Lake Poyang,the largest freshwater lake in China,is critical to regional water security and wetland ecosystem integrity.Seasonal isolated lakes(SILs),key components of the Lake Poyang wetland system,experience dynamic changes in water level and volume that directly influence the lake's water balance and biodiversity conservation.However,due to sparse in situ observa-tions,complex surface conditions,and frequent wet-dry transitions,existing water volume estimation methods remain limited in ac-curacy and applicability.Here,we develop a novel framework for estimating SIL water volume by integrating multi-source remote sensing data,hydrological connectivity analysis,digital elevation models(DEMs),and limited hydrological measurements.For the first time,high-resolution time-series(8-day,30-m)data on water surface area,water level,and water volume were reconstructed for 102 SILs from 2000 to 2024.The results indicate that:(1)the timing of isolation varies spatially,with average Xingzi Station water levels of 13.85 m and 14.28 m marking the start and end of isolation in the Ganjiang North tributary;(2)the 102 SILs had an average area of 305.20 km2,accounting for 17.98％of Lake Poyang's surface water area,with the largest isolated area recorded in 2023(134.03 km2,8.29％of the lake's area that year);(3)during the rising,falling,and dry stages,the water volume of SILs represented 1.91％,4.13％,and 6％of the total lake volume,respectively.From 2000 to 2024,water volume in northern SILs showed a declining trend,while lakes in central and southern regions exhibited increasing trends,contributing positively to drought mitigation in the basin.Overall,this study provides a robust approach for hydrological monitoring and management of Lake Poyang and other small,shallow seasonal lakes,offering a scientific basis for sustainable water resource use and ecological conser-vation.
Stream ecosystems possess significant ecological value due to their rich aquatic biodiversity and unique characteristics,yet they are highly vulnerable and require urgent attention and protection.Zooplankton,as an important component of the aquatic food web,is often overlooked in terms of its functional role in stream ecosystems.To better understand the ecological function of zo-oplankton in these environments,this study focused on the headwaters of the Chishui River,a minimally disturbed basin,and com-pared the taxonomic and functional group characteristics of zooplankton under two distinct hydrological conditions:the dry season(December)and the wet season(May).Relationships between these characteristics and water environmental factors were also ana-lyzed.A total of 29 zooplankton species were identified,with species richness in the dry season(24 species)being twice that in the wet season(12 species).Compared to other aquatic systems,stream zooplankton density was extremely low,ranging from 0.02 to 4.90 ind./L.Based on functional traits such as habitat preference,body size,and feeding habit,taxonomic groups were classi-fied into 11 functional groups.Dominant functional groups included the occasional planktonic benthic scraper,the small to medi-um-sized swimming predator,and the small filter-feeder,all reflecting adaptive strategies to turbulent lotic habitats.Notably,the proportion of the benthic scraper group increased sharply from 17.7％in the dry season to 68.4％in the wet season,demonstrating high sensitivity to hydrological shifts.Mantel tests further revealed that functional group composition was significantly correlated with multiple environmental factors,including phytoplankton cell density,water temperature,pH,oxidation-reduction potential,total phosphorus,and ammonium nitrogen,indicating that functional groups serve as more sensitive environmental indicators than taxonomic groups.This study demonstrates that functional group classification can integrate species with similar ecological niches,effectively compensating for the limitations of taxonomic approaches in assessing stream zooplankton standing stock,thereby offering a new theoretical perspective for constructing diagnostic indicator systems for stream ecological health.
The interactive stress relationship between ecological security and urbanization within lake basins fundamentally mani-fests the interactive dynamics between humans and the environment.Against the backdrop of accelerating urbanization and mount-ing pressure on natural resource and environmental carrying capacity,lake basins face growing challenges in providing stable mate-rial support and ecological guarantees for regional sustainable development.Within the theoretical framework of the human-land re-lationship in regional systems,this study quantitatively analyzes ecological security and urbanization levels across various lake ba-sins and explores the spatial heterogeneity of their interactive stress relationship.The results indicate that:(1)Under the combined influence of ecological governance and regional development,ecological security and urbanization levels in different lake basins have improved to varying degrees,with their spatiotemporal evolution exhibiting significant spatial heterogeneity.(2)The stress ex-perienced in the interaction between ecological environment and urbanization varies across basins,showing distinct patterns of cou-pling and coordinated evolution.Developed basins tend to achieve a higher level of coordination,whereas basins with a strong eco-logical foundation often experience lagging urbanization.The differing degrees of stress exerted and endured in the ecological secur-ity-urbanization interaction across basins reflect regional disparities shaped by the combined effects of natural conditions and devel-opmental stages.(3)A complex interactive stress relationship exists between ecological security and urbanization,influenced by factors such as natural endowments and developmental stages.Ecological constraints in developed basins have progressively weak-ened;in ecologically sound but underdeveloped basins,ecological factors strongly constrain urbanization;in ecologically fragile and underdeveloped basins,a bidirectional stress pattern is observed.Promoting ecological governance and urbanization processes in a context-sensitive manner and exploring development pathways characterized by high adaptability and synergy are key to achie-ving high-quality development in lake basins.This study aims to systematically delineate the interactive stress relationship and evo-lutionary characteristics between ecological security and urbanization,thereby providing scientific reference and practical insights for sustainable urbanization and ecological civilization construction in lake basins.
