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How sediment dredging alters phosphorus dynamics in a lowland rural river?

Journal of Environmental sciences 2025年第1期147卷 189-199页

作者： Qimou Zhang Jiacong Huang Yulai Ji Jing Zhang Shuai Zhang Junfeng Gao key laboratory of watershed geographic sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China University of Chinese Academy of sciences Beijing 10094China

China’s lowland rural rivers are facing severe eutrophication problems due to excessive phosphorus(P)from anthropogenic ***,quantifying P dynamics in a lowland rural river is challenging due to its complex interaction with surrounding areas.A P dynamic model(River-P)was specifically designed for lowland rural rivers to address this *** modelwas coupled with the Environmental Fluid Dynamics Code(EFDC)and the Phosphorus Dynamic Model for lowland Polder systems(PDP)to characterize P dynamics under the impact of dredging in a lowland rural *** on a two-year(2020-2021)dataset from a representative lowland rural river in the Lake Taihu Basin,China,the coupled model was calibrated and achieved a model performance(R^(2)>0.59,RMSE<0.04 mg/L)for total P(TP)*** research in the study river revealed that(1)the time scale for the effectiveness of sediment dredging for P control was~300 days,with an increase in P retention capacity by 74.8 kg/year and a decrease in TP concentrations of 23%after dredging.(2)Dredging significantly reduced P release from sediment by 98%,while increased P resuspension and settling capacities by 16%and 46%,respectively.(3)The sediment-water interface(SWI)plays a critical role in P transfer within the river,as resuspension accounts for 16%of TP imports,and settling accounts for 47%of TP *** the large P retention capacity of lowland rural rivers,drainage ditches and ponds with macrophytes are promising approaches to enhance P retention *** study provides valuable insights for local environmental departments,allowing a comprehensive understanding of P dynamics in lowland rural *** enable the evaluation of the efficacy of sediment dredging in P control and the implementation of corresponding P control measures.

关键词： Lowland rural river Phosphorus Sediment dredging Model ensemble Retention capacity

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Effects of water level variations on the water quality of Huayang Lakes,China

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Journal of geographical sciences 2025年第1期35卷 173-188页

作者： AN Lesheng LIU Chun FAN Zhongya LIAO Kaihua WANG Wencai WANG Nan School of Resources and Environment Anqing Normal UniversityAnqingAnhui246133China South China Institute of Environmental sciences Ministry of Ecology and EnvironmentGuangzhou510655China The key laboratory of watershed geographic sciences Nanjing Institute of Geography and LimnologyCASNanjing210008China

To explore water level variations and their dynamic influence on the water quality of Huayang Lakes,the water level from 1967 to 2023 and water quality from 2015 to 2023 were analyzed using the Mann–Kendall trend test,box plots,and violin *** results show a notable hydrological rhythm of water level alternation between dry and flood seasons in Huayang Lakes,with an average water level of 12.82 m and a monthly range of 11.21–*** 2017,the water level of Huayang Rivers has shown a decreasing trend of–0.02 m/*** phosphorus(TP)has become the primary *** TP concentrations in Longgan Lake(the largest lake)during the dry,rising,flood,and retreating seasons from 2015 to 2023were 0.083,0.061,0.050,and 0.059 mg/L,*** effect of water level on TP was mainly observed during the low-water *** the water level in the dry season rose to 12.25 and 13.00 m,the percentage of TP exceeding 0.1 mg/L in Longgan Lake decreased to 55.8%and 33.3%,*** the dry season,wind and wave disturbances caused the release of endogenous phosphorus in Huayang *** led to drastic fluctuations in TP concentration,reducing the correlation between water level and *** external control is limited,the water level during the dry season should be maintained between 12.25 and 13.0 ***,it is necessary to accelerate the restoration of submerged macrophyte species(such as Hydrilla verticillata and Vallisneria natans)in the Huayang Rivers.

关键词： shallow lake water level water quality total phosphorus Huayang Lakes

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Chemical weathering in Manas River Basin:Driven by sulfuric acid or carbonic acid?

