Great Lakes Regions(GLRs)in China often confront landscape fragmentation,wetland degradation,and ecological resilience(ER)losses owing to extensive and intensive urbanization.In GLRs,however,the ER responses to urbani...Great Lakes Regions(GLRs)in China often confront landscape fragmentation,wetland degradation,and ecological resilience(ER)losses owing to extensive and intensive urbanization.In GLRs,however,the ER responses to urbanization remain unclear.This study explored the spatiotemporal evolution of ER and urbanization in five GLRs in China to analyze the ER dynamic patterns along center−lakeside−periphery gradient.The Spatial Durbin Model(SDM)and Panel Threshold Model(PTM)were combined to reveal the spillover and threshold effects of urbanization in five GLRs.The results indicate that the ER in five GLRs declined with a rate of 21%from 2000 to 2020.There was a clear“center-periphery”contraction trend with low ER areas primarily spreading to human activity-concentrated regions such as lakesides,riversides,and road networks.Driven by economic and land urbanization,the average urbanization level increased from 0.06 to 0.13,where lakesides,riversides,and road networks were key areas undergoing expansion.The urbanization showed a noticeable negative spatial spillover effect on ER.Away from central lakes,the negative impacts on ER exhibited a two-phase decrease with the threshold of 81 km.This study contributes to the understanding of human-environment interactions by examining the ecological resilience response process of GLRs under the impact of urbanization.Based on a multidimensional“center−lakeside−periphery”analytical model,this study provides a strategic framework for ecological construction in GLRs in China,promoting sustainable development and adaptive capacity in vulnerable areas.展开更多
Glacial lake outburst floods(GLOFs)are increasingly frequent under warming and degradation,exerting profound impacts on regional ecosystems,geomorphology,and human systems.Ice-dammed lakes account for nearly 70% of GL...Glacial lake outburst floods(GLOFs)are increasingly frequent under warming and degradation,exerting profound impacts on regional ecosystems,geomorphology,and human systems.Ice-dammed lakes account for nearly 70% of GLOFs worldwide,yet their dynamics remain poorly understood in remote regions such as the interior Tibetan Plateau.Here,we present the first systematic assessment of the evolution and drainage of ice-dammed lakes across the region using multi-source satellite imagery.Between 1973 and 2024,the number of ice-dammed lakes increased from 256 to 323,while the total area declined from 22.66±0.93 km^(2) to 20.43±1.6 km^(2) due to repeated drainage and diminished reservoir capacity.Newly formed lakes tended to shift toward higher elevations.A total of 775 previously unreported GLOFs were detected based on abrupt lake area loss.Bayesian regression reveals a sharp rise in GLOF frequency,from an average of 11 GLOFs per year during 1990-1994 to 42.6 GLOFs per year during 2020-2024.Meanwhile,GLOF timing has shifted earlier by 9.07±3.71 days,and pre-drainage lake areas declined by 0.02±0.01 km^(2) compared to 1990.These findings highlight the evolving behavior of ice-dammed lakes in response to climate change and glacial recession,with important implications for regional cryospheric research and disaster mitigation.展开更多
Lacustrine groundwater discharge(LGD)plays an important role in water resources management.Previous studies have focused on LGD process in a single lake,but the differences in LGD process within the same region have n...Lacustrine groundwater discharge(LGD)plays an important role in water resources management.Previous studies have focused on LGD process in a single lake,but the differences in LGD process within the same region have not been thoroughly investigated.In this study,multiple tracers(hydrochemistry,𝛿D,𝛿18O and 222Rn)were used to compare mechanisms of LGD in Daihai and Ulansuhai Lake in Inner Mongoli1,Northwest China.The hydrochemical types showed a trend from groundwater to lake water,indicating a hydraulic connection between them.In addition,the𝛿D and𝛿18O values of sediment pore water were between the groundwater and lake water,indicating the LGD processes.The radon mass balance model was used to estimate the average groundwater discharge rates of Daihai and Ulansuhai Lake,which were 2.79 mm/day and 3.02 mm/day,respectively.The total nitrogen(TN),total phosphorus(TP),and fluoride inputs associated with LGD in Daihai Lake accounted for 97.52%,96.59%,and 95.84%of the total inputs,respectively.In contrast,TN,TP and fluoride inputs in Ulansuhai Lake were 53.56%,40.98%,and 36.25%,respectively.This indicates that the pollutant inputs associated with LGD posed a potential threat to the ecological stability of Daihai and Ulansuhai Lake.By comparison,the differences of LGD process and associated pollutant flux were controlled by hydrogeological conditions,lakebed permeability and human activities.This study provides a reference for water resources management in Daihai and Ulansuhai Lake basins while improving the understanding of LGD in the Yellow River basin.展开更多
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 tes...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 plots.The 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 11.21–17.24m.Since 2017,the water level of Huayang Rivers has shown a decreasing trend of–0.02 m/a.Total phosphorus(TP)has become the primary pollutant.The 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,respectively.The effect of water level on TP was mainly observed during the low-water period.When 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%,respectively.During the dry season,wind and wave disturbances caused the release of endogenous phosphorus in Huayang Lakes.This led to drastic fluctuations in TP concentration,reducing the correlation between water level and TP.When external control is limited,the water level during the dry season should be maintained between 12.25 and 13.0 m.Additionally,it is necessary to accelerate the restoration of submerged macrophyte species(such as Hydrilla verticillata and Vallisneria natans)in the Huayang Rivers.展开更多
Biological nitrogen fixation(BNF)is a crucial process that provides bioavailable nitrogen and supports primary production in freshwater lake ecosystems.However,the characteristics of diazotrophic community and nitroge...Biological nitrogen fixation(BNF)is a crucial process that provides bioavailable nitrogen and supports primary production in freshwater lake ecosystems.However,the characteristics of diazotrophic community and nitrogenase activity in freshwater lake sediments remain poorly understood.Here,we investigated the diazotrophic communities and nitrogenase activities in the sediments of three large river-connected freshwater lakes in eastern China using 15N-isotope tracing and nifH sequencing.The sediments in these lakes contained diverse nitrogenase genes that were phylogenetically grouped into Clusters I and III.The diazotrophic communities in the sedimentswere dominated by stochastic processes in Hongze Lake and Taihu Lake,which had heterogeneous habitats and shallower water depths,while in Poyang Lake,which had deeper water and a shorter hydraulic retention time,the assembly of the diazotrophic community in the sediments was dominated by homogeneous selection processes.Temperature and water depth were also found the key environmental factors affecting the sediment diazotrophic communities.Sediment nitrogenase activities varied in the three lakes and within distinct regions of an individual lake,ranging from 0 to 14.58 nmol/(kg·hr).Nitrogenase activity was significantly correlated with ferric iron,total phosphorus,and organic matter contents.Our results suggested that freshwater lake sediment contain high diversity of nitrogen-fixing microorganisms with potential metabolic diversity,and the community assembly patterns and nitrogenase activities varied with the lake habitat.展开更多
