modern analogues of the fossils studied here are now part of the forests that integrate the Atlantic forest and Araucaria forest biogeographic provinces in South America. [ABSTRACT FROM AUTHOR]

Water resources sustainability is an increasing concern, requiring accurate estimates of the hydrological processes involved. This study evaluates the impacts of climate change (CC) and land use (LU) in a river basin in the Brazilian semi-arid. Using the Soil & Water Assessment Tool (SWAT), calibration/ validation was carried out based on limited measurements for discharge and using complementary remote sensing information for evapotranspiration (ET), as well as experimental data for soil moisture (SM). The evapotranspiration data used for calibration were obtained from the MOD16A2 product, at sub-basin scale. Principal component analysis was used to evaluate the interaction between variables. To assess the impacts of CC e and LU two scenarios were investigated: S1 – LU map without insertion of Permanent Preservation Areas (PPA), and S2 – with insertion of PPA. The Regional Climate Models (RCM) Eta-MIROC5 and Eta-HADGEM-ES for the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios were adopted. The SWAT model adequately represented evapotranspiration, with Nash-Sutcliffe coefficient (NS) of 0.67 for calibration, and 0.74 for validation. For wet periods, the SM simulated values were similar to the experimental measurements with a coefficient of determination (R²) of 0.68. Complementary information for evapotranspiration and soil moisture across sub-basins successfully allowed consistent spatially distributed hydrological variables to be simulated. The model performance for validation using ET data was higher (NS = 0.77) compared to previous streamflow-only calibration strategies for flow (NS = 0.42) and soil moisture (NS = 0.46). Under the CC scenarios, natural vegetation restoration would compensate reductions in water availability. [ABSTRACT FROM AUTHOR]

Comprehensive analysis of the Economy-Energy-Carbon Emission (EECE) system is beneficial for promoting sustainable social development. This study analyzes the system development of major watersheds in China from 2010 to 2019. The research fully considers the system's internal and external inputs and outputs and proposes an evaluation index system for regional EECE coupling and coordinated development. Then, using the difference in system weight allocation to improve the coupling and coordination model, the study explores the dynamic system's coupling and coordination. The results show that (1) The development of the system structure is relatively stable, but the overall development status is not ideal; (2) The downstream of China's main river basins has obvious economic advantages, while the energy system fluctuates greatly. The efficiency of the carbon emission system will decrease in areas with rapid economic development. The coupling and coordination level of the EECE system is better in the Yangtze River Basin than in the Yellow River Basin; (3) From the perspective of dynamic coordinated development, the main river basins have been divided into two states since 2012, but it is relatively stable overall. Regional dynamic coordination is often at a disadvantage in regions with rapid economic and energy development; (4) The coupling coordination degree of the two river basins has significant positive spatial autocorrelation. Most provinces' significant spatial clustering characteristics of the coupling coordination degree are High-High type. Low-Low type provinces are mainly concentrated downstream. The research process has certain reference significance for the collaborative governance of complex regional systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Wider distribution of invasive snails compared with native snails in the Limpopo River system. • cox 1 genetic data shows multiple lineages of invasive snails outside their native ranges. • More digenean species occurred in Pseudosuccinea columella than in the other snails. • The present xiphidiocercaria represents an unknown species of Orientocreadium. Invasive snails are associated with ecological problems in freshwater bodies worldwide. However, their impact on the transmission of digenean infections remain underreported. In the present study, 1708 specimens representing four snail species were sampled from four impoundments in the Limpopo River system in South Africa. Gyraulus chinensis (Planorbidae), Physella acuta (Physidae) and Pseudosuccinea columella (Lymnaeidae), which are invasive, were found in all the sampling sites. In contrast, the native lymnaeid Radix natalensis occurred at only one study site. Digeneans were observed only from R. natalensis (prevalence = 49%) and Ps. columella (prevalence = 23%). Morphological and genetic analyses revealed four digeneans: Fasciola nyanzae , Orientocreadium sp., Petasiger sp. and Patagifer vioscai. Pseudosuccinea columella was infected by the four digeneans while R. natalensis harboured only Orientocreadium sp. and Petasiger sp. Partial sequences of Orientocreadium sp. from the current study differed from congeners whose DNA data are available on GenBank, by p-distances of at least 1.84 and 2.2% for 28S and the internal transcribed spacer (ITS) rDNA, respectively. Phylogenetic analyses demonstrated that the present species is sister to Orientocreadium batrachoides. Genetic and phylogenetic data based on 28S and ITS rDNA suggested that Petasiger sp. from the present study and isolates of three unidentified Petasiger spp. from Kenya, Hungary and Australia, were representatives of the same species. This is the first known report of Orientocreadium , Petasiger and Patagifer from Ps. columella. The occurrence of F. nyanzae in Ps. columella indicates spillback from R. natalensis. These findings echo the concerns raised in previous studies about the potential role of Ps. columella in the amplification of digenean diseases in its introduced range. Phylogenetic analyses of partial sequences of the cytochrome c oxidase subunit 1 mitochondrial gene (cox 1) showed multiple lineages of Ps. columella in North and South America. Pseudosuccinea columella specimens from the present study belong to an invasive genotype that has spread globally and has been reported from Zimbabwe, Egypt, Portugal, Australia, Argentina, Colombia and New Mexico (USA). Physella acuta from the current study had a stronger genetic relationship with isolates from Canada and Iceland, than with isolates from other parts of Africa, suggesting several invasion routes into Africa. This is the first known DNA characterisation of G. chinensis from Africa. Phylogenetic reconstruction indicated multiple exit events of G. chinensis from Asia into Europe and Africa. South African isolates clustered in a recent branch containing isolates from the Czech Republic and Hong Kong, China. Considering the presence of invasive snails in all the sampling sites in the present study, it is necessary to investigate the factors that enhance their establishment and to monitor their effects on the native snail populations. [ABSTRACT FROM AUTHOR]

