The aim was to explore dynamic changes of organic matter and nitrogen pol ution in Dongchang Lake. [Method] Monitoring data, including BOD5, CODCr, NH3-N and TN, of Dongchang Lake were chosen for analysis during 2002-...The aim was to explore dynamic changes of organic matter and nitrogen pol ution in Dongchang Lake. [Method] Monitoring data, including BOD5, CODCr, NH3-N and TN, of Dongchang Lake were chosen for analysis during 2002-2011. [Result] Water quality of the six lake districts showed deteriorating in monitor-ing period, and TN was the dominant pol ution factor; BOD5/CODCr ratio was low, suggesting biodegradability of organic pol utant in the lake was lower. NH3/TN ratio was higher, indicating NH3-N was a major factor causing nitrogen exceeding in 2010. In addition, correlations between BOD5 and CODCr and between NH3-N and TN in the lake districts maintained at a significant level. [Conclusion] The research provides references for improving water in Dongchang Lake.展开更多
This study is focused on the kinetic characteristics of photocatalytic degradation of gaseous organic compounds on modified titanium dioxide/activated carbon composite photocatalyst(MTA).The MTA,which co-doping with i...This study is focused on the kinetic characteristics of photocatalytic degradation of gaseous organic compounds on modified titanium dioxide/activated carbon composite photocatalyst(MTA).The MTA,which co-doping with iron(Fe) and nitrogen(N),was synthesized by a sol-gel method,and its photocatalytic performance was investigated under different reaction conditions.The experimental data obtained were tested by the zero,first and second order kinetic model,and the factors affecting the kinetic model were analyzed.It was clearly demonstrated that the experimental data of toluene and acetone on MTA fit quite well with second order kinetic model equation,but the experimental data of formaldehyde fits well with zero order kinetic model equation.展开更多
This study examined the spatiotemporal dynamics of colored dissolved organic matter (CDOM) and spectral slope (S), and further to analyze its sources in three productive water supplies (Eagle Creek, Geist and Mor...This study examined the spatiotemporal dynamics of colored dissolved organic matter (CDOM) and spectral slope (S), and further to analyze its sources in three productive water supplies (Eagle Creek, Geist and Morse reservoirs) from Indiana, USA. The re- sults showed that he absorption coefficient aCDOM(440) ranged from 0.37 m-1 to 3.93 m-1 with an average of 1.89 ± 0.76 m-1 (±SD) for the aggregated dataset, and S varied from 0.0048 nm -1 to 0.0239 nm-1 with an average of 0.0108 ±0.0040 nmI. A significant relation- ship between S and aCDOM(440) can be fitted with a power equation (S = 0.013 × aCDOM(440)-0.42, R2 = 0.612), excluding data from Geist Reservoir during high flow (12 April 2010) and the Morse Reservoir on 25 June 2010 due to a T-storm achieves even higher determina- tion coefficient (R2 = 0.842). Correlation analysis indicated that aCDOM(440) has strong association with inorganic suspended matter (ISM) concentration (0.231 〈 R2 〈 0.786) for each of the field surveys, and this trend followed the aggregated datasets (R2 = 0.447, p 〈 0.001). In contrast, chlorophyll-a was only correlated with aCDOM(440) in summer and autumn (0.081 〈 R2 〈 0.763), indicating that CDOM is mainly from terrigenous sources in early spring and that phytoplankton contributed during the algal blooming season. The S value was used to characterize CDOM origin. The results indicate that the CDOM source is mainly controlled by hydrological varia- tions, while phytoplankton originated organic matter also closely linked with CDOM dynamics in three productive reservoirs.展开更多
In this study we have successfully characterized the fluorescent components of chromophoric dissolved organic matter(CDOM) in the Yellow Sea and the East China Sea in autumn using excitation-emission matrix fluorescen...In this study we have successfully characterized the fluorescent components of chromophoric dissolved organic matter(CDOM) in the Yellow Sea and the East China Sea in autumn using excitation-emission matrix fluorescence spectroscopy(EEMs) combined with parallel factor analysis(PARAFAC).PARAFAC aids the characterization of fluorescence CDOM by decomposing the fluorescence matrices into individual components.Four humic-like components(C1,C2,C3,and C4),one marine biological production component(C6),and two protein-like components(C5 and C7) were identified by PARAFAC.We researched the distributional patterns of fluorescence intensity,regression analyses between salinity,chlorophyll a concentration and fluorescence intensities of individual fluorophore,and regression analysis between salinity and fluorescence intensities percent of individual fluorophore.The results revealed that C2 and