Yunnan Province is located in southwestern China,at the core and intersection of the“Himalaya”,“Indo-Burma”and“Mountains of Southwest China”biodiversity hotspots.It is the most biodiverse province in China,actin...Yunnan Province is located in southwestern China,at the core and intersection of the“Himalaya”,“Indo-Burma”and“Mountains of Southwest China”biodiversity hotspots.It is the most biodiverse province in China,acting as a major center for the origin and diversification of numerous species,and of which lignicolous freshwater fungi are one of the rich bioresources.As a part of our ongoing studies on freshwater fungi in Yunnan Province China,we collected lignicolous freshwater ascomycetes from Yunnan plateau lakes,combining morphological characteristics and multi-gene phylogenetic analysis(including,ITS,LSU,SSU,tef1-α,tub2 and rpb2)to identify the species and reveal their phylogenetic placement.A total of 293 freshwater ascomycetes were collected,and through rigorous analysis,126 species were identified,spanning three classes,24 orders,39 families,and 70 genera.Most of these fungi belong to Dothideomycetes and Sordariomycetes,with a few of Eurotiomycetes.Based on morphological and phylogenetic analyses,we introduce two new genera,Neomoromyces and Rostraeuseptisporum,and 40 new species,viz.,Apiospora fuxianhuensis,A.lacustris,Atractospora hydei,Chaetopsina hydei,C.septata,Chloridium hydei,Ch.yunnanense,Dematiosporium hydei,D.muriforme,Dictyocheirospora yunnanensis,Distoseptispora dujuanhuensis,Di.hongheensis,Di.jingdongensis,Halobyssothecium hydei,Hongkongmyces hydei,Kirschsteiniothelia hydei,Mytilinidion hydei,Neomoromyces hydei,Obliquifusoideum hydei,Ophioceras yunnanense,Plagiascoma hydei,Pseudodactylaria lacustris,Pseudostanjehughesia hydei,Rostraeuseptisporum hydei,Sporidesmiella dujuanhuensis,S.guttulata,S.hongheensis,S.hydei,S.lacustris,Sporidesmium dianchiense,Sp.distoseptatum,Sp.dujuanhuense,Sp.hongheense,Sp.lacustris,Sp.kunmingense,Sp.yangzonghaiense,Sp.yilonghuense,Thysanorea hydei,Tetraploa verrucosa,Xylolentia hydei.Detailed morphological descriptions and illustrations of these species are provided,along with a discussion of their phylogenetic relationships and distinctive morphological characters.Furthermore,five new combinations are introduced,viz.,Pseudodactylaria flammulicornuta(≡Dodactylaria flammulicornuta),P.palmae(≡Do.palmae),P.tunicata(≡Do.tunicata),P.uliginicola(≡Do.uliginicola)and Pseudostanjehughesia verrucosa(≡Ceratosporium verrucosum).Based on molecular sequence data and morphological characteristics,Dictyocheirospora aquadulcis and Dic.lithocarpi have been synonymized with Dic.heptaspora,Dic.alangii synonymized with Dic.appendiculata;Dictyosporium lakefuxianense synonymized with Pseudodictyosporium wauense,Distoseptispora nanchangensis synonymized with Distoseptispora aquatica,Chaetopsina beijingensis synonymized with Ch.fulva.Ten new geographical records are reported in China and 10 species are first reported from freshwater habitats,and 6 species are newly reported both from China and from freshwater habitats.This study fills a gap in the research on fungal diversity in Yunnan Province,and improves our understanding of their ecological roles in freshwater ecosystems.Phylogenetic analysis provides a reliable molecular framework for the classification of lignicolous freshwater fungi,supporting the reassessment of fungal taxonomy and ensuring a more objective and evolutionarily natural classification of species.This work is dedicated to Professor Kevin D.Hyde on his 70th birthday,in recognition of his lifetime contributions to mycology and his extensive research and training of students.His wide-ranging work on freshwater fungi is highlighted in this paper.展开更多
The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowle...The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowledgement section of the original article has been revised to:Acknowledgments:This research was funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)and supported by the Chey Institute for Advanced Studies“International Scholarship Exchange Fellowship for the academic year of 2024-2025”,Republic of Korea,and the National University of Mongolia.We would like to acknowledge the National University of Mongolia and Soumik Das from the Center for the Study of Regional Development,Jawaharlal Nehru University,New Delhi-110067,for his valuable assistance in preparing the geological maps.展开更多
Microplastics have emerged as one of the most significant threats to the Earth's ecosystems due to their persistence,ability to carry high loads of contaminants,and biotoxicity.The Tibetan Plateau is a hotspot for...Microplastics have emerged as one of the most significant threats to the Earth's ecosystems due to their persistence,ability to carry high loads of contaminants,and biotoxicity.The Tibetan Plateau is a hotspot for global biodiversity conservation,but its ecosystem is fragile.This study systematically investigated the characteristics,distribution,sources,and ecological risk of microplastics in rivers and lakes across the Tibetan Plateau using the Laser Direct Infrared Imaging Spectroscopy(LDIR).The results indicated that the mean abundances of microplastics in water and sediments were 4250 items/m^(3)(n=50)and 3750 items/kg(n=44),respectively.Microplastics with small sizes(50-200μm),characterized by transparent and white fragments,were predominant.The most common polymers identified were polyamide(PA),polyurethane(PU),polyethylene terephthalate(PET),polyvinyl chloride(PVC),polypropylene(PP),and polyethylene(PE).Water sampling sites near urban/suburban effluent outfalls showed high levels of contamination.Microplastics in water are primarily derived from sewage effluent and atmospheric deposition.No single driver has been identified as the key factor influencing the spatial distribution of microplastics in water.The abundance of microplastics in sediments was significantly negatively correlated with the distance to the nearest city/town(p<0.01,R=-0.56)and significantly positively correlated with precipitation(p<0.01,R=0.60).Discarded or landfilled plastic waste is a major source of microplastics in sediments,which accumulate through transport by stormwater runoff caused by precipitation.Three ecological risk assessment models for microplastics were applied,and the high proportion of hazardous polymers such as PU,PVC,and PA was found to be responsible for the high ecological risk in the study area.This study provides an accurate and detailed exploration of the characteristics,sources,and spatial distribution of microplastic pollution by advanced automatic detection method in rivers and lakes on the Tibetan Plateau.展开更多
Lake ecosystems are extremely sensitive to nitrogen growth,which leads to water quality degradation and ecosystem health decline.Nitrogen depositions,as one of the main sources of nitrogen in water,are expected to cha...Lake ecosystems are extremely sensitive to nitrogen growth,which leads to water quality degradation and ecosystem health decline.Nitrogen depositions,as one of the main sources of nitrogen in water,are expected to change under future climate change scenarios.However,it remains not clear how nitrogen deposition to lakes respond to future meteorological conditions.In this study,a source-oriented version of Community Multiscale Air Quality(CMAQ)Model was used to estimate nitrogen deposition to 263 lakes in 2013 and under three RCP scenarios(4.5,6.0 and 8.5)in 2046.Annual total deposition of 58.2 Gg nitrogen was predicted for all lakes,with 23.3 Gg N by wet deposition and 34.9 Gg N by dry deposition.Nitrate and ammonium in aerosol phase are the major forms of wet deposition,while NH3 and HNO_(3)in gas phase are the major forms of dry deposition.Agriculture emissions contribute to 57%of wet deposition and 44%of dry deposition.Under future meteorological conditions,wet deposition is predicted to increase by 5.5%to 16.4%,while dry deposition would decrease by 0.3%to 13.0%.Changes in wind speed,temperature,relative humidity(RH),and precipitation rates are correlated with dry and wet deposition changes.The predicted changes in deposition to lakes driven by meteorological changes can lead to significant changes in aquatic chemistry and ecosystem functions.Apart from future emission scenarios,different climate scenarios should be considered in future ecosystem health evaluation in response to nitrogen deposition.展开更多
