Lake Baiyangdian is one of China’s largest macrophyte-derived lakes,facing severe challenges related to water quality maintenance and eutrophication prevention.Dissolved organic matter(DOM)was a huge carbon pool and ...Lake Baiyangdian is one of China’s largest macrophyte-derived lakes,facing severe challenges related to water quality maintenance and eutrophication prevention.Dissolved organic matter(DOM)was a huge carbon pool and its abundance,property,and transformation played important roles in the biogeochemical cycle and energy flow in lake ecosystems.In this study,Lake Baiyangdian was divided into four distinct areas:Unartificial Area(UA),Village Area(VA),Tourism Area(TA),and Breeding Area(BA).We examined the diversity of DOM properties and sources across these functional areas.Our findings reveal that DOM in this lake is predominantly composed of protein-like substances,as determined by excitation-emission matrix and parallel factor analysis(EEM-PARAFAC).Notably,the exogenous tyrosine-like component C1 showed a stronger presence in VA and BA compared to UA and TA.Ultrahigh-resolution mass spectrometry(FT-ICR MS)unveiled a similar DOM molecular composition pattern across different functional areas due to the high relative abundances of lignan compounds,suggesting that macrophytes significantly influence the material structure of DOM.DOM properties exhibited specific associations with water quality indicators in various functional areas,as indicated by the Mantel test.The connections between DOM properties and NO_(3)-N andNH3-Nwere more pronounced in VA and BA than in UA and TA.Our results underscore the viability of using DOM as an indicator for more precise and scientific water quality management.展开更多
Aiming to control lake eutrophication,proposed methods for convenient and faithworthy lake water quality evaluation are warranted.Optical measurement of dissolved organic matter(DOM)demonstrates great potential for es...Aiming to control lake eutrophication,proposed methods for convenient and faithworthy lake water quality evaluation are warranted.Optical measurement of dissolved organic matter(DOM)demonstrates great potential for estimating organic matter(OM)composition,and can thus serve as a proxy for conventional chemical oxygen demand(COD_(Mn))measurements,which are considered as imprecise and environmentally unfriendly.Hence,we conducted a field campaign across 30 lakes in Wuhan's metropolitan area,collecting 255 samples from varying trophic states to evaluate the predictive capability of COD_(Mn)using DOM optical measurements combined with parallel factor(PARAFAC)analysis.The DOM optical properties and chemical composition exhibited considerable variability across varying trophic state levels(TSLs).Fluorescence components C1-C3 and C5,fluorescence index(FI),and absorption at 254 nm(α_(254)),increased as TSL increased,while the DOM spectral slope(SR)decreased.COD_(Mn)was positively and significantly correlated with fluorescence components C1-C3 and C5,freshness index(β/α),autochthonous index(BIX),humification index(HIX),α_(254),the ratio ofα_(250)toα_(365)(E2/E3)while being negatively correlated with SR.Parametersα_(254),C1,C3,C4,FI,β/α,and HIX were identified as key predictors of COD_(Mn).The multiple linear regression model successfully predicted COD_(Mn)(r^(2)=0.63,p<0.01,n=1113)and demonstrated superior performance in mesotrophic lakes.These findings highlight the potential for establishing high-frequency,continuous,and multi-regional COD monitoring programs.展开更多
Objective Several epidemiological observational studies have related particulate matter(PM)exposure to Inflammatory bowel disease(IBD),but many confounding factors make it difficult to draw causal links from observati...Objective Several epidemiological observational studies have related particulate matter(PM)exposure to Inflammatory bowel disease(IBD),but many confounding factors make it difficult to draw causal links from observational studies.The objective of this study was to explore the causal association between PM_(2.5)exposure,its absorbance,and IBD.Methods We assessed the association of PM_(2.5)and PM_(2.5)absorbance with the two primary forms of IBD(Crohn’s disease[CD]and ulcerative colitis[UC])using Mendelian randomization(MR)to explore the causal relationship.We conducted two-sample MR analyses with