Accurate identification of sediment sources and erosion hotspots is crucial for implementing targeted soil and water conservation measures.This study analyzed the temporal dynamics of sediment source contributions dur...Accurate identification of sediment sources and erosion hotspots is crucial for implementing targeted soil and water conservation measures.This study analyzed the temporal dynamics of sediment source contributions during seven rainfall events(A_(1)–A_(7))that generated both runoff and suspended sediment at the outlet of the Hantaichuan watershed,located in the wind–water erosion crisscross region of the northern Loess Plateau,China.A total of 82 suspended sediment samples were collected at the Xiangshawan hydrological station during 2021 and 2022.Additionally,145 soil samples were collected from three primary potential sources:sandy soil,loess soil,and Pisha sandstone.Mid-infrared(MIR)spectroscopy and geochemical fingerprinting were used to trace and quantify sediment sources.For MIRbased source apportionment,twelve predictive models were developed using partial least squares regression(PLSR)and support vector machine regression(SVMR)in combination with six spectral preprocessing techniques.The PLSR model with first-derivative Savitzky–Golay(SGD1)preprocessing achieved the best performance.Source apportionment results indicated that Pisha sandstone was the dominant sediment source(44.00%–72.23%),followed by sandy soil(14.23%–37.00%)and loess soil(10.01%–24.00%).Among the analyzed rainfall events,the contribution of Pisha sandstone was lowest in the small flow magnitude event A3(57.53%)and highest in the large flow magnitude event A6(63.48%),suggesting that sediment source composition was strongly controlled by rainfall event magnitude.Both MIR spectroscopic and geochemical fingerprinting methods showed high consistency,confirming MIR spectroscopy as a reliable,non-destructive,and cost-effective alternative for rapid sediment source apportionment and for supporting erosion control prioritization in highly erodible catchments.展开更多
Fluoroquinolones(FQs)have the propensity to accumulate in sediments once introduction into aquatic envi-ronments,thereby posing potential threats to benthic organisms,yet the ecotoxicity of sediment-associated FQs rem...Fluoroquinolones(FQs)have the propensity to accumulate in sediments once introduction into aquatic envi-ronments,thereby posing potential threats to benthic organisms,yet the ecotoxicity of sediment-associated FQs remains unclear.In this study,the toxicokinetics and responses of multiple biomarkers in Bellamya aeruginosa,exposed to the three commonly used FQs(norfloxacin,NOR;ciprofloxacin,CIP;levofloxacin,LEVO)at envi-ronmentally relevant concentrations were investigated under sediment exposure scenario.The results revealed that FQs were effectively ingested by B.aeruginosa from sediments,CIP showing the highest bioaccumulation(180.59μg/kg),followed by NOR(74.49μg/kg)and LEVO(36.02μg/kg).CIP exhibiting a highest uptake rate constant(Ks)(4.64 g/(g·day))and the lowest elimination rate constant(K_(e))(0.05 g/(g·day)).The descending order of biological half-life is as follows:CIP(13.62 days),LEVO(8.14 days),and NOR(6.83 days).NOR induced the activity of superoxide dismutase,catalase,and glutathione-S-transferase while CIP and LEVO depressed their activities and increased malondialdehyde content,indicating a more pronounced oxidative damage to B.aerug-inosa caused by CIP and LEVO than NOR.Furthermore,all three FQs were found to induce DNA damage and elevate acetylcholinesterase activity,suggesting distinct genotoxic and neurotoxic effects.Interestingly,despite its low bioaccumulation potential,LEVO exhibited high toxicity towards B.aeruginosa.These findings enhance our understanding of the ecotoxicity of FQs in sediments,providing further evidence of their potential ecological risks.展开更多
Noncohesive particle clusters are identified and tracked in turbulent flows to determine the breakdown and time evolution of cluster statistics and their implications for interscale mass transfer,which has connections...Noncohesive particle clusters are identified and tracked in turbulent flows to determine the breakdown and time evolution of cluster statistics and their implications for interscale mass transfer,which has connections to the classical turbulent energy cascade and its mass cascade counterpart running in parallel.In particular,the formation and dynamics of sediment and larvae clusters are of interest to coral larvae settlement in coastal regions and particularly the resilience of green-gray coastal protection solutions.Analogous cluster behavior is relevant to cloud microphysics and precipitation initiation,radiation transport and light transmission through colloids and suspensions,heat and mass transfer in particle-laden flows,and viral and pollutant transmission.Following a comparison between various clustering techniques,we adopt a density-based cluster identification algorithm based on its simplicity and efficiency,where particles are clustered based on the number of neighboring particles in their individual spheres of influence.We establish parallels with lattice-based percolation theory,as evident in the power-law scaling of the cluster size distribution near the percolation threshold.The degree of discontinuity of the phase transition associated with this percolation threshold is observed to broaden with larger Stokes numbers and thereby large-scale clustering.The sensitivity of our findings to the employed clustering algorithm is discussed.A novel cluster tracking algorithm is deployed to determine the interscale transfer rate along the particle-number phase-space dimension via accounting of cluster breakup and merger events,extending previous work on the bubble breakup cascade beneath surface breaking waves.Our findings shed light on the interaction between particle clusters and their carrier turbulent flows,with an eye toward transport models incorporating cluster characteristics and dynamics.展开更多
With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving...With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving mechanism was still unclear.In this study,direct disintegration of biopolymers and indirect broken of connection point were investigated on the hydrolysis and component separation.Three typical sewer sediment treatment approaches,i.e.,alkaline,thermal and cation exchange treatments were proposed,which represented the hydrolysis-driving forces of chemical hydrolysis,physical hydrolysis and innovative cation bridging break-age.The results showed that the organic and inorganic separation rates of sewer sediment driven by alkaline,thermal and cation exchange treatments reached 21.26%,23.80%,and 19.56%-48.0%,respectively,compared to 4.43%in control.The secondary structure of proteins was disrupted,transitioning from𝛼α-helix to𝛽β-turn and random coil.Meanwhile,much biopolymers were released from solid to the liquid phase.From thermody-namic perspective,sewer sediment deposition was controlled by short-range interfacial interactions described by extended Derjaguin-Landau-Verwey-Overbeek theory.Additionally,the separation of organic and inorganic components was positively correlated with the thermodynamic parameters(Corr=0.87),highlighted the robust-ness of various driving forces.And the flocculation energy barriers were 2.40(alkaline),1.60 times(thermal),and 4.02–4.97 times(cation exchange)compared to control group.The findings revealed the contrition differ-ence of direct disintegration of gelatinous biopolymers and indirect breakage of composition connection sites in sediment composition separation,filling the critical gaps in understanding the specific mechanisms of sediment biopolymer disintegration and intermolecular connection breakage.展开更多
The variation laws of runoff and sediment load under different climate,vegetation,and human activity scenarios are significantly different.Exploring the impacts of climate change and human activities on runoff and sed...The variation laws of runoff and sediment load under different climate,vegetation,and human activity scenarios are significantly different.Exploring the impacts of climate change and human activities on runoff and sediment load dynamics can provide a profound understanding of the mechanism of runoff and sediment load variability in basins,which is crucial for the sustainable development of regional ecosystems.This study investigates the Tao River Basin(TRB)on the Tibetan Plateau,as well as the Zuli River Basin(ZRB)and Jing River Basin(JRB)on the Loess Plateau,to differentiate the impacts of climate change and human activities on runoff and sediment load dynamics.The runoff and sediment load of the three watersheds have shown a decreasing trend over the past 40 years,and combined with the DMC(Dual mass curve)method,it was found that the slope of the runoff sediment gradually tends to flatten out.After the time period was divided,the CA(Cumulative anomaly)method was used for verification,which revealed good correspondence between the two before 2000 and then gradual deviations.The power function best represents the relationship between runoff and sediment load.During the initial period,climate had a significant impact on runoff variation in the TRB and JRB,with contribution rates of-54.93%and-63.02%,respectively.In the later period,human activities became the dominant influence,contributing more than-60%of the runoff variation.In the ZRB,human activities consistently dominated runoff variation,with contribution rates of-72.72%and-55.66%during both periods.In the early stages of research,the impact of climate change on sediment load was more severe in the TRB and JRB,and human activities played a significant role in the later stages.However,in the ZRB,human activities have always been the main contributor.Based on the actual local situation,runoff and sediment load in the TRB are influenced primarily by engineering measures,and vegetation and check dams exert greater impacts on the ZRB and JRB.This study explores the attribution of water and sediment load changes in different ecological geographic regions from a comparative perspective,providing a valuable theoretical basis and reference for understanding global runoff and sediment transport changes in similar areas.展开更多