This study represents a pioneering effort to analyze the impact of avalanches descending into Morskie Oko from Marchwiczny Gully,the most active avalanche path around the lake.It focuses on catastrophic avalanches tha...This study represents a pioneering effort to analyze the impact of avalanches descending into Morskie Oko from Marchwiczny Gully,the most active avalanche path around the lake.It focuses on catastrophic avalanches that descended from the analyzed gully,as reported in the literature from the 1900s until now.However,only the data collected in recent years,our field studies,combined with modern LIDAR data and GIS-based modeling,allowed us to perform a detailed analysis.The GIS-based approach effectively uses spatial data to address snow avalanche modeling challenges.Although the study area lies within Tatra National Park,no official services carry out systematic avalanche monitoring or measurements.The impact of hazardous events,such as snow avalanches,on the most famous Polish mountain lake,Morskie Oko,has been poorly described in the literature and has yet to be discovered.Therefore,to analyze the selected avalanche parameters,we mainly used our ground and additional aerial photographs taken by local mountain services and related field measurements.Our analysis resulted in figurative estimates of the extent and volume of avalanche snow and its weight,both on the surface of the ice sheet and the part of the avalanche that did not reach the lake's shore and remained on the slope of Marchwiczny Gully.For example,the values for the mighty avalanche on February 3,2023,are 23,500 m~3 and 4,700 tons on the ice surface and 20,000 m~3 and 4,000 tons on the slope.It was determined that avalanches that descend onto the studied lake's surface result in its shallowing.This process occurs because of sedimentation of slope material carried by avalanches,especially during the final phase of ice cover melting.When openings appear in the solid ice cover in spring,floating ice can migrate,driven by wind pressure,and deposit avalanche material in various parts of the lake bottom.Thus,avalanches contributed to the gradual disappearance of the lake.展开更多
Global warming and human activities have reduced the concentrations of dissolved oxygen in the bottom water of lakes,resulting in increased anoxia in surface sediments.This increased anoxia likely alters carbon cyclin...Global warming and human activities have reduced the concentrations of dissolved oxygen in the bottom water of lakes,resulting in increased anoxia in surface sediments.This increased anoxia likely alters carbon cycling processes(e.g.,organic carbon mineralization)by altering microbial community composition and functions in lakes.However,it remains unclear how organic carbon mineralization responds to increased anoxia in surface sediments of lakes(particularly saline lakes).In this study,CO_(2)production in surface sediments of six lakes with different salinity(0.47-250 g/L)on the Tibetan Plateau was investigated using microcosm incubations under aerobic and anaerobic conditions,respectively,followed by geochemical and microbial analyses.The results showed that for the freshwater lake,CO_(2)production rates in anaerobic sediment microcosms were significantly(P<0.05)lower than their aerobic counterparts.In contrast,an opposite trend was observed for CO_(2)production in saline lakes.Furthermore,the CO_(2)production rates decreased significantly(P<0.05)under aerobic conditions,while it exhibited a hump-like relationship with increasing salinity under anaerobic conditions.Taken together,our results suggest that increased anoxia would enhance organic carbon mineralization in surface sediments of saline lakes and help understand carbon feedback on global changes in saline lakes.展开更多
The African continent habituated with volatile conflicts and protracted violence,be it intra-state or inter-state is also acquainted with multi-ethnic tensions breeding different militias.The trend,although not new,is...The African continent habituated with volatile conflicts and protracted violence,be it intra-state or inter-state is also acquainted with multi-ethnic tensions breeding different militias.The trend,although not new,is the expanding phenomenon of Jihadism and general terrorism.Some of these and other forms of conflicts summarize the geopolitics of Africa’s Great Lakes Region(AGLR).The bloodbath wherein the subregion engrosses itself is not solely guided by political considerations.Both endogenous and exogenous capitalist economic profit have stirred the system while ethnic politics and politics on ethnic leanings have amplified the scenario.The endeavors of both the international community and regional blocs appear deficient-a consequence of the frailty of the UN system and general multilateralism.Peace is possible for AGLR when humanity is placed over the tidal wave of capitalist profit,patriotism over toxic ethnicity and respect is accorded to international jurisprudence emblemed by the bona fide principle of pacta sunt Servanda,without neglecting the capacity of the youth and peace education.展开更多
Phosphorus(P)is the main limiting factor in eutrophication.Sediment P can be released decades after its accumulation.Lake restoration requires the reduction of internal sediment P loading.Although we tried to provide ...Phosphorus(P)is the main limiting factor in eutrophication.Sediment P can be released decades after its accumulation.Lake restoration requires the reduction of internal sediment P loading.Although we tried to provide a comprehensive summary of the state-of-the-art sediment P control technologies,our analyses in this review are focused on the mechanisms,control effects,and application conditions of different in-situ technologies including physical control,chemical control,ecological remediation,and combined control technology.The design principles,feasibility,operation parameters,and pros&cons of these technologies are analyzed and compared.More efforts are needed to improve in-situ sediment P control technologies so as to enhance the interaction between materials and plant communities and promote the adsorption and fixation of active P in sediments.The control materials for internal sediment P loading need to be further studied in terms of their functional properties,pre-evaluation of the P control effect,and engineering applications.展开更多