aggregated data from the UK Biobank genome-wide association study.Single-nucleotide polymorphisms linked with PM_(2.5)concentrations or their absorbance were used as instrumental variables(IVs).We used inverse variance weighting(IVW)as the primary analytical approach and four other standard methods as supplementary analyses for quality control.Results The results of MR demonstrated that PM_(2.5)had an adverse influence on UC risk(odds ratio[OR]=1.010;95%confidence interval[CI]=1.001–1.019,P=0.020).Meanwhile,the results of IVW showed that PM_(2.5)absorbance was also causally associated with UC(OR=1.012;95%CI=1.004–1.019,P=0.002).We observed no causal relationship between PM_(2.5),PM_(2.5)absorbance,and CD.The results of sensitivity analysis indicated the absence of heterogeneity or pleiotropy,ensuring the reliability of MR results.Conclusion Based on two-sample MR analyses,there are potential positive causal relationships between PM_(2.5),PM_(2.5)absorbance,and UC.展开更多
Intracerebral hemorrhage is the most dangerous subtype of stroke,characterized by high mortality and morbidity rates,and frequently leads to significant secondary white matter injury.In recent decades,studies have rev...Intracerebral hemorrhage is the most dangerous subtype of stroke,characterized by high mortality and morbidity rates,and frequently leads to significant secondary white matter injury.In recent decades,studies have revealed that gut microbiota can communicate bidirectionally with the brain through the gut microbiota–brain axis.This axis indicates that gut microbiota is closely related to the development and prognosis of intracerebral hemorrhage and its associated secondary white matter injury.The NACHT,LRR,and pyrin domain-containing protein 3(NLRP3)inflammasome plays a crucial role in this context.This review summarizes the dysbiosis of gut microbiota following intracerebral hemorrhage and explores the mechanisms by which this imbalance may promote the activation of the NLRP3 inflammasome.These mechanisms include metabolic pathways(involving short-chain fatty acids,lipopolysaccharides,lactic acid,bile acids,trimethylamine-N-oxide,and tryptophan),neural pathways(such as the vagus nerve and sympathetic nerve),and immune pathways(involving microglia and T cells).We then discuss the relationship between the activated NLRP3 inflammasome and secondary white matter injury after intracerebral hemorrhage.The activation of the NLRP3 inflammasome can exacerbate secondary white matter injury by disrupting the blood–brain barrier,inducing neuroinflammation,and interfering with nerve regeneration.Finally,we outline potential treatment strategies for intracerebral hemorrhage and its secondary white matter injury.Our review highlights the critical role of the gut microbiota–brain axis and the NLRP3 inflammasome in white matter injury following intracerebral hemorrhage,paving the way for exploring potential therapeutic approaches.展开更多
Primordial black holes(PBHs) offer a compelling candidate for dark matter. The production of PBHs through well-tested and accepted physical processes is highly worthy of investigation. This work highlights the role of...Primordial black holes(PBHs) offer a compelling candidate for dark matter. The production of PBHs through well-tested and accepted physical processes is highly worthy of investigation. This work highlights the role of turbulences in the very early universe in sustaining intense and persistent fluctuations in energy or mass density,which could provide a natural mechanism for PBH formation in the primordial universe. We analyze the mass range and abundance of PBHs produced in the magnetohydrodynamic turbulence induced by the electroweak phase transition. Remarkably, we find that the mass range of the produced PBHs falls within the most viable“asteroid mass” window from the present-day observations, and within natural parameter regions their abundance can be sufficiently large. These findings suggest that PBHs produced during magnetohydrodynamic turbulence in the very early universe may comprise a dominant part of dark matter.展开更多
