Over the past decades,a number of water sciences and management programs have been developed to better understand and manage the water cycles at multiple temporal and spatial scales for various purposes,such as ecohyd...Over the past decades,a number of water sciences and management programs have been developed to better understand and manage the water cycles at multiple temporal and spatial scales for various purposes,such as ecohydrology,global hydrology,sociohydrology,supply management,demand management,and integrated water resources management(IWRM).At the same time,rapid advancements have also been taking place in tracing,mapping,remote sensing,machine learning,and modelling technologies in hydrological research.Despite those programs and advancements,a water crisis is intensifying globally.The missing link is effective interactions between the hydrological research and water resource management to support implementation of the UN Sustainable Development Goals(SDGs)at multiple spatial scales.Since the watershed is the natural unit for water resources management,watershed science offers the potential to bridge this missing link.This study first reviews the advances in hydrological research and water resources management,and then discusses issues and challenges facing the global water community.Subsequently,it describes the core components of watershed science:(1)hydrological analysis;(2)water-operation policies;(3)governance;(4)management and feedback.The framework takes into account water availability,water uses,and water quality;explicitly focuses on the storage,fluxes,and quality of the hydrological cycle;defines appropriate local water resource thresholds through incorporating the planetary boundary framework;and identifies specific actionable measures for water resources management.It provides a complementary approach to the existing water management programs in addressing the current global water crisis and achieving the UN SDGs.展开更多
The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is av...The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is available on how the rainfall affect nutrient dynamics in subtropicalmontane rivers with complex land use.This study conducted high-frequency monitoring to study the effects of rainfall on nutrients dynamics in an agricultural river draining to Lake Qiandaohu,a montane reservoir of southeast China.The results showed that riverine total nitrogen(TN)and total phosphorus(TP)concentrations increased continuously with increasing rainfall intensity,while TN:TP decreased.The heavy rainfall and rainstorm drove more than 30%of the annual N and P loading in only 5.20%of the total rainfall period,indicating that increased storm runoff is likely to exacerbate eutrophication in montane reservoirs.NO_(3)^(−)-N is the primary nitrogen form lost,while particulate phosphorus(PP)dominated phosphorus loss.Themain source of N is cropland,and themain source of P is residential area.Spatially,forestedwatersheds have better drainage quality,while it is still a potential source of nonpoint pollution during rainfall events.TN and TP concentrations were significantly higher at sites dominated by cropland and residential area,indicating their substantial contributions to deteriorating river water quality.Temporally,TN and TP concentrations reached high values in May-August when rainfall was most intense,while they were lower in autumn and winter than that in spring and summer under the same rainfall intensities.The results emphasize the influence of rainfall-runoff and land use on dynamics of riverine N and P loads,providing guidance for nutrient load reduction planning for Lake Qiandaohu.展开更多
Urban lakes are vital components of the modern urban water system and landscape design.They play an important role in the construction of urban ecological civilization.However,in recent years,the urban lake ecosystem ...Urban lakes are vital components of the modern urban water system and landscape design.They play an important role in the construction of urban ecological civilization.However,in recent years,the urban lake ecosystem has been increasingly degraded,especially with the frequent cyanobacteria blooms,which directly threatens the maintenance of ecosystem service function and sustainable urban development.In this study,several sedimentary cores were collected from Hudie Lake located in the Yangtze River Delta in China that had not been dredged for centuries.Using one of the sediment cores that spans the past 200 years,we reconstructed the long-term environmental changes and examined the driving mechanisms of both human activities and natural factors affecting the lake's dynamics.Our results indicated that,with the growth of the city,organic matter and nutrients in the lake had gradually increased.Notably,the significant increase in phosphorus had been a key factor driving cyanobacteria blooms in Hudie Lake.Since the 1960s,urban development and changes in land use around the lake had severely disturbed its natural habitats,leading to peak nutrient levels during the period from 2000 to 2010.展开更多
Polycyclic aromatic hydrocarbons(PAHs)are of great concern because they threaten pri-mary productivity,but their specific effects on ecosystem functioning are scarce,hindering a comprehensive understanding of their ec...Polycyclic aromatic hydrocarbons(PAHs)are of great concern because they threaten pri-mary productivity,but their specific effects on ecosystem functioning are scarce,hindering a comprehensive understanding of their ecological risks,especially in eutrophicwaters.The present study was conducted by adding PAHs to four marine phytoplankton species and showed that naphthalene(Nap)and phenanthrene(Phe)induced both stimulatory and in-hibitory effects(>50%)on urea and NO_(3)−uptake by phytoplankton species.In addition,the apparent stimulative effects(>50%)for NH_(4)^(+)were also observed.Overall,38.9%of the sam-ples exhibited stimulation effects after 24 h exposure,which increased to 61.1%after 96 h exposure.This suggested the existence of a lag period,during which a tolerant cell popula-tion could adapt to PAHs.Significant positive correlations(P<0.01)between low and high concentrations of PAH individuals demonstrated that the mode of action for both pollutants on nitrogen uptake by phytoplankton was the same.Species-specific responses were also observed,with 19.0%of Thalassiosira sp.and 24.0%of Tetraselmis sp.exhibited inhibition effects greater than 50%,while 40.9%of Karlodinium veneficum and 27.3%of Rhodomonas salina demonstrated stimulation effects exceeding 50%,providing a unique perspective for exploring the harmful algal bloom of the mixotrophic K.veneficum,in addition to the original consideration of nutrients.The internal mechanisms may lie in differences in energy consumption between N-forms,exposure time and chemical concentrations,aswell as mor-phological characteristics and biochemical structures of the species,which require further investigation.展开更多
China’s lowland rural rivers are facing severe eutrophication problems due to excessive phosphorus(P)from anthropogenic activities.However,quantifying P dynamics in a lowland rural river is challenging due to its com...China’s lowland rural rivers are facing severe eutrophication problems due to excessive phosphorus(P)from anthropogenic activities.However,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 challenge.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 river.Based 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)concentrations.Our 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 exports.Given the large P retention capacity of lowland rural rivers,drainage ditches and ponds with macrophytes are promising approaches to enhance P retention capacity.Our study provides valuable insights for local environmental departments,allowing a comprehensive understanding of P dynamics in lowland rural rivers.This enable the evaluation of the efficacy of sediment dredging in P control and the implementation of corresponding P control measures.展开更多
Soil organic carbon(SOC):total nitrogen(TN):total phosphorus(TP)(C:N:P)stoichiometry can give important information about biogeochemical cycling in terrestrial ecosystems.The spatial patterns and driving mechanisms of...Soil organic carbon(SOC):total nitrogen(TN):total phosphorus(TP)(C:N:P)stoichiometry can give important information about biogeochemical cycling in terrestrial ecosystems.The spatial patterns and driving mechanisms of soil C:N:P ratios are still poorly understood on the Qinghai-Tibetan Plateau of China.In this study,we therefore combined data of the geography,climate,soil properties,and vegetation characteristics from 319 sites across the plateau to investigate their relationships with the horizontal and vertical patterns of SOC,TN,and TP concentrations and their stoichiometric ratios(C:N and N:P).We observed higher SOC(30.5–46.8 mg g^(-1)),TN(2.4–3.4 mg g^(-1)),C:N(14.7–18.0),and N:P(6.9–8.0)in alpine meadows,forests,and shrublands and higher TP(1.6 mg g^(-1))in croplands.Overall,SOC,TN,TP,C:N,and N:P showed decreasing trends(by 67%,64%,19%,12%,and 54%,respectively)along the whole soil profile(0–100 cm).Soil cation exchange capacity and bulk density were the stronger environmental drivers of SOC and TN.Soil TP showed latitudinal and longitudinal increasing trends in all soil layers.Soil properties explained most of the variations in SOC(67%–90%),TN(67%–87%),C:N(61%–89%),and N:P(64%–85%),with increasing impacts along the soil profile.Geography and climate influenced soil TP directly and indirectly through their impacts on soil properties,with geography being the predominant driver(46%–65%)along the soil profile.The variation in soil C:N was mostly driven by SOC and TN,and the direct and indirect effects of the environmental factors were relatively weak.Geography,climate,soil properties,and vegetation characteristics indirectly impacted soil N:P through their impacts on TN and TP in all the soil layers.Altogether,our findings illuminate the relative contributions of geography,climate,soil properties,and vegetation characteristics to soil C:N and N:P,thus enhancing our understanding of C,N,and P cycling across the Qinghai-Tibetan Plateau.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