Estuaries are key areas for organic carbon cycling,where polymeric carbohydrates are abundant and chemically diverse.The recycling of these polymers by microbes depends on a variety of carbohydrate-active enzymes(CAZy...Estuaries are key areas for organic carbon cycling,where polymeric carbohydrates are abundant and chemically diverse.The recycling of these polymers by microbes depends on a variety of carbohydrate-active enzymes(CAZymes).However,it remains unclear whether other gene traits,particularly those related to cell motility toward polymeric carbohydrates,are intertwined with carbohydrate depolymerization and niche specialization in estuarine sediment soils.In this study,estuarine sediments were incubated with four prevalent polymeric carbohydrates(laminarin,fucan,cellulose,and chitin) under anaerobic conditions.Based on metagenomic analysis,we identified potential responses to the degradation and utilization of polymeric carbohydrate substrates from the perspectives of CAZymes and sugar transporters.The analysis of metagenomic gene data also revealed a positive correlation between chemotaxis and the abundance of CAZymes genes.Furthermore,metagenomes-assembled genomes(MAGs) that exhibited higher abundance in polysaccharide-treated samples compared to controls also featured elevated copies of genes involved in polysaccharide utilization loci(PULs),chemotaxis,as well as those associated with flagellar or gliding movement.SprB and CTDs associated with gliding proteins genes are essential for type Ⅸ secretion system-mediated secretion of CAZymes and gliding motility in Bacteroidota.The enhanced potential for mobility,coupled with the ability to degrade polymeric carbohydrates,may enable these bacteria to exploit nutrients beyond carbon sources,thereby potentially broadening their ecological niches.展开更多
Organic-rich sediments represent vital components of Earth's geochemical cycles, acting both as potential hydrocarbon and coal reservoirs and as unconventional archives for critical metals such as rare earth eleme...Organic-rich sediments represent vital components of Earth's geochemical cycles, acting both as potential hydrocarbon and coal reservoirs and as unconventional archives for critical metals such as rare earth elements(REEs). With the growing emphasis on clean energy technologies, the Cenozoic organic deposits of India have gained renewed significance;however, those from the southern state of Kerala remain understudied. This study investigates lignite and associated carbonaceous sediments from the Cheruvathur and Warkalli Formations using a multi-proxy approach integrating organic petrography,infrared spectroscopy, stable carbon isotopes, and REE geochemistry. The lignite exhibits huminite dominance with Type Ⅲ kerogen, deposited in a wet, mesotropic bog forest swamp under anoxic conditions. The mineral assemblage, dominated by kaolinite, quartz, illite, montmorillonite, feldspar,and pyrite/marcasite, reflects strong chemical alteration in a reducing environment. The δ^(13)C values(-25.1 to-27.3) indicate a C_(3) angiosperm source and deposition in tropical to subtropical swamp settings. REE patterns reveal LREE enrichment in carbonaceous shales and HREE enrichment in lignite,with distinct Ce, Eu, and Gd anomalies associated with provenance and redox conditions. The findings provide new insights into the paleoenvironmental evolution of Kerala's Cenozoic basins and highlight their potential as unconventional REE-bearing resources in the context of the global energy transition.展开更多
Soil erosion is a fundamental physical process driving land degradation across various spatial and temporal scales.The Soil and Water Assessment Tool(SWAT)model is a robust tool for predicting soil erosion and evaluat...Soil erosion is a fundamental physical process driving land degradation across various spatial and temporal scales.The Soil and Water Assessment Tool(SWAT)model is a robust tool for predicting soil erosion and evaluating water and soil quality within watersheds.The latest version,SWAT+,introduces advanced encoding capabilities and improved performance,making it better suited for addressing complex watershed modeling challenges.This study implemented the SWAT+model to quantify soil erosion rates within the Chehelchay watershed in northern Iran.The foundational dataset comprises a 30-meter resolution Digital Elevation Model(DEM),land use classification,soil,and weather data.Model performance was evaluated using Nash-Sutcliffe Efficiency(NSE),coefficient of determination(R^(2)),root mean square error(RMSE),and percent bias(PBIAS).The SWAT+simulation revealed substantial spatial variation in erosion patterns across the watershed,with annual sediment yields in critical HRUs,reflecting diverse erosion intensities driven by variations in land use,soil characteristics,and slope.Among the Hydrological Response Units(HRUs),50 critical units,representing approximately 9%of the total watershed area,generate sediment yields exceeding 5 tons per hectare per year.The most severe erosion occurs predominantly in the central zone of the watershed.Downstream regions exhibit minimal soil loss due to gentle topography while upstream areas maintain soil stability through protective forest cover,resulting in negligible erosion rates.Best Management Practices(BMPs)were designed to safeguard water and soil resources at a watershed level.The study evaluated three strategic conservation interventions:alfalfa cultivation,agroforestry implementation,and garden development.When applied in combination,these measures achieved approximately 30%reduction in sediment yield at the HRU level.This integrated approach demonstrates the potential of combining multiple land management strategies to combat erosion effectively.展开更多
This study compares the environmental sustainability of five alternatives for the remediation of marine sediments of one of the most polluted coastal sites in Europe(Bagnoli-Coroglio bay,Mediterranean Sea),using the L...This study compares the environmental sustainability of five alternatives for the remediation of marine sediments of one of the most polluted coastal sites in Europe(Bagnoli-Coroglio bay,Mediterranean Sea),using the Life Cycle Assessment(LCA)methodology.The treatments are either in-situ or exsitu,the latter requiring an initial dredging to transport the contaminated sediments to the management site.More in detail,four ex-situ remediation technologies based on landfilling,bioremediation,electrokinetic technique and soil washing were identified.These technologies are compared to an in-situ strategy currently under validation for enhancing bioremediation of the polluted sediments of the Bagnoli-Coroglio site.Our results indicate that the disposal in landfilling site is the worst option in most categories(e.g.,650 kg CO_(2) eq./t of treated sediment,considering the nearest landfilling site),followed by the bioremediation,mainly due to the high energy demand.Electrokinetic remediation,soil washing,and innovative in-situ technology represent the most sustainable options.In particular,the new in-situ technology appears to be the least impacting in all categories(e.g.,54 kg CO_(2) eq./t of treated sediment),although it is expected to require longer treatment time(estimated up to 12 months based on its potential efficiency).It can reduce the impact on climate change more than 12 times compared to the disposal and 7 times compared to bioremediation in addition to the possibility to avoid/reduce the dredging operations and the consequent dispersion of pollutants.The results open relevant perspectives towards more eco-sustainable and costly effective actions for the reclamation of contaminated marine sediments.展开更多
Sedimentary microbial communities play an important role in driving biogeochemical cycles in river ecosystems.The Yellow River is one of the rivers with the highest turbidity over the world.However,limited is known ab...Sedimentary microbial communities play an important role in driving biogeochemical cycles in river ecosystems.The Yellow River is one of the rivers with the highest turbidity over the world.However,limited is known about the microbial variation and its influencing factors in the Yellow River.In this study,we examined the microbial communities and their influencing factors in the sediment of Upper and Mid–Lower reaches of the Yellow River.The results showed that Gammaproteobacteria were most dominant(with Hydrogenophilaceae being the predominant family)in the studied Yellow River sediments.Phyla of Deltaproteobacteria,Nitrospirae and family of Bacillaceae,Geobaceraceae were more abundant in the Mid–Lower reaches than in the Upper reaches,while phyla of Gammaproteobacteria,Verrucomicrobia and family of Caldilineaceae,Llumatobacteraceae were more abundant in the Upper reaches than in the Mid–Lower reaches.The microbial communities were predominantly affected by nutrient factors(such as NH_(4)^(+),TN and TP),followed by the spatial and the content of Chla in the Mid–Lower reaches,while they were by predominantly affected by spatial factors,followed by the nutrient factors and the content of Chla in the Upper reaches.The dominant microbial taxa were mostly correlated with COD,NH_(4)^(+),TP and temperature,but they responded differently to these physiochemical factors between the Upper and Mid–Lower reaches.In summary,the sedimentary microbial communities differ between the Upper and Mid–Lower reaches and respond differently to the environmental and spatial factors in the sediment of the Yellow River.展开更多