C4 showed conservative mixing behavior,while C1 and C3 possessed conservative mixing behavior in high salinity region and additional behavior in low and middle salinity region,which were considered to be derived from riverine and degradation of organic matter from resuspended and/or sinking particles and show non-conservative mixing behavior.In addition to riverine sources,the tryptophan-like C5 may receive widespread addition(likely from photo-degradation or biodegradation),while the most likely sources for the one marine humic-like C6 and tyrosine-like C7 were biological activity and microbial processing of plankton-derived CDOM,which were suggested to be of autochthonous origin and biologically labile.The application of EEM-PARAFAC modeling presents a unique opportunity to observe compositional changes,different mixing behavior and temporal variability in CDOM in the Yellow Sea and the East China Sea.展开更多
Invasion of an exotic C4 plant Spartina alterniflora has been shown to increase soil organic carbon (SOC) concentrations in native C3 plant-dominated coastal wetlands of China. However, little is known about the eff...Invasion of an exotic C4 plant Spartina alterniflora has been shown to increase soil organic carbon (SOC) concentrations in native C3 plant-dominated coastal wetlands of China. However, little is known about the effects of S. alterniflora invasion on SOC concentrations and fractions in tidal marshes dominated by native C4 plants. In this study, a field experiment was conducted in a tidal marsh dominated by the native C4 plant Cyperus malaccensis in the Minjiang River estuary, China. Concentrations of SOC and liable SOC fractions, dissolved organic carbon (DOG), microbial biomass carbon (MBC), and easily oxidizable carbon (EOC), were measured in the top 50-cm soils of the C. malaccensis community, as well as those of three S. alterniflova communities with an invasion duration of 0-4 years (SA-4), 4-8 years (SA-8), and 8-12 years (SA-12), respectively. Results showed that both SOC stocks in the 50-cm soils and mean SOC concentrations in the surface soils (0-10 cm) of the C. malaccensis community increased with the duration of S. alterniflora invasion, whereas SOC concentrations in the 10-50-cm soils decreased slightly during the initial period of S. alterniflora invasion, before increasing again. The pattern of changes in labile SOC fractions (DOC, MBC, and EOC) with invasion duration was generally similar to that of SOC, while the ratios of labile SOC fractions to total SOC (DOC:SOC, MBC:SOC, and EOC:SOC) decreased significantly with the duration of S. alterniflora invasion. The findings of this study suggest that invasion of the exotic C4 plant S. alternifora into a marsh dominated by the native C4 plant C. malaecensis would enhance SOC sequestration owing to the greater amount of biomass and lower proportion of labile SOC fractions present in the S. alterniflora communities.展开更多
基金Supported by Major Science and Technology Program for Water Pollution Control and Treatment(2009ZX07106-03)Shandong Provincial Natural Science Foundation(ZR2013DM012,ZR2010DL008,ZR2013DL005)Undergraduate Scientific and Technological Innovation Project(SF2013138,SF2013140,SF2012076,SF2012077,SF2012090)~~
文摘The aim was to explore dynamic changes of organic matter and nitrogen pol ution in Dongchang Lake. [Method] Monitoring data, including BOD5, CODCr, NH3-N and TN, of Dongchang Lake were chosen for analysis during 2002-2011. [Result] Water quality of the six lake districts showed deteriorating in monitor-ing period, and TN was the dominant pol ution factor; BOD5/CODCr ratio was low, suggesting biodegradability of organic pol utant in the lake was lower. NH3/TN ratio was higher, indicating NH3-N was a major factor causing nitrogen exceeding in 2010. In addition, correlations between BOD5 and CODCr and between NH3-N and TN in the lake districts maintained at a significant level. [Conclusion] The research provides references for improving water in Dongchang Lake.
基金Supported by the Natural Science Foundation of Guangdong Province,China(8151064101000049)
文摘This study is focused on the kinetic characteristics of photocatalytic degradation of gaseous organic compounds on modified titanium dioxide/activated carbon composite photocatalyst(MTA).The MTA,which co-doping with iron(Fe) and nitrogen(N),was synthesized by a sol-gel method,and its photocatalytic performance was investigated under different reaction conditions.The experimental data obtained were tested by the zero,first and second order kinetic model,and the factors affecting the kinetic model were analyzed.It was clearly demonstrated that the experimental data of toluene and acetone on MTA fit quite well with second order kinetic model equation,but the experimental data of formaldehyde fits well with zero order kinetic model equation.