Reliable surface height observations over inland water bodies are useful for understanding the hydrological cycle.Satellite radar altimetry particularly contributed with its long-term archive and minimal cloud interfe...Reliable surface height observations over inland water bodies are useful for understanding the hydrological cycle.Satellite radar altimetry particularly contributed with its long-term archive and minimal cloud interference.Specialized inland water altimetry,developed from oceanography and geodesy,is still being extensively investigated.By synthesizing pioneering studies on“retracking algorithms”,this review demonstrates,from a user perspective,why optimizing conventional retracking is still important and how it can extend reliable historical water level retrieval over more ungauged sites.Numerous unrevealed inland water bodies have small sizes or complex surroundings,posing challenges to maintaining accuracy.Applications have shown that a critical key lies in the retracking correction during range retrieval(uncertainty likely on the order of meters),compared with other corrections(on the order of centimeters or decimeters).From multiple uncertainty factors in range retrieval,signal entanglements from land contamination and off-nadir effects are core issues.We evaluate and compared key strategies from prototype retrackers to improved retrackers,especially the empirical ones optimized for inland waters.Sub-waveform extraction and adjustment for Delay-Doppler modes has advanced range retrieval to a new stage.Four innovative inland-water-compatible retrackers are introduced in detail,with a highlight on their distinct approaches to robustly improve performance.Considering the selection of different data and retrackers in varying scenarios,a synthesis analysis is conducted based on results reported in previous literature.In conclusion,the empirical retracking has been enhanced to offer stable decimeter-level accuracy in intricate landscapes(e.g.,small lakes and rivers with varied surroundings).In comparison,the physical retracking has been upgraded to provide greater precision for homogeneous surface in large lakes.For future inland water altimetry,we articulate how additionally retracked results can benefit hydrological applications,and what difficulties would arise when extending study scales.展开更多
China is the largest emitter of anthropogenic CO_(2) globally,with its cities recognized as significant emission hotspots.Consequently,evaluating anthropogenic CO_(2) emissions and the carbon neutral capability(CNC)of...China is the largest emitter of anthropogenic CO_(2) globally,with its cities recognized as significant emission hotspots.Consequently,evaluating anthropogenic CO_(2) emissions and the carbon neutral capability(CNC)of Chinese cities is critical for climate change mitigation.Despite this importance,no studies to date have assessed recent and future city-scale CNCs using the top-down atmospheric inversion approach,revealing substantial knowledge gaps regarding regional CO_(2) budgets.To address these issues,this research focused on Hangzhou,a megacity known for having the highest forest cover among China’s provincial capitals,as study region.Year-round atmospheric CO_(2) concentration measurements were conducted from December 2020 to November 2021 at two sites:one urban and one suburban.These observations,along with their difference,were utilized to derive city-scale posterior anthropogenic CO_(2) emissions and to evaluate recent and future CNCs.Our key findings are as follows:(1)The manufacturing industry,energy industry and oil refineries/transformation industry were identified as the largest contributors to urban-suburban CO_(2) difference,accounting for 36.5%,21.3%,and 16.6%,respectively.Additionally,82.5%,65.2%,81.2%and 86.3%of total anthropogenic CO_(2) enhancements were attributed to emissions within Hangzhou city in winter,spring,summer and autumn,respectively.(2)The posterior annual anthropogenic CO_(2) emission for Hangzhouwas estimated at 4.65(±0.72)×10^(10) kg/a,indicating significant biases among different prior CO_(2) emission inventories.The annual biological CO_(2) sink,derived from multiple products,was estimated at-0.48(±0.16)×10^(10) kg.(3)The calculated CNC for 2021was 10.3%±3.4%,highlighting a substantial gap towards achieving full carbon neutrality.Considering potential increases in ecosystem carbon sinks due to forest age and uncertainties from climate change,it was predicted that at least 65.2%-82.6%of anthropogenic CO_(2) emissions must be reduced to achieve the goal of full carbon neutrality by year of 2060.展开更多
Interactions between surface water and groundwater are dynamic and complex in large endorheic river watersheds in Northwest China due to the influence of both irrigation practices and the local terrain. These interact...Interactions between surface water and groundwater are dynamic and complex in large endorheic river watersheds in Northwest China due to the influence of both irrigation practices and the local terrain. These interactions interchange numerous times throughout the middle reaches, making streamflow simulation a challenge in endorheic river watersheds. In this study, we modified the linear-reservoir groundwater module in SWAT(Soil and Water Assessment Tools, a widely used hydrological model) with a new nonlinear relationship to better represent groundwater processes; we then applied the original SWAT and modified SWAT to the Heihe River Watershed, the second largest endorheic river watershed in Northwest China, to simulate streamflow. After calibrating both the original SWAT model and the modified SWAT model, we analyzed model performance during two periods: an irrigation period and a non-irrigation period. Our results show that the modified SWAT model with the nonlinear groundwater module performed significantly better during both the irrigation and non-irrigation periods. Moreover, after comparing different runoff components simulated by the two models, the results show that, after the implementation of the new nonlinear groundwater module in SWAT, proportions of runoff components changed-and the groundwater flow had significantly increased, dominating the discharge season. Therefore, SWAT coupled with the non-linear groundwater module represents the complex hydrological process in the study area more realistically. Moreover, the results for various runoff components simulated by the modified SWAT models can be used to describe the hydrological characteristics of lowland areas. This indicates that the modified SWAT model is applicable to simulate complex hydrological process of arid endorheic rivers.展开更多
Taste and odor compounds(T&Os),which is often associated with plankton in water sources,pose significant challenges to water quality in the world.Identifying the potential producers and understanding the driving f...Taste and odor compounds(T&Os),which is often associated with plankton in water sources,pose significant challenges to water quality in the world.Identifying the potential producers and understanding the driving factors are critical for effective treatment.While most studies focused on outbreak of T&Os linked with summer cyanobacterial blooms,questions remain about the mechanisms and environmental factors driving spring outbreaks when cyanobacteria are typically in low abundance.Therefore,changes in the concentrations of T&Os,i.e.,2-methylisoborneol(2-MIB)and three others,in relation to the phytoplankton community,the physico-chemical and hydrological conditions in a mesotrophic reservoir surrounded by hills in East China were investigated from March to June 2023.Results show that 2-MIB was the main T&O during the spring outbreak of phytoplankton,and peaked at 96.10 ng/L,which is nearly 10 times of its odor threshold concentration(OTC)of 10 ng/L.The filamentous cyanobacterium Pseudanabaena sp.was identified as the primary producer of 2-MIB,and the cell concentration of 4000 cells/mL of Pseudanabaena sp.could potentially result in 10 ng/L of 2-MIB in this reservoir.The abundance of Pseudanabaena sp.and 2-MIB were correlated significantly with turbidity,suggesting that a lower light environment might be critical to promote the dominance of Pseudanabaena sp.and the subsequent production of 2-MIB.Moreover,the combination of consistently decreased water level,moderate water stratification,optimal water temperature ranging~14-23℃,the increase of the chemical oxygen demand using permanganate as an oxidant(CODMn)and total nitrogen(TN)concentration were likely to drive the accumulation and outbreak of 2-MIB.The hydrodynamic disturbance(i.e.,a sudden rapid flow of water)triggered the abrupt disappearance of both Pseudanabaena sp.and 2-MIB.This study suggests that proliferation of Pseudanabaena sp.in spring is important in contributing to 2-MIB outbreak,and flushing may be an effective approach to mitigate T&O issues in water sources.展开更多