Recent evidence suggests that ferroptosis plays a crucial role in the occurrence and development of white matter lesions.However,the mechanisms and regulatory pathways involved in ferroptosis within white matter lesio...Recent evidence suggests that ferroptosis plays a crucial role in the occurrence and development of white matter lesions.However,the mechanisms and regulatory pathways involved in ferroptosis within white matter lesions remain unclear.Long non-coding RNAs(lnc RNAs)have been shown to influence the occurrence and development of these lesions.We previously identified lnc_011797 as a biomarker of white matter lesions by high-throughput sequencing.To investigate the mechanism by which lnc_011797 regulates white matter lesions,we established subjected human umbilical vein endothelial cells to oxygenglucose deprivation to simulate conditions associated with white matter lesions.The cells were transfected with lnc_011797 overexpression or knockdown lentiviruses.Our findings indicate that lnc_011797 promoted ferroptosis in these cells,leading to the formation of white matter lesions.Furthermore,lnc_011797 functioned as a competitive endogenous RNA(ce RNA)for mi R-193b-3p,thereby regulating the expression of WNK1 and its downstream ferroptosis-related proteins.To validate the role of lnc_011797 in vivo,we established a mouse model of white matter lesions through bilateral common carotid artery stenosis.The results from this model confirmed that lnc_011797 regulates ferroptosis via WNK1 and promotes the development of white matter lesions.These findings clarify the mechanism by which lnc RNAs regulate white matter lesions,providing a new target for the diagnosis and treatment of white matter lesions.展开更多
The main objective of the study was to investigate the characteristics of dissolved organic matter （DOM） in leachate with different landfill ages through the chemical, spectroscopic, and elemental analysis. Humic ac...The main objective of the study was to investigate the characteristics of dissolved organic matter （DOM） in leachate with different landfill ages through the chemical, spectroscopic, and elemental analysis. Humic acid （HA）, fulvic acid （FA）, and hydrophilic （HyI） fractions were isolated and purified by the XAD-8 resin combined with the cation exchange resin method. The analytical results of fluorescence excitation-emission matrix spectroscopy （EEMs） revealed that the fluorescence peaks were protein-like fluorescence for young landfill leachate, while the fluorescence peaks for medium and old landfill leachate were humic-like and fulvic-like fluorescence, respectively. Elemental analysis showed that carbon, hydrogen, and nitrogen content decreased with landfill age, while the oxygen content increased. Moreover, the nitrogen content in these isolated fractions followed： HA 〉 HyI 〉 FA. The results of elemental analysis, FT-IR, and fluorescence EEMs also confirmed that aromatic carbons and portions of aliphatic functional groups were more abundant in leachate samples with increasing landfill age.展开更多
To find a simple and economical way for treating the domestic wastewater irt small counties and towns, a process combining chemically enhanced primary treatment and a trickling filter （CEPT-TF, representing the physi...To find a simple and economical way for treating the domestic wastewater irt small counties and towns, a process combining chemically enhanced primary treatment and a trickling filter （CEPT-TF, representing the physical and biological effects） was constructed and operated in laboratory conditions. The characteristic behaviors of dissolved organic matter in raw wastewater and effluents were examined during steady-state operation. Experimental results showed that the process of CEPT and TF in series was beneficial for the removal of hydrophobic and hydrophilic organics. Specially, the hydrophobic and aromatic materials could be preferentially removed in the CEPT unit, and the hydrophilic fraction in the TF. Structural changes of the organic fractions during the operation of the different units were also characterized via spectrum analysis.展开更多