Liquid-solid phase transfer promotes the interaction of perfluoroalkyl acids(PFAAs)with the microbial system of river sediments,which may affect the environmental behavior of antibiotic resistance genes(ARGs)contained...Liquid-solid phase transfer promotes the interaction of perfluoroalkyl acids(PFAAs)with the microbial system of river sediments,which may affect the environmental behavior of antibiotic resistance genes(ARGs)contained in benthic environments.Sediments collected from the receiving water of the largest fluoropolymer production facility in China were analyzed to investigate the impact of PFAAs on microbial communities and ARG profiles.The main contributors to the PFAAs were perfluorooctanoic acid and perfluorobutanoic acid,whose proportions(86.9%-93.4%)in the downstream surface sediments affected by industrial effluents were significantly higher than in the corresponding upstream samples(53.3%).A reduction in microbial diversity and richness was observed in the presence of high concentrations of PFAAs at the downstream sites.144 ARG subtypes,including three high-risk subtypes(bacA,aac(6′)-I and aadA),were identified in sediment samples.The discharge of fluorochemical effluents also results in a reduction of ARG diversity at subtype level.PFAAs exert a pronounced influence on the profile of ARGs in sediment.PFAAs and water quality parameters(e.g.pH and total phosphorus)were key drivers of the microbial community composition in the sediment.The regulation of microbial communities by PFAAs may represent an important pathway by which these compounds affect ARG profiles.展开更多
In sediment transport on a mobile erodible bed,near-bed particles tend to preferentially locate under specific flow regions and form an uneven bedform.These moving and mobile particles can significantly modulate turbu...In sediment transport on a mobile erodible bed,near-bed particles tend to preferentially locate under specific flow regions and form an uneven bedform.These moving and mobile particles can significantly modulate turbulence at various scales,from inertial large-scale motions to small viscous motions.This study analyzes the particle-resolved direct numerical simulation data of particle-laden two-phase flow with multilayers of particles in turbulent flows over static and mobile beds.The double-average method is adopted for energy transfer analysis.The result shows that the alternative streaky bedform in the spanwise directions correlates with the streak structures in the near-wall turbulence in the mobile bed case.The energy redistribution and exchange,as well as the dissipation,are analyzed in detail,and an energy transfer diagram is given in the last to summarize the energy transfer processes.In both the static and mobile bed cases,flow energy is introduced into the system via the work performed by volume forces acting on the mean flow.The viscous dissipations in the double mean and form-induced fields are more pronounced in the static bed case,and the work done by the fluid-particle interfacial stress in the double mean and turbulent fields is more pronounced in the mobile bed case.The prominent energy contribution in the form-induced field is the production by the form-induced stress on the mean strain in the mobile bed case.In addition,sediment transport involving a limited number of mobile particles is insufficient to capture the energy transfer processes that occur over the troughs and may intertwine the energy transfer processes over the mobile particles and the fixed particle bed.展开更多
Aeolian sediments in the eastern Qinghai Lake region,China serve as sensitive paleoclimate archives,offering an ideal window into past environmental conditions.This study investigated the Dashuitang(QDST)profile in th...Aeolian sediments in the eastern Qinghai Lake region,China serve as sensitive paleoclimate archives,offering an ideal window into past environmental conditions.This study investigated the Dashuitang(QDST)profile in the eastern Qinghai Lake region by integrating sediment grain size,chroma,and magnetic susceptibility(MS)proxies to reconstruct the regional environmental evolution since the Last Glacial Interstadial and to investigate its relationship with the water level fluctuations of Qinghai Lake.Grain size end-member modeling analysis(EMMA)identified three end-members:end-member 1(EM1)represented fine-grained material transported over longer distances through mixing processes,which could reveal the regional moisture conditions;end-member 2(EM2)primarily consisted of coarse-grained material from nearby sources transported via saltation or creep,indicating the intensity of the winter monsoon;and end-member 3(EM3)mainly reflected deposition from dust storm events controlled by regional low-altitude wind systems.In addition,the regional environmental sequence demonstrated coherence with other records,collectively elucidating the sub-orbital-scale dynamics of the Asian monsoon.The environmental sequence was divided into four principal phases on the basis of sedimentary characteristics and climatic responses:the late Last Glacial Interstadial,Last Glacial Maximum,Last Deglaciation,and Holocene phases.Additionally,the results of this study revealed that there is a close linkage between desertification and lake evolution in the eastern Qinghai Lake region.Since the Last Glacial Interstadial,desertification and lake evolution processes have generally exhibited a trade-off relationship,wherein lake level decline and desert expansion exhibited a direct positive feedback.However,during the early period of the Late Holocene(approximately 2.80–1.50 ka BP),a synergistic response pattern emerged,characterized by relatively high lake levels alongside moderate desert expansion,reflecting an asymmetric decoupling mechanism between the hydrological processes and aeolian dynamics during climatic transition periods.This study provides important insights for predicting the future evolution trends of lake-desert systems under climate change.展开更多
This study aims to prepare ternary all-solid-waste cementitious materials to completely replace ordinary Portland cement(OPC).Ground granulated blast-furnace slag(GGBS),carbide slag(CS),sulfate solid waste phosphogyps...This study aims to prepare ternary all-solid-waste cementitious materials to completely replace ordinary Portland cement(OPC).Ground granulated blast-furnace slag(GGBS),carbide slag(CS),sulfate solid waste phosphogypsum(PG),electrolytic manganese residue(EMR)and desulfurized gypsum(DG)were used as raw materials to prepare GGBS-PG-CS(GPC),GGBS-EMR-CS(GEC)and GGBS-DG-CS(GDC)ternary all-solid-waste cementitious materials.Macro and microscopic tests were carried out to reveal the mechanical properties and microscopic characteristics,as well as to quantitatively evaluate the environmental and economic benefits.The results show that the optimal ratios of GPC,GEC and GDC are 80:18:2,60:36:4 and 80:18:2,respectively.The corresponding 28 d-unconfined compressive strength(UCS)are 1.62,1.22 and 1.01 times that of OPC,respectively.Carbon emissions and costs per unit strength can be reduced by more than 97%and 57%,respectively.Microscopic analysis shows that the incorporation of sulfate solid waste can synergistically activate GGBS with CS to induce the growth of more needle-like ettringite(AFt),which filled the internal pores and improved the strength of the cementitious material.The better mechanical properties of solidified engineering sediment waste(ESW)also confirm the feasibility of replacing OPC.In summary,this study developed all-solid-waste cementitious materials with excellent mechanical performance,low costs and carbon emissions,which provided a sustainable and economic solution for ESW stabilization.展开更多
Benthic habitat mapping is an emerging discipline in the international marine field in recent years,providing an effective tool for marine spatial planning,marine ecological management,and decision-making applications...Benthic habitat mapping is an emerging discipline in the international marine field in recent years,providing an effective tool for marine spatial planning,marine ecological management,and decision-making applications.Seabed sediment classification is one of the main contents of seabed habitat mapping.In response to the impact of remote sensing imaging quality and the limitations of acoustic measurement range,where a single data source does not fully reflect the substrate type,we proposed a high-precision seabed habitat sediment classification method that integrates data from multiple sources.Based on WorldView-2 multi-spectral remote sensing image data and multibeam bathymetry data,constructed a random forests(RF)classifier with optimal feature selection.A seabed sediment classification experiment integrating optical remote sensing and acoustic remote sensing data was carried out in the shallow water area of Wuzhizhou Island,Hainan,South China.Different seabed sediment types,such as sand,seagrass,and coral reefs were effectively identified,with an overall classification accuracy of 92%.Experimental results show that RF matrix optimized by fusing multi-source remote sensing data for feature selection were better than the classification results of simple combinations of data sources,which improved the accuracy of seabed sediment classification.Therefore,the method proposed in this paper can be effectively applied to high-precision seabed sediment classification and habitat mapping around islands and reefs.展开更多