Particulate organic matter(POM)plays a crucial role in the organic composition of lakes;however,its characteristics remain poorly understood.This study aimed to characterize the structure and composition of POM in Lak...Particulate organic matter(POM)plays a crucial role in the organic composition of lakes;however,its characteristics remain poorly understood.This study aimed to characterize the structure and composition of POM in Lake Baiyangdian usingmany kinds of techniques and investigate the effects of different extracted forms of POM on water quality.The suspended particulatematter in the lake had complex compositions,with its components primarily derived from aquatic plants and their detritus.The organic matter content of the suspended particulatematterwas relatively high(organic carbon content 27.29–145.94 g/kg)for the sum of three extractable states(water-extracted organic matter[WEOM],humic acid,and fulvic acid)and one stable bound state(humin).Spatial distribution analysis revealed that the POM content in the water increased from west to east,which was consistent with the water flow pattern influenced by the Baiyangdian water diversion project.Fluorescence spectroscopy analysis of the WEOM showed three prominent peaks with excitation/emission wavelengths similar to those of dissolved organic matter peaks.These peaks were potentially initial products of POM conversion into dissolved organic matter.Furthermore,the intensity of the WEOM fluorescence peak(total fluorescence peak intensity)was negatively correlated with the inorganic nitrogen concentration in water(p<0.01),while the intensity of the HA fluorescence peak showed a positive correlation with the inorganic nitrogen concentration(p<0.01).This suggested that exogenous organic matter inputs led to the diffusion of alkaline dissolved nitrogen from sediment intowater,while degradation processes of aquatic plant debris contributed to the decrease in inorganic nitrogen concentrations in the water column.These findings enhance our understanding of POM characteristics in shallow lakes and the role of POM in shallow lake ecosystems.展开更多
The sparsity of ground gauges poses a significant challenge for evaluating and merging satellite-based and reanalysis-based precipitation datasets in lake regions.While the standard triple collocation(TC)method offers...The sparsity of ground gauges poses a significant challenge for evaluating and merging satellite-based and reanalysis-based precipitation datasets in lake regions.While the standard triple collocation(TC)method offers a solution without access to ground-based observations,it fails to address rain/no-rain classification and its suitability for assessing and merging lake precipitation has not been explored.This study combines categorical triple collocation(CTC)with standard TC to create an integrated framework(CTC-TC)tailored to evaluate and merge global gridded precipitation products(GPPs).We assess the efficacy of CTC-TC using six GPPs(ERA5-Land,SM2 RAIN-ASCAT,IMERG-Early,IMERG-Late,GSMaPMVK,and PERSIANN-CCS)across the five largest freshwater lakes in China.CTC-TC effectively captures the spatial patterns of metrics for all GPPs,and precisely estimates the correlation coefficient and root mean square error for satellite-based datasets apart from SM2 RAIN-ASCAT,but overestimates the classification accuracy indicator V for all GPPs.Regarding multi-source fusion,CTC-TC leverages the strengths of individual products of triplets,resulting in significant improvements in the critical success index(CSI)by over 11.9%and the modified Kling-Gupta efficiency(KGE')by more than 13.3%.Compared to baseline models,including standard TC,simple model averaging,one outlier removal,and Bayesian model averaging,CTC-TC achieves gains in CSI and KGE'of no less than 24.7%and 3.6%,respectively.In conclusion,the CTC-TC framework offers a thorough evaluation and efficient fusion of GPPs,addressing both categorical and continuous accuracy in data-scarce regions such as lakes.展开更多
Jianghan Lakes lie in the middle reaches of the Yangtze River. The evolution of the lakes during Holocene can be divided into three periods. Since Ming Dynasty, owing to natural factors and human activity, the lakes h...Jianghan Lakes lie in the middle reaches of the Yangtze River. The evolution of the lakes during Holocene can be divided into three periods. Since Ming Dynasty, owing to natural factors and human activity, the lakes have accelerated the shrinking process. This has resulted in a series of rural and urban environmental problems, such as the disasters of flooding, inundation, and water\|logging; declination of aquatic resources; increase of diseases; swamping of lake districts; and deterioration of urban environment (taking Wuhan City into consideration). In order to realize sustainable development in this area, several corresponding countermeasures should be taken.展开更多
Conditions of the water environment in the region of the Zhaling and Eling lakes, which are located in the frozen earth zone on the Qingzang plateau, are unique. The equilibrium of the water quantity of the two lakes...Conditions of the water environment in the region of the Zhaling and Eling lakes, which are located in the frozen earth zone on the Qingzang plateau, are unique. The equilibrium of the water quantity of the two lakes is maladjustment under the condition of a dry and cold climate in which evaporation is greater than precipitation. The Zhaling and Eling lakes have been atrophying, leaving three lake terraces and star studded lagoons around the two lakes since Holocene. When these lagoons were separated from the original lakes, they became cut lake basins, and were transformed from fresh water lakes into salt water lakes, salt lakes or salt playas owing to strong evaporation. This kind of evolutionary process will continue in the future.展开更多
The shallow lake wetlands in the middle and lower Yangtze River floodplain are important wintering and stopover habitats for migratory waterbirds on the East Asia-Australia Flyway.With increasing fishery practices in ...The shallow lake wetlands in the middle and lower Yangtze River floodplain are important wintering and stopover habitats for migratory waterbirds on the East Asia-Australia Flyway.With increasing fishery practices in recent years,however,the wetlands have deteriorated significantly and now threaten wintering waterbirds.To gain insight into the influence of deteriorating wetlands on waterbirds,we conducted a survey of wintering waterbird species,population size,and distribution across 11 belt transects in Caizi Lake and Shengjin Lake,two shallow lakes along the Yangtze River in Anhui Province from November 2007-April 2008 and from November 2008-April 2009,respectively.The impacts of different fishery patterns on the distribution of waterbirds were also analyzed.A total of 43 waterbirds species belong to 7 orders of 12 families were counted during the surveys,of which 38 were found in Caizi Lake with a density of 8.2 ind./hm2,and 42 in Shengjin Lake with a density of 3.5 ind./hm2.Geese（Anser cygnoides）,bean geese（Anser fabalis）,tundra swan（Cygnus columbianus）,and dunlin（Calidris alpina） were the dominant species in the two shallow lakes.Species number and individual assemble reached maximum at the end of December and in early January of the following year,without coincidence of the largest flock for different ecological groups.Based on waterbird diversity across the 11 belt transects and the fishery patterns,habitats could be divided into three groups.Gruiformes,Anseriformes and Charadriiformes had relatively higher densities in the natural fishery zones and lower densities in the cage fishery zones;whereas,the density of Ardeidae showed little change across all lake zones.It is important to develop sustainable fishery patterns in shallow lakes along the middle and lower Yangtze River floodplain to better protect resources of wintering waterbirds.展开更多
基金supported by the National Natural Science Foundation of China(Grants No.42301226,42271209 and 42471199)the Fundamental Research Funds for the Central Universities(Grant No.2024CDJXY014)+2 种基金the Natural Science Foundation of Jiangxi Province(Grant No.20242BAB25170)Special Funds for Water Resources in Jiangxi Province(Science and Technology Projects)(Grant No.202425YBKT16)the Young Talent Cultivation and Innovation Fund Project of Nanchang University(Grant No.XX202506030028).