The spatiotemporal distribution pattern of marine-origin matter on the Antarctica ice sheet was used to study variations in the source regions, transport mechanisms and postdepositional influences. We present data on ...The spatiotemporal distribution pattern of marine-origin matter on the Antarctica ice sheet was used to study variations in the source regions, transport mechanisms and postdepositional influences. We present data on sea salt ions, sulfur components and stable isotopes from surface and snow pit samples collected along the transect route from Zhongshan Station to Dome A during the austral summer in 2012–2013. A general decreasing trend in the accumulation, sea salt ions and sulfur components occurred with increasing distance from the coast and increasing elevation. However, different sources of the marine components, transport pathways and post-depositional influences were responsible for their different spatial distribution patterns. The marine ions in the coastal snow pit varied seasonally, with higher sea salt ion concentrations in the winter and lower concentrations in the summer; the opposite pattern was found for the sulfur compounds. The sea ice area surrounding Antarctica was the main source region for the deposited sea salt and the open sea water for the sulfur compounds. No significant trends in the marine-origin components were detected during the past 3 decades. Several periods of elevated deposition of sea salt ions were associated with lower temperatures（based on δD and δ18O） or intensified wind fields. In comparison to the sea salt ions, the sulfur concentrations exhibited the opposite distribution patterns and were associated with changes in the surrounding sea ice extent.展开更多
A controlled experiment was designed to resolve the influence of nitrogen abundance on sediment organic matters in macrophyte-dominated lakes using fluorescence analysis.Macrophyte biomass showed coincident growth tre...A controlled experiment was designed to resolve the influence of nitrogen abundance on sediment organic matters in macrophyte-dominated lakes using fluorescence analysis.Macrophyte biomass showed coincident growth trends with time, but different variation rates with nitrogen treatment. All plant growth indexes with nitrogen addition（N, NH4Cl100, 200, 400 mg/kg, respectively） were lower than those of the control group. Four humiclike components, two autochthonous tryptophan-like components, and one autochthonous tyrosine-like component were identified using the parallel factor analysis model. The results suggested that the relative component changes of fluorescence in the colonized sediments were in direct relation to the change of root biomass with time. In the experiment, the root formation parameters of the plants studied were significantly affected by adding N in sediments, which may be related to the reason that the root growth was affected by N addition.Adding a low concentration of N to sediments can play a part in supplying nutrients to the plants. However, the intensive uptake of NH4^＋may result in an increase in the intracellular concentration of ammonia, which is highly toxic to the plant cells. Hence, our experiment results manifested that organic matter cycling in the macrophyte-dominated sediment was influenced by nitrogen enrichment through influencing vegetation and relevant microbial activity.展开更多
In order to better understand the compositional and structural complexity of dissolved organic matter(DOM) macromolecules and provide mechanistic information on the binding of hydrophobic organic contaminants(HOCs) to...In order to better understand the compositional and structural complexity of dissolved organic matter(DOM) macromolecules and provide mechanistic information on the binding of hydrophobic organic contaminants(HOCs) to DOM, we fractionated large amounts of lake water into three hydrophobic DOM-fractions. The variation of the partitioning coef?cients(K_(DOC)) of pyrene at different p H levels was examined by ?orescence quenching titration. Results show that, relative to the more polar acidic DOM-fractions, the hydrophobic neutral fraction exhibits a higher sorption ability to pyrene. Generally, the sorption of pyrene to the three hydrophobic fractions is strongly pH-dependent. The K_(DOC) values of pyrene generally increase with decreasing p H levels, which is especially obvious in the sorption of pyrene to the fulvic acid fractions, suggesting that the binding is controlled by hydrophobic interactions. The mechanisms underlying the binding of pyrene to the hydrophobic fractions were also discussed. Our data are bene?cial to further understanding the binding of HOCs to DOM and how it has been affected,which may result in more accurate predictions of K_(DOC).展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFC3204000).