Under the background of global climate change, anthropogenic processes have profoundly altered the sources and transport mechanisms of coastal sediments. While previous research has primarily focused on large river de...Under the background of global climate change, anthropogenic processes have profoundly altered the sources and transport mechanisms of coastal sediments. While previous research has primarily focused on large river delta coasts,the responses of the widely distributed small bays dominated by ocean dynamics, has received comparatively less attention. To address this gap, this study examines the Weihai Bay, located in the northeast of Shandong Peninsula,China. By integrating total organic carbon isotope tracers(δ^(13)C and C/N) with sediment transport modeling, we systematically analyze the spatiotemporal patterns of surface sediment grain size inside and outside the bay, along with their responses to natural and human-induced drivers. Our findings reveal that the sedimentary environment of Weihai Bay is governed by the combined effects of tidal currents, ocean currents, wave activity, and sediment supply. Tidal dynamics dominate the hydrodynamic conditions within the bay, while ocean currents predominate offshore. Surface sediments in the bay are primarily composed of silt, originating from sediments carried by the Yellow Sea Warm Current. These sediments enter the bay through the southern bay mouth under tidal forcing, are redistributed counterclockwise by residual tidal currents, and eventually exit via the northern bay mouth. Coarser sediments in specific areas are primarily controlled by strong wave action and terrestrial inputs. Between 1988 and 2023, Weihai Bay sediments have undergone a noticeable coarsening trend, primarily driven by anthropogenic modifications to sediment supply and hydrodynamic regimes. Coastal reclamation, shoreline modification, and infrastructure development have intensified coarse-grained terrestrial sediment input. Concurrently, shoreline advancement has reduced wave dissipation, enhancing nearshore hydrodynamics and accelerating sediment coarsening. This study highlights the sensitivity of small bay sedimentary environments to anthropogenic forcing, advancing our understanding of the coupled human-marine sediment system and providing a scientific basis for coastal sediment evolution under the dual influences of climate change and human activity.展开更多
The Malacca Strait(MS)is a vital conduit for the exchange of water and sediment between the Indian Ocean and the Pacific Ocean,serving as a critical‘gateway'for sediment transport.Here,we present the geochemical ...The Malacca Strait(MS)is a vital conduit for the exchange of water and sediment between the Indian Ocean and the Pacific Ocean,serving as a critical‘gateway'for sediment transport.Here,we present the geochemical characteristics of surface sediments in the MS to elucidate the relationship between terrestrial material inputs and modern oceanic dynamic transport processes in the strait.The results reveal that the MS can be divided into three distinct geochemical provinces.ProvinceⅠ,located in the central region of the strait,is characterized by residual deposits.The preservation of these residual deposits can be attributed to the restricted sediment supply and the relatively weaker modern sedimentary hydrodynamic conditions.ProvinceⅡ,situated to the north of ProvinceⅠ,exhibits provenance differences between its southern and northern regions.The northern region is primarily supplied by sediments originating from the eastern shelf of the Andaman Sea,whereas sediments derived from Sumatra and the Sunda Shelf are predominantly deposited in the southern part of ProvinceⅡ.ProvinceⅢextends along the western coast of the Malaysian Peninsula,with sediments primarily sourced from the Malaysian Peninsula and the Sunda Shelf,while contributions from Sumatra and the eastern shelf of the Andaman Sea are negligible.River sediments from the Malaysian Peninsula and Sumatra are transported northwestward along their respective coasts by prevailing currents,which also facilitate the transportation of Sunda Shelf sediments within the strait,while sediments from the eastern shelf of the Andaman Sea are delivered to the MS via southward coastal currents during the southwest monsoon period.The southward currents and well-developed eddies potentially impede the northward transport of sediments from the Sunda Shelf and restrict the distribution of Andaman Sea sediments within the strait.This study substantially enhances the understanding of source-to-sink processes in the Indo-Pacific region.展开更多
Organic phosphorus(OP)constitutes an important fraction of total phosphorus in lake sediments,with its mobility being influenced by mineralization and transformation of organic carbon(OC).OP and OC co-exist in various...Organic phosphorus(OP)constitutes an important fraction of total phosphorus in lake sediments,with its mobility being influenced by mineralization and transformation of organic carbon(OC).OP and OC co-exist in various forms in the environment,thus a thorough investigation on the impact of OC fractions on the release of OP in sediments should be comprehensively carried out.This study determined the chemical forms of OP and OC in the sediments over four seasons in Lake Taihu and found temporal and spatial variations in their concentrations.The concentration of total OP and total OC ranged from 133 to 348 mg/kg and 4.77 to 21.19 mg/kg,respectively.Correlation between chemical fractions of OP and OC also revealed that Na OH-extracted OP,and fulvic acid-bound and humic acid-bound OP were positively correlated with humic-OC and hot hydrolysis-OC.These results suggest that the algal-derived OC degradation and mineralization may enhance OP mineralization,converting stable or moderately active OP into active forms or inorganic phosphorus under cyanobacterial bloom.This study provides insight and guiding support for investigating the impact of organic matter components on the transformation of OP after cyanobacterial degradation in eutrophic lakes.展开更多
The distribution of the sediment material storage quantity along the debris flow channels(SMSQ_DFC)can provide a foundation for runoffgenerated debris flow prediction or susceptibility assessment.Current models for es...The distribution of the sediment material storage quantity along the debris flow channels(SMSQ_DFC)can provide a foundation for runoffgenerated debris flow prediction or susceptibility assessment.Current models for estimating SMSQ_DFC do not consider the capacity of the channel cross-section to accommodate sediment materials.This accommodation condition serves as a limiting factor in determining whether the expected surplus of sediment materials can ultimately be stored.To address this issue,a mass-conservative index was used to represent the balance of deposit materials at any cross-section,considering the influx from upstream,outflux to downstream,and accommodation capacity.Based on this index,a new model for estimating SMSQ_DFC was developed and subsequently evaluated.The evaluation results show that the model meets the accuracy requirements with average error rates of 14.06%for self-validation and 14.81%for generalization ability validation.To assess its practical applications,the model was applied to the Yeniu Gully in Wenchuan County,Sichuan Province,an area with detailed field survey data.The results show that the model exhibits a commendable performance.Compared to traditional theoretical and semi-theoretical statistical models,our model is easier to use(input parameters can be obtained using Geographic Information Systems(GIS)).The modeling parameters chosen in this study have more theoretical significance than those used in existing purely statistical models,offering more effective technical support for estimating SMSQ_DFC.展开更多
Soft-sediment deformation structures(SSDS)in water-saturated,unconsolidated sediments are the product of various causes and provide a valuable record of environmental and geological perturbations.We report a record of...Soft-sediment deformation structures(SSDS)in water-saturated,unconsolidated sediments are the product of various causes and provide a valuable record of environmental and geological perturbations.We report a record of SSDS preserved in a~166 m-long drill core(DX-2)extracted from the Late Pleistocene Diexi Palaeolake,eastern Tibetan Plateau.Two factors make this an outstanding site for studying SSDS:(1)it is among the most seismically active regions on Earth,and(2)it has experienced extremely fast sedimentation rates(~15 mm/yr)thanks to the prodigious sediment supply from seismically perturbed hillslopes and rivers upstream.We describe and interpret 13 SSDS types within the DX-2 based on detailed sedimentological,morphological,and lithological analysis.We consider the genesis of the abundant SSDS observed in the DX-2 core with several possibilities:mass movement,rock avalanche-driven tsunamis,rapid sedimentation,and seismic shaking as the most probable triggering mechanisms.We suggest high-intensity earthquakes of VI(Modified Mercalli Intensity)or greater as drivers of SSDS in the DX-2.Based on our observations,we propose a conceptual model that attempts to explain the transition from ductile to brittle SSDS behaviour with progressive accumulation and consolidation of the sediment pile.This paper highlights the value of SSDS analysis in palaeo-earthquake identification,aiming to improve the applicability of SSDS as a palaeo-earthquake marker in alpine and canyon areas.展开更多
基金supported by the National Key Scientific Research Project(Grant No.2023YFC3209303)jointly funded by the National Natural Sciences Foundation of China(Grant Nos.42577406 and 42077076)the National Natural Science Foundation of China and Yellow River Water Science Research Joint Fund(Grant No.U2243211).
