To elucidate the geographical differentiation characteristics and driving mechanisms of Dissolved Organic Matter(DOM)in typical rivers,this study conducted a multi-spectral investigation on three representative river ...To elucidate the geographical differentiation characteristics and driving mechanisms of Dissolved Organic Matter(DOM)in typical rivers,this study conducted a multi-spectral investigation on three representative river types within Shandong Province:The mountainous Dawen River,the plain Tuhai River,and the artificial East Grand Canal.The DOM composition was analyzed using Ultraviolet-Visible(UV-Vis)absorption spectroscopy,Excitation-Emission Matrix(EEM)fluorescence spectroscopy,and parallel factor analysis(PARAFAC),while Principal Component Analysis(PCA)was employed to quantify the synergistic effects of natural processes and anthropogenic activities.Results revealed significant spatial heterogeneity in DOM composition and sources.The plain river exhibited the highest aromaticity(humic-like components:43.3%)due to long-term agricultural non-point source inputs and urban wastewater discharge.The mountain stream,shaped by complex terrain and relatively intact ecosystems,was dominated by autochthonous DOM derived from microbial metabolism,with higher Fluorescence Index(FI=2.12)and biological index(BIX=1.35)than other river types.The artificial canal retained protein-like components(64.2%),largely attributed to winter hydrological stagnation and disturbances from shipping activities.Further analysis demonstrated that geographical settings(e.g.,mountain terrain)and anthropogenic activities(e.g.,agriculture,shipping)jointly regulated DOM composition by altering the balance between input and transformation processes.Integrated fluorescence parameters and PCA results suggested differentiated management strategies:protecting ecological integrity in mountain streams to sustain selfpurification,enhancing non-point source interception in plain rivers,and mitigating shipping pollution in canals.This study systematically reveals the natural-anthropogenic coupling mechanisms driving DOM dynamics in northern China rivers,providing critical insights for precision water environment management at the watershed scale.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
基金supported by the National Natural Science Foundation(42472325)the Fundamental Research Funds of Chinese Academy of Geological Science(SK202103).
文摘To elucidate the geographical differentiation characteristics and driving mechanisms of Dissolved Organic Matter(DOM)in typical rivers,this study conducted a multi-spectral investigation on three representative river types within Shandong Province:The mountainous Dawen River,the plain Tuhai River,and the artificial East Grand Canal.The DOM composition was analyzed using Ultraviolet-Visible(UV-Vis)absorption spectroscopy,Excitation-Emission Matrix(EEM)fluorescence spectroscopy,and parallel factor analysis(PARAFAC),while Principal Component Analysis(PCA)was employed to quantify the synergistic effects of natural processes and anthropogenic activities.Results revealed significant spatial heterogeneity in DOM composition and sources.The plain river exhibited the highest aromaticity(humic-like components:43.3%)due to long-term agricultural non-point source inputs and urban wastewater discharge.The mountain stream,shaped by complex terrain and relatively intact ecosystems,was dominated by autochthonous DOM derived from microbial metabolism,with higher Fluorescence Index(FI=2.12)and biological index(BIX=1.35)than other river types.The artificial canal retained protein-like components(64.2%),largely attributed to winter hydrological stagnation and disturbances from shipping activities.Further analysis demonstrated that geographical settings(e.g.,mountain terrain)and anthropogenic activities(e.g.,agriculture,shipping)jointly regulated DOM composition by altering the balance between input and transformation processes.Integrated fluorescence parameters and PCA results suggested differentiated management strategies:protecting ecological integrity in mountain streams to sustain selfpurification,enhancing non-point source interception in plain rivers,and mitigating shipping pollution in canals.This study systematically reveals the natural-anthropogenic coupling mechanisms driving DOM dynamics in northern China rivers,providing critical insights for precision water environment management at the watershed scale.
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.