文摘Lake Baiyangdian is one of China’s largest macrophyte-derived lakes,facing severe challenges related to water quality maintenance and eutrophication prevention.Dissolved organic matter(DOM)was a huge carbon pool and its abundance,property,and transformation played important roles in the biogeochemical cycle and energy flow in lake ecosystems.In this study,Lake Baiyangdian was divided into four distinct areas:Unartificial Area(UA),Village Area(VA),Tourism Area(TA),and Breeding Area(BA).We examined the diversity of DOM properties and sources across these functional areas.Our findings reveal that DOM in this lake is predominantly composed of protein-like substances,as determined by excitation-emission matrix and parallel factor analysis(EEM-PARAFAC).Notably,the exogenous tyrosine-like component C1 showed a stronger presence in VA and BA compared to UA and TA.Ultrahigh-resolution mass spectrometry(FT-ICR MS)unveiled a similar DOM molecular composition pattern across different functional areas due to the high relative abundances of lignan compounds,suggesting that macrophytes significantly influence the material structure of DOM.DOM properties exhibited specific associations with water quality indicators in various functional areas,as indicated by the Mantel test.The connections between DOM properties and NO_(3)-N andNH3-Nwere more pronounced in VA and BA than in UA and TA.Our results underscore the viability of using DOM as an indicator for more precise and scientific water quality management.
基金This study was funded by Wuhan Institute of Technology(Grant Nos.24QD26,21QD02,22QD64)National Natural Science Foundation of China(Grant No.32102823).
文摘Aiming to control lake eutrophication,proposed methods for convenient and faithworthy lake water quality evaluation are warranted.Optical measurement of dissolved organic matter(DOM)demonstrates great potential for estimating organic matter(OM)composition,and can thus serve as a proxy for conventional chemical oxygen demand(COD_(Mn))measurements,which are considered as imprecise and environmentally unfriendly.Hence,we conducted a field campaign across 30 lakes in Wuhan's metropolitan area,collecting 255 samples from varying trophic states to evaluate the predictive capability of COD_(Mn)using DOM optical measurements combined with parallel factor(PARAFAC)analysis.The DOM optical properties and chemical composition exhibited considerable variability across varying trophic state levels(TSLs).Fluorescence components C1-C3 and C5,fluorescence index(FI),and absorption at 254 nm(α_(254)),increased as TSL increased,while the DOM spectral slope(SR)decreased.COD_(Mn)was positively and significantly correlated with fluorescence components C1-C3 and C5,freshness index(β/α),autochthonous index(BIX),humification index(HIX),α_(254),the ratio ofα_(250)toα_(365)(E2/E3)while being negatively correlated with SR.Parametersα_(254),C1,C3,C4,FI,β/α,and HIX were identified as key predictors of COD_(Mn).The multiple linear regression model successfully predicted COD_(Mn)(r^(2)=0.63,p<0.01,n=1113)and demonstrated superior performance in mesotrophic lakes.These findings highlight the potential for establishing high-frequency,continuous,and multi-regional COD monitoring programs.
基金supported by the National Natural Science Foundation of China(No.82303169)the Key Research and Development Program of Shaanxi(No.2021ZDLSF02-06).
文摘Objective Several epidemiological observational studies have related particulate matter(PM)exposure to Inflammatory bowel disease(IBD),but many confounding factors make it difficult to draw causal links from observational studies.The objective of this study was to explore the causal association between PM_(2.5)exposure,its absorbance,and IBD.Methods We assessed the association of PM_(2.5)and PM_(2.5)absorbance with the two primary forms of IBD(Crohn’s disease[CD]and ulcerative colitis[UC])using Mendelian randomization(MR)to explore the causal relationship.We conducted two-sample MR analyses with aggregated data from the UK Biobank genome-wide association study.Single-nucleotide polymorphisms linked with PM_(2.5)concentrations or their absorbance were used as instrumental variables(IVs).We used inverse variance weighting(IVW)as the primary analytical approach and four other standard methods as supplementary analyses for quality control.Results The results of MR demonstrated that PM_(2.5)had an adverse influence on UC risk(odds ratio[OR]=1.010;95%confidence interval[CI]=1.001–1.019,P=0.020).Meanwhile,the results of IVW showed that PM_(2.5)absorbance was also causally associated with UC(OR=1.012;95%CI=1.004–1.019,P=0.002).We observed no causal relationship between PM_(2.5),PM_(2.5)absorbance,and CD.The results of sensitivity analysis indicated the absence of heterogeneity or pleiotropy,ensuring the reliability of MR results.Conclusion Based on two-sample MR analyses,there are potential positive causal relationships between PM_(2.5),PM_(2.5)absorbance,and UC.