Vertical deformation associated with the displacement of rock glaciers in the upper Mapocho river basin, in the central Andes of Chile, was monitored using a series of PAZ radar satellite images and the DInSAR technique. Forty-one PAZ images of ascending and descending orbit were processed with the Small Baseline Subset (SBAS) technique. Regarding the obtained results, it was estimated that the vertical displacement velocity of rock glaciers between October 9, 2019 and April 22, 2021 reached up to -22 mm/year and the movement in the W-E direction ranged from -47 to 38 mm/year. This remote sensing technique is a useful tool to measure the surface displacement of rock glaciers, compared to conventional techniques such as GNSS point measurements, especially in the semi-arid Andes, which is one of the most important reservoirs of these geoforms worldwide. [ABSTRACT FROM AUTHOR]

The Supraśl River is a stable water ecosystem in North-Eastern Poland. This is indicated by the flow rate over many years, as well as the water quality monitored for years. Despite this, there are periods of oxygen deficiency in the water, causing massive fish kills. Our research shows that climate change resulting in an increase in the frequency of hydro-meteorological extremes may contribute to negative processes taking place in aquatic ecosystems. On the example of Supraśl Water System (SWS), we present an analysis of the phenomenon of suspension caused by the underground inflow, supplying the surface waters with a significant load of organic matter. The accelerated decomposition of peat formations in the Supraśl River catchment after heavy rains makes it easier for organic matter to penetrate into the aquatic ecosystem. Intensive flushing of valley and river bed sediments during summer floods has a particularly negative impact on the ecosystem of inland waters. If there are organic sediments on the bottom, their re-suspension is very dangerous. Then there is the immediate demand for oxygen, which can lead to deoxygenation of the water. Although this is a natural process, alarm and monitoring procedures should be established and countermeasures sought to respond in time and prevent mass fish kills. [ABSTRACT FROM AUTHOR]

Some young physicians decide their ultimate life goals early in life. The purpose of this article is to convey the message with feeling that because everyone lives only once, I want them to try many various things. The author introduces several unpredictable episodes that became watershed moments for him, and describes how he each behaved. Although all of the episodes were unexpected, they all shared a common thread that ultimately led the author in a positive direction. I made the decision to not build walls for myself before I even began, and to think about how I wanted to be a more evolved version of myself in the future than I am today. I would like to convey this message to young physicians to encourage them. To act, you must be determined, and to resolve, you must have a dream. As long as you have a dream and work hard, you can achieve your dreams. [ABSTRACT FROM AUTHOR]

Aeolian sediments and landforms of the former continental ice sheets' periphery can be used as invaluable sources of information on palaeoenvironmental changes. In the Northeastern Europe, there is very limited knowledge on the structure and age of the aeolian deposits and landforms. This study presents the first data on distribution and chronology of aeolian sediments and landforms in the Vychegda River basin (northeast of the East European Plain). Using grain-size analysis, radiocarbon and OSL dating, we were able to determine the age of the sediments found in the region and study their lithological composition. We discovered aeolian sediments comprising the upper parts of the most river terraces throughout the valley; they come in forms of dunes, dune fields, and sandy or loess-like covers. Previously it was argued that the terraces' upper parts were comprised by glaciolacustrine deposits, but lithological composition of these sediments showed their aeolian origin. It was found that most of the aeolian sediments have formed in the Late Glacial, between 17 and 10.5 ka. We consider that increased fluvial activity and melting of permafrost were the main causes of the aeolian processes activization and that sediment availability was the most important controlling factor during that time. [ABSTRACT FROM AUTHOR]

We discuss geological and biotic aspects of the extensive Akchagylian transgression that occurred in the Caspian region of Eurasia near the Plio-Pleistocene transition, in Piacenzian and Gelasian. It is shown that the onset of the Akchagylian marine sedimentation in Western Turkmenistan (ca. 3.2 Ma) preceded that in the Kura Basin (ca. 3.0 Ma). The position of the upper boundary of the Akchagylian remains uncertain (ca. 2.1 or 1.8 Ma). The analyzed biotic content of the Akchagylian includes molluscs, microfossils (pollen, dinocysts, foraminifers), and mammals. It is noted that specific forms of the Akchagylian aquatic biota co-occur with microfossils that clearly indicate a connection with the World Ocean or related seas. The palynology of the Akchagylian time signals a directed cooling in the Pliocene and Early Pleistocene with several warm and humid epochs. The Akchagylian transgression was preceded by a change of a structural-sedimentary pattern of the region. In the latest Miocene and Early Pliocene, a pre-existed longitudinal tectonic zonation of the Caucasian-Caspian segment of the Paratethys gradually changed into clearly transverse tectonic zonation. The latter was manifested in the tectonic uplift of the Greater Caucasus, its northern piedmonts and the Lesser Caucasus, and in the subsidence of the western parts of the South and Middle Caspian basins. The interplay of longitudinal and transverse tectonic features shaped the configuration of the Akchagylian brackish-water basin and controlled thickness of its deposits. It was the transverse zonation that dominated in the thickness pattern. The increasing role of the transverse zonation in the post-Akchagylian time is manifested in the magnitudes and rates of the Quaternary tectonic uplift. These parameters were calculated based on current heights of the top of the Akchagylian marine deposits in different parts of the basin. The highest magnitudes of uplift are found in the Eastern Caucasus (up to 1980 m on the NE slope and about 2500 m in the axial part) and in the west of the Lesser Caucasus in eastern Turkey (up to 1750 m). The maximum level of the Akchagylian transgression is estimated at 40–50 m above the present level of the World Ocean. We show a low probability of connection of the Akchagylian basin with the Mediterranean Sea or the Persian Gulf, and a high probability of its connection with the Arctic Ocean through the northern tributaries of the Kama River and the Pechora Basin in the NE of East European Plain. [ABSTRACT FROM AUTHOR]