The Yangtze River Economic Belt(YREB)is a pivotal contributor to China's economic growth,particularly as the nation undergoes a green transformation.Achieving synergistic reductions on pollution and carbon emissio...The Yangtze River Economic Belt(YREB)is a pivotal contributor to China's economic growth,particularly as the nation undergoes a green transformation.Achieving synergistic reductions on pollution and carbon emissions is deemed crucial for this transition.This paper examines the spatial and temporal changes in the synergy of pollution and carbon reduction in the YREB and delves into the underlying mechanisms.Our findings indicate that while the synergy in the YREB is increasing,it manifests disparities across regions,with the lower reaches outperforming the middle and upper ones.Enterprise behavior,government guidance,and regional endowments influence this synergy.Cities in the YREB must strategically plan their urban scale,curb population overgrowth,recalibrate their industrial structures,curtail energy consumption,and enhance policy efficacy.Distinct regions should prioritize various objectives:the lower reaches should hasten scientific advancements and technological innovations;the middle reaches should foster innovation and industrial upgrades;and the upper reaches should prioritize rural and urban land intensification.展开更多
For a long time,due to lack of accurate data covering large areas,it is difficult to capture the continuous spatial evolutionary trajectory of rural settlements shaped by rapid urbanization and rural land use policies...For a long time,due to lack of accurate data covering large areas,it is difficult to capture the continuous spatial evolutionary trajectory of rural settlements shaped by rapid urbanization and rural land use policies.To fill this gap,based on theoretical analysis this paper systemically detected the changing characteristics of scale,spatial morphology,distribution,and land use pattern of rural settlements in Southern Jiangsu in the past 20 years depending on the data of land resource survey in 2009 and 2019.The study suggests that the total area and per capita size of rural settlements declined by 30%and 2%respectively as a result of rural land consolidation and the influx of enormous immigrants from underdeveloped regions.The spatial density and average shape index dropped by 14%and 44%respectively in the recent decade,indicating an evident trend of decentralization in spatial distribution,and regularization in the spatial morphology.Furthermore,residential land within rural settlements decreased by 33%over the past decade while the land for industry and commercial service steadily increased,demonstrating that the function for manufacturing and diversified services had been strengthened.Considering the emerging issue of the aging population and new business opportunities in rural Southern Jiangsu,rural settlements regeneration might be the focus offutureresearch.展开更多
Meiotic recombination is essential for sexual reproduction and its regulation has been extensively studied in many taxa.However,genome-wide recombination landscape has not been reported in ciliates and it remains unkn...Meiotic recombination is essential for sexual reproduction and its regulation has been extensively studied in many taxa.However,genome-wide recombination landscape has not been reported in ciliates and it remains unknown how it is affected by the unique features of ciliates:the synaptonemal complex(SC)-independent meiosis and the nuclear dimorphism.Here,we show the recombination landscape in the model ciliate Tetrahymena thermophila by analyzing single-nucleotide polymorphism datasets from 38 hybrid progeny.We detect 1021 crossover(CO)events(35.8 per meiosis),corresponding to an overall CO rate of 9.9 cM/Mb.However,gene conversion by non-crossover is rare(1.03 per meiosis)and not biased towards G or C alleles.Consistent with the reported roles of SC in CO interference,we find no obvious sign of CO interference.CO tends to occur within germ-soma common genomic regions and many of the 44 identified CO hotspots localize at the centromeric or subtelomeric regions.Gene ontology analyses show that CO hotspots are strongly associated with genes responding to environmental changes.We discuss these results with respect to how nuclear dimorphism has potentially driven the formation of the observed recombination landscape to facilitate environmental adaptation and the sharing of machinery among meiotic and somatic recombination.展开更多
As a typical region with high water demand for agricultural production,understanding the spatiotemporal surface water changes in Northeast China is critical for water resources management and sustainable development.H...As a typical region with high water demand for agricultural production,understanding the spatiotemporal surface water changes in Northeast China is critical for water resources management and sustainable development.However,the long-term variation characteristics of surface water of different water body types in Northeast China remain rarely explored.This study investigated how surface water bodies of different types(e.g.,lake,reservoir,river,coastal aquaculture,marsh wetland,ephemeral water) changed during1999–2020 in Northeast China based on various remote sensing-based datasets.The results showed that surface water in Northeast China grew dramatically in the past two decades,with an equivalent area increasing from 24 394 km^(2) in 1999 to 34 595 km^(2) in 2020.The surge of ephemeral water is the primary driver of surface water expansion,which could ascribe to shifted precipitation pattern.Marsh wetlands,rivers,and reservoirs experienced a similar trend,with an approximate 20% increase at the interdecadal scale.By contrast,coastal aquacultures and natural lakes remain relatively stable.This study is expected to provide a more comprehensive investigation of the surface water variability in Northeast China and has important practical significance for the scientific management of different types of surface water.展开更多
The Three Gorges Reservoir Area(TGRA)is an important ecological barrier in the Yangtze River Basin,China.Therefore,it is of great importance to understand the spatio-temporal variation and the driving factors of produ...The Three Gorges Reservoir Area(TGRA)is an important ecological barrier in the Yangtze River Basin,China.Therefore,it is of great importance to understand the spatio-temporal variation and the driving factors of production-living-ecological spaces for sustainable and high-quality development in the TGRA.This study investigated the dynamic variation of production-living-ecological spaces in the TGRA by employing land use data in 2000,2005,2010,2015,and 2018,and detected the influencing factors by using the Geographic detector(GeoDetector).Results implied that the structure and dynamic trajectories of production-living-ecological spaces in the TGRA varied in both horizontal and vertical directions,and the study area was dominated by ecological space.A spatial orientation towards the northeast was detected in the evolution of production-living-ecological spaces during 2000-2018.In terms of quantity,the transition from ecological space(grassland and woodland)to agriculture land accounted for the largest proportion from 2000 to 2018.However,the reverse transition from agriculture land to ecological space has increased since 2000 with the efforts of“Grain for Green”.In terms of temporal scale,there was a fluctuating trend in production space with the continuous expansion of living space,while ecological space showed an inverted U-shaped trend during 2000-2018.The dynamic pattern of production-living-ecological spaces in the TGRA was influenced by both physical and socio-economic variables as basic determinants and dominant driving factors,respectively.Finally,the harmonization and protection of production-living-ecological spaces still require policy-makers’efforts.This work may have potential in advancing our understanding about land use conflicts,and provide a reference for rational layout of spatial functions and the realization of sustainable development in the TGRA.展开更多