基金supported by the Guangdong Basic and Applied Basic Research Foundation,No.2023A1515030045(to HS)Presidential Foundation of Zhujiang Hospital of Southern Medical University,No.yzjj2022ms4(to HS)。
文摘Intracerebral hemorrhage is the most dangerous subtype of stroke,characterized by high mortality and morbidity rates,and frequently leads to significant secondary white matter injury.In recent decades,studies have revealed that gut microbiota can communicate bidirectionally with the brain through the gut microbiota–brain axis.This axis indicates that gut microbiota is closely related to the development and prognosis of intracerebral hemorrhage and its associated secondary white matter injury.The NACHT,LRR,and pyrin domain-containing protein 3(NLRP3)inflammasome plays a crucial role in this context.This review summarizes the dysbiosis of gut microbiota following intracerebral hemorrhage and explores the mechanisms by which this imbalance may promote the activation of the NLRP3 inflammasome.These mechanisms include metabolic pathways(involving short-chain fatty acids,lipopolysaccharides,lactic acid,bile acids,trimethylamine-N-oxide,and tryptophan),neural pathways(such as the vagus nerve and sympathetic nerve),and immune pathways(involving microglia and T cells).We then discuss the relationship between the activated NLRP3 inflammasome and secondary white matter injury after intracerebral hemorrhage.The activation of the NLRP3 inflammasome can exacerbate secondary white matter injury by disrupting the blood–brain barrier,inducing neuroinflammation,and interfering with nerve regeneration.Finally,we outline potential treatment strategies for intracerebral hemorrhage and its secondary white matter injury.Our review highlights the critical role of the gut microbiota–brain axis and the NLRP3 inflammasome in white matter injury following intracerebral hemorrhage,paving the way for exploring potential therapeutic approaches.
基金supported by the International Partnership Program of the Chinese Academy of Sciences (Grant No.025GJHZ2023106GC)。
文摘Primordial black holes(PBHs) offer a compelling candidate for dark matter. The production of PBHs through well-tested and accepted physical processes is highly worthy of investigation. This work highlights the role of turbulences in the very early universe in sustaining intense and persistent fluctuations in energy or mass density,which could provide a natural mechanism for PBH formation in the primordial universe. We analyze the mass range and abundance of PBHs produced in the magnetohydrodynamic turbulence induced by the electroweak phase transition. Remarkably, we find that the mass range of the produced PBHs falls within the most viable“asteroid mass” window from the present-day observations, and within natural parameter regions their abundance can be sufficiently large. These findings suggest that PBHs produced during magnetohydrodynamic turbulence in the very early universe may comprise a dominant part of dark matter.
基金supported by the Qingdao Medical Health Research Project,No.2023-WJZD212(to XX)。
文摘Recent evidence suggests that ferroptosis plays a crucial role in the occurrence and development of white matter lesions.However,the mechanisms and regulatory pathways involved in ferroptosis within white matter lesions remain unclear.Long non-coding RNAs(lnc RNAs)have been shown to influence the occurrence and development of these lesions.We previously identified lnc_011797 as a biomarker of white matter lesions by high-throughput sequencing.To investigate the mechanism by which lnc_011797 regulates white matter lesions,we established subjected human umbilical vein endothelial cells to oxygenglucose deprivation to simulate conditions associated with white matter lesions.The cells were transfected with lnc_011797 overexpression or knockdown lentiviruses.Our findings indicate that lnc_011797 promoted ferroptosis in these cells,leading to the formation of white matter lesions.Furthermore,lnc_011797 functioned as a competitive endogenous RNA(ce RNA)for mi R-193b-3p,thereby regulating the expression of WNK1 and its downstream ferroptosis-related proteins.To validate the role of lnc_011797 in vivo,we established a mouse model of white matter lesions through bilateral common carotid artery stenosis.The results from this model confirmed that lnc_011797 regulates ferroptosis via WNK1 and promotes the development of white matter lesions.These findings clarify the mechanism by which lnc RNAs regulate white matter lesions,providing a new target for the diagnosis and treatment of white matter lesions.