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Acta Geochimica 2025年第1期44卷 59-85页

作者： Jiaxin Zhang Bingqi Zhu key laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingChina University of Chinese Academy of sciences BeijingChina

Carbonic acid produced by the dissolution of atmospheric and soil CO_(2)in water is usually the most dominant catalyst for chemical weathering,but a sulfuric aciddriven phenomenon,different from usual,was found in the orogenic belt watersheds dominated by silicate *** study,rooted in comprehensive field investigations in the Manas River Basin(MRB)north of the Tianshan Mountains,delves into the mechanisms and impacts of sulfuric and carbonic acid as catalysts driving diff erent types of chemical weathering in the Central Asian Orogenic *** analyses elucidate that carbonate weathering constitutes 52.4%of the total chemical weathering,while silicate and evaporite account for 18.6%and 25.3%,respectively,with anthropogenic activities and atmospheric precipitation having little eff *** estimated total chemical weathering rate in MRB is approximately 0.075×10^(6)mol/km^(2)/*** findings further suggest that,preceding carbonate precipitation(<10^(4)year),chemical weathering can absorb CO_(2).Subsequently,and following carbonate precipitation(10^(4)-10^(7)year),it will release CO_(2).The release significantly surpasses the global average CO_(2)consumption,contributing to a noteworthy climate *** study underscores the distinctive weathering mechanisms,wherein sulfuric acid emerges as the predominant *** quantity of sulfuric acid as a catalyst is approximately three times that of carbonic *** acid-driven carbonate rock weathering(SCW)is identified as the sole chemical weathering type with a net CO_(2)release eff *** CO_(2)release flux(5176 mol/km^(2)/year)is roughly 2.5 times the CO_(2)absorption by Ca-Mg silicate weathering,highlighting the pivotal role of chemical weathering in sourcing atmospheric CO_(2)over the timescales of carbonate precipitation and sulfate ***,this study posits that catalyst and transport limitations are the most plausible critical factors in *** interplay between s

关键词： Catchment chemical weathering Mid-latitude orogenic belt Sulﬁde oxidation Manas River Basin

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Global Fire Season Types and Their Characteristics Based on MODIS Burned Area Data

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Chinese geographical Science 2025年第2期35卷 374-383页

作者： ZHANG Weihan LIU Ronggao HE Jiaying LIU Yang WU Chao State key laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences University of Chinese Academy of sciences Department of Earth System Science Ministry of Education Key Laboratory for Earth System Modeling Institute for Global Change Studies Tsinghua University

Fire season affects the dynamic changes of post-fire vegetation communities and carbon emissions. Analyzing its global patterns supports understanding of the ecological impacts of fires and responses of fires to climate change. Meteorological variables have been widely used to quantify fire season in current studies. However, their results can not be used to assess climate impacts on the seasonality of fire activities. Here we utilized satellite-based Moderate Resolution Imaging Spectroradiometer(MODIS) burned area data from 2001 to 2022 to identify global fire season types based on the number of peaks within a year. Using satellite data and innovatively processing the data to obtain a more accurate length of the fire season. We divided fire season types and examined the spatial distribution of fire season types across the K?ppen-Geiger climate(KGC) zones. At a global scale, we identified three major fire season types,including unimodal(31.25%), bimodal(52.07%), and random(16.69%). The unimodal fire season primarily occurs in boreal and tropical regions lasting about 2.7 mon. In comparison, temperate ecosystems tend to have a longer fire season(3 mon) with two peaks throughout the year. The KGC zones show divergent contributions from the fire season types, indicating potential impacts of the climatic conditions on fire seasonality in these regions.

关键词： burned area data fire season fire season types global terrestrial ecosystems Köppen-Geiger climate classification system Moderate Resolution Imaging Spectroradiometer (MODIS)

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Unintentional emissions of polychlorinated naphthalenes in China:Sources,composition,and historical trends

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Journal of Environmental sciences 2025年第2期148卷 221-229页

作者： Ye Huang Lin Huang Ying Li Nazupar Sidikjan Yunshan Zhang Yan Chen Yangmin Chen Ye Li Wei Du Long Chen YanWu Shanshan Zhang Jing Yang Wenjun Meng Guofeng Shen Min Liu Shu Tao key laboratory of geographic Information Science of the Ministry of Education School of Geographic SciencesEast China Normal UniversityShanghai 200241China Yunnan Provincial key laboratory of Soil Carbon Sequestration and Pollution Control Faculty of Environmental Science&EngineeringKunming University of Science&TechnologyKunming 650500China laboratory of Earth Surface Processes College of Urban and Environmental SciencePeking UniversityBeijing 100871China

Polychlorinated naphthalenes(PCNs)are detrimental to human health and the *** the commercial production of PCNs banned,unintentional releases have emerged as a significant environmental ***,relevant information is still *** this study,provincial emissions for eight PCNs homologues from 37 sources in the Chinese mainland during the period of 1960-2019 were estimated based on a source-specific and time-varying emission factor *** results showed that the total PCNs emissions in 2019 reached 757.0 kg with Hebei ranked at the top among all the provinces and iron&steel industry as the biggest ***-chlorinated PCNs comprised 90%of emissions by mass,while highly chlorinated PCNs dominated in terms of toxicity,highlighting divergent priorities for mitigating emissions and safeguarding human *** emissions showed an overall upward trend from 1960 to 2019 driven by emission increase from iron&steel industry in terms of source,and from North China and East China in terms of geographic ***-capita emissions followed an inverted U-shaped environmental Kuznets curvewhile emission intensities decreased with increasing per-capita Gross Domestic Product(GDP)following a nearly linear pattern when log-transformed.

