Concentrations of heavy metals (Cu, Pb, Zn, Cr and Cd), and phosphorous (P) were determined in surface tidal flat sediments of the Yangtze estuary and Shanghai coast. Results demonstrate that there were significant di...Concentrations of heavy metals (Cu, Pb, Zn, Cr and Cd), and phosphorous (P) were determined in surface tidal flat sediments of the Yangtze estuary and Shanghai coast. Results demonstrate that there were significant differences among the accumulation of the heavy metals in sediments, following the order: Zn > Cu > Cr > Pb > Cd. The spatial distribution and chemical forms of heavy metals in tidal flat sediments were closely related to the distribution of pollution resources (outlet of sewage) and the local sedimentary and hydrodynamic conditions. The dominated form of non-residual heavy metals is bound to Fe/Mn oxides, and the next form is bound to carbonates. Moreover, contents of total P in sediments range from 18.0 μmol.g?1 to 31.4 μmol.g?1 along the coastline, speciation of P in sediments was different, most of P in tidal flat sediments is associated with calcium phases (as Ca-P) similar to marine sediments.展开更多
Twenty-nine samples of surface sediments from tidal flats in the Northern Shandong Province were collected for grain size, heavy metal(Hg, Cu, Pb, Zn, Cd, and Cr), and oil pollution analyses. The geoaccumulation index...Twenty-nine samples of surface sediments from tidal flats in the Northern Shandong Province were collected for grain size, heavy metal(Hg, Cu, Pb, Zn, Cd, and Cr), and oil pollution analyses. The geoaccumulation index(Igeo) and factor analysis were introduced to evaluate sediment quality and source of contaminants. The mean concentrations of Hg, Cu, Pb, Zn, Cd, Cr, and oil in the surface sediments in the study area are 0.033, 17.756, 19.121, 55.700, 0.291, 59.563, and 14.213 μg g-1, respectively. The heavy metal contamination in the old delta lobe is slightly higher than that in the abandoned delta lobe; however, the opposite was observed for oil pollution. The Igeo results revealed that the overall quality of the surface sediments in the study area is in good condition. The heavy metal pollution levels show a descending order: Cd> Hg> Cr> Cu> Zn> Pb, Cd being the main pollutant. The contamination level for in the study area is relatively lower than those for China's other tidal flats. Heavy metals are mainly derived from natural sources of rock weathering and erosion, partly influenced by industrial and agricultural discharge. However, oil pollution is mainly from runoff input, motorized fishing boat sewage, and oil exploitation.展开更多
The Nanhui tidal flat is located in the area of slow current where the ebb currents from the Changjiang Estuaryand the Hangzhou Bay converge and the flood current from the sea diverges into the estuary and the bay. Th...The Nanhui tidal flat is located in the area of slow current where the ebb currents from the Changjiang Estuaryand the Hangzhou Bay converge and the flood current from the sea diverges into the estuary and the bay. The flat extends seaward in tongue shape and has a wide and gentle surface with a marked difference of tidal levels on its two sides, which results in the sediment longitudinal transport on the flat. The water-sediment conditions are diverse at different locations. The velocity and sediment concentration in intertidal zone are higher during the flood tide than those during the ebb tide. The net sediment transport is landward, resulting in a large amount of deposition of sediments on the shoal. However, the ebb current is the dominant one in deep-water area where the net sediment transport is seaward. There exist two circulation systems in plane view on the shoal and in its adjacent deep-water area, which results in the sediment exchanges between the flat and channel and between the estuary and the bay. The landward storm waves erode shoal face, causing the rise of water level on the flat, originating the formation of the vertical circulation system of the sediment transport, and consequently * accelerating the evolution process of the tidal flat.展开更多
From July 2003 to July 2004,samples were collected on Chongming Island east tidal flat every two months.The research showed that the nitrous oxide(N2O)production rate was very low in the water,Chongming east tidal fla...From July 2003 to July 2004,samples were collected on Chongming Island east tidal flat every two months.The research showed that the nitrous oxide(N2O)production rate was very low in the water,Chongming east tidal flat(CM)sediment was the N2O source of the water.Sediment N2O natural production rate was between-0.08 and 1.74μmolN·m-2·h-1.N2O natural production rate was higher in the summer.The difference of the N2O natural production rate in the different tidal flats,the correlation between the N2O natural production rate and the denitrification rate,and those with the temperature and DO indicate that middle tidal flat sediment denitrification was the main process of the N2O production,while in the low tidal flat sediment,the production of the N2O came from several processes of the nitrogen cycling.Tidal flat sediment denitrification reaction was stronger in summer and winter but relatively lower in the late autumn and early spring.Seasonal change of the sediment denitrification rate was wide,from 1.12 to 33.34μmolN·m-2·h-1.Temperature,DO and the coactions of them had the prominent effect on the tidal flat sediment denitrification.展开更多