The availability of nitrogen(N)is crucial for both the productivity of terrestrial and aquatic ecosystems globally.However,the overuse of artificial fertilizers and the energy required to fix nitrogen have pushed the ...The availability of nitrogen(N)is crucial for both the productivity of terrestrial and aquatic ecosystems globally.However,the overuse of artificial fertilizers and the energy required to fix nitrogen have pushed the global nitrogen cycle(N-cycle)past its safe operating limits,leading to severe nitrogen pollution and the production of significant amounts of greenhouse gas nitrous oxide(N2O).The anaerobic ammonium oxidation(anammox)mechanism can counteract the release of ammonium and N2O in many oxygenlimited situations,assisting in the restoration of the homeostasis of the Earth’s N biogeochemistry.In this work,we looked into the characteristics of the anammox hotspots’distribution across various types of ecosystems worldwide.Anammox hotspots are present at diverse oxic-anoxic interfaces in terrestrial systems,and they are most prevalent at the oxic-anoxic transition zone in aquatic ecosystems.Based on the discovery of an anammox hotspot capable of oxidizing ammonium anoxically into N2 without N2O by-product,we then designed an innovative concept and technical routes of nature-based anammox hotspot geoengineering for climate change,biodiversity loss,and efficient utilization of water resources.After 15 years of actual use,anammox hotspot geoengineering has proven to be effective in ensuring clean drinking water,regulating the climate,fostering plant and animal diversity,and enhancing longterm environmental quality.The sustainable biogeoengineering of anammox could be a workable natural remedy to resolve the conflicts between environmental pollution and food security connected to N management.展开更多
The widespread use of antibiotics has significantly increased their presence in aquatic environments,particularly in sensitive Karst River systems.In this study,the distribution and ecological,human health,and resista...The widespread use of antibiotics has significantly increased their presence in aquatic environments,particularly in sensitive Karst River systems.In this study,the distribution and ecological,human health,and resistance selection risk assessment of 44 antibiotics in the typical Karst River,Lijiang River,were investigated during the influenza season,a period marked by heightened antibiotic usage.27 antibiotics could be found in the water of Lijiang River,among which azithromycin showing the highest concentrations.The concentrations of total antibiotics were in the range 171.70–2003.75 ng/L,with an average value of 704.76 ng/L.Macrolide was the predominant class,constituting an average of 57.65%of the total antibiotic concentrations.Risk assessments revealed that certain antibiotics,especially macrolides,posed moderate to high ecological risks to algae,displayed potential human health risks at low levels and contributed to antimicrobial resistance.Among all the antibiotics,azithromycin was the only one could cause ecological risk to algae,human health risk towards infants and antimicrobial resistance selection risk,which should be identified as the priority antibiotic for control in the Lijiang River during the influenza season.There was no difference in the concentrations,human health and antimicrobial resistance selection risk of antibiotics between mainstream and tributaries of Lijiang River.This study contributes to a better understanding of antibiotic pollution and provides insights into potential risk management practices in vulnerable aquatic systems worldwide.展开更多
Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetland. Poyang Lake, the largest freshwater lake in China, has been encountering dra...Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetland. Poyang Lake, the largest freshwater lake in China, has been encountering dramatic changes in hydrological conditions in last decade, which greatly influenced the wetland vegetations. To explore the relationships between hydrology and vegetation distri- bution, water-table depth, soil moisture, species composition, diversity and biomass were measured at a seasonally flooded wetland section at Wucheng National Nature Reserve. Three plant communities, Artemisia capillaris, Phragmites australis and Carex cineras- cens communities, were examined which are zonally distributed from upland to lakeshore with decreasing elevation. Canonical corre- spondence analysis （CCA）, spearmen correlation and logistic regression were adopted to analyze the relationships between vegetation characteristics and hydrological variables of water-table depth and soil moisture. Results show that significant hydrological gradient exist along the wetland transect. Water-table demonstrates a seasonal variation and is consistently deepest in A. capillaris community （ranging from q）.5 m above ground to ＋10.3 m below ground）, intermediate in P. australis community （-2.6 m to ＋7.8 m） and shallow- est in C. cinerascens community （-4.5 m to ＋6.1 m）. Soil moisture is lowest and most variable in A. capillaris community, highest and least variable in P. australis community, and intermediate and moderate variable in C. cinerascens community. The CCA ordination indicated that variables of water-table depth and soil moisture are strongly related to community distribution, which explained 81.7% of the vegetation variations. Species diversity indices are significantly positively correlated with soil moisture and negatively correlated with moisture variability, while above- and belowground biomass are positively correlated with moisture. Above- and belowground biomass present Gaussian models along the gradient of average water-table depth in growing season, while species diversity indices show bimodal patterns. The optimal average water-table depths for above- and belowground biomass are 0.8 m and 0.5 m, respectively, and are 2.2 m and 2.4 m for species richness and Shannon-Wiener indices, respectively. Outcomes of this work improved the under- standings of the relationship between hydrology and vegetation.展开更多
Seasonal water-level fluctuations （WLF） play a dominate role in lacustrine ecosys- tems. River-lake interaction is a direct factor in changes of seasonal lake WLF, especially for those lakes naturally connected to u...Seasonal water-level fluctuations （WLF） play a dominate role in lacustrine ecosys- tems. River-lake interaction is a direct factor in changes of seasonal lake WLF, especially for those lakes naturally connected to upstream and downstream rivers. During the past decade, the modification of WLF in the Poyang Lake （the largest freshwater lake in China） has caused intensified flood and irrigation crises, reduced water availability, compromised water quality and extensive degradation of the lake ecosystem. There has been a conjecture as to whether the modification was caused by its interactions with Yangtze River. In this study, we investi- gated the variations of seasonal WLF in China＇s Poyang Lake by comparing the water levels during the four distinct seasons （the dry season, the rising season, the flood season, and the retreating season） before and after 2003 when the Three Gorge Dam operated. The Water Surface Slope （WSS） was used as a representative parameter to measure the changes in river-lake interaction and its impacts on seasonal WLF. The results showed that the magni- tude of seasonal WLF has changed considerably since 2003; the seasonal WLF of the Poy- ang Lake have been significantly altered by the fact that the water levels both rise and retreat earlier in the season and lowered water levels in general. The fluctuations of river-lake in- teractions, in particular the changes during the retreating season, are mainly responsible for these variations in magnitude of seasonal WLF. This study demonstrates that WSS is a rep- resentative parameter to denote river-lake interactions, and the results indicate that more emphasis should be placed on the decrease of the Poyang Lake caused by the lowered water levels of the Yangtze River, especially in the retreating season.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42030501,41530752,and 91125010)the Scherer Endowment Fund of Department of Geography,Western Michigan University。
文摘Over the past decades,a number of water sciences and management programs have been developed to better understand and manage the water cycles at multiple temporal and spatial scales for various purposes,such as ecohydrology,global hydrology,sociohydrology,supply management,demand management,and integrated water resources management(IWRM).At the same time,rapid advancements have also been taking place in tracing,mapping,remote sensing,machine learning,and modelling technologies in hydrological research.Despite those programs and advancements,a water crisis is intensifying globally.The missing link is effective interactions between the hydrological research and water resource management to support implementation of the UN Sustainable Development Goals(SDGs)at multiple spatial scales.Since the watershed is the natural unit for water resources management,watershed science offers the potential to bridge this missing link.This study first reviews the advances in hydrological research and water resources management,and then discusses issues and challenges facing the global water community.Subsequently,it describes the core components of watershed science:(1)hydrological analysis;(2)water-operation policies;(3)governance;(4)management and feedback.The framework takes into account water availability,water uses,and water quality;explicitly focuses on the storage,fluxes,and quality of the hydrological cycle;defines appropriate local water resource thresholds through incorporating the planetary boundary framework;and identifies specific actionable measures for water resources management.It provides a complementary approach to the existing water management programs in addressing the current global water crisis and achieving the UN SDGs.