Sedimentary rocks from the early Eocene Green River Formation comprise the largest known lacustrine oil shale deposits, contain remarkably well-preserved fossils, and provide a unique record of climate evolution across the Early Eocene Climate Optimum, a period of high atmospheric CO 2. The depositional environment of these intermountain lakes spanned from relatively fresh and fluvially influenced to expanded and stratified saline closed basin lakes under the influence of the Laramide orogeny and alternating humid and arid climatic conditions. As the surface area of the lakes expanded, alkalinity and salinity increased, with depositional cycles that linked to evaporative cycles and marked by an increasing abundance of organic matter-rich shales (TOC > 10 wt%). Simultaneously, an intriguing 20 ‰ positive shift in the sulfur isotope composition of sulfide minerals and organic sulfur is observed. Given that this trend cannot be simply explained by a change in the source of sulfate delivered to the basin, the evolution of biogeochemical sulfur cycling and the balance of fluxes in response to basin evolution remain unresolved. Here, we combine the sulfur isotope compositions of pyrite, organic sulfur, and carbonate-associated sulfate and molecular proxies of euxinia in samples from the Uinta basin's depocenter. We find that organic matter-rich sediments reflect deposition in a stratified water column with enhanced burial of pyrite and sulfurized organic matter, while organic-lean facies present evidence of, at least transiently, euxinic conditions reaching the photic zone during arid conditions presumably because of evaporation. As the lake became both saline-stratified and euxinic, we observe that δ34S values of all measured sulfur-bearing sedimentary proxies increase and evolve along a 1:1 line, a trend independent of facies that we interpret as reflecting a sulfate-limited system despite saline conditions. The isotopic mass balance of sulfur fluxes implies the existence of a sink of sulfur depleted in 34S that is spatially decoupled from burial in the depocenter. Modeling sulfur biogeochemical processes in a saline stratified lake system allows us to estimate that at least 50 % of the sulfur entering the lake could have been lost from the upper part of the euxinic water column where the fractionation factor imparted by microbial sulfate reduction is expressed. We propose that the overall isotopic enrichment of the system was caused by H 2 S degassing during arid climate intervals, presumably enhanced by transient water column mixing events. Further, episodic intrusion of euxinic bottom waters into the upper part of the water column might have triggered mass fish and plankton mortality, consequently facilitating the formation of these exceptionally fossiliferous and organic matter-rich rocks. Our study finds that volatile outgassing may be an underappreciated mechanism for the sulfur mass balance of stratified lacustrine systems. [ABSTRACT FROM AUTHOR]

Understanding how temporal precipitation variability will behave in the future is crucial. Change point detection and sub-trend analysis were done on monthly total precipitation data acquired from the Coordinated Regional Climate Downscaling Experiment project in this study. Sub-periods have been determined based on the natural structure of the data set, as opposed to standard sub-period determination approaches. For the period 1971–2100, six different time series were used under three global climate models (CNRM-CERFACS-CNRM-CM5, ICHEC-EC-EARTH, MPI-M-MPI-ESM-LR) and two emission scenarios (Representative Concentration Pathway (RCP) 4.5 and RCP 8.5). The study area has been selected to be the Konya Endorheic Basin in Turkey, which has been significantly influenced by climate change and human impacts. For change point detection, the Pruned Exact Linear Time method (PELT) and Binary Segmentation (BS) were employed, for trend analysis, Mann Kendall (MK) and Şen-Innovative Trend Analysis (Şen-ITA), and for both change point detection and sub-trend analysis, the Onyutha Trend Test (OTT) was utilized. The findings revealed four change points and five sub-periods. Summer precipitation has reduced considerably at a 95% significance level. There is strong evidence that precipitation has decreased between 1981 and 2070. Precipitation decreases similarly in the middle basin for the 1981–2000 and 2041–2070 years. [ABSTRACT FROM AUTHOR]

• KDE and DBSCAN were used in spatial distribution analysis of ICH. • The overall and various types of ICH in the YRB showed a agglomeration distribution. • ICH mainly concentrated in the middle-lower reaches and cultural areas of the YRB. • Socioeconomic factors had the most significant influence on the distribution of ICH. Given the background of ecological protection and high-quality development strategies in the Yellow River Basin (YRB), studying the spatial distribution characteristics and influencing mechanisms of intangible cultural heritage (ICH) in the YRB is of great significance for objectively understanding the entire process of cultural occurrence, evolution, protection, and development in the YRB. Considering 787 counties in nine provincial areas of the YRB as the research area, this study adopted density-based spatial clustering of applications with noise (DBSCAN), kernel density estimation (KDE), and GeoDetector, and explored the spatial distribution characteristics and influencing mechanisms of 892 national-level ICH items. The results showed that the entire ICH was spatially agglomerated in the YRB. Concurrently, regional differences were apparent, mainly concentrated in the middle–lower reaches and several cultural areas. Although all 10 ICH types showed spatial gathering characteristics, the degree of agglomeration of folk art and literature, traditional sports recreation, and acrobatics was relatively low. DBSCAN clustering showed that the middle and lower reaches of the Yellow River were the core areas of ICH and various types of ICH clustering. The kernel density also showed an agglomeration distribution trend and formed a "3 + 4 + 5" kernel density hierarchy, exhibiting prominent "center–periphery" characteristics. Among the natural environmental, socioeconomic, and historical–cultural factors, the socioeconomic factors significantly affected ICH spatial distribution, whereas natural environmental factors were less influential. The gross domestic product (GDP), national historical and culturally famous towns and villages, populations, and museums strongly influenced ICH spatial distribution. The factor interaction explanatory force was greater than that of a single factor, indicating synergistic effects between the factors. The explanatory force of GDP, urbanization level, population, minority population, and traffic interaction with other factors on ICH spatial distribution significantly improved. [ABSTRACT FROM AUTHOR]