文摘The main objective of the study was to investigate the characteristics of dissolved organic matter （DOM） in leachate with different landfill ages through the chemical, spectroscopic, and elemental analysis. Humic acid （HA）, fulvic acid （FA）, and hydrophilic （HyI） fractions were isolated and purified by the XAD-8 resin combined with the cation exchange resin method. The analytical results of fluorescence excitation-emission matrix spectroscopy （EEMs） revealed that the fluorescence peaks were protein-like fluorescence for young landfill leachate, while the fluorescence peaks for medium and old landfill leachate were humic-like and fulvic-like fluorescence, respectively. Elemental analysis showed that carbon, hydrogen, and nitrogen content decreased with landfill age, while the oxygen content increased. Moreover, the nitrogen content in these isolated fractions followed： HA 〉 HyI 〉 FA. The results of elemental analysis, FT-IR, and fluorescence EEMs also confirmed that aromatic carbons and portions of aliphatic functional groups were more abundant in leachate samples with increasing landfill age.
基金supported by the National Critical Scientific and Technological Project of Water Pollution Control and Management (No. 2009ZX07317-009-08)the National Nature Science Foundation of China (No.51121062)
文摘To find a simple and economical way for treating the domestic wastewater irt small counties and towns, a process combining chemically enhanced primary treatment and a trickling filter （CEPT-TF, representing the physical and biological effects） was constructed and operated in laboratory conditions. The characteristic behaviors of dissolved organic matter in raw wastewater and effluents were examined during steady-state operation. Experimental results showed that the process of CEPT and TF in series was beneficial for the removal of hydrophobic and hydrophilic organics. Specially, the hydrophobic and aromatic materials could be preferentially removed in the CEPT unit, and the hydrophilic fraction in the TF. Structural changes of the organic fractions during the operation of the different units were also characterized via spectrum analysis.
基金financially supported by the Innovative Research Group,the National Natural Science Foundation of China(No.41121001)the National Basic Research Program of China(973 Program,No.2013CBA01804)+3 种基金the State Key Laboratory of Cryospheric Sciences supporting fund(No.SKLCS-ZZ-2015-01)the National Natural Science Foundation of China(Nos.41201069,41476164)the State Oceanic Administration of People's Republic of China Project on Climate in Polar Regions(Nos.CHINARE 2015-04-04 and CHINARE 2015-02-02)the Foundation for Excellent Youth Scholars of Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences(CAREERI,CAS)
文摘The spatiotemporal distribution pattern of marine-origin matter on the Antarctica ice sheet was used to study variations in the source regions, transport mechanisms and postdepositional influences. We present data on sea salt ions, sulfur components and stable isotopes from surface and snow pit samples collected along the transect route from Zhongshan Station to Dome A during the austral summer in 2012–2013. A general decreasing trend in the accumulation, sea salt ions and sulfur components occurred with increasing distance from the coast and increasing elevation. However, different sources of the marine components, transport pathways and post-depositional influences were responsible for their different spatial distribution patterns. The marine ions in the coastal snow pit varied seasonally, with higher sea salt ion concentrations in the winter and lower concentrations in the summer; the opposite pattern was found for the sulfur compounds. The sea ice area surrounding Antarctica was the main source region for the deposited sea salt and the open sea water for the sulfur compounds. No significant trends in the marine-origin components were detected during the past 3 decades. Several periods of elevated deposition of sea salt ions were associated with lower temperatures（based on δD and δ18O） or intensified wind fields. In comparison to the sea salt ions, the sulfur concentrations exhibited the opposite distribution patterns and were associated with changes in the surrounding sea ice extent.