文摘Accurate identification of sediment sources and erosion hotspots is crucial for implementing targeted soil and water conservation measures.This study analyzed the temporal dynamics of sediment source contributions during seven rainfall events(A_(1)–A_(7))that generated both runoff and suspended sediment at the outlet of the Hantaichuan watershed,located in the wind–water erosion crisscross region of the northern Loess Plateau,China.A total of 82 suspended sediment samples were collected at the Xiangshawan hydrological station during 2021 and 2022.Additionally,145 soil samples were collected from three primary potential sources:sandy soil,loess soil,and Pisha sandstone.Mid-infrared(MIR)spectroscopy and geochemical fingerprinting were used to trace and quantify sediment sources.For MIRbased source apportionment,twelve predictive models were developed using partial least squares regression(PLSR)and support vector machine regression(SVMR)in combination with six spectral preprocessing techniques.The PLSR model with first-derivative Savitzky–Golay(SGD1)preprocessing achieved the best performance.Source apportionment results indicated that Pisha sandstone was the dominant sediment source(44.00%–72.23%),followed by sandy soil(14.23%–37.00%)and loess soil(10.01%–24.00%).Among the analyzed rainfall events,the contribution of Pisha sandstone was lowest in the small flow magnitude event A3(57.53%)and highest in the large flow magnitude event A6(63.48%),suggesting that sediment source composition was strongly controlled by rainfall event magnitude.Both MIR spectroscopic and geochemical fingerprinting methods showed high consistency,confirming MIR spectroscopy as a reliable,non-destructive,and cost-effective alternative for rapid sediment source apportionment and for supporting erosion control prioritization in highly erodible catchments.
基金supported by the Hunan Provincial Natural Science Foundation of China(Nos.2023JJ40518 and 2023JJ30490)the Scientific Research Foundation of Hunan Provincial Education Department(Nos.21B0511 and 22A0384)the Research Funding Project of Jishou University for talent introduction.
文摘Fluoroquinolones(FQs)have the propensity to accumulate in sediments once introduction into aquatic envi-ronments,thereby posing potential threats to benthic organisms,yet the ecotoxicity of sediment-associated FQs remains unclear.In this study,the toxicokinetics and responses of multiple biomarkers in Bellamya aeruginosa,exposed to the three commonly used FQs(norfloxacin,NOR;ciprofloxacin,CIP;levofloxacin,LEVO)at envi-ronmentally relevant concentrations were investigated under sediment exposure scenario.The results revealed that FQs were effectively ingested by B.aeruginosa from sediments,CIP showing the highest bioaccumulation(180.59μg/kg),followed by NOR(74.49μg/kg)and LEVO(36.02μg/kg).CIP exhibiting a highest uptake rate constant(Ks)(4.64 g/(g·day))and the lowest elimination rate constant(K_(e))(0.05 g/(g·day)).The descending order of biological half-life is as follows:CIP(13.62 days),LEVO(8.14 days),and NOR(6.83 days).NOR induced the activity of superoxide dismutase,catalase,and glutathione-S-transferase while CIP and LEVO depressed their activities and increased malondialdehyde content,indicating a more pronounced oxidative damage to B.aerug-inosa caused by CIP and LEVO than NOR.Furthermore,all three FQs were found to induce DNA damage and elevate acetylcholinesterase activity,suggesting distinct genotoxic and neurotoxic effects.Interestingly,despite its low bioaccumulation potential,LEVO exhibited high toxicity towards B.aeruginosa.These findings enhance our understanding of the ecotoxicity of FQs in sediments,providing further evidence of their potential ecological risks.
文摘Noncohesive particle clusters are identified and tracked in turbulent flows to determine the breakdown and time evolution of cluster statistics and their implications for interscale mass transfer,which has connections to the classical turbulent energy cascade and its mass cascade counterpart running in parallel.In particular,the formation and dynamics of sediment and larvae clusters are of interest to coral larvae settlement in coastal regions and particularly the resilience of green-gray coastal protection solutions.Analogous cluster behavior is relevant to cloud microphysics and precipitation initiation,radiation transport and light transmission through colloids and suspensions,heat and mass transfer in particle-laden flows,and viral and pollutant transmission.Following a comparison between various clustering techniques,we adopt a density-based cluster identification algorithm based on its simplicity and efficiency,where particles are clustered based on the number of neighboring particles in their individual spheres of influence.We establish parallels with lattice-based percolation theory,as evident in the power-law scaling of the cluster size distribution near the percolation threshold.The degree of discontinuity of the phase transition associated with this percolation threshold is observed to broaden with larger Stokes numbers and thereby large-scale clustering.The sensitivity of our findings to the employed clustering algorithm is discussed.A novel cluster tracking algorithm is deployed to determine the interscale transfer rate along the particle-number phase-space dimension via accounting of cluster breakup and merger events,extending previous work on the bubble breakup cascade beneath surface breaking waves.Our findings shed light on the interaction between particle clusters and their carrier turbulent flows,with an eye toward transport models incorporating cluster characteristics and dynamics.
基金supported by Shaanxi Key Research and Development Program(No.2024SF-YBXM-546)the National Natural Science Foundation of China(No.52470161)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF21007).
文摘With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving mechanism was still unclear.In this study,direct disintegration of biopolymers and indirect broken of connection point were investigated on the hydrolysis and component separation.Three typical sewer sediment treatment approaches,i.e.,alkaline,thermal and cation exchange treatments were proposed,which represented the hydrolysis-driving forces of chemical hydrolysis,physical hydrolysis and innovative cation bridging break-age.The results showed that the organic and inorganic separation rates of sewer sediment driven by alkaline,thermal and cation exchange treatments reached 21.26%,23.80%,and 19.56%-48.0%,respectively,compared to 4.43%in control.The secondary structure of proteins was disrupted,transitioning from𝛼α-helix to𝛽β-turn and random coil.Meanwhile,much biopolymers were released from solid to the liquid phase.From thermody-namic perspective,sewer sediment deposition was controlled by short-range interfacial interactions described by extended Derjaguin-Landau-Verwey-Overbeek theory.Additionally,the separation of organic and inorganic components was positively correlated with the thermodynamic parameters(Corr=0.87),highlighted the robust-ness of various driving forces.And the flocculation energy barriers were 2.40(alkaline),1.60 times(thermal),and 4.02–4.97 times(cation exchange)compared to control group.The findings revealed the contrition differ-ence of direct disintegration of gelatinous biopolymers and indirect breakage of composition connection sites in sediment composition separation,filling the critical gaps in understanding the specific mechanisms of sediment biopolymer disintegration and intermolecular connection breakage.
基金funding from the Natural Science Foundation of Shanxi Province(202403021222245,20240302121217)。
文摘The variation laws of runoff and sediment load under different climate,vegetation,and human activity scenarios are significantly different.Exploring the impacts of climate change and human activities on runoff and sediment load dynamics can provide a profound understanding of the mechanism of runoff and sediment load variability in basins,which is crucial for the sustainable development of regional ecosystems.This study investigates the Tao River Basin(TRB)on the Tibetan Plateau,as well as the Zuli River Basin(ZRB)and Jing River Basin(JRB)on the Loess Plateau,to differentiate the impacts of climate change and human activities on runoff and sediment load dynamics.The runoff and sediment load of the three watersheds have shown a decreasing trend over the past 40 years,and combined with the DMC(Dual mass curve)method,it was found that the slope of the runoff sediment gradually tends to flatten out.After the time period was divided,the CA(Cumulative anomaly)method was used for verification,which revealed good correspondence between the two before 2000 and then gradual deviations.The power function best represents the relationship between runoff and sediment load.During the initial period,climate had a significant impact on runoff variation in the TRB and JRB,with contribution rates of-54.93%and-63.02%,respectively.In the later period,human activities became the dominant influence,contributing more than-60%of the runoff variation.In the ZRB,human activities consistently dominated runoff variation,with contribution rates of-72.72%and-55.66%during both periods.In the early stages of research,the impact of climate change on sediment load was more severe in the TRB and JRB,and human activities played a significant role in the later stages.However,in the ZRB,human activities have always been the main contributor.Based on the actual local situation,runoff and sediment load in the TRB are influenced primarily by engineering measures,and vegetation and check dams exert greater impacts on the ZRB and JRB.This study explores the attribution of water and sediment load changes in different ecological geographic regions from a comparative perspective,providing a valuable theoretical basis and reference for understanding global runoff and sediment transport changes in similar areas.