关键词： PCNs Emission inventory Emission factor Composition profile Emission intensity Chinese mainland

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Temporal stability responses to nitrogen addition in Tibetan alpine grasslands:A community composition perspective

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Journal of Integrative Agriculture 2025年第3期24卷 871-884页

作者： Ning Zong Peili Shi key laboratory of Ecosystem Network Observation and Modelling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of sciences Beijing 100049China

Plant community composition typically undergoes progressive changes along environmental ***,most experimental studies have focused on individual communities,so it remains unclear how exogenous nutrient inputs affect the stability of plant communities along environmental *** a rainfall gradient on the northern Tibetan Plateau,we conducted an 8-year nitrogen(N)addition experiment in four alpine grasslands:alpine desert steppe(ADS),alpine steppe(AS),alpine meadow steppe(AMS),alpine meadow(AM),and we used twoway ANOVA to examine the effects of N addition on the temporal stability of these different alpine *** found that community aboveground biomass showed saturation trends in AM and AMS with increasing N gradients,while there was no change in AS and a gradual increase in *** temporal stability showed different patterns of gradual decreases in ADS and AM,and a unimodal trend in AMS with increasing N ***,N addition had no effect on the temporal stability of *** species stability was the controlling factor for alpine grasslands along the transect,while the effect of asynchrony gradually increased with decreasing *** findings highlight that community composition,especially the dominant species,along the environmental gradient can mediate the effects of N inputs on community temporal ***,the conservation and restoration of the dominant species are particularly important under future scenarios of increased atmospheric N deposition.

关键词： community composition dominant species environmental gradient plant abundance group Tibetan Plateau

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Reconstructing forest and grassland cover changes in China over the past millennium

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Science China Earth sciences 2025年第1期68卷 94-110页

作者： Fanneng HE Fan YANG Yafei WANG key laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing100101China key Research Institute of Yellow River Civilization and Sustainable Development Henan UniversityKaifeng475001China University of Chinese Academy of sciences Beijing100049China

Historical forest and grassland cover changes not only are critical indicators for quantifying ecological and environmental change processes but also serve as fundamental data for long-term climate change simulations and terrestrial ecosystem carbon emission ***,because of limitations in historical data,quantitative estimations and spatially gridded reconstructions of these changes remain challenging,necessitating further methodological *** study focused on China's present-day land area over the past millennium,objectively capturing the characteristics and drivers of forest and grassland cover *** this basis,using the forest transition theory and the space-for-time substitution method,we depicted the historical deforestation process as an inverted“S”curve and developed a model to reconstruct historical forest area changes based on the functional relationship between the forest area and population size ***,a gridded forest allocation model was established on the basis of deforestation *** the grassland cover,we implemented regionspecific methods,such as the cropland area deduction method and the habitat constraint method,to quantitatively reconstruct historical ***,we obtained provincial forest and grassland area changes over the past millennium and mapped 10-km-resolution gridded data of forest and grassland *** results indicated the following.(1)The methods developed using population data as a proxy objectively reproduced the spatiotemporal evolution of forest and grassland cover in China over the past *** feasible methods offer a novel pathway for the quantitative reconstruction of historical forest and grassland cover changes.(2)The data indicated that China's forest area generally decreased over the past millennium,characterized by a“decrease-then-increase”*** forest area experienced three distinct phases:a slow decline(AD 1000–1650),a rapid decline(AD 16

关键词： Land use and land cover change Forest Grassland Quantitative reconstruction Gridded reconstruction China historical period

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The development characteristics and formation modes of rainstorm-triggered flash flood disasters in the Hengduan Mountains

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Journal of geographical sciences 2025年第3期35卷 619-640页

作者： LI Yifan ZHANG Chendi ZHANG Guotao key laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

