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[Display omitted] • Ancient reservoir sediments can be used as a potential tool for reconstructing long-term history of human activity and water level. • Anthropogenic activities had significantly affected vegetation conditions in the western Guizhou Plateau since ∼ 1700 CE. • Human-modulated dramatic fluctuation in the water level can markedly change reservoir ecosystem. Knowledge of the responses of reservoir ecosystems to anthropogenic and climatic impacts on multi-centennial timescales is relatively poor, but is crucial for the management of numerous reservoirs in China. In this study, the history of an ancient reservoir system was reconstructed for the last ∼ 700 yr based on multiple dating methods (210Pb, 137Cs, and 14C) and geochemical data (e.g., the mass accumulation rates, loss-on-ignition values, total organic carbon, total nitrogen, total phosphorus contents, and stable carbon isotope ratios of organic matter) obtained for sediment cores from Gongqing Reservoir in Guizhou Province, southwestern China. Combined with historical literature and regional climatic records, the response of the aquatic ecosystem in Gongqing Reservoir to water level fluctuations, anthropogenic activity, and climatic changes during the last ∼ 700 yr was assessed. The results suggest that dramatic changes in the water level due to dam heightening in 1950 s significantly changed the aquatic ecosystem of Gongqing Reservoir. During periods of low water levels (average water depth = 1–2 m; 1345–1957 CE), aquatic macrophytes contributed more to the sedimentary organic matter, whereas phytoplankton increasingly contributed more during periods of high water levels (∼ 5 m; 1957–2020 CE). During the late stage (1700–1957 CE) of low water levels, the reservoir ecosystem was significantly affected by human activities. Combined with regional geological and historical records, we consider that increased population and enhanced human activities have markedly affected vegetation conditions in western Guizhou Province since ∼ 1700 CE. After 1957 CE, anthropogenic activities were key in affecting the aquatic ecosystem of Gongqing Reservoir. Especially in the last decade, large housing developments and enhanced agricultural activities in the watershed have led to enhanced catchment erosion and transport of more nutrients into the reservoir, thus promoting the algae productivity. These results provide new insights into how reservoir ecosystems respond to water level fluctuations, anthropogenic activity and climatic changes on multi-centennial timescales. [ABSTRACT FROM AUTHOR]

• The ET value of various crops in different soils were determined by SWAP model. • Farmland target ET indicator was separated from the regional target ET. • Soil and water resources were optimally allocated under farmland target ET. • Multi-objective optimal allocation of soil and water resources model was established. • The results showed that the economic benefit and water use efficiency were improved. There is a mismatch between crop water demand, the spatial and temporal distribution of natural rainfall, surface water sources, and arable land resources in the North China Plain. This has been compensated for by massive groundwater exploitation, and as a result, ground water levels have continuously declined and groundwater landing funnels have formed in some areas. Consequently, there is an urgent need for the rational allocation of soil and water resources. In this study, regional soil types and the corresponding crops in Guangping County, Hebei Province, China, alongside the regional annual average total water consumption were used to determine reasonable allocations for crop planting structures, with an aim of maximizing the water utilization efficiency and economic benefits while also achieving a regional groundwater dynamic equilibrium. Daily meteorological data from 1973 to 2021, including precipitation, temperature, sunshine hours, wind speed, and humidity, as well as crop data, including irrigation systems and crop growth status, were collected. Water consumption models for eight soil types and seven typical crops forming 56 calculation partitions were established to obtain annual average water consumption values for the different crops. The maximum economic benefit and water-use efficiency were then used as the objective functions and total water consumption as the control condition for the non-dominated sorted genetic algorithm-Ⅱ (NSGA-II), to optimize the allocation of soil and water resources in the region; the adjusted quantities for the different crops cultivated under different soil types in the study area were obtained. The areas growing sweet potato and vegetable-fruits were found to increase by 0.5255 km2 and 4.4452 km2, respectively, when compared to the pre-optimization period, whereas the areas with winter wheat-summer maize, millet, peanut, cotton, and summer maize decreased by 1.3481 km2, 0.1812 km2, 0.7316 km2, 2.0896 km2, and 0.62 km2, respectively. The economic benefit increased from 810.37 to 853.64 million yuan, while the water-use efficiency increased from 1.5426 kg/m3 to 1.5859 kg/m3. The results provide a basis for soil and water resource management in the region and a technical reference for similar areas to improve agricultural water-use efficiency and economic benefits. [ABSTRACT FROM AUTHOR]

• Constructed a groundwater numerical model by Visual MODFLOW and studized the feasibility of mine water recharge to aquifers. • Analyzed the impact of mine water recharge on the water level and inflow of aquifers. • To ensure the safe mining in the future, the dynamic water inflow under different mining levels was predicted. Water inflow poses a critical safety concern in coal mining. The pressing challenge in current mine water inflow research is the need to enhance the prediction of dynamic changes in mine water inflow across different mining stages. In this study, the hydrogeological conditions and aquifer structural characteristics of the Wutongzhuang Coal Mine in Hebei Province, China were analyzed, and the results were combined with pumping test and drilling data. A numerical model of groundwater flow in the study area was established using Visual MODFLOW and the model was calibrated and verified by comparing its results with the measured values to ensure that it realistically reflected the state of groundwater movement in the study area. The results of numerical simulation indicated that: (1) The water level of the Ordovician aquifer varies significantly by season. A large exposed area of Ordovician limestone in the western mountainous region receives a large amount of rainfall infiltration recharge in the summer rainy period that raises the water level of the Ordovician aquifer in the study area. (2) The groundwater system in the study area is in an equilibrium state, with the water inflow approximately equal to the outflow. (3) The recharge of mine drainage water has a slight positive effect on the Ordovician water level and the floor water inflow, with the impact on the water level of the aquifer decreasing as the distance from the recharge well and the import of Ordovician limestone water increase. In cases in which there is mine water recharge, the water level of the Ordovician aquifer is approximately 0.33 to 1.37 m higher than in cases without recharge, resulting in an increase in water inflow of approximately 10.6 m3/d. (4) In cases in which there is recharge of all drainage water, the maximum water inflow into the fifth mining area is 3,491.3 m3/d, which is 12.5 m3/d higher than in the case without recharge. These results provide important technical references for the formulation of mining schemes and water prevention measures in mining areas. [ABSTRACT FROM AUTHOR]