基金supported by the National Natural Science Foundation of China(Nos.42073078,U1901211 and 41876126)the National Key Research and Development Program of China(Nos.2023YFC3905003,2023-67 and 2017FY100700)+4 种基金the Hainan Province Science and Technology Special Fund(ZDYF2023SHFZ172)the Natural Science Foundation of Guangdong Province(Nos.2020A1515011137,2023A1515012004 and 2024A1515011203)Nansha District High-Level Talent Innovation Team Project in 2021(Mangrove Wetland Blue Carbon Sequestration Technology Innovation Team)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA19060204)the Key Tasks Guarantee Special Fund Project for Green-Beautiful Guangdong Ecological Construction in 2024(Precise Restoration and Ecological Function Evaluation of Mangroves).
文摘Estuaries are key areas for organic carbon cycling,where polymeric carbohydrates are abundant and chemically diverse.The recycling of these polymers by microbes depends on a variety of carbohydrate-active enzymes(CAZymes).However,it remains unclear whether other gene traits,particularly those related to cell motility toward polymeric carbohydrates,are intertwined with carbohydrate depolymerization and niche specialization in estuarine sediment soils.In this study,estuarine sediments were incubated with four prevalent polymeric carbohydrates(laminarin,fucan,cellulose,and chitin) under anaerobic conditions.Based on metagenomic analysis,we identified potential responses to the degradation and utilization of polymeric carbohydrate substrates from the perspectives of CAZymes and sugar transporters.The analysis of metagenomic gene data also revealed a positive correlation between chemotaxis and the abundance of CAZymes genes.Furthermore,metagenomes-assembled genomes(MAGs) that exhibited higher abundance in polysaccharide-treated samples compared to controls also featured elevated copies of genes involved in polysaccharide utilization loci(PULs),chemotaxis,as well as those associated with flagellar or gliding movement.SprB and CTDs associated with gliding proteins genes are essential for type Ⅸ secretion system-mediated secretion of CAZymes and gliding motility in Bacteroidota.The enhanced potential for mobility,coupled with the ability to degrade polymeric carbohydrates,may enable these bacteria to exploit nutrients beyond carbon sources,thereby potentially broadening their ecological niches.
文摘Organic-rich sediments represent vital components of Earth's geochemical cycles, acting both as potential hydrocarbon and coal reservoirs and as unconventional archives for critical metals such as rare earth elements(REEs). With the growing emphasis on clean energy technologies, the Cenozoic organic deposits of India have gained renewed significance;however, those from the southern state of Kerala remain understudied. This study investigates lignite and associated carbonaceous sediments from the Cheruvathur and Warkalli Formations using a multi-proxy approach integrating organic petrography,infrared spectroscopy, stable carbon isotopes, and REE geochemistry. The lignite exhibits huminite dominance with Type Ⅲ kerogen, deposited in a wet, mesotropic bog forest swamp under anoxic conditions. The mineral assemblage, dominated by kaolinite, quartz, illite, montmorillonite, feldspar,and pyrite/marcasite, reflects strong chemical alteration in a reducing environment. The δ^(13)C values(-25.1 to-27.3) indicate a C_(3) angiosperm source and deposition in tropical to subtropical swamp settings. REE patterns reveal LREE enrichment in carbonaceous shales and HREE enrichment in lignite,with distinct Ce, Eu, and Gd anomalies associated with provenance and redox conditions. The findings provide new insights into the paleoenvironmental evolution of Kerala's Cenozoic basins and highlight their potential as unconventional REE-bearing resources in the context of the global energy transition.
文摘Soil erosion is a fundamental physical process driving land degradation across various spatial and temporal scales.The Soil and Water Assessment Tool(SWAT)model is a robust tool for predicting soil erosion and evaluating water and soil quality within watersheds.The latest version,SWAT+,introduces advanced encoding capabilities and improved performance,making it better suited for addressing complex watershed modeling challenges.This study implemented the SWAT+model to quantify soil erosion rates within the Chehelchay watershed in northern Iran.The foundational dataset comprises a 30-meter resolution Digital Elevation Model(DEM),land use classification,soil,and weather data.Model performance was evaluated using Nash-Sutcliffe Efficiency(NSE),coefficient of determination(R^(2)),root mean square error(RMSE),and percent bias(PBIAS).The SWAT+simulation revealed substantial spatial variation in erosion patterns across the watershed,with annual sediment yields in critical HRUs,reflecting diverse erosion intensities driven by variations in land use,soil characteristics,and slope.Among the Hydrological Response Units(HRUs),50 critical units,representing approximately 9%of the total watershed area,generate sediment yields exceeding 5 tons per hectare per year.The most severe erosion occurs predominantly in the central zone of the watershed.Downstream regions exhibit minimal soil loss due to gentle topography while upstream areas maintain soil stability through protective forest cover,resulting in negligible erosion rates.Best Management Practices(BMPs)were designed to safeguard water and soil resources at a watershed level.The study evaluated three strategic conservation interventions:alfalfa cultivation,agroforestry implementation,and garden development.When applied in combination,these measures achieved approximately 30%reduction in sediment yield at the HRU level.This integrated approach demonstrates the potential of combining multiple land management strategies to combat erosion effectively.
基金support in the literature analysis.This study has been carried out in the framework of the project funded by EU entitled“Bioremediation of contaminated sediments in coastal areas of exindustrial sites-LIFE SEDREMED”(No.LIFE20 ENV/IT/000572).
文摘This study compares the environmental sustainability of five alternatives for the remediation of marine sediments of one of the most polluted coastal sites in Europe(Bagnoli-Coroglio bay,Mediterranean Sea),using the Life Cycle Assessment(LCA)methodology.The treatments are either in-situ or exsitu,the latter requiring an initial dredging to transport the contaminated sediments to the management site.More in detail,four ex-situ remediation technologies based on landfilling,bioremediation,electrokinetic technique and soil washing were identified.These technologies are compared to an in-situ strategy currently under validation for enhancing bioremediation of the polluted sediments of the Bagnoli-Coroglio site.Our results indicate that the disposal in landfilling site is the worst option in most categories(e.g.,650 kg CO_(2) eq./t of treated sediment,considering the nearest landfilling site),followed by the bioremediation,mainly due to the high energy demand.Electrokinetic remediation,soil washing,and innovative in-situ technology represent the most sustainable options.In particular,the new in-situ technology appears to be the least impacting in all categories(e.g.,54 kg CO_(2) eq./t of treated sediment),although it is expected to require longer treatment time(estimated up to 12 months based on its potential efficiency).It can reduce the impact on climate change more than 12 times compared to the disposal and 7 times compared to bioremediation in addition to the possibility to avoid/reduce the dredging operations and the consequent dispersion of pollutants.The results open relevant perspectives towards more eco-sustainable and costly effective actions for the reclamation of contaminated marine sediments.
基金funded by the National Natural Science Foundation of China(No.42402310)the Natural Science Foundation of Henan Province(No.242300421657)+1 种基金the National Key Research and Development Program(No.2024YFD2402005)the China Agriculture Research System(No.CARS-50)。
文摘Sedimentary microbial communities play an important role in driving biogeochemical cycles in river ecosystems.The Yellow River is one of the rivers with the highest turbidity over the world.However,limited is known about the microbial variation and its influencing factors in the Yellow River.In this study,we examined the microbial communities and their influencing factors in the sediment of Upper and Mid–Lower reaches of the Yellow River.The results showed that Gammaproteobacteria were most dominant(with Hydrogenophilaceae being the predominant family)in the studied Yellow River sediments.Phyla of Deltaproteobacteria,Nitrospirae and family of Bacillaceae,Geobaceraceae were more abundant in the Mid–Lower reaches than in the Upper reaches,while phyla of Gammaproteobacteria,Verrucomicrobia and family of Caldilineaceae,Llumatobacteraceae were more abundant in the Upper reaches than in the Mid–Lower reaches.The microbial communities were predominantly affected by nutrient factors(such as NH_(4)^(+),TN and TP),followed by the spatial and the content of Chla in the Mid–Lower reaches,while they were by predominantly affected by spatial factors,followed by the nutrient factors and the content of Chla in the Upper reaches.The dominant microbial taxa were mostly correlated with COD,NH_(4)^(+),TP and temperature,but they responded differently to these physiochemical factors between the Upper and Mid–Lower reaches.In summary,the sedimentary microbial communities differ between the Upper and Mid–Lower reaches and respond differently to the environmental and spatial factors in the sediment of the Yellow River.
基金supported by the National Key Research and Develop-ment Program of China(No.2021YFC3200805)the National Natu-ral Science Foundation of China(Nos.52325001 and 52170009).