基金supported by the National Basic Research Program (973) of China (No. 2012CB417004)the National Natural Science Foundation of China (Nos. U1202235,41173118, 41301544)the Shandong Provincial Natural Science Foundation (No. ZR2012DQ003)
文摘A controlled experiment was designed to resolve the influence of nitrogen abundance on sediment organic matters in macrophyte-dominated lakes using fluorescence analysis.Macrophyte biomass showed coincident growth trends with time, but different variation rates with nitrogen treatment. All plant growth indexes with nitrogen addition（N, NH4Cl100, 200, 400 mg/kg, respectively） were lower than those of the control group. Four humiclike components, two autochthonous tryptophan-like components, and one autochthonous tyrosine-like component were identified using the parallel factor analysis model. The results suggested that the relative component changes of fluorescence in the colonized sediments were in direct relation to the change of root biomass with time. In the experiment, the root formation parameters of the plants studied were significantly affected by adding N in sediments, which may be related to the reason that the root growth was affected by N addition.Adding a low concentration of N to sediments can play a part in supplying nutrients to the plants. However, the intensive uptake of NH4^＋may result in an increase in the intracellular concentration of ammonia, which is highly toxic to the plant cells. Hence, our experiment results manifested that organic matter cycling in the macrophyte-dominated sediment was influenced by nitrogen enrichment through influencing vegetation and relevant microbial activity.
文摘采用三维荧光-平行因子法(3D EEMs-PARAFAC)解析了厌氧-缺氧-好氧(A^(2)O)污水生物处理过程中DOM特征,并对各工艺单元生成的N_(2)O进行了定量分析,之后运用机器学习模型对二者的变化关系进行了响应预测.结果表明,污水处理厂进水中DOM主要包含类色氨酸C1,类富里酸C2,类腐殖酸C3和类酪氨酸C4四种组分,并以C1和C4为主,且各组分含量沿污水处理流程逐渐降低,易生物降解的C1和C4的去除速率明显高于C2和C3.N_(2)O排放是直接碳排放的主要组成部分,其变化表现出明显的空间异质性,各处理单元N_(2)O生成总量由高到低依次为好氧池、辐流沉淀池、缺氧池、厌氧池、细格栅、钟式沉砂池.Shapley Additive ex Planation(SHAP)分析表明,C1和C2对N_(2)O生成影响较大,而C3和C4几乎没有影响,其中C1对N_(2)O的生成表现出促进作用,C2则不利于N_(2)O的生成.高通量测序结果表明,能够利用易生物降解有机物进行反硝化的Methylotenera和Terrimonas是污水处理厂内的优势菌属.本研究揭示了A^(2)O污水生物处理过程中N_(2)O生成对不同DOM组分的差异性响应,并为完善当前污水处理厂的碳排放核算方法并优化污水处理厂低碳运行工艺提供了理论支撑.
基金supported by the National Natural Science Foundation of China (No. 41173128)
文摘In order to better understand the compositional and structural complexity of dissolved organic matter(DOM) macromolecules and provide mechanistic information on the binding of hydrophobic organic contaminants(HOCs) to DOM, we fractionated large amounts of lake water into three hydrophobic DOM-fractions. The variation of the partitioning coef?cients(K_(DOC)) of pyrene at different p H levels was examined by ?orescence quenching titration. Results show that, relative to the more polar acidic DOM-fractions, the hydrophobic neutral fraction exhibits a higher sorption ability to pyrene. Generally, the sorption of pyrene to the three hydrophobic fractions is strongly pH-dependent. The K_(DOC) values of pyrene generally increase with decreasing p H levels, which is especially obvious in the sorption of pyrene to the fulvic acid fractions, suggesting that the binding is controlled by hydrophobic interactions. The mechanisms underlying the binding of pyrene to the hydrophobic fractions were also discussed. Our data are bene?cial to further understanding the binding of HOCs to DOM and how it has been affected,which may result in more accurate predictions of K_(DOC).