基金supported by the National Natural Science Foundation of China(Nos.U2340209,and 42271126)the NIGLAS Foundation(No.NIGLAS2022GS03)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20220041)the US National Science Foundation Projects(Nos.1831096,1803697,and 2108917).
文摘The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is available on how the rainfall affect nutrient dynamics in subtropicalmontane rivers with complex land use.This study conducted high-frequency monitoring to study the effects of rainfall on nutrients dynamics in an agricultural river draining to Lake Qiandaohu,a montane reservoir of southeast China.The results showed that riverine total nitrogen(TN)and total phosphorus(TP)concentrations increased continuously with increasing rainfall intensity,while TN:TP decreased.The heavy rainfall and rainstorm drove more than 30%of the annual N and P loading in only 5.20%of the total rainfall period,indicating that increased storm runoff is likely to exacerbate eutrophication in montane reservoirs.NO_(3)^(−)-N is the primary nitrogen form lost,while particulate phosphorus(PP)dominated phosphorus loss.Themain source of N is cropland,and themain source of P is residential area.Spatially,forestedwatersheds have better drainage quality,while it is still a potential source of nonpoint pollution during rainfall events.TN and TP concentrations were significantly higher at sites dominated by cropland and residential area,indicating their substantial contributions to deteriorating river water quality.Temporally,TN and TP concentrations reached high values in May-August when rainfall was most intense,while they were lower in autumn and winter than that in spring and summer under the same rainfall intensities.The results emphasize the influence of rainfall-runoff and land use on dynamics of riverine N and P loads,providing guidance for nutrient load reduction planning for Lake Qiandaohu.
基金State Key Laboratory of Lake and Watershed Science for Water Security,No.2024SKL016National Natural Science Foundation of China,No.42002204,No.42373060+1 种基金Innovative Training Program for University Students,No.2024219,No.2024224Jiangsu Provincial Government Scholarship Program for Studying Abroad,No.2024-075。
文摘Urban lakes are vital components of the modern urban water system and landscape design.They play an important role in the construction of urban ecological civilization.However,in recent years,the urban lake ecosystem has been increasingly degraded,especially with the frequent cyanobacteria blooms,which directly threatens the maintenance of ecosystem service function and sustainable urban development.In this study,several sedimentary cores were collected from Hudie Lake located in the Yangtze River Delta in China that had not been dredged for centuries.Using one of the sediment cores that spans the past 200 years,we reconstructed the long-term environmental changes and examined the driving mechanisms of both human activities and natural factors affecting the lake's dynamics.Our results indicated that,with the growth of the city,organic matter and nutrients in the lake had gradually increased.Notably,the significant increase in phosphorus had been a key factor driving cyanobacteria blooms in Hudie Lake.Since the 1960s,urban development and changes in land use around the lake had severely disturbed its natural habitats,leading to peak nutrient levels during the period from 2000 to 2010.
基金supported by the National Natural Science Foundation of China(No.42277404)the State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in the Middle and Lower Reaches of Yangtze River(No.AEHKF2023004)+2 种基金the National Key Research and Development Programof China(No.2022YFC3202703)the International Collaboration Program of Chinese Academy of Sciences(Nos.SAJC202403,067GJHZ2023034MI)the Autonomous Deployment Project of Key Laboratory of Lake andWatershed Science for Water Security(No.NKL2023-KP01).
文摘Polycyclic aromatic hydrocarbons(PAHs)are of great concern because they threaten pri-mary productivity,but their specific effects on ecosystem functioning are scarce,hindering a comprehensive understanding of their ecological risks,especially in eutrophicwaters.The present study was conducted by adding PAHs to four marine phytoplankton species and showed that naphthalene(Nap)and phenanthrene(Phe)induced both stimulatory and in-hibitory effects(>50%)on urea and NO_(3)−uptake by phytoplankton species.In addition,the apparent stimulative effects(>50%)for NH_(4)^(+)were also observed.Overall,38.9%of the sam-ples exhibited stimulation effects after 24 h exposure,which increased to 61.1%after 96 h exposure.This suggested the existence of a lag period,during which a tolerant cell popula-tion could adapt to PAHs.Significant positive correlations(P<0.01)between low and high concentrations of PAH individuals demonstrated that the mode of action for both pollutants on nitrogen uptake by phytoplankton was the same.Species-specific responses were also observed,with 19.0%of Thalassiosira sp.and 24.0%of Tetraselmis sp.exhibited inhibition effects greater than 50%,while 40.9%of Karlodinium veneficum and 27.3%of Rhodomonas salina demonstrated stimulation effects exceeding 50%,providing a unique perspective for exploring the harmful algal bloom of the mixotrophic K.veneficum,in addition to the original consideration of nutrients.The internal mechanisms may lie in differences in energy consumption between N-forms,exposure time and chemical concentrations,aswell as mor-phological characteristics and biochemical structures of the species,which require further investigation.
基金supported by the National Key Research and Development Program of China(No.2021YFD1700600)the National Natural Science Foundation of China(Nos.42222104 and 41971138)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA23020201)and the Science and Technology Planning Project of NIGLAS(No.NIGLAS2022GS10).
文摘China’s lowland rural rivers are facing severe eutrophication problems due to excessive phosphorus(P)from anthropogenic activities.However,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 challenge.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 river.Based 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)concentrations.Our 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 exports.Given the large P retention capacity of lowland rural rivers,drainage ditches and ponds with macrophytes are promising approaches to enhance P retention capacity.Our study provides valuable insights for local environmental departments,allowing a comprehensive understanding of P dynamics in lowland rural rivers.This enable the evaluation of the efficacy of sediment dredging in P control and the implementation of corresponding P control measures.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program of China(No.2019QZKK0306-02)the National Natural Science Foundation of China(Nos.42322102 and 42271058)+1 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2021310)the Science&Technology Fundamental Resources Investigation Program of China(No.2022FY100202)
文摘Soil organic carbon(SOC):total nitrogen(TN):total phosphorus(TP)(C:N:P)stoichiometry can give important information about biogeochemical cycling in terrestrial ecosystems.The spatial patterns and driving mechanisms of soil C:N:P ratios are still poorly understood on the Qinghai-Tibetan Plateau of China.In this study,we therefore combined data of the geography,climate,soil properties,and vegetation characteristics from 319 sites across the plateau to investigate their relationships with the horizontal and vertical patterns of SOC,TN,and TP concentrations and their stoichiometric ratios(C:N and N:P).We observed higher SOC(30.5–46.8 mg g^(-1)),TN(2.4–3.4 mg g^(-1)),C:N(14.7–18.0),and N:P(6.9–8.0)in alpine meadows,forests,and shrublands and higher TP(1.6 mg g^(-1))in croplands.Overall,SOC,TN,TP,C:N,and N:P showed decreasing trends(by 67%,64%,19%,12%,and 54%,respectively)along the whole soil profile(0–100 cm).Soil cation exchange capacity and bulk density were the stronger environmental drivers of SOC and TN.Soil TP showed latitudinal and longitudinal increasing trends in all soil layers.Soil properties explained most of the variations in SOC(67%–90%),TN(67%–87%),C:N(61%–89%),and N:P(64%–85%),with increasing impacts along the soil profile.Geography and climate influenced soil TP directly and indirectly through their impacts on soil properties,with geography being the predominant driver(46%–65%)along the soil profile.The variation in soil C:N was mostly driven by SOC and TN,and the direct and indirect effects of the environmental factors were relatively weak.Geography,climate,soil properties,and vegetation characteristics indirectly impacted soil N:P through their impacts on TN and TP in all the soil layers.Altogether,our findings illuminate the relative contributions of geography,climate,soil properties,and vegetation characteristics to soil C:N and N:P,thus enhancing our understanding of C,N,and P cycling across the Qinghai-Tibetan Plateau.