文摘Liquid-solid phase transfer promotes the interaction of perfluoroalkyl acids(PFAAs)with the microbial system of river sediments,which may affect the environmental behavior of antibiotic resistance genes(ARGs)contained in benthic environments.Sediments collected from the receiving water of the largest fluoropolymer production facility in China were analyzed to investigate the impact of PFAAs on microbial communities and ARG profiles.The main contributors to the PFAAs were perfluorooctanoic acid and perfluorobutanoic acid,whose proportions(86.9%-93.4%)in the downstream surface sediments affected by industrial effluents were significantly higher than in the corresponding upstream samples(53.3%).A reduction in microbial diversity and richness was observed in the presence of high concentrations of PFAAs at the downstream sites.144 ARG subtypes,including three high-risk subtypes(bacA,aac(6′)-I and aadA),were identified in sediment samples.The discharge of fluorochemical effluents also results in a reduction of ARG diversity at subtype level.PFAAs exert a pronounced influence on the profile of ARGs in sediment.PFAAs and water quality parameters(e.g.pH and total phosphorus)were key drivers of the microbial community composition in the sediment.The regulation of microbial communities by PFAAs may represent an important pathway by which these compounds affect ARG profiles.
基金supported by the National Natural Science Foundation of China(Grant Nos.12388101 and 12472221)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2024-oy10).
文摘In sediment transport on a mobile erodible bed,near-bed particles tend to preferentially locate under specific flow regions and form an uneven bedform.These moving and mobile particles can significantly modulate turbulence at various scales,from inertial large-scale motions to small viscous motions.This study analyzes the particle-resolved direct numerical simulation data of particle-laden two-phase flow with multilayers of particles in turbulent flows over static and mobile beds.The double-average method is adopted for energy transfer analysis.The result shows that the alternative streaky bedform in the spanwise directions correlates with the streak structures in the near-wall turbulence in the mobile bed case.The energy redistribution and exchange,as well as the dissipation,are analyzed in detail,and an energy transfer diagram is given in the last to summarize the energy transfer processes.In both the static and mobile bed cases,flow energy is introduced into the system via the work performed by volume forces acting on the mean flow.The viscous dissipations in the double mean and form-induced fields are more pronounced in the static bed case,and the work done by the fluid-particle interfacial stress in the double mean and turbulent fields is more pronounced in the mobile bed case.The prominent energy contribution in the form-induced field is the production by the form-induced stress on the mean strain in the mobile bed case.In addition,sediment transport involving a limited number of mobile particles is insufficient to capture the energy transfer processes that occur over the troughs and may intertwine the energy transfer processes over the mobile particles and the fixed particle bed.
基金supported by the National Natural Science Foundation of China(41171018,41161036).
文摘Aeolian sediments in the eastern Qinghai Lake region,China serve as sensitive paleoclimate archives,offering an ideal window into past environmental conditions.This study investigated the Dashuitang(QDST)profile in the eastern Qinghai Lake region by integrating sediment grain size,chroma,and magnetic susceptibility(MS)proxies to reconstruct the regional environmental evolution since the Last Glacial Interstadial and to investigate its relationship with the water level fluctuations of Qinghai Lake.Grain size end-member modeling analysis(EMMA)identified three end-members:end-member 1(EM1)represented fine-grained material transported over longer distances through mixing processes,which could reveal the regional moisture conditions;end-member 2(EM2)primarily consisted of coarse-grained material from nearby sources transported via saltation or creep,indicating the intensity of the winter monsoon;and end-member 3(EM3)mainly reflected deposition from dust storm events controlled by regional low-altitude wind systems.In addition,the regional environmental sequence demonstrated coherence with other records,collectively elucidating the sub-orbital-scale dynamics of the Asian monsoon.The environmental sequence was divided into four principal phases on the basis of sedimentary characteristics and climatic responses:the late Last Glacial Interstadial,Last Glacial Maximum,Last Deglaciation,and Holocene phases.Additionally,the results of this study revealed that there is a close linkage between desertification and lake evolution in the eastern Qinghai Lake region.Since the Last Glacial Interstadial,desertification and lake evolution processes have generally exhibited a trade-off relationship,wherein lake level decline and desert expansion exhibited a direct positive feedback.However,during the early period of the Late Holocene(approximately 2.80–1.50 ka BP),a synergistic response pattern emerged,characterized by relatively high lake levels alongside moderate desert expansion,reflecting an asymmetric decoupling mechanism between the hydrological processes and aeolian dynamics during climatic transition periods.This study provides important insights for predicting the future evolution trends of lake-desert systems under climate change.
基金support from the Key R&D Program Project of Hubei Province of China(Grant No.2023BCB074)the National Natural Science Foundation of China(Grant No.42307232).
文摘This study aims to prepare ternary all-solid-waste cementitious materials to completely replace ordinary Portland cement(OPC).Ground granulated blast-furnace slag(GGBS),carbide slag(CS),sulfate solid waste phosphogypsum(PG),electrolytic manganese residue(EMR)and desulfurized gypsum(DG)were used as raw materials to prepare GGBS-PG-CS(GPC),GGBS-EMR-CS(GEC)and GGBS-DG-CS(GDC)ternary all-solid-waste cementitious materials.Macro and microscopic tests were carried out to reveal the mechanical properties and microscopic characteristics,as well as to quantitatively evaluate the environmental and economic benefits.The results show that the optimal ratios of GPC,GEC and GDC are 80:18:2,60:36:4 and 80:18:2,respectively.The corresponding 28 d-unconfined compressive strength(UCS)are 1.62,1.22 and 1.01 times that of OPC,respectively.Carbon emissions and costs per unit strength can be reduced by more than 97%and 57%,respectively.Microscopic analysis shows that the incorporation of sulfate solid waste can synergistically activate GGBS with CS to induce the growth of more needle-like ettringite(AFt),which filled the internal pores and improved the strength of the cementitious material.The better mechanical properties of solidified engineering sediment waste(ESW)also confirm the feasibility of replacing OPC.In summary,this study developed all-solid-waste cementitious materials with excellent mechanical performance,low costs and carbon emissions,which provided a sustainable and economic solution for ESW stabilization.
基金Supported by the National Natural Science Foundation of China(Nos.42376185,41876111)the Shandong Provincial Natural Science Foundation(No.ZR2023MD073)。
文摘Benthic habitat mapping is an emerging discipline in the international marine field in recent years,providing an effective tool for marine spatial planning,marine ecological management,and decision-making applications.Seabed sediment classification is one of the main contents of seabed habitat mapping.In response to the impact of remote sensing imaging quality and the limitations of acoustic measurement range,where a single data source does not fully reflect the substrate type,we proposed a high-precision seabed habitat sediment classification method that integrates data from multiple sources.Based on WorldView-2 multi-spectral remote sensing image data and multibeam bathymetry data,constructed a random forests(RF)classifier with optimal feature selection.A seabed sediment classification experiment integrating optical remote sensing and acoustic remote sensing data was carried out in the shallow water area of Wuzhizhou Island,Hainan,South China.Different seabed sediment types,such as sand,seagrass,and coral reefs were effectively identified,with an overall classification accuracy of 92%.Experimental results show that RF matrix optimized by fusing multi-source remote sensing data for feature selection were better than the classification results of simple combinations of data sources,which improved the accuracy of seabed sediment classification.Therefore,the method proposed in this paper can be effectively applied to high-precision seabed sediment classification and habitat mapping around islands and reefs.