Hydrogen is not only an important energy carrier needed to achieve the global goal of carbon neutrality, but also an important way of international energy trade in the future. This research analyzes the advantages and challenges of China's participation in international hydrogen trade in detail, proposes the possible routes of China's international hydrogen trade, and proposes specific measures to enhance China's participation in international hydrogen trade. This paper proposes that China should take green hydrogen as its development direction, and guide the development of China's hydrogen trade with the principle of blue green cooperation and gray hydrogen withdrawal. In the future, China's hydrogen trade forms will be diversified, and the types of trade will cover the entire hydrogen energy industry chain. Therefore, China should accelerate the overall deployment of hydrogen trade and the construction of hydrogen trade infrastructure, and build a more sophisticated hydrogen economy. [Display omitted] • The advantages of China's international hydrogen trade are analyzed. • Discussed China's possible international hydrogen trade routes in the future. • The obstacles affecting China's hydrogen competitiveness are analyzed. • Put forward suggestions to promote China's international hydrogen trade. [ABSTRACT FROM AUTHOR]

• Shrub-herb and herbaceous associations have stronger carbon storage benefits. • Different elevational patterns of plant and soil carbon stocks. • Different mechanisms of plant and soil carbon accumulation. • Specific leaf area and leaf nutrient content have an effect on carbon stocks. Exploring the distribution characteristics of plant community functional diversity, functional traits and plant and soil carbon stocks along elevation and the effects of functional diversity and functional traits on carbon stocks is of great significance for revealing the distribution characteristics of plant community functional diversity and carbon stocks in the desert area and understanding the carbon accumulation mechanism. In this study, we took the leaf functional traits of plant community species and the carbon stocks of plants and soils of sample plots in the pre-Hola Mountain desert area as the research objects and explored their altitudinal distribution characteristics and their interrelationships. The results showed that (1) the plant carbon storage capacity of the shrub - herb association was the strongest, and the soil carbon storage capacity of the herb association was the strongest. (2) Functional richness and plant carbon storage capacity tended to increase and then decrease with elevation, while functional evenness and leaf phosphorus content tended to decrease and then increase with elevation. Functional dispersion, leaf water content, chlorophyll content, leaf carbon, nitrogen content, and soil carbon stock all showed a gradual increase with elevation, and the total carbon stock gradually increased with elevation in the middle and low elevation areas (1200–1800 m), and showed a wave-like change in the high elevation areas (1800–2400 m). (3) The accumulation of soil carbon stocks in the study area is mainly dominated by the "mass ratio hypothesis", while the accumulation of plant carbon stocks is mainly dominated by the "ecological niche complementarity hypothesis", and plant and soil carbon stocks are mainly affected by the specific leaf area and the content of carbon, nitrogen, and phosphorus in leaves. [ABSTRACT FROM AUTHOR]

[Display omitted] • The CUO has systemic vertical variations in mineral assemblages and pitchblende geochemistry. • The vertical variations were caused by the ascent of deep oxidizing fluid and decreased upwardly during U mineralization. • REE of pitchblende could be used to guide deep uranium exploration. The Changjiang uranium (U) orefield in northern Guangdong (South China) contains several important granite-related uranium deposits, including the Mianhuakeng deposit. The hydrothermal evolution and mineralization mechanism of the deposit remain unclear, and hence in this study we analyzed the mineral compositional variations of pitchblende from different elevation (−300 to −50 m) in the orebody at Mianhuakeng deposit. The results indicate that with decreasing depth, the hydrothermal mineral assemblage changes from a reducing one (pitchblende, pyrite, and chlorite) to a moderately oxidizing one (pitchblende, coffinite, hematite, and goethite). The contents of U, Sr, ∑REE, U/Th, and LREE/HREE ratios in the pitchblende decrease (whereas the Cu-Pb-Zn-Ni-Co-Sc-Rb contents increase) progressively with decreasing depth. Also, Ce anomaly (Ce/Ce*) changes from positive to negative, and Eu anomaly (Eu/Eu*) becomes more negative with decreasing depth. We interpreted such vertical variations to be caused by the ascent of deep, mid-to-high temperature, highly-oxidizing ore-forming fluid, which was reduced by early-stage reducing minerals in the wallrock, a process that also formed the mineralization at Changjiang. In addition, the pitchblende REE distribution patterns and Eu/Eu* at depth (−300 m) resemble those of the Zhuguang pluton, indicating that the ore-forming materials were originated from the U-bearing granite wallrocks. Therefore, the Ce/Ce* and Eu/Eu* variations of pitchblende can be used to guide deep uranium ore exploration. [ABSTRACT FROM AUTHOR]