Sediment denitrification rates at six Yangtze River estuary tidal flat locations(mudflats and salt marshes)were measured from July 2003 to October 2004.In winter and summer,spatial distribution of denitrification rate...Sediment denitrification rates at six Yangtze River estuary tidal flat locations(mudflats and salt marshes)were measured from July 2003 to October 2004.In winter and summer,spatial distribution of denitrification rates was not great in the Yangtze estuary,while in spring and autumn,denitrification rates had a great spatial distribution because of the human activity effect.The temporal change of denitrification rates was greater.They ranged from 0.2 to 36.4 umolN·m^(-2)·h^(-1),and were higher in the summertime.The annual average of sediment denitrification rate was 18.2±12.3 mu molN·m^(-2)·h^(-1)in the middle tidal flat and 15.1±9.45 mu molN·m^(-2)·h^(-1)in the low tidal flat in the Yangtze estuary.Data analysis indicated that the temperature was the primary factor controlling the process of denitrification(significant positive correlation,P<0.01);at the same time,the content of sediment total nitrogen(TN)and the molar ratio of sediment carbon and nitrogen(C/N)had significant positive correlation(P<0.05)and negative correlation(P<0.05)with denitrification rates,respectively.In the Yangtze estuary,increasing of water salinity had no significant inhibition of denitrification because of the wide change range of water salinity.展开更多
The sequence stratigraphic framework of Shanxi Formation in the northeast Zhoukou Depression was established based on detailed sequence stratigraphical and sedimentological analysis by utilizing the logging and core d...The sequence stratigraphic framework of Shanxi Formation in the northeast Zhoukou Depression was established based on detailed sequence stratigraphical and sedimentological analysis by utilizing the logging and core data of six wells drilled in the eastern tectonic unit of Zhoukou Depression.It was divided into three third-order sequences,namely SQs1,SQs2,and SQs3 from bottom to top.Each sequence can be divided into a transgressive system tract(TST)and a highstand system tract(HST).Furthermore,four sequence boundaries and three maximum flooding surfaces were identified,and they are the bottom interface SBs and maximum flooding surface mfss1 of SQs1,the bottom interface SBs1 and maximum flooding surface mfss2 of SQs2,the bottom interface SBs3 and maximum flooding surface mfss3 of SQs3,and the top interface SBx from bottom to top.Carbonate tidal flat–clastic tidal flat sedimentary system developed in Shanxi Formation in the northeast Zhoukou Depression(also referred to as the study area)under the control of regression.Meanwhile,four sedimentary microfacies were identified in the sedimentary system,which are lime-mud flats,sand flats,mixed flats,and mud flats.The transgression in the study area occurred from the southeast to the northwest.Therefore,the northwestern part is the seaward side,and the southeastern part is the landward side.As revealed by relevant drilling data,SQs1 of the Shanxi Formation is characterized by the development of limestone and carbonaceous mudstone,with limestone,dark mudstone,and carbonaceous mudstone mainly developing.Meanwhile,lime-mud flats were mainly deposited in it.During the periods of SQs2 and SQs3,the sedimentary environment of the study area changed from the carbonate tidal flats to clastic tidal flats as the coastline migrated towards the sea.In these periods,sand flats mainly developed near the maximum flooding surfaces and were relatively continuous in the eastern and southern parts of the transgressive system tract;mixed flats were relatively continuous in the western and northern parts of the transgressive system tract as well as the eastern and southern parts of the highstand system tract;mud flats widely developed in the highstand system tract.Peat flats mainly developed in the period of HSTs2,with coal seams relatively developing in the southeastern part of the study area as revealed by drilling data.The peat flats in SQs2 are favorable hydrocarbon source layers,the lime-mud flats in SQs1 and sand flats formed in the transgression periods of SQs2 and SQs3 constitute favorable hydrocarbon reservoirs,and the mud flats form in the transgressions periods serve as favorable cap rocks.Therefore,the study area features a reservoir-cap assemblage for self-generating and self-storing of hydrocarbon,and the southeastern part of the study area can be taken as a favorable exploration area.展开更多
基金National Natural Science Foundation of China, No.49901015No. 40131020.
文摘Concentrations of heavy metals (Cu, Pb, Zn, Cr and Cd), and phosphorous (P) were determined in surface tidal flat sediments of the Yangtze estuary and Shanghai coast. Results demonstrate that there were significant differences among the accumulation of the heavy metals in sediments, following the order: Zn > Cu > Cr > Pb > Cd. The spatial distribution and chemical forms of heavy metals in tidal flat sediments were closely related to the distribution of pollution resources (outlet of sewage) and the local sedimentary and hydrodynamic conditions. The dominated form of non-residual heavy metals is bound to Fe/Mn oxides, and the next form is bound to carbonates. Moreover, contents of total P in sediments range from 18.0 μmol.g?1 to 31.4 μmol.g?1 along the coastline, speciation of P in sediments was different, most of P in tidal flat sediments is associated with calcium phases (as Ca-P) similar to marine sediments.
基金supported by the 908 Special Coastal Surveys of Shandong Province Project (No. SD908-01