基金The Fund of National Archaeological Talent Promotion Program of China under contract No.2024-269“2024 Shandong Weihai Underwater Archaeological Survey” program by National Center for Archaeology under contract No. 20243160A0965+2 种基金Fujian Provincial Science and Technology Planning Projects under contract No. 2022L3001Provincial Natural Science Foundation of Fujian under contract No. 2023J01020MEL Internal Program of Xiamen University under contract No. MELRI2303。
文摘Under the background of global climate change, anthropogenic processes have profoundly altered the sources and transport mechanisms of coastal sediments. While previous research has primarily focused on large river delta coasts,the responses of the widely distributed small bays dominated by ocean dynamics, has received comparatively less attention. To address this gap, this study examines the Weihai Bay, located in the northeast of Shandong Peninsula,China. By integrating total organic carbon isotope tracers(δ^(13)C and C/N) with sediment transport modeling, we systematically analyze the spatiotemporal patterns of surface sediment grain size inside and outside the bay, along with their responses to natural and human-induced drivers. Our findings reveal that the sedimentary environment of Weihai Bay is governed by the combined effects of tidal currents, ocean currents, wave activity, and sediment supply. Tidal dynamics dominate the hydrodynamic conditions within the bay, while ocean currents predominate offshore. Surface sediments in the bay are primarily composed of silt, originating from sediments carried by the Yellow Sea Warm Current. These sediments enter the bay through the southern bay mouth under tidal forcing, are redistributed counterclockwise by residual tidal currents, and eventually exit via the northern bay mouth. Coarser sediments in specific areas are primarily controlled by strong wave action and terrestrial inputs. Between 1988 and 2023, Weihai Bay sediments have undergone a noticeable coarsening trend, primarily driven by anthropogenic modifications to sediment supply and hydrodynamic regimes. Coastal reclamation, shoreline modification, and infrastructure development have intensified coarse-grained terrestrial sediment input. Concurrently, shoreline advancement has reduced wave dissipation, enhancing nearshore hydrodynamics and accelerating sediment coarsening. This study highlights the sensitivity of small bay sedimentary environments to anthropogenic forcing, advancing our understanding of the coupled human-marine sediment system and providing a scientific basis for coastal sediment evolution under the dual influences of climate change and human activity.
基金the National Natural Science Foundation of China(Nos.42206076,42476078)the National Program on Global Change and Air-Sea Interaction(No.GASI-02-SCSCJB01)the China-Malaysia Cooperation Project‘Effect on variability of seasonal monsoon on sedimentary process in Peninsular Malaysia waters’。
文摘The Malacca Strait(MS)is a vital conduit for the exchange of water and sediment between the Indian Ocean and the Pacific Ocean,serving as a critical‘gateway'for sediment transport.Here,we present the geochemical characteristics of surface sediments in the MS to elucidate the relationship between terrestrial material inputs and modern oceanic dynamic transport processes in the strait.The results reveal that the MS can be divided into three distinct geochemical provinces.ProvinceⅠ,located in the central region of the strait,is characterized by residual deposits.The preservation of these residual deposits can be attributed to the restricted sediment supply and the relatively weaker modern sedimentary hydrodynamic conditions.ProvinceⅡ,situated to the north of ProvinceⅠ,exhibits provenance differences between its southern and northern regions.The northern region is primarily supplied by sediments originating from the eastern shelf of the Andaman Sea,whereas sediments derived from Sumatra and the Sunda Shelf are predominantly deposited in the southern part of ProvinceⅡ.ProvinceⅢextends along the western coast of the Malaysian Peninsula,with sediments primarily sourced from the Malaysian Peninsula and the Sunda Shelf,while contributions from Sumatra and the eastern shelf of the Andaman Sea are negligible.River sediments from the Malaysian Peninsula and Sumatra are transported northwestward along their respective coasts by prevailing currents,which also facilitate the transportation of Sunda Shelf sediments within the strait,while sediments from the eastern shelf of the Andaman Sea are delivered to the MS via southward coastal currents during the southwest monsoon period.The southward currents and well-developed eddies potentially impede the northward transport of sediments from the Sunda Shelf and restrict the distribution of Andaman Sea sediments within the strait.This study substantially enhances the understanding of source-to-sink processes in the Indo-Pacific region.
基金supported by the Project of Ecological and Environmental Protection Integration Research Institute in Yangtze River Delta(No.ZX2023SZY118)the Special Basic Research Service for the Central Level Public Welfare Research Institute(No.GYZX230409)+1 种基金the National Natural Science Foundation of China(No.42407557)the Belt and Road Special Foundation of the National Key Laboratory of Water Disaster Prevention,China(No.2023491611)。
文摘Organic phosphorus(OP)constitutes an important fraction of total phosphorus in lake sediments,with its mobility being influenced by mineralization and transformation of organic carbon(OC).OP and OC co-exist in various forms in the environment,thus a thorough investigation on the impact of OC fractions on the release of OP in sediments should be comprehensively carried out.This study determined the chemical forms of OP and OC in the sediments over four seasons in Lake Taihu and found temporal and spatial variations in their concentrations.The concentration of total OP and total OC ranged from 133 to 348 mg/kg and 4.77 to 21.19 mg/kg,respectively.Correlation between chemical fractions of OP and OC also revealed that Na OH-extracted OP,and fulvic acid-bound and humic acid-bound OP were positively correlated with humic-OC and hot hydrolysis-OC.These results suggest that the algal-derived OC degradation and mineralization may enhance OP mineralization,converting stable or moderately active OP into active forms or inorganic phosphorus under cyanobacterial bloom.This study provides insight and guiding support for investigating the impact of organic matter components on the transformation of OP after cyanobacterial degradation in eutrophic lakes.
基金supported by Geological Disaster Patterns and Mitigation Strategies Under River-Reservoir Hydrodynamics in the Three Gorges Reservoir Fluctuation Zone(5000002024CC20004)the National Key Research and Development Program of China(2023YFC3007205)+1 种基金the National Natural Science Foundation of China(No.42271013)the West Light Foundation of the Chinese Academy of Sciences.
文摘The distribution of the sediment material storage quantity along the debris flow channels(SMSQ_DFC)can provide a foundation for runoffgenerated debris flow prediction or susceptibility assessment.Current models for estimating SMSQ_DFC do not consider the capacity of the channel cross-section to accommodate sediment materials.This accommodation condition serves as a limiting factor in determining whether the expected surplus of sediment materials can ultimately be stored.To address this issue,a mass-conservative index was used to represent the balance of deposit materials at any cross-section,considering the influx from upstream,outflux to downstream,and accommodation capacity.Based on this index,a new model for estimating SMSQ_DFC was developed and subsequently evaluated.The evaluation results show that the model meets the accuracy requirements with average error rates of 14.06%for self-validation and 14.81%for generalization ability validation.To assess its practical applications,the model was applied to the Yeniu Gully in Wenchuan County,Sichuan Province,an area with detailed field survey data.The results show that the model exhibits a commendable performance.Compared to traditional theoretical and semi-theoretical statistical models,our model is easier to use(input parameters can be obtained using Geographic Information Systems(GIS)).The modeling parameters chosen in this study have more theoretical significance than those used in existing purely statistical models,offering more effective technical support for estimating SMSQ_DFC.
基金financially supported by the National Natural Science Foundation for Distinguished Young Scholars of China(42125702)the National Natural Science Foundation for International Cooperation and Exchange(W2412050)+4 种基金the National Science and Technology Major Project of Sichuan Province(2024ZDZX0020)the New Cornerstone Science Foundation through the XPLORER PRIZE(XPLORER-2022-1012)the Activity Prediction and Risk Identification of LargeScale Plateau Debris Flows(XZ202401ZY0029)the Formation Mechanisms and Monitoring-Warning Methods for Moraine Soil Debris Flows in the Eastern Himalayan Syntaxis Region(XZ202401ZR0073)funding from the Czech Science Foundation(22-13190S)。
文摘Soft-sediment deformation structures(SSDS)in water-saturated,unconsolidated sediments are the product of various causes and provide a valuable record of environmental and geological perturbations.We report a record of SSDS preserved in a~166 m-long drill core(DX-2)extracted from the Late Pleistocene Diexi Palaeolake,eastern Tibetan Plateau.Two factors make this an outstanding site for studying SSDS:(1)it is among the most seismically active regions on Earth,and(2)it has experienced extremely fast sedimentation rates(~15 mm/yr)thanks to the prodigious sediment supply from seismically perturbed hillslopes and rivers upstream.We describe and interpret 13 SSDS types within the DX-2 based on detailed sedimentological,morphological,and lithological analysis.We consider the genesis of the abundant SSDS observed in the DX-2 core with several possibilities:mass movement,rock avalanche-driven tsunamis,rapid sedimentation,and seismic shaking as the most probable triggering mechanisms.We suggest high-intensity earthquakes of VI(Modified Mercalli Intensity)or greater as drivers of SSDS in the DX-2.Based on our observations,we propose a conceptual model that attempts to explain the transition from ductile to brittle SSDS behaviour with progressive accumulation and consolidation of the sediment pile.This paper highlights the value of SSDS analysis in palaeo-earthquake identification,aiming to improve the applicability of SSDS as a palaeo-earthquake marker in alpine and canyon areas.