Rivers play a crucial role as sources of freshwater worldwide. The Yangtze and Yellow rivers, often regarded as the lifelines of China, significantly contribute to the nation's economy through their abundant water resources. Maintaining the quality of water in these river basins is essential for both human health and a thriving ecological system. This study intended to assess the historical water quality of China's two mother river basins including the Yangtze River, and the Yellow River. This assessment analyzes the historical dissolved oxygen, Ammonium nitrogen, and permanganate, and calculates comprehensive water quality identification (CWQII) values to find the trend and predict future values using a Machine learning model. To evaluate the stationarity of historical data, different tests and measures have been taken such as ADF and KSPP to test stationarity. Autocorrelation and partial autocorrelation also have been performed to understand the nature of the data. According to the SARIMA model, the Mean Absolute Percentage Error (MAPE) for the CWQII was 9.1% for the Yangtze and 13.3% for the Yellow River. In contrast, the LSTM model yielded MAPE values of 7% and 14%, respectively. For Dissolved Oxygen (DO) prediction, the SARIMA model showed MAPEs of 8.9% for the Yangtze and 9.87% for the Yellow River, while the LSTM model resulted in 8% and 16%, respectively. The current and future forecasting of CWQII values suggest that, based on model forecasts, the water quality in the Yellow River basin may be poorer compared to the Yangtze River basin This study might help the government, researchers, and other stakeholders to take proper steps to develop water pollution control strategy. [ABSTRACT FROM AUTHOR]

• Sb and As concentrations in surface water, sediment, and pore water were studied. • As was more likely to bind to sediments than Sb according Log K d value. • The bioavailability of As was higher than that of Sb in sediment. • It is necessary to evaluate contamination and ecological risk with multiple indices. • The release of Sb/As from sediment at the river-lake junction has a potential threat. As typical metalloid toxic elements widely distributed in environmental media, the geochemical behaviour of antimony (Sb) and arsenic (As) affects environmental safety. We selected the surface waters and sediments at the river-lake junction of Dongting Lake as the research objects, analysed the concentration and chemical partitioning of Sb and As, assessed its contamination and ecological risk levels, and discussed its sources and potential influencing factors. The concentrations of dissolved Sb and As in surface waters were low (< 5.46 µg/L), and the concentrations of Sb and As in surface sediments were 2.49-22.65 mg/kg and 11.10-136.34 mg/kg, respectively. Antimony and As in sediments were mainly enriched in the fraction of residues, but the proportion of As in bioavailability was significantly higher than that of Sb. Although the contamination level of Sb was higher than that of As, the risk assessment code (RAC) showed that the ecological risk level of As was higher than that of Sb. Rainwater erosion and mining activities (in the midstream of Zijiang River) were the main contaminated sources of Sb, while As was affect mainly by rainwater erosion. The contamination and ecological risk of Sb in the inlet of the Zijiang River should receive considerable attention, while those of As in the inlet of the Xiangjiang River should also be seriously considered. This study highlights the need for multi-index-based assessments of contamination and ecological risk and the importance of further studies on the environmental behaviour of metalloids in specific hydrological conditions, such as river-lake junctions. [Display omitted] [ABSTRACT FROM AUTHOR]

Clay-hosted rare earth element (REE) deposits, generally considered products of extended subtropical weathering of REE-rich igneous protoliths, are a critical source of REEs globally. The Koppamurra deposit of southeast South Australia, in contrast, is developed in Pleistocene lacustrine clays overlying a REE-poor marine limestone. Here we examine the REE + Y (REY) sources and enrichment mechanisms of this unusual setting. We find that the greatest REY enrichment (up to 5000 ppm) occurs in lacustrine clays at the base of a ∼1–2 m thick contact zone with the underlying limestone. This zone features an increased proportion of leachable REYs (>50 %), increased smectite abundance and a sharp increase in pH from ∼5.0 to ∼8.3. Co-variation of HREEs with a suite of clay-specific elements demonstrates that HREEs are hosted mainly by Fe-rich smectite, with separate sorbed vs structurally bound HREE pools that are of similar magnitude. LREEs are mainly hosted in secondary LREE carbonates, these are preferentially intergrown with smectite but are only rarely present in kaolinite domains. Cerium occurs mainly as cerianite. The narrow range and overlapping εNd of samples within and above the REY enriched zone suggests that enrichment is related to internal redistribution within the clay unit. The clays are isotopically incompatible with local igneous or metasedimentary rocks, but 87Sr/86Sr and εNd isotopic fingerprinting shows that they were deposited by the Murray River, Australia's largest river system. Murray sediments are enriched in REY due to the presence of material eroded from the Lachlan Orogen granites of southeast Australia. Deposition of these sediments occurred in a coastal lacustrine setting analogous to the modern-day Coorong, with tectonic uplift and shoreline progradation allowing the onset of subaerial weathering ∼1–2 Mya. We propose that vertical and lateral solute transport allowed for the concentration of REEs in local depressions in the karst-weathering surface which separates the limestone and overlying clay, facilitated by water table oscillation and pore water redox cycling driven by seasonally contrasted rainfall. Poor soil drainage, evaporative concentration of soil waters and alkaline pH adjacent to the limestone immobilized REEs in secondary carbonates and Fe-rich smectite. Our findings illustrate that REE mobilization and enrichment in clay deposits can occur more rapidly, over a larger area and in a broader range of host phases and geologic settings than is currently appreciated, with important implications not only for REE exploration but also for the use of REEs as tracers in the Earth Sciences. [ABSTRACT FROM AUTHOR]

• Erosion and deposition are continuous processes in the Old Brahmaputra River. • Erosion threats to the settlements and surrounding ecosystems. • GIS and RS approaches are used to delineate channel shifting, erosion, and deposition calculation. • The recommended restored channel is expected to reduce riverbank erosion. River meandering causes riverbank erosion, which triggers socioeconomic and environmental issues in the riparian region and raises river sedimentation, thus, needing river restoration. This research depicts a channel restoration model to control river bank erosion and susceptible resource management along the Old Brahmaputra River course based on channel characteristics from 1980 to 2021. The secondary data of Landsat satellite time series and SRTM images were collected from the USGS website, while we used Google Earth images to verify the morphological features. Satellite images were on-screen visualized by ArcMap (10.3) to extract the river channels and measure the erosion and accretion areas. Results showed that the Old Brahmaputra River channel shifted its position due to erosion and accretion. Over the last forty-one years, ∼ 52 km2 area was eroded while ∼ 49 km2 area was accreted, and the average shifting of the river channel was 1.3 km2 per year. Accordingly, the river channel has become more sinuous decade by decade and threatens nearby settlements. Hence, this study proposed a river channel based on previous river channels, where the base channel is from the 2000s, which was more stable and flowed through the middle of the floodplain. Parts of the 1980, 2000, and 2021 river channels were also selected, which are relatively far from the susceptible settlements, to draw the proposed restoring channel. This model is likely to aid in developing government strategies for protecting riverbank erosion and river restoration in the forthcoming period. Finally, this study recommends that this newly proposed channel will be conducive to reducing riverbank erosion and the extreme threat to the settlements and their livelihoods. [ABSTRACT FROM AUTHOR]