The Hengduan Mountains region(HMR)is one of the most densely distributed and severe flash flood disaster-prone areas in southwest *** is also a key area for major engineering projects and beautiful countryside construction in Southwest ***,previous studies have not systematically summarized the development characteristics and formation modes of flash flood disasters in the HMR,which limits the development of theoretical and technical system for flood *** this study,we focused on the physical processes of flash flood disasters in the HMR,including generation,movement,and disaster formation,and clarified the dominant disaster-inducing conditions(multiple humid monsoon circulation,high potential energy and high heterogenous underlying surface)and disaster development characteristics(high spatio-temporal heterogeneity,highly concentrated energy,chain and cascading effects,and clustered occurrence)of flash floods in the *** on the entire processes of flash flood disasters,three major formation modes have been summarized:the runoff generation mode of vegetation-hydrology-soil coupling dominated by high hydraulic gradient in mountainous areas,strong flow-sediment coupling movement,and serious disaster losses due to high exposure of disaster bearing ***,based on the issues in previous research,four future research challenges for flash flood disaster in the HMR were *** study provides insights into disaster prevention and reduction research,including fundamental theoretical system,precise risk assessment of regional disasters,and accurate early warning and forecasting of flash floods.

关键词： Hengduan Mountains region rainstorm-triggered flash flood disaster-inducing condition disaster developmentcharacteristic formation mode

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Regional revitalizing divergences and reasons for targeted policy-driven rural development in China: An assessment based on provincial-level data

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Journal of geographical sciences 2025年第3期35卷 483-500页

作者： LIU Zhengjia WANG Haoning key laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

Rural development is an important part of national development in ***,the lack of rural development degree(RDD)changes and divergence analyses limited our understanding for how to promote rural development in different ***,this work introduced a rural development assessment index and equal weighting system,consisting of five dimensions and 25 indicators,to investigate provincial RDD and changes in 2015 and *** results showed that national RDD increased from 0.403±0.066 in 2015 to 0.486±0.054 in 2021 and the scores for each of the five dimensions also ***'s rural areas had a good development foundation,but rural industrial prosperity and wealthy lifestyle were *** rural development policies promoted provincial-level in-creases in these *** RDD top-ranked provinces were mainly in eastern *** of the bottom-ranked provinces were in central and western *** top-ranked provinces usually had three or four strong dimensions that supported regional rural ***,weak performances in all dimensions were usually observed in the bot-tom-ranked provinces,which limited RDD *** bottom-ranked provinces are encouraged to improve their ecological livability,effective governance,and wealthy lifestyle.

关键词： rural multifunctionality rural development degree(RDD) equal weighting method provincial-level assessment China

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The co-evolution of East Asian subtropical westerly jet and East Asian summer monsoon during different time periods in the Holocene and its influence on precipitation patterns in China

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Science China Earth sciences 2025年第4期68卷 1100-1115页

作者： Yawen LIU Mi YAN Jian LIU Sumin WANG Zhengyu LIU Liang NING Ziyi WANG key laboratory for Virtual geographic Environment Ministry of Education/State Key Laboratory Cultivation Base of Geographical Environment Evolution and Regional Response/Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and ApplicationSchool of GeographyNanjing Normal University Jiangsu Provincial key laboratory for Numerical Simulation of Large Scale Complex Systems School of Mathematical SciencesNanjing Normal University Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Department of Geography The Ohio State University

Generally, the interaction between the East Asian subtropical westerly jet(EASWJ) and the East Asian summer monsoon(EASM) is regarded as a critical dynamic factor in the evolution of precipitation patterns in China. Using simulation results from the transient climate evolution since the last glacial maximum, this study applies the multivariate empirical orthogonal function(MVEOF) analysis method to investigate the co-evolution relationships of the EASWJ and the EASM during the early, middle, and late Holocene, as well as their influence on precipitation patterns in China. The results indicate that all the first MVEOF modes in different time periods of the Holocene display an out-of-phase relationship in the intensity anomaly between the EASWJ and the EASM. However, the jet stream is wider and more tilted in the late Holocene. Under the influence of secondary circulations formed during their co-evolution, a north-south dipolar precipitation pattern in eastern China(“flood in the south and drought in the north” or “drought in the south and flood in the north”) and an east-west dipolar pattern in northern China(“wet in the west and dry in the east” or “wet in the east and dry in the west”) are found in the early and middle Holocene, while in the late Holocene a regionally-consistent precipitation pattern is witnessed across the whole region. In this mode, the precipitation in the middle and late Holocene is primarily dominated by trend changes. The second MVEOF mode reveals that the EASM weakens when the EASWJ shifts eastward and the jet steam axis shortens during the early Holocene,resulting in a north-south dipolar precipitation pattern in eastern China and a regionally-consistent pattern in northern China. In the middle Holocene, dipolar precipitation patterns are also observed in both eastern China and northern China when the EASWJ moves northward and the EASM strengthens, while the moisture condition in North China is less pronounced, and vice versa. In the late H

关键词： Holocene East Asian subtropical westerly jet East Asian summer monsoon Co-evolution Precipitation pattern

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