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funded by the National Key Research and Development Program of China(2022YFF0711603)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA28020503)+2 种基金the National Natural Science Foundation of China(Grant No.42371399,42301431)Basic Research Program of Jiangsu(Grant No.BK20240112)the Science and Technology Planning Project of NIGLAS(Grant No.2022NIGLAS-CJH04).
文摘Reliable surface height observations over inland water bodies are useful for understanding the hydrological cycle.Satellite radar altimetry particularly contributed with its long-term archive and minimal cloud interference.Specialized inland water altimetry,developed from oceanography and geodesy,is still being extensively investigated.By synthesizing pioneering studies on“retracking algorithms”,this review demonstrates,from a user perspective,why optimizing conventional retracking is still important and how it can extend reliable historical water level retrieval over more ungauged sites.Numerous unrevealed inland water bodies have small sizes or complex surroundings,posing challenges to maintaining accuracy.Applications have shown that a critical key lies in the retracking correction during range retrieval(uncertainty likely on the order of meters),compared with other corrections(on the order of centimeters or decimeters).From multiple uncertainty factors in range retrieval,signal entanglements from land contamination and off-nadir effects are core issues.We evaluate and compared key strategies from prototype retrackers to improved retrackers,especially the empirical ones optimized for inland waters.Sub-waveform extraction and adjustment for Delay-Doppler modes has advanced range retrieval to a new stage.Four innovative inland-water-compatible retrackers are introduced in detail,with a highlight on their distinct approaches to robustly improve performance.Considering the selection of different data and retrackers in varying scenarios,a synthesis analysis is conducted based on results reported in previous literature.In conclusion,the empirical retracking has been enhanced to offer stable decimeter-level accuracy in intricate landscapes(e.g.,small lakes and rivers with varied surroundings).In comparison,the physical retracking has been upgraded to provide greater precision for homogeneous surface in large lakes.For future inland water altimetry,we articulate how additionally retracked results can benefit hydrological applications,and what difficulties would arise when extending study scales.
基金supported by the National Natural Science Foundation of China(Nos.42475125,42105117,42021004 and 41975143)the National Key R&D Program of China(Nos.2019YFA0607202 and 2020YFA0607501)+4 种基金Jiangsu Science Foundation for Distinguished Young Scholar(No.BK20220055)the 333 Project of Jiangsu Province(No.BRA2017402)the R&D Foundation of Jiangsu Province,China(No.BK20220020)Zhejiang Provincial Basic Public Welfare Research Project(No.LGF22D050004)the Key Laboratory of Ecosystem Carbon Source and Sink,China Meteorological Administration(ECSSCMA).
文摘China is the largest emitter of anthropogenic CO_(2) globally,with its cities recognized as significant emission hotspots.Consequently,evaluating anthropogenic CO_(2) emissions and the carbon neutral capability(CNC)of Chinese cities is critical for climate change mitigation.Despite this importance,no studies to date have assessed recent and future city-scale CNCs using the top-down atmospheric inversion approach,revealing substantial knowledge gaps regarding regional CO_(2) budgets.To address these issues,this research focused on Hangzhou,a megacity known for having the highest forest cover among China’s provincial capitals,as study region.Year-round atmospheric CO_(2) concentration measurements were conducted from December 2020 to November 2021 at two sites:one urban and one suburban.These observations,along with their difference,were utilized to derive city-scale posterior anthropogenic CO_(2) emissions and to evaluate recent and future CNCs.Our key findings are as follows:(1)The manufacturing industry,energy industry and oil refineries/transformation industry were identified as the largest contributors to urban-suburban CO_(2) difference,accounting for 36.5%,21.3%,and 16.6%,respectively.Additionally,82.5%,65.2%,81.2%and 86.3%of total anthropogenic CO_(2) enhancements were attributed to emissions within Hangzhou city in winter,spring,summer and autumn,respectively.(2)The posterior annual anthropogenic CO_(2) emission for Hangzhouwas estimated at 4.65(±0.72)×10^(10) kg/a,indicating significant biases among different prior CO_(2) emission inventories.The annual biological CO_(2) sink,derived from multiple products,was estimated at-0.48(±0.16)×10^(10) kg.(3)The calculated CNC for 2021was 10.3%±3.4%,highlighting a substantial gap towards achieving full carbon neutrality.Considering potential increases in ecosystem carbon sinks due to forest age and uncertainties from climate change,it was predicted that at least 65.2%-82.6%of anthropogenic CO_(2) emissions must be reduced to achieve the goal of full carbon neutrality by year of 2060.
基金Under the auspices of Natural Science Foundation of Qinghai Province(No.2017-ZJ-961Q)National Natural Science Foundation of China(No.91125010,41530752)Scherer Endowment Fund of Department of Geography,Western Michigan University
文摘Interactions between surface water and groundwater are dynamic and complex in large endorheic river watersheds in Northwest China due to the influence of both irrigation practices and the local terrain. These interactions interchange numerous times throughout the middle reaches, making streamflow simulation a challenge in endorheic river watersheds. In this study, we modified the linear-reservoir groundwater module in SWAT(Soil and Water Assessment Tools, a widely used hydrological model) with a new nonlinear relationship to better represent groundwater processes; we then applied the original SWAT and modified SWAT to the Heihe River Watershed, the second largest endorheic river watershed in Northwest China, to simulate streamflow. After calibrating both the original SWAT model and the modified SWAT model, we analyzed model performance during two periods: an irrigation period and a non-irrigation period. Our results show that the modified SWAT model with the nonlinear groundwater module performed significantly better during both the irrigation and non-irrigation periods. Moreover, after comparing different runoff components simulated by the two models, the results show that, after the implementation of the new nonlinear groundwater module in SWAT, proportions of runoff components changed-and the groundwater flow had significantly increased, dominating the discharge season. Therefore, SWAT coupled with the non-linear groundwater module represents the complex hydrological process in the study area more realistically. Moreover, the results for various runoff components simulated by the modified SWAT models can be used to describe the hydrological characteristics of lowland areas. This indicates that the modified SWAT model is applicable to simulate complex hydrological process of arid endorheic rivers.