Gully erosion is a severe environmental issue that poses threats to agriculture, human safety, habitats, infrastructure, and soil integrity. Selecting the right machine learning model is vital for accurate Gully Erosion Susceptibility Mapping (GESM) due to varying environmental hazard performance. This study employed a comparative analysis of two machine learning techniques, Random Forest (RF) and Extreme Gradient Boost (XGBoost), to develop a highly precise GESM for the Silabati watershed (India). The analysis incorporated 24 controlling factors and examined a dataset of 460 sample points, with equal representation of gullies and non-gullies. Variance Inflation Factors (VIF) and Information Gain Ratio (IGR) techniques were applied to assess multicollinearity test among the controlling factors. Lithology, elevation, distance from the road, LULC, geomorphology, rainfall, drainage density, and coarse fragments emerged as crucial factors in determining GESM. Statistical tests, including the Kappa index, Root Mean Square Error (RMSE), Accuracy (ACC), Mean Absolute Error (MAE), Coefficient of Determination (R2), and Receiver Operating Characteristic (ROC), were employed to evaluate the RF and XGB models on training and testing data. Both models demonstrated strong performance, with the XGBoost and RF models achieving ROC values of 84.1% and 83.2%, respectively. The applied quantile classification method resulted in the creation of five distinct GESMs, categorized as very high (VH), high (H), moderate (M), low (L), and very low (VL). We found that the very high GESM areas of the watershed were 4.10% in the XGBoost model and 4.61%. in the RF model. Out of the 26 sub-watersheds, the results have identified five sub-watersheds as highly prioritized for sustainable management. Therefore, the present study provides an accurate gully erosion identification using advanced models, offering valuable insights for policymakers to proper management implementation. [ABSTRACT FROM AUTHOR]

Increasing interest in carbon storage and fluxes in river systems opens space for comparison of methods for the determination of total organic carbon (TOC) and inorganic carbon (TIC) in soil/sediment samples. We analysed 150 soil (leptosols and fluvisols) and sediment samples from three rivers using methods mostly used in studies. Widely used dry combustion method (with CO 2 detection) for determination of TOC and TIC was compared with other methods for determination TOC (modified Walkley–Black method), total organic matter (TOM determined by loss on ignition) and TIC (calcimeter, loss on ignition). Furthermore, we proposed a procedure for calculation TOC from TOM together with relative standard deviation resulting from this conversion. Our results showed that the modified Walkley–Black method provides almost identical results of TOC as dry combustion and therefore can be used as an alternative method for the determination of TOC. A strong correlation was found between TOC and TOM (R2 = 0.97 for both methods for determination TOC). The mean relative deviation of TOC values resulting from calculation TOC based on TOM varied between 10.1% and 14.5%. Thus, the calculation TOC from TOM is possible, but only with deviations referred to above. We suggest that for samples with TOM values below 1%, the TOC values cannot be reliably calculated, and in this case, the dry combustion or modified Walkley–Black method must be used for TOC determination. TIC values determined by the three methods vary to a greater extent than those of organic carbon. We assume that in the case of low TIC content (below 1%), various methods can give markedly different results. Due to the higher relative standard deviation in case of dry combustion, it is probably better to use a calcimeter for the determination of TIC in samples with TIC content below 1%. [ABSTRACT FROM AUTHOR]

The southeast coast of China is a crucial area for the spread of agriculture from mainland Asia to Taiwan and the islands of Southeast Asia. However, whether prehistoric rice cultivation in this region was lowland or upland remains unclear. This study used a detailed phytolith analysis to evaluate temporal changes in structure at three coastal sites of varying altitudes in the Fujian Province of China, Longgang, Zhengjiashan, and Gehongshan. Samples were collected from two cultural phases, the Neolithic Huangguashan and Bronze Age Huangtulun cultures. Additionally, a new physical index, the sensitive-to-fixed phytolith ratio, was used to identify the environmental conditions in which crops were cultivated. Using this method, the number of sensitive types can be less or greater than that of fixed types, corresponding to drought or paddy field rice cultivation systems, respectively. The results showed an interplay of rice and millet farming at these sites. The crop phytolith ratio revealed that rice was dominant in the crop structure. However, notable differences existed in the proportion of different crops and phytolith assemblages across the various sites. The sensitive-to-fixed phytolith ratios, indicative of wet-dry environmental changes, were 1.56 and 1.07 at the low-altitude Longgang and water-rich Zhengjiashan sites, respectively, suggesting lowland rice cultivation. In contrast, the sensitive-to-fixed ratio at the high-altitude Gehongshan site was only 0.8, implying upland rice cultivation. The phytolith assemblage variation among the different sites also revealed an increase in dryland crops from low to high altitudes, indicating that the inhabitants of the southeastern coastal mountainous area modified their crop structure and rice cultivation methods during the Neolithic–Bronze Age transition to overcome environmental limitations. In summary, this study presents phytolith evidence for prehistoric upland rice cultivation on the southeast coast of China, offering valuable insights into the development of the prehistoric subsistence economy in the region. [ABSTRACT FROM AUTHOR]