文摘Great Lakes Regions(GLRs)in China often confront landscape fragmentation,wetland degradation,and ecological resilience(ER)losses owing to extensive and intensive urbanization.In GLRs,however,the ER responses to urbanization remain unclear.This study explored the spatiotemporal evolution of ER and urbanization in five GLRs in China to analyze the ER dynamic patterns along center−lakeside−periphery gradient.The Spatial Durbin Model(SDM)and Panel Threshold Model(PTM)were combined to reveal the spillover and threshold effects of urbanization in five GLRs.The results indicate that the ER in five GLRs declined with a rate of 21%from 2000 to 2020.There was a clear“center-periphery”contraction trend with low ER areas primarily spreading to human activity-concentrated regions such as lakesides,riversides,and road networks.Driven by economic and land urbanization,the average urbanization level increased from 0.06 to 0.13,where lakesides,riversides,and road networks were key areas undergoing expansion.The urbanization showed a noticeable negative spatial spillover effect on ER.Away from central lakes,the negative impacts on ER exhibited a two-phase decrease with the threshold of 81 km.This study contributes to the understanding of human-environment interactions by examining the ecological resilience response process of GLRs under the impact of urbanization.Based on a multidimensional“center−lakeside−periphery”analytical model,this study provides a strategic framework for ecological construction in GLRs in China,promoting sustainable development and adaptive capacity in vulnerable areas.
基金supported by the National Natural Science Foundation of China(Grant Nos.424B2002,U23A2011)National Key R&D Program of China(Grant No.2024YFF0808603)Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(Grant Nos.2024QZKK0500,2024QZKK0400).
文摘Glacial lake outburst floods(GLOFs)are increasingly frequent under warming and degradation,exerting profound impacts on regional ecosystems,geomorphology,and human systems.Ice-dammed lakes account for nearly 70% of GLOFs worldwide,yet their dynamics remain poorly understood in remote regions such as the interior Tibetan Plateau.Here,we present the first systematic assessment of the evolution and drainage of ice-dammed lakes across the region using multi-source satellite imagery.Between 1973 and 2024,the number of ice-dammed lakes increased from 256 to 323,while the total area declined from 22.66±0.93 km^(2) to 20.43±1.6 km^(2) due to repeated drainage and diminished reservoir capacity.Newly formed lakes tended to shift toward higher elevations.A total of 775 previously unreported GLOFs were detected based on abrupt lake area loss.Bayesian regression reveals a sharp rise in GLOF frequency,from an average of 11 GLOFs per year during 1990-1994 to 42.6 GLOFs per year during 2020-2024.Meanwhile,GLOF timing has shifted earlier by 9.07±3.71 days,and pre-drainage lake areas declined by 0.02±0.01 km^(2) compared to 1990.These findings highlight the evolving behavior of ice-dammed lakes in response to climate change and glacial recession,with important implications for regional cryospheric research and disaster mitigation.
基金supported by the Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2023QN04011)the National Natural Science Foundation of China(Nos.42307092 and 52279067)+1 种基金Ordos Science and Technology Major Project(No.ZD20232303)Project of Key Laboratory of River and Lake in Inner Mongolia Autonomous Region(No.2022QZBZ0003).
文摘Lacustrine groundwater discharge(LGD)plays an important role in water resources management.Previous studies have focused on LGD process in a single lake,but the differences in LGD process within the same region have not been thoroughly investigated.In this study,multiple tracers(hydrochemistry,𝛿D,𝛿18O and 222Rn)were used to compare mechanisms of LGD in Daihai and Ulansuhai Lake in Inner Mongoli1,Northwest China.The hydrochemical types showed a trend from groundwater to lake water,indicating a hydraulic connection between them.In addition,the𝛿D and𝛿18O values of sediment pore water were between the groundwater and lake water,indicating the LGD processes.The radon mass balance model was used to estimate the average groundwater discharge rates of Daihai and Ulansuhai Lake,which were 2.79 mm/day and 3.02 mm/day,respectively.The total nitrogen(TN),total phosphorus(TP),and fluoride inputs associated with LGD in Daihai Lake accounted for 97.52%,96.59%,and 95.84%of the total inputs,respectively.In contrast,TN,TP and fluoride inputs in Ulansuhai Lake were 53.56%,40.98%,and 36.25%,respectively.This indicates that the pollutant inputs associated with LGD posed a potential threat to the ecological stability of Daihai and Ulansuhai Lake.By comparison,the differences of LGD process and associated pollutant flux were controlled by hydrogeological conditions,lakebed permeability and human activities.This study provides a reference for water resources management in Daihai and Ulansuhai Lake basins while improving the understanding of LGD in the Yellow River basin.
基金The Joint Research Project for Yangtze River Conservation,No.2022-LHYJ-02-0504-05-08Anhui Provincial Scientific Research Project for Universities,China No.2023AH050508。
文摘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 plots.The 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 11.21–17.24m.Since 2017,the water level of Huayang Rivers has shown a decreasing trend of–0.02 m/a.Total phosphorus(TP)has become the primary pollutant.The 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,respectively.The effect of water level on TP was mainly observed during the low-water period.When 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%,respectively.During the dry season,wind and wave disturbances caused the release of endogenous phosphorus in Huayang Lakes.This led to drastic fluctuations in TP concentration,reducing the correlation between water level and TP.When external control is limited,the water level during the dry season should be maintained between 12.25 and 13.0 m.Additionally,it is necessary to accelerate the restoration of submerged macrophyte species(such as Hydrilla verticillata and Vallisneria natans)in the Huayang Rivers.
基金supported by the National Natural Science Foundation of China(Nos.51839011,42203079,and U2240208)the Carbon Peak/Neutralization Technology Innovation Project of Jiangsu Province,China(No.BK20220043)the Excellent Postdoctoral Project of Jiangsu Province,China(No.2022ZB452).
文摘Biological nitrogen fixation(BNF)is a crucial process that provides bioavailable nitrogen and supports primary production in freshwater lake ecosystems.However,the characteristics of diazotrophic community and nitrogenase activity in freshwater lake sediments remain poorly understood.Here,we investigated the diazotrophic communities and nitrogenase activities in the sediments of three large river-connected freshwater lakes in eastern China using 15N-isotope tracing and nifH sequencing.The sediments in these lakes contained diverse nitrogenase genes that were phylogenetically grouped into Clusters I and III.The diazotrophic communities in the sedimentswere dominated by stochastic processes in Hongze Lake and Taihu Lake,which had heterogeneous habitats and shallower water depths,while in Poyang Lake,which had deeper water and a shorter hydraulic retention time,the assembly of the diazotrophic community in the sediments was dominated by homogeneous selection processes.Temperature and water depth were also found the key environmental factors affecting the sediment diazotrophic communities.Sediment nitrogenase activities varied in the three lakes and within distinct regions of an individual lake,ranging from 0 to 14.58 nmol/(kg·hr).Nitrogenase activity was significantly correlated with ferric iron,total phosphorus,and organic matter contents.Our results suggested that freshwater lake sediment contain high diversity of nitrogen-fixing microorganisms with potential metabolic diversity,and the community assembly patterns and nitrogenase activities varied with the lake habitat.