基金Under the auspices of National Aeronautics and Space Administration of US(NASA)(No.NNG06GA92G)National Natural Science Foundation of China(No.41171293)
文摘This study examined the spatiotemporal dynamics of colored dissolved organic matter (CDOM) and spectral slope (S), and further to analyze its sources in three productive water supplies (Eagle Creek, Geist and Morse reservoirs) from Indiana, USA. The re- sults showed that he absorption coefficient aCDOM(440) ranged from 0.37 m-1 to 3.93 m-1 with an average of 1.89 ± 0.76 m-1 (±SD) for the aggregated dataset, and S varied from 0.0048 nm -1 to 0.0239 nm-1 with an average of 0.0108 ±0.0040 nmI. A significant relation- ship between S and aCDOM(440) can be fitted with a power equation (S = 0.013 × aCDOM(440)-0.42, R2 = 0.612), excluding data from Geist Reservoir during high flow (12 April 2010) and the Morse Reservoir on 25 June 2010 due to a T-storm achieves even higher determina- tion coefficient (R2 = 0.842). Correlation analysis indicated that aCDOM(440) has strong association with inorganic suspended matter (ISM) concentration (0.231 〈 R2 〈 0.786) for each of the field surveys, and this trend followed the aggregated datasets (R2 = 0.447, p 〈 0.001). In contrast, chlorophyll-a was only correlated with aCDOM(440) in summer and autumn (0.081 〈 R2 〈 0.763), indicating that CDOM is mainly from terrigenous sources in early spring and that phytoplankton contributed during the algal blooming season. The S value was used to characterize CDOM origin. The results indicate that the CDOM source is mainly controlled by hydrological varia- tions, while phytoplankton originated organic matter also closely linked with CDOM dynamics in three productive reservoirs.
基金supported by the National High-Tech Research and Development Program of China(2009AA063005)the National Basic Research Program of China(2010CD428701)
文摘In this study we have successfully characterized the fluorescent components of chromophoric dissolved organic matter(CDOM) in the Yellow Sea and the East China Sea in autumn using excitation-emission matrix fluorescence spectroscopy(EEMs) combined with parallel factor analysis(PARAFAC).PARAFAC aids the characterization of fluorescence CDOM by decomposing the fluorescence matrices into individual components.Four humic-like components(C1,C2,C3,and C4),one marine biological production component(C6),and two protein-like components(C5 and C7) were identified by PARAFAC.We researched the distributional patterns of fluorescence intensity,regression analyses between salinity,chlorophyll a concentration and fluorescence intensities of individual fluorophore,and regression analysis between salinity and fluorescence intensities percent of individual fluorophore.The results revealed that C2 and C4 showed conservative mixing behavior,while C1 and C3 possessed conservative mixing behavior in high salinity region and additional behavior in low and middle salinity region,which were considered to be derived from riverine and degradation of organic matter from resuspended and/or sinking particles and show non-conservative mixing behavior.In addition to riverine sources,the tryptophan-like C5 may receive widespread addition(likely from photo-degradation or biodegradation),while the most likely sources for the one marine humic-like C6 and tyrosine-like C7 were biological activity and microbial processing of plankton-derived CDOM,which were suggested to be of autochthonous origin and biologically labile.The application of EEM-PARAFAC modeling presents a unique opportunity to observe compositional changes,different mixing behavior and temporal variability in CDOM in the Yellow Sea and the East China Sea.
基金supported by the National Natural Science Foundation of China(Nos.31000262 and 41671088)the Program for Innovative Research Team at Fujian Normal University,China(No.IRTL1205)+1 种基金the Research Grants Council of the Hong Kong Special Administrative Region,China(No.CUHK458913)the Chinese University of Hong Kong Direct Grant(No.4052119)
文摘Invasion of an exotic C4 plant Spartina alterniflora has been shown to increase soil organic carbon (SOC) concentrations in native C3 plant-dominated coastal wetlands of China. However, little is known about the effects of S. alterniflora invasion on SOC concentrations and fractions in tidal marshes dominated by native C4 plants. In this study, a field experiment was conducted in a tidal marsh dominated by the native C4 plant Cyperus malaccensis in the Minjiang River estuary, China. Concentrations of SOC and liable SOC fractions, dissolved organic carbon (DOG), microbial biomass carbon (MBC), and easily oxidizable carbon (EOC), were measured in the top 50-cm soils of the C. malaccensis community, as well as those of three S. alterniflova communities with an invasion duration of 0-4 years (SA-4), 4-8 years (SA-8), and 8-12 years (SA-12), respectively. Results showed that both SOC stocks in the 50-cm soils and mean SOC concentrations in the surface soils (0-10 cm) of the C. malaccensis community increased with the duration of S. alterniflora invasion, whereas SOC concentrations in the 10-50-cm soils decreased slightly during the initial period of S. alterniflora invasion, before increasing again. The pattern of changes in labile SOC fractions (DOC, MBC, and EOC) with invasion duration was generally similar to that of SOC, while the ratios of labile SOC fractions to total SOC (DOC:SOC, MBC:SOC, and EOC:SOC) decreased significantly with the duration of S. alterniflora invasion. The findings of this study suggest that invasion of the exotic C4 plant S. alternifora into a marsh dominated by the native C4 plant C. malaecensis would enhance SOC sequestration owing to the greater amount of biomass and lower proportion of labile SOC fractions present in the S. alterniflora communities.