• 11001 t of N, 68 t of P, and 73528 t of S were delivered in 2021. • Atmospheric deposition contributes 9% for N and 21% for P input to the Middle Route. • There were 988 t of N, 29 t of P and 2,540 t of S accumulated in the main channel. Nutrient levels in the artificial channel constructed for the Middle Route Project are significant indicators of water quality safety and aquatic ecological integrity for this large, inter-basin scheme. However, the distribution and transport of nutrients along the channel were poorly understood. Based on a time-series dataset as well as mass balance and material flow analysis methods, the water and nutrient transport fluxes in the Middle Route of the South-to-North Water Diversion Project were identified in this study. The results indicate that the nutrient concentrations varied considerably with time, but there was no significant difference among the 30 stations of the main channel. Seasonal temperature difference was the major factor in the large fluctuations of water quality indicators over time. The nutrient loadings varied with the water volume outputs from the main channel to the water-receiving cities. Atmospheric deposition was an important source of nutrients in the main channel, accounting for 9.13%, 20.6%, and 0.635% of the nitrogen, phosphorus, and sulfur input from the Danjiangkou Reservoir, respectively. In 2021, a net accumulation of 988 tons of N, 29 tons of P, and 2,540 tons of S, respectively, were present in the main channel. The increase of these external and internal nutrient loadings would cause water quality fluctuation and deterioration in some local sections of the main channel. Our study quantified the spatial and temporal patterns of nutrient transport in the Middle Route and revealed the ecological effects on the aquatic environment, assisting authorities on the project to develop effective water conservation strategies. [Display omitted] [ABSTRACT FROM AUTHOR]

Since the Normalized Difference Water Index (NDWI) was proposed, water indices have served as useful tools for surface water detection. However, existing water indices are highly influenced by atmospheric and other environmental conditions and suffer from limited performance, especially in urban areas. At the core of the limitation is the sole dependency on the spectral distribution of reflectance signals. To overcome this, we propose to utilize topographic data as additional information for better water detection. Accordingly, the new index, namely Combined Water Index (CWI), is developed as the product of the topographic index and the reflectance-based index. These two indices excellently compensate each other: the former is free from noise issues but invariant over time while the latter can capture temporal dynamics of waterbody extents. The CWI is applied to four study areas of different development levels (natural, medium-sized cities, and megalopolis) in the Han River basin, South Korea. The water detection results of the CWI is promising, particularly in the heavily developed urban setting, demonstrated through visual images as well as various statistical measures. [ABSTRACT FROM AUTHOR]

• Baseflow accounting is essential for water resources management. • Isotopic and RDF methods were used to analyze the stream of the Red River in Vietnam. • The isotopic method showed consistent results with those of RDF method. • The isotopic technique is a tool for verifying conventional baseflow separation models. River streams, in general, comprise of two flows: quick flow and baseflow. The baseflow is closely related to geological catchment properties, and understanding the baseflow contribution to stream flow is very important in the planning of water resources management. The baseflow in a sub-catchment of the Red River in Vietnam was quantified using the isotopic technique, and results were compared with Eckhardt's recursive digital filter (RDF) method. Results of the isotopic approach showed that groundwater is recharged from regions at 300 to 800 m above mean sea level. The upstream baseflow gains from Holocene and Pleistocene aquifers throughout the year, contributing to 65 ± 4 % of the river discharge. On the contrary, the midstream baseflow contributes 44.6 ± 6.5 % of the river's annual discharge to both Holocene and Pleistocene aquifers. The downstream is more complicated, where the baseflow loses to the Pleistocene aquifer and gains 73 ± 17 % of the river's annual discharge from the Holocene aquifer. The loss of baseflow was attributed to the high rate of groundwater mining. Maintaining the vegetative cover over the recharge areas is recommended to reduce runoff and increase groundwater potential so that the baseflow could sustain the river stream. [ABSTRACT FROM AUTHOR]

The transformation of blue and green water is an important hydrological process at the watershed, which is an important supplement to the study of hydrological processes. The Soil and Water Assessment Tool (SWAT) was used to investigate the evolution characteristics of hydrological processes and the transformation mechanism at the watershed and ecosystem scales in the Dongjiang River. The results show that: (1) the annual average total water flows in the Dongjiang River Basin are 37.80 and 22.287 billion m³, respectively. The blue and green water flows during the wet season account for more than 75% of the total year. The blue and green flows of the grassland ecosystem increased significantly, with the most significant change in the downstream ecosystem. (2) From 1980 to 1990 and from 2010 to 2020, the Dongjiang River Basin experienced a transition from blue to green water flow. Blue water flow accounts for the majority of total water flow in the paddy field and dry cropland ecosystems, and green water flow changed to blue water flow from 1980 to 2010. (3) The correlation between blue and green flow and land use was weak throughout the year and during the wet season, but it was significant during the dry season. This study can serve as a model for the integrated management of water resources and ecosystems in the Dongjiang River Basin. [ABSTRACT FROM AUTHOR]

Urban ecohydrology research has assessed how several drivers interfere with the basin's response. These interactions can be utilized in urban basins to enhance flood risk management. This paper aims to show how socioeconomic narratives influence rainfall-runoff transformation under changing conditions. For this, the study used the Millennium Ecosystem Assessment (MA) scenarios to measure the influence of different storylines on the land cover and, consequently, the basin's response, measured as the Percentage of Peak Flow Variations (PPFV) of the starting scenario. MA scenarios consider postures reactive and proactive to solve problems and different levels of the protagonist of nature. We used 13 urban ecohydrological variables that are sensitive to the socioeconomic narrative and include the use of Nature-based Solutions (NbS). Then, we set up the qualitative scenarios to apply in two Brazilian urban basins (78.00 and 15.42 km2) to create quantitative scenarios. Finally, we used rainfall-monitored events in these basins and registered their responses as PPFV. The results indicated that socioeconomic narratives significantly impacted the urban basins. PPFV medians ranged, in the reactive scenarios, between 259 % and 70.5 %, and in the proactive scenario, between 54.5 % and -47.5 %. The scenario with NbS in their narrative shows significant decreases in the two basins. We concluded that socioeconomic narratives influence urban flood risk management. Societies with international cooperation focused on environmental solutions, such as using NbS, achieve better adaptation to challenging futures in the face of hydrological threats than reactive societies that do not prioritize the environment. [ABSTRACT FROM AUTHOR]