基金the National Natural Science Foundation of China(Project ID:32060005,U2002203)National Science and Technology Fundamental Resources Investigation Program of China(2021FY100900)+4 种基金the Yunnan Fundamental Research Project(202201AW070001)High-Level Talents Program of Yunnan Province(YNQR-QNRC-2020-113)Foundation of Yunnan Province Science and Technology Department(202305AM070003)Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2024QZKK02010303)Distinguished Scientist Fellowship Programme(DSFP)of King Saud University.
文摘Yunnan Province is located in southwestern China,at the core and intersection of the“Himalaya”,“Indo-Burma”and“Mountains of Southwest China”biodiversity hotspots.It is the most biodiverse province in China,acting as a major center for the origin and diversification of numerous species,and of which lignicolous freshwater fungi are one of the rich bioresources.As a part of our ongoing studies on freshwater fungi in Yunnan Province China,we collected lignicolous freshwater ascomycetes from Yunnan plateau lakes,combining morphological characteristics and multi-gene phylogenetic analysis(including,ITS,LSU,SSU,tef1-α,tub2 and rpb2)to identify the species and reveal their phylogenetic placement.A total of 293 freshwater ascomycetes were collected,and through rigorous analysis,126 species were identified,spanning three classes,24 orders,39 families,and 70 genera.Most of these fungi belong to Dothideomycetes and Sordariomycetes,with a few of Eurotiomycetes.Based on morphological and phylogenetic analyses,we introduce two new genera,Neomoromyces and Rostraeuseptisporum,and 40 new species,viz.,Apiospora fuxianhuensis,A.lacustris,Atractospora hydei,Chaetopsina hydei,C.septata,Chloridium hydei,Ch.yunnanense,Dematiosporium hydei,D.muriforme,Dictyocheirospora yunnanensis,Distoseptispora dujuanhuensis,Di.hongheensis,Di.jingdongensis,Halobyssothecium hydei,Hongkongmyces hydei,Kirschsteiniothelia hydei,Mytilinidion hydei,Neomoromyces hydei,Obliquifusoideum hydei,Ophioceras yunnanense,Plagiascoma hydei,Pseudodactylaria lacustris,Pseudostanjehughesia hydei,Rostraeuseptisporum hydei,Sporidesmiella dujuanhuensis,S.guttulata,S.hongheensis,S.hydei,S.lacustris,Sporidesmium dianchiense,Sp.distoseptatum,Sp.dujuanhuense,Sp.hongheense,Sp.lacustris,Sp.kunmingense,Sp.yangzonghaiense,Sp.yilonghuense,Thysanorea hydei,Tetraploa verrucosa,Xylolentia hydei.Detailed morphological descriptions and illustrations of these species are provided,along with a discussion of their phylogenetic relationships and distinctive morphological characters.Furthermore,five new combinations are introduced,viz.,Pseudodactylaria flammulicornuta(≡Dodactylaria flammulicornuta),P.palmae(≡Do.palmae),P.tunicata(≡Do.tunicata),P.uliginicola(≡Do.uliginicola)and Pseudostanjehughesia verrucosa(≡Ceratosporium verrucosum).Based on molecular sequence data and morphological characteristics,Dictyocheirospora aquadulcis and Dic.lithocarpi have been synonymized with Dic.heptaspora,Dic.alangii synonymized with Dic.appendiculata;Dictyosporium lakefuxianense synonymized with Pseudodictyosporium wauense,Distoseptispora nanchangensis synonymized with Distoseptispora aquatica,Chaetopsina beijingensis synonymized with Ch.fulva.Ten new geographical records are reported in China and 10 species are first reported from freshwater habitats,and 6 species are newly reported both from China and from freshwater habitats.This study fills a gap in the research on fungal diversity in Yunnan Province,and improves our understanding of their ecological roles in freshwater ecosystems.Phylogenetic analysis provides a reliable molecular framework for the classification of lignicolous freshwater fungi,supporting the reassessment of fungal taxonomy and ensuring a more objective and evolutionarily natural classification of species.This work is dedicated to Professor Kevin D.Hyde on his 70th birthday,in recognition of his lifetime contributions to mycology and his extensive research and training of students.His wide-ranging work on freshwater fungi is highlighted in this paper.
文摘The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowledgement section of the original article has been revised to:Acknowledgments:This research was funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)and supported by the Chey Institute for Advanced Studies“International Scholarship Exchange Fellowship for the academic year of 2024-2025”,Republic of Korea,and the National University of Mongolia.We would like to acknowledge the National University of Mongolia and Soumik Das from the Center for the Study of Regional Development,Jawaharlal Nehru University,New Delhi-110067,for his valuable assistance in preparing the geological maps.
基金supported by the National Natural Science Foundation of China(42322105)Outstanding Youth Fund of Gansu Province(23JRRA612)Postdoctoral Fellowship Program of CPSF(GZC20232952).
文摘Microplastics have emerged as one of the most significant threats to the Earth's ecosystems due to their persistence,ability to carry high loads of contaminants,and biotoxicity.The Tibetan Plateau is a hotspot for global biodiversity conservation,but its ecosystem is fragile.This study systematically investigated the characteristics,distribution,sources,and ecological risk of microplastics in rivers and lakes across the Tibetan Plateau using the Laser Direct Infrared Imaging Spectroscopy(LDIR).The results indicated that the mean abundances of microplastics in water and sediments were 4250 items/m^(3)(n=50)and 3750 items/kg(n=44),respectively.Microplastics with small sizes(50-200μm),characterized by transparent and white fragments,were predominant.The most common polymers identified were polyamide(PA),polyurethane(PU),polyethylene terephthalate(PET),polyvinyl chloride(PVC),polypropylene(PP),and polyethylene(PE).Water sampling sites near urban/suburban effluent outfalls showed high levels of contamination.Microplastics in water are primarily derived from sewage effluent and atmospheric deposition.No single driver has been identified as the key factor influencing the spatial distribution of microplastics in water.The abundance of microplastics in sediments was significantly negatively correlated with the distance to the nearest city/town(p<0.01,R=-0.56)and significantly positively correlated with precipitation(p<0.01,R=0.60).Discarded or landfilled plastic waste is a major source of microplastics in sediments,which accumulate through transport by stormwater runoff caused by precipitation.Three ecological risk assessment models for microplastics were applied,and the high proportion of hazardous polymers such as PU,PVC,and PA was found to be responsible for the high ecological risk in the study area.This study provides an accurate and detailed exploration of the characteristics,sources,and spatial distribution of microplastic pollution by advanced automatic detection method in rivers and lakes on the Tibetan Plateau.