基金Supported by the National Natural Science Foundation of China(Nos.42271080,U2340209)the Science and Technology Planning Project of NIGLAS(Nos.NIGLAS2022GS03,NIGLAS2022TJ08)。
文摘Taste and odor compounds(T&Os),which is often associated with plankton in water sources,pose significant challenges to water quality in the world.Identifying the potential producers and understanding the driving factors are critical for effective treatment.While most studies focused on outbreak of T&Os linked with summer cyanobacterial blooms,questions remain about the mechanisms and environmental factors driving spring outbreaks when cyanobacteria are typically in low abundance.Therefore,changes in the concentrations of T&Os,i.e.,2-methylisoborneol(2-MIB)and three others,in relation to the phytoplankton community,the physico-chemical and hydrological conditions in a mesotrophic reservoir surrounded by hills in East China were investigated from March to June 2023.Results show that 2-MIB was the main T&O during the spring outbreak of phytoplankton,and peaked at 96.10 ng/L,which is nearly 10 times of its odor threshold concentration(OTC)of 10 ng/L.The filamentous cyanobacterium Pseudanabaena sp.was identified as the primary producer of 2-MIB,and the cell concentration of 4000 cells/mL of Pseudanabaena sp.could potentially result in 10 ng/L of 2-MIB in this reservoir.The abundance of Pseudanabaena sp.and 2-MIB were correlated significantly with turbidity,suggesting that a lower light environment might be critical to promote the dominance of Pseudanabaena sp.and the subsequent production of 2-MIB.Moreover,the combination of consistently decreased water level,moderate water stratification,optimal water temperature ranging~14-23℃,the increase of the chemical oxygen demand using permanganate as an oxidant(CODMn)and total nitrogen(TN)concentration were likely to drive the accumulation and outbreak of 2-MIB.The hydrodynamic disturbance(i.e.,a sudden rapid flow of water)triggered the abrupt disappearance of both Pseudanabaena sp.and 2-MIB.This study suggests that proliferation of Pseudanabaena sp.in spring is important in contributing to 2-MIB outbreak,and flushing may be an effective approach to mitigate T&O issues in water sources.
基金National Natural Science Foundation of China,No.42371318。
文摘The Yangtze River Economic Belt(YREB)is a pivotal contributor to China's economic growth,particularly as the nation undergoes a green transformation.Achieving synergistic reductions on pollution and carbon emissions is deemed crucial for this transition.This paper examines the spatial and temporal changes in the synergy of pollution and carbon reduction in the YREB and delves into the underlying mechanisms.Our findings indicate that while the synergy in the YREB is increasing,it manifests disparities across regions,with the lower reaches outperforming the middle and upper ones.Enterprise behavior,government guidance,and regional endowments influence this synergy.Cities in the YREB must strategically plan their urban scale,curb population overgrowth,recalibrate their industrial structures,curtail energy consumption,and enhance policy efficacy.Distinct regions should prioritize various objectives:the lower reaches should hasten scientific advancements and technological innovations;the middle reaches should foster innovation and industrial upgrades;and the upper reaches should prioritize rural and urban land intensification.
基金National Natural Science Foundation of China,No.42171211。
文摘For a long time,due to lack of accurate data covering large areas,it is difficult to capture the continuous spatial evolutionary trajectory of rural settlements shaped by rapid urbanization and rural land use policies.To fill this gap,based on theoretical analysis this paper systemically detected the changing characteristics of scale,spatial morphology,distribution,and land use pattern of rural settlements in Southern Jiangsu in the past 20 years depending on the data of land resource survey in 2009 and 2019.The study suggests that the total area and per capita size of rural settlements declined by 30%and 2%respectively as a result of rural land consolidation and the influx of enormous immigrants from underdeveloped regions.The spatial density and average shape index dropped by 14%and 44%respectively in the recent decade,indicating an evident trend of decentralization in spatial distribution,and regularization in the spatial morphology.Furthermore,residential land within rural settlements decreased by 33%over the past decade while the land for industry and commercial service steadily increased,demonstrating that the function for manufacturing and diversified services had been strengthened.Considering the emerging issue of the aging population and new business opportunities in rural Southern Jiangsu,rural settlements regeneration might be the focus offutureresearch.
基金supported by the Wuhan Branch,Supercomputing Center,Chinese Academy of Sciences,Chinasupported by the National Aquatic Biological Resource Center(NABRC)+4 种基金supported by the Bureau of Frontier Sciences and Education,Chinese Academy of Sciences(ZDBS-LY-SM026)the National Natural Science Foundation of China(32370457,32122015,32130011,31900316,and 31900339)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0480000)PJA3 grant of ARC Foundation(ARCPJA2021060003830)Equipes 2022 grant of Foundation Recherche Medicale(EQU202203014651).
文摘Meiotic recombination is essential for sexual reproduction and its regulation has been extensively studied in many taxa.However,genome-wide recombination landscape has not been reported in ciliates and it remains unknown how it is affected by the unique features of ciliates:the synaptonemal complex(SC)-independent meiosis and the nuclear dimorphism.Here,we show the recombination landscape in the model ciliate Tetrahymena thermophila by analyzing single-nucleotide polymorphism datasets from 38 hybrid progeny.We detect 1021 crossover(CO)events(35.8 per meiosis),corresponding to an overall CO rate of 9.9 cM/Mb.However,gene conversion by non-crossover is rare(1.03 per meiosis)and not biased towards G or C alleles.Consistent with the reported roles of SC in CO interference,we find no obvious sign of CO interference.CO tends to occur within germ-soma common genomic regions and many of the 44 identified CO hotspots localize at the centromeric or subtelomeric regions.Gene ontology analyses show that CO hotspots are strongly associated with genes responding to environmental changes.We discuss these results with respect to how nuclear dimorphism has potentially driven the formation of the observed recombination landscape to facilitate environmental adaptation and the sharing of machinery among meiotic and somatic recombination.
基金Under the auspices of Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA28020503,XDA23100102)National Key Research and Development Program of China(No.2019YFA0607101)+1 种基金Project of China Geological Survey(No.DD20230505)Excellent Scientific Research and Innovation Team of Universities in Anhui Province(No.2023AH010071)。
文摘As a typical region with high water demand for agricultural production,understanding the spatiotemporal surface water changes in Northeast China is critical for water resources management and sustainable development.However,the long-term variation characteristics of surface water of different water body types in Northeast China remain rarely explored.This study investigated how surface water bodies of different types(e.g.,lake,reservoir,river,coastal aquaculture,marsh wetland,ephemeral water) changed during1999–2020 in Northeast China based on various remote sensing-based datasets.The results showed that surface water in Northeast China grew dramatically in the past two decades,with an equivalent area increasing from 24 394 km^(2) in 1999 to 34 595 km^(2) in 2020.The surge of ephemeral water is the primary driver of surface water expansion,which could ascribe to shifted precipitation pattern.Marsh wetlands,rivers,and reservoirs experienced a similar trend,with an approximate 20% increase at the interdecadal scale.By contrast,coastal aquacultures and natural lakes remain relatively stable.This study is expected to provide a more comprehensive investigation of the surface water variability in Northeast China and has important practical significance for the scientific management of different types of surface water.
基金the National Natural Science Foundation of China(41971215,42371205)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2022317).