The investigation of the correlation between groundwater and surface water in terms of water origin and transformation is crucial for comprehending hydrological processes. Focuses on the Wulagai river and Xiliugou river basin located in East and West Inner Mongolia. It employs hydrochemical analysis and stable H O isotopes techniques to investigate the hydrochemical properties of the basin and quantitatively assess the interconversion between groundwater and surface water. The results suggest that the Xiliugou and Wulagai river basins were originally nourished by atmospheric precipitation, with lower δD and δ18O values in groundwater compared to surface water, attributed to factors such as evaporation, water vapor source, altitude, and latitude. The surface waters in the Xiliugou and Wulagai River exhibit dominance of Na•Ca-SO 4 •HCO 3 and Ca•Na-HCO 3 types, respectively, while the groundwater is characterized by dominance of Na•Ca-HCO 3 and Ca•Mg-HCO 3 types, respectively. The water chemistry of surface water and groundwater in the two basins is influenced by water-rock interactions and processes of evaporation and concentration, primarily observed in the dissolution of carbonate rocks and evaporites. Hydrograph separation using End-Members Mixing Analysis (EMMA) revealed that during the growing season, groundwater in Xiliugou was primarily recharged by precipitation (76.87 %) and surface water (23.13 %), while in Wulagai, groundwater was mainly recharged by precipitation (65 %) and surface water (35 %). The presence of comparable hydrochemical constituents and shared regulatory mechanisms between groundwater and surface water within a given basin provides further evidence of a discernible hydraulic interconnection, primarily driven by the replenishment of groundwater through surface water recharge. [ABSTRACT FROM AUTHOR]

Woody vegetation cover in South Africa has increased over the past 100-150 years owing to the establishment of commercial forestry plantations, the spread of alien invasive plants (AIPs) and indigenous woody encroachment (WE). Extensive research conducted over the past 50 years has shown that AIPs can lead to dramatic declines in catchment water yields as a result of their high evapotranspiration (ET) rates. This has raised concern that WE may also be responsible for increasing ET losses and adversely impacting the country's limited water resources. In this paper, we used a combined systematic review and meta-analysis approach to explore trends in the water use of different vegetation types located in various climates across South Africa, to ultimately evaluate the likelihood of WE increasing ET losses in South Africa's savannas. This study revealed mixed support for whether WE in South Africa's savannas is increasing ET losses. On one hand, the fact that WE species replace grasses and form dense thickets indicates that there is high potential for WE to increase ET losses. On the other hand, rainfall, appears to be a primary factor limiting ET in semi-arid climates, indicating little potential for WE to have any effect on ET, unless there is an above-average rainfall year, or the vegetation has access to an additional water source. This study justifies the need for additional ET monitoring in South Africa's savannas in order to determine whether large-scale WE control should be implemented to conserve water resources in one of the country's driest regions. [ABSTRACT FROM AUTHOR]

Drought is a normal disaster that profoundly impacts several factors, including the economy, agriculture, environment, and society. Using spectral indices from Landsat, the current research evaluated droughts' magnitude and frequency in the Diyala River Catchment, Iraq, during the growing season for 2013 through 2022. Fifteen mosaics were created over ten years using forty images in TM and ETM+ (167/36 and 168/37) that had been gathered from 2013 to 2022. The scenes are from two Landsat time series. The drought situation was assessed using the Normalized Difference Vegetation Index (NDVI), Vegetation Condition Index, and Normalized Difference Water Index. The research's findings revealed a rise in the DRC's occurrence and severity of drought over the past ten years, especially in 2000 and 2008. However, between 2021 and 2022, the total vegetation covered based on NDVI decreased by 20.67% and 36.33%, respectively. In 2021 and 2022, the vegetation cover significantly decreased (54.3% and 29.5%, respectively). Derbendekan and Hemrin lakes, conversely, experienced declines of 15.1%, 7.12%, 108.38%, and 143.33% in 2021 and 2022, respectively. Between 2013 and 2022, the DRC experienced an increase in drought, a decline in water body surface area, and a decrease in precipitation averages. [ABSTRACT FROM AUTHOR]

[Display omitted] Reducing soil salinization of croplands with optimized irrigation and water management is essential to achieve land degradation neutralization (LDN). The effectiveness and sustainability of various irrigation and water management measures to reduce basin-scale salinization remain uncertain. Here we used remote sensing to estimate the soil salinity of arid croplands from 1984 to 2021. We then use Bayesian network analysis to compare the spatial–temporal response of salinity to water management, including various irrigation and drainage methods, in ten large arid river basins: Nile, Tigris-Euphrates, Indus, Tarim, Amu, Ili, Syr, Junggar, Colorado, and San Joaquin. In basins at more advanced phases of development, managers implemented drip and groundwater irrigation and thus effectively controlled salinity by lowering groundwater levels. For the remaining basins using conventional flood irrigation, economic development and policies are crucial for establishing a virtuous circle of "improving irrigation systems, reducing salinity, and increasing agricultural incomes" which is necessary to achieve LDN. [ABSTRACT FROM AUTHOR]