基金supported by the project of Guangzhou Institute of Geochemistry the Chinese Academy of Sciences(No.51TGC202209)Shenzhen Science and Technology Plan(Nos.KJYY20180206180737010 and 6020320003K)the National Key R&D Program of China(No.2022YFC3701105).
文摘Lake ecosystems are extremely sensitive to nitrogen growth,which leads to water quality degradation and ecosystem health decline.Nitrogen depositions,as one of the main sources of nitrogen in water,are expected to change under future climate change scenarios.However,it remains not clear how nitrogen deposition to lakes respond to future meteorological conditions.In this study,a source-oriented version of Community Multiscale Air Quality(CMAQ)Model was used to estimate nitrogen deposition to 263 lakes in 2013 and under three RCP scenarios(4.5,6.0 and 8.5)in 2046.Annual total deposition of 58.2 Gg nitrogen was predicted for all lakes,with 23.3 Gg N by wet deposition and 34.9 Gg N by dry deposition.Nitrate and ammonium in aerosol phase are the major forms of wet deposition,while NH3 and HNO_(3)in gas phase are the major forms of dry deposition.Agriculture emissions contribute to 57%of wet deposition and 44%of dry deposition.Under future meteorological conditions,wet deposition is predicted to increase by 5.5%to 16.4%,while dry deposition would decrease by 0.3%to 13.0%.Changes in wind speed,temperature,relative humidity(RH),and precipitation rates are correlated with dry and wet deposition changes.The predicted changes in deposition to lakes driven by meteorological changes can lead to significant changes in aquatic chemistry and ecosystem functions.Apart from future emission scenarios,different climate scenarios should be considered in future ecosystem health evaluation in response to nitrogen deposition.
文摘This study represents a pioneering effort to analyze the impact of avalanches descending into Morskie Oko from Marchwiczny Gully,the most active avalanche path around the lake.It focuses on catastrophic avalanches that descended from the analyzed gully,as reported in the literature from the 1900s until now.However,only the data collected in recent years,our field studies,combined with modern LIDAR data and GIS-based modeling,allowed us to perform a detailed analysis.The GIS-based approach effectively uses spatial data to address snow avalanche modeling challenges.Although the study area lies within Tatra National Park,no official services carry out systematic avalanche monitoring or measurements.The impact of hazardous events,such as snow avalanches,on the most famous Polish mountain lake,Morskie Oko,has been poorly described in the literature and has yet to be discovered.Therefore,to analyze the selected avalanche parameters,we mainly used our ground and additional aerial photographs taken by local mountain services and related field measurements.Our analysis resulted in figurative estimates of the extent and volume of avalanche snow and its weight,both on the surface of the ice sheet and the part of the avalanche that did not reach the lake's shore and remained on the slope of Marchwiczny Gully.For example,the values for the mighty avalanche on February 3,2023,are 23,500 m~3 and 4,700 tons on the ice surface and 20,000 m~3 and 4,000 tons on the slope.It was determined that avalanches that descend onto the studied lake's surface result in its shallowing.This process occurs because of sedimentation of slope material carried by avalanches,especially during the final phase of ice cover melting.When openings appear in the solid ice cover in spring,floating ice can migrate,driven by wind pressure,and deposit avalanche material in various parts of the lake bottom.Thus,avalanches contributed to the gradual disappearance of the lake.
基金supported by grants from the National Natural Science Foundation of China(Nos.42272356,92251304)the Kunlun Talented People of Qinghai Province,High-End Innovation and Entrepreneurship talents(Grant to Jiang Hongchen)+4 种基金the Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes(the Science and Technology Plan Project of Qinghai Province Incentive Fund,No.2024-KFKTA08)the 111 Program(the State Administration of Foreign Experts Affairs&the Ministry of Education of China,No.B18049)the Second Tibetan Plateau Scientific Expedition and Research Program(Polymenakou et al.)(No.2019QZKK0805)the Science and Technology Plan Project of Qinghai Province(No.2022-ZJ-Y08)Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)。
文摘Global warming and human activities have reduced the concentrations of dissolved oxygen in the bottom water of lakes,resulting in increased anoxia in surface sediments.This increased anoxia likely alters carbon cycling processes(e.g.,organic carbon mineralization)by altering microbial community composition and functions in lakes.However,it remains unclear how organic carbon mineralization responds to increased anoxia in surface sediments of lakes(particularly saline lakes).In this study,CO_(2)production in surface sediments of six lakes with different salinity(0.47-250 g/L)on the Tibetan Plateau was investigated using microcosm incubations under aerobic and anaerobic conditions,respectively,followed by geochemical and microbial analyses.The results showed that for the freshwater lake,CO_(2)production rates in anaerobic sediment microcosms were significantly(P<0.05)lower than their aerobic counterparts.In contrast,an opposite trend was observed for CO_(2)production in saline lakes.Furthermore,the CO_(2)production rates decreased significantly(P<0.05)under aerobic conditions,while it exhibited a hump-like relationship with increasing salinity under anaerobic conditions.Taken together,our results suggest that increased anoxia would enhance organic carbon mineralization in surface sediments of saline lakes and help understand carbon feedback on global changes in saline lakes.
文摘The African continent habituated with volatile conflicts and protracted violence,be it intra-state or inter-state is also acquainted with multi-ethnic tensions breeding different militias.The trend,although not new,is the expanding phenomenon of Jihadism and general terrorism.Some of these and other forms of conflicts summarize the geopolitics of Africa’s Great Lakes Region(AGLR).The bloodbath wherein the subregion engrosses itself is not solely guided by political considerations.Both endogenous and exogenous capitalist economic profit have stirred the system while ethnic politics and politics on ethnic leanings have amplified the scenario.The endeavors of both the international community and regional blocs appear deficient-a consequence of the frailty of the UN system and general multilateralism.Peace is possible for AGLR when humanity is placed over the tidal wave of capitalist profit,patriotism over toxic ethnicity and respect is accorded to international jurisprudence emblemed by the bona fide principle of pacta sunt Servanda,without neglecting the capacity of the youth and peace education.
基金financially supported by the National Natural Science Foundation of China(Nos.32201384,31830013,U20A2010)。
文摘Phosphorus(P)is the main limiting factor in eutrophication.Sediment P can be released decades after its accumulation.Lake restoration requires the reduction of internal sediment P loading.Although we tried to provide a comprehensive summary of the state-of-the-art sediment P control technologies,our analyses in this review are focused on the mechanisms,control effects,and application conditions of different in-situ technologies including physical control,chemical control,ecological remediation,and combined control technology.The design principles,feasibility,operation parameters,and pros&cons of these technologies are analyzed and compared.More efforts are needed to improve in-situ sediment P control technologies so as to enhance the interaction between materials and plant communities and promote the adsorption and fixation of active P in sediments.The control materials for internal sediment P loading need to be further studied in terms of their functional properties,pre-evaluation of the P control effect,and engineering applications.