文摘The Three Gorges Reservoir Area(TGRA)is an important ecological barrier in the Yangtze River Basin,China.Therefore,it is of great importance to understand the spatio-temporal variation and the driving factors of production-living-ecological spaces for sustainable and high-quality development in the TGRA.This study investigated the dynamic variation of production-living-ecological spaces in the TGRA by employing land use data in 2000,2005,2010,2015,and 2018,and detected the influencing factors by using the Geographic detector(GeoDetector).Results implied that the structure and dynamic trajectories of production-living-ecological spaces in the TGRA varied in both horizontal and vertical directions,and the study area was dominated by ecological space.A spatial orientation towards the northeast was detected in the evolution of production-living-ecological spaces during 2000-2018.In terms of quantity,the transition from ecological space(grassland and woodland)to agriculture land accounted for the largest proportion from 2000 to 2018.However,the reverse transition from agriculture land to ecological space has increased since 2000 with the efforts of“Grain for Green”.In terms of temporal scale,there was a fluctuating trend in production space with the continuous expansion of living space,while ecological space showed an inverted U-shaped trend during 2000-2018.The dynamic pattern of production-living-ecological spaces in the TGRA was influenced by both physical and socio-economic variables as basic determinants and dominant driving factors,respectively.Finally,the harmonization and protection of production-living-ecological spaces still require policy-makers’efforts.This work may have potential in advancing our understanding about land use conflicts,and provide a reference for rational layout of spatial functions and the realization of sustainable development in the TGRA.
基金supported by the National Natural Science Foundation of China(91851204 and 42021005)the Special project of eco-environmental technology for peak carbon dioxide emissions and carbon neutrality(RCEES-TDZ-2021-20).
文摘The availability of nitrogen(N)is crucial for both the productivity of terrestrial and aquatic ecosystems globally.However,the overuse of artificial fertilizers and the energy required to fix nitrogen have pushed the global nitrogen cycle(N-cycle)past its safe operating limits,leading to severe nitrogen pollution and the production of significant amounts of greenhouse gas nitrous oxide(N2O).The anaerobic ammonium oxidation(anammox)mechanism can counteract the release of ammonium and N2O in many oxygenlimited situations,assisting in the restoration of the homeostasis of the Earth’s N biogeochemistry.In this work,we looked into the characteristics of the anammox hotspots’distribution across various types of ecosystems worldwide.Anammox hotspots are present at diverse oxic-anoxic interfaces in terrestrial systems,and they are most prevalent at the oxic-anoxic transition zone in aquatic ecosystems.Based on the discovery of an anammox hotspot capable of oxidizing ammonium anoxically into N2 without N2O by-product,we then designed an innovative concept and technical routes of nature-based anammox hotspot geoengineering for climate change,biodiversity loss,and efficient utilization of water resources.After 15 years of actual use,anammox hotspot geoengineering has proven to be effective in ensuring clean drinking water,regulating the climate,fostering plant and animal diversity,and enhancing longterm environmental quality.The sustainable biogeoengineering of anammox could be a workable natural remedy to resolve the conflicts between environmental pollution and food security connected to N management.
基金Knowledge Innovation Program of Wuhan-Shugung Project,Grant/Award Number:2023020201020363。
文摘The widespread use of antibiotics has significantly increased their presence in aquatic environments,particularly in sensitive Karst River systems.In this study,the distribution and ecological,human health,and resistance selection risk assessment of 44 antibiotics in the typical Karst River,Lijiang River,were investigated during the influenza season,a period marked by heightened antibiotic usage.27 antibiotics could be found in the water of Lijiang River,among which azithromycin showing the highest concentrations.The concentrations of total antibiotics were in the range 171.70–2003.75 ng/L,with an average value of 704.76 ng/L.Macrolide was the predominant class,constituting an average of 57.65%of the total antibiotic concentrations.Risk assessments revealed that certain antibiotics,especially macrolides,posed moderate to high ecological risks to algae,displayed potential human health risks at low levels and contributed to antimicrobial resistance.Among all the antibiotics,azithromycin was the only one could cause ecological risk to algae,human health risk towards infants and antimicrobial resistance selection risk,which should be identified as the priority antibiotic for control in the Lijiang River during the influenza season.There was no difference in the concentrations,human health and antimicrobial resistance selection risk of antibiotics between mainstream and tributaries of Lijiang River.This study contributes to a better understanding of antibiotic pollution and provides insights into potential risk management practices in vulnerable aquatic systems worldwide.
基金National Natural Science Foundation of China(No.41371062)Collaborative Innovation Center for Major Ecological Security Issues of Jiangxi Province and Monitoring Implementation(No.JXS-EW-00)+1 种基金National Basic Research Program of China(No.2012CB417003)Science Foundation of Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences(No.NIGLAS2012135001)
文摘Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetland. Poyang Lake, the largest freshwater lake in China, has been encountering dramatic changes in hydrological conditions in last decade, which greatly influenced the wetland vegetations. To explore the relationships between hydrology and vegetation distri- bution, water-table depth, soil moisture, species composition, diversity and biomass were measured at a seasonally flooded wetland section at Wucheng National Nature Reserve. Three plant communities, Artemisia capillaris, Phragmites australis and Carex cineras- cens communities, were examined which are zonally distributed from upland to lakeshore with decreasing elevation. Canonical corre- spondence analysis （CCA）, spearmen correlation and logistic regression were adopted to analyze the relationships between vegetation characteristics and hydrological variables of water-table depth and soil moisture. Results show that significant hydrological gradient exist along the wetland transect. Water-table demonstrates a seasonal variation and is consistently deepest in A. capillaris community （ranging from q）.5 m above ground to ＋10.3 m below ground）, intermediate in P. australis community （-2.6 m to ＋7.8 m） and shallow- est in C. cinerascens community （-4.5 m to ＋6.1 m）. Soil moisture is lowest and most variable in A. capillaris community, highest and least variable in P. australis community, and intermediate and moderate variable in C. cinerascens community. The CCA ordination indicated that variables of water-table depth and soil moisture are strongly related to community distribution, which explained 81.7% of the vegetation variations. Species diversity indices are significantly positively correlated with soil moisture and negatively correlated with moisture variability, while above- and belowground biomass are positively correlated with moisture. Above- and belowground biomass present Gaussian models along the gradient of average water-table depth in growing season, while species diversity indices show bimodal patterns. The optimal average water-table depths for above- and belowground biomass are 0.8 m and 0.5 m, respectively, and are 2.2 m and 2.4 m for species richness and Shannon-Wiener indices, respectively. Outcomes of this work improved the under- standings of the relationship between hydrology and vegetation.
基金National Basic Research Program of China （＂973＂ Program）, No.2012CB417006 National Natural Science Foundation of China, No.41171024 No.41271500
文摘Seasonal water-level fluctuations （WLF） play a dominate role in lacustrine ecosys- tems. River-lake interaction is a direct factor in changes of seasonal lake WLF, especially for those lakes naturally connected to upstream and downstream rivers. During the past decade, the modification of WLF in the Poyang Lake （the largest freshwater lake in China） has caused intensified flood and irrigation crises, reduced water availability, compromised water quality and extensive degradation of the lake ecosystem. There has been a conjecture as to whether the modification was caused by its interactions with Yangtze River. In this study, we investi- gated the variations of seasonal WLF in China＇s Poyang Lake by comparing the water levels during the four distinct seasons （the dry season, the rising season, the flood season, and the retreating season） before and after 2003 when the Three Gorge Dam operated. The Water Surface Slope （WSS） was used as a representative parameter to measure the changes in river-lake interaction and its impacts on seasonal WLF. The results showed that the magni- tude of seasonal WLF has changed considerably since 2003; the seasonal WLF of the Poy- ang Lake have been significantly altered by the fact that the water levels both rise and retreat earlier in the season and lowered water levels in general. The fluctuations of river-lake in- teractions, in particular the changes during the retreating season, are mainly responsible for these variations in magnitude of seasonal WLF. This study demonstrates that WSS is a rep- resentative parameter to denote river-lake interactions, and the results indicate that more emphasis should be placed on the decrease of the Poyang Lake caused by the lowered water levels of the Yangtze River, especially in the retreating season.