Carbonate weathering plays a significant role in regulating global carbon budget at short time scales, and thus needs to be better constrained in the context of global warming. Riverine magnesium isotopes (δ26Mg) have the potential to trace carbonate weathering intensity (CWI) but require further testing under various climatic and geological settings. Cation exchange is an important mechanism buffering river water chemistry, especially in catchments characterized by high erosion. However, field evidence on the influence of cation exchange on riverine δ26Mg is rare. In this study, spatial riverine δ26Mg variation within the Three Rivers (i.e., the Jinsha Jiang, the Lancang Jiang, and the Nu Jiang), three extremely-high-erosion catchments in the southeastern Tibetan Plateau, was investigated to address this issue. The results showed that riverine δ26Mg values present a wide range from –1.11 ‰ to –0.59 ‰ in the Jinsha Jiang, from –1.39 ‰ to –0.65 ‰ in the Lancang Jiang, and from –1.19 ‰ to –0.50 ‰ in the Nu Jiang. An inversion model was used to partition riverine Mg2+ sources and confirmed that the riverine Mg2+ budget was dominated by carbonate weathering, followed by evaporite dissolution. However, conservative mixing could not explain riverine δ26Mg variation within the Three Rivers catchments, because measured δ26Mg values (δ26Mg measured) systematically deviated from the modeled ones (δ26Mg modeled), with Δ26Mg measured–modeled (δ26Mg measured – δ26Mg modeled) up to 0.79 ‰. The positive correlations between Δ26Mg measured–modeled and suspended particulate matter (SPM) concentrations indicate Mg isotopic fractionation was related to high suspended loads owing to extremely-high erosion rates. Given the significant cation exchange capacity of SPM, Mg2+-Na+ exchange is proposed for the first time as an explanation for the observed δ26Mg variations in the rivers draining the Tibetan Plateau, although the role of carbonate precipitation could not be excluded. The strong positive correlations between riverine δ26Mg and exchangeable Mg/Na ratios in the Three Rivers further support that light Mg isotopes may be preferentially retained in the riverine exchange pool during Mg2+-Na+ exchange, driving riverine δ26Mg towards higher values. Expanding our finding to global rivers, the negative correlation between riverine δ26Mg and CWI can be interpreted by a competition between the fast dissolution of carbonates leading to the enrichment of 24Mg in waters and Mg isotope fractionation induced by cation exchange leading to the depletion of 24Mg in the residual waters. This study provides new insight into cation exchange as a regulator of riverine δ26Mg and Mg cycling, highlighting the robustness of riverine δ26Mg in tracing CWI and constraining the carbon cycle. [ABSTRACT FROM AUTHOR]

Large Arctic rivers are an important source of iron (Fe) to the Arctic Ocean, though seasonal variations in the terrestrial source and supply of Fe to the ocean are unknown. To constrain the seasonal variability, we present Fe concentrations and isotopic compositions (δ56Fe) for particulate (>0.22 µm) and colloidal (<0.22 µm–1 kDa) Fe from the Lena River, NE Russia. Samples were collected every month during winter baseflow (September 2012–March 2013) and every 2–3 days before, during and after river ice break-up (May 2015). Iron in particles have isotope ratios lower than crustal values during winter (e.g., δ56Fe Part = −0.37 ± 0.16‰), and crustal-like values during river ice break-up and spring flood (e.g., δ56Fe Part = 0.07 ± 0.08‰), indicating a change in the source of particulate Fe between winter and spring flood. Low isotope values are indicative of mineral dissolution, transport of reduced Fe in sub-oxic, ice-covered sub-permafrost groundwaters and near-quantitative precipitation of Fe as particles. Crustal-like isotopic compositions result from the increased supply of detrital particles from riverbank and soil erosion during river ice break-up and flooding. Iron colloids (<0.22 μm) have δ56Fe values that are comparable to or lower than crustal values during winter (e.g., δ56Fe Col = −0.08 ± 0.05‰) but similar to or higher than crustal values during spring flood (e.g., δ56Fe Col = +0.24 ± 0.11‰). Low δ56Fe ratios for colloidal Fe during winter are consistent with precipitation from isotopically light Fe(II) aq transported in sub-permafrost groundwaters. Higher colloidal δ56Fe ratios during the spring flood indicate that these colloids are supplied from surface soils, where Fe is fractionated via oxidation or organic carbon complexation, similar to during summer. Approximately half of the annual colloidal Fe flux occurs during spring flood while most of the remaining colloidal Fe is supplied during summer months. The total amount of colloidal Fe transported during winter was relatively low. The seasonal variation in colloidal Fe isotope values may be a useful tool to trace the source of colloidal Fe to the Arctic Ocean and monitor future changes in the sources and supply of Fe from the permafrost landscape to the Lena River basin. [ABSTRACT FROM AUTHOR]

Digital elevation models (DEMs) are crucial for numerous assessments of the Earth's surface, so this research aim to evaluate the quality of several open source DEMs like advanced spaceborne thermal emission and reflection radiometer global DEM (ASTER GDEM), shuttle radar topography mission DEM (SRTM DEM), SENTINEL-1, and TerraSAR-X for digital elevation measurement (TanDEM-X). TanDEM-X is one of the newest DEM models; however, ASTER and SRTM are still the most used. To evaluate the qualities of these DEMs, the vertical accuracies of ASTER, STRM (all 30 m), SRTM, TanDEM-X (90 m), and SENTINEL 1 (range from 5 to 12.5 m) were tested using GPS reference points and The RMSE gave the values of ± 3.56 m ± 57.68 m, ±5.89 m, ±10.21 m and ± 20.25 m for used SRTM1, SENTINEL-1, SRTM3, TanDEM-X, and ASTER DEMs respectively. As is well known, obtaining a high-quality DEM is exceedingly challenging since it is time-consuming, expensive, and often constrained, therefore this study examined how to enhance SRTM1 as it gave the best result and assessed the effects of increasing the number of points on digital elevation model accuracy by using raster calculator and merge model in ArcGIS. The results showed that the merge model method gave the best result and, by increasing the number of reference points, the accuracy increased. The DEM produced by the enhanced SRTM (iSRTM) demonstrated noticeably better outcomes than the baseline SRTM DEM, with around 3.56 m RMSE. In this research, STRM-1 DEM is used to determine watershed basin delineation. The topographic map showed significant variations in the level of the Earth's surface, as the heights of the area ranged between 20 m and 120 m. The number of watersheds extracted in the Benban is 132 with different areas, the large area is about 72.14 km 2 , while the small area is about 1.13 km 2 , and between those areas, there are various areas. The largest recorded watershed circumference reached 48.94 km in area (72.14 km 2), while the lowest recorded perimeter is 5.40 km for the area (1.13 km 2). [ABSTRACT FROM AUTHOR]