基金supported by the National Key Research and Development Program of China(No.2022YFC3204003)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Wenqiang Zhang,No.2018058).
文摘Particulate organic matter(POM)plays a crucial role in the organic composition of lakes;however,its characteristics remain poorly understood.This study aimed to characterize the structure and composition of POM in Lake Baiyangdian usingmany kinds of techniques and investigate the effects of different extracted forms of POM on water quality.The suspended particulatematter in the lake had complex compositions,with its components primarily derived from aquatic plants and their detritus.The organic matter content of the suspended particulatematterwas relatively high(organic carbon content 27.29–145.94 g/kg)for the sum of three extractable states(water-extracted organic matter[WEOM],humic acid,and fulvic acid)and one stable bound state(humin).Spatial distribution analysis revealed that the POM content in the water increased from west to east,which was consistent with the water flow pattern influenced by the Baiyangdian water diversion project.Fluorescence spectroscopy analysis of the WEOM showed three prominent peaks with excitation/emission wavelengths similar to those of dissolved organic matter peaks.These peaks were potentially initial products of POM conversion into dissolved organic matter.Furthermore,the intensity of the WEOM fluorescence peak(total fluorescence peak intensity)was negatively correlated with the inorganic nitrogen concentration in water(p<0.01),while the intensity of the HA fluorescence peak showed a positive correlation with the inorganic nitrogen concentration(p<0.01).This suggested that exogenous organic matter inputs led to the diffusion of alkaline dissolved nitrogen from sediment intowater,while degradation processes of aquatic plant debris contributed to the decrease in inorganic nitrogen concentrations in the water column.These findings enhance our understanding of POM characteristics in shallow lakes and the role of POM in shallow lake ecosystems.
基金National Key R&D Program of China,No.2022YFC3202802National Natural Science Foundation of China,No.52009081,No.52121006,No.52279071Special Funded Project for Basic Scientific Research Operation Expenses of the Central Public Welfare Scientific Research Institutes of China,No.Y524017。
文摘The sparsity of ground gauges poses a significant challenge for evaluating and merging satellite-based and reanalysis-based precipitation datasets in lake regions.While the standard triple collocation(TC)method offers a solution without access to ground-based observations,it fails to address rain/no-rain classification and its suitability for assessing and merging lake precipitation has not been explored.This study combines categorical triple collocation(CTC)with standard TC to create an integrated framework(CTC-TC)tailored to evaluate and merge global gridded precipitation products(GPPs).We assess the efficacy of CTC-TC using six GPPs(ERA5-Land,SM2 RAIN-ASCAT,IMERG-Early,IMERG-Late,GSMaPMVK,and PERSIANN-CCS)across the five largest freshwater lakes in China.CTC-TC effectively captures the spatial patterns of metrics for all GPPs,and precisely estimates the correlation coefficient and root mean square error for satellite-based datasets apart from SM2 RAIN-ASCAT,but overestimates the classification accuracy indicator V for all GPPs.Regarding multi-source fusion,CTC-TC leverages the strengths of individual products of triplets,resulting in significant improvements in the critical success index(CSI)by over 11.9%and the modified Kling-Gupta efficiency(KGE')by more than 13.3%.Compared to baseline models,including standard TC,simple model averaging,one outlier removal,and Bayesian model averaging,CTC-TC achieves gains in CSI and KGE'of no less than 24.7%and 3.6%,respectively.In conclusion,the CTC-TC framework offers a thorough evaluation and efficient fusion of GPPs,addressing both categorical and continuous accuracy in data-scarce regions such as lakes.
文摘Jianghan Lakes lie in the middle reaches of the Yangtze River. The evolution of the lakes during Holocene can be divided into three periods. Since Ming Dynasty, owing to natural factors and human activity, the lakes have accelerated the shrinking process. This has resulted in a series of rural and urban environmental problems, such as the disasters of flooding, inundation, and water\|logging; declination of aquatic resources; increase of diseases; swamping of lake districts; and deterioration of urban environment (taking Wuhan City into consideration). In order to realize sustainable development in this area, several corresponding countermeasures should be taken.
文摘Conditions of the water environment in the region of the Zhaling and Eling lakes, which are located in the frozen earth zone on the Qingzang plateau, are unique. The equilibrium of the water quantity of the two lakes is maladjustment under the condition of a dry and cold climate in which evaporation is greater than precipitation. The Zhaling and Eling lakes have been atrophying, leaving three lake terraces and star studded lagoons around the two lakes since Holocene. When these lagoons were separated from the original lakes, they became cut lake basins, and were transformed from fresh water lakes into salt water lakes, salt lakes or salt playas owing to strong evaporation. This kind of evolutionary process will continue in the future.
基金Supported partly by the National Natural Science Foundation of China(30870317)EU-China Biodiversity Programme(00056783)Anhui Academic and Technical Leader Fund
文摘The shallow lake wetlands in the middle and lower Yangtze River floodplain are important wintering and stopover habitats for migratory waterbirds on the East Asia-Australia Flyway.With increasing fishery practices in recent years,however,the wetlands have deteriorated significantly and now threaten wintering waterbirds.To gain insight into the influence of deteriorating wetlands on waterbirds,we conducted a survey of wintering waterbird species,population size,and distribution across 11 belt transects in Caizi Lake and Shengjin Lake,two shallow lakes along the Yangtze River in Anhui Province from November 2007-April 2008 and from November 2008-April 2009,respectively.The impacts of different fishery patterns on the distribution of waterbirds were also analyzed.A total of 43 waterbirds species belong to 7 orders of 12 families were counted during the surveys,of which 38 were found in Caizi Lake with a density of 8.2 ind./hm2,and 42 in Shengjin Lake with a density of 3.5 ind./hm2.Geese（Anser cygnoides）,bean geese（Anser fabalis）,tundra swan（Cygnus columbianus）,and dunlin（Calidris alpina） were the dominant species in the two shallow lakes.Species number and individual assemble reached maximum at the end of December and in early January of the following year,without coincidence of the largest flock for different ecological groups.Based on waterbird diversity across the 11 belt transects and the fishery patterns,habitats could be divided into three groups.Gruiformes,Anseriformes and Charadriiformes had relatively higher densities in the natural fishery zones and lower densities in the cage fishery zones;whereas,the density of Ardeidae showed little change across all lake zones.It is important to develop sustainable fishery patterns in shallow lakes along the middle and lower Yangtze River floodplain to better protect resources of wintering waterbirds.