Strategic critical minerals such as lithium,boron,and potassium play an irreplaceable role in global energy transition and high-technology sectors.However,systematic research on the multi-element synergistic enrichment mechanisms and their dy-namic driving factors in deep-water salt lakes remains insufficient.The Longmu Co salt lake in Tibet,a typical high-altitude deep-water salt lake characterized by brines enriched in lithium(Li),boron(B),potassium(K),rubidium(Rb),and cesium(Cs),serves as an ideal object for investigating these processes.This study employed a 2 km×2 km grid sampling strategy combined with a hydrological-climatic analysis model to systematically analyze the spatial distribution and vertical differentiation patterns of LiCl,B2O3,KCl,Rb2O,and Cs2O in the surface brines of Longmu Co salt lake in 2024,and to explore the driving factors behind the dynamic evolution of LiCl,B2O3,and KCl concentrations during 2009-2024.The results indicate that the average concentrations of LiCl,B2O3,and KCl in the Longmu Co salt lake brines in 2024 were 620.07 mg/L,441.44 mg/L,and 5.12 g/L,respective-ly.Vertical differentiation was pronounced,with LiCl concentrations in deep layers(＞30 m)increasing by 7.50％relative to sur-face layers(0-10 m),accompanied by synchronous enrichment of Rb2O and Cs2O.The thermocline barrier and bottom anoxic en-vironment represent the primary factors contributing to this vertical differentiation.Horizontally,high-value zones of LiCl and KCl formed in the eastern part of the salt lake due to evaporation-concentration effects,whereas concentrations decreased in the north-western region influenced by spring-water recharge dilution(mean annual discharge:3.41 m3/s).The differentiation of Rb2O and Cs2O was primarily controlled by clay mineral adsorption and hydrothermal input.The distribution of resource elements in Longmu Co salt lake is driven by the triple coupling of high-altitude extreme climate,plate tectonics,and hydrothermal activity;vertical differentiation is predominantly governed by physical water-body barriers,while horizontal differentiation is controlled by hydrologi-cal conditions and topographic variations.During 2009-2024,LiCl,KCl,and B2O3 concentrations declined by 21.87％,24.81％,and 28.83％,respectively.Glacier melting,spring runoff,and atmospheric precipitation recharge constitute the princi-pal factors influencing these concentration changes.The multi-element synergistic enrichment mechanism of this salt lake provides a scientific basis for the efficient exploitation and utilization of salt lake resources in Tibet,and holds significant strategic impor-tance for reducing China's external dependence on lithium resources.
The sustainable development of a river basin relies on the supply of ecosystem services from its aquatic ecosystems,mak-ing the health of riverine water ecosystems a critical safeguard.Taking the Weihe River Basin as the study area,this paper employs bibliometric analysis to review relevant domestic and international data and research findings from 2004 to 2024,and conducts an in-depth exploration of the water quality,habitat quality,biodiversity,and aquatic ecological health status in the basin.It summa-rizes the selection of indicators for aquatic ecological health assessment in the Weihe River Basin and clarifies the strengths,limita-tions,and applicable scopes of different assessment methods.On this basis,the study synthesizes the evolutionary trends of aquatic ecological health in the Weihe River Basin from 2004 to 2024.Overall,water quality in the Weihe River has improved.The diver-sity of plankton and periphytic algae declined during a certain period but has shown signs of recovery in recent years.Water pollu-tion and habitat degradation remain the primary factors threatening the aquatic ecological health of the basin,with the middle and lower reaches still facing severe pollution issues.Furthermore,by integrating ecological protection policies and regulations of the Weihe River Basin,this study evaluates the importance of aquatic ecological environment management for maintaining ecological health.Finally,in light of the"Hanjiang-to-Weihe Water Transfer Project",the potential impacts of increased water resources on the aquatic ecological health of the Weihe River Basin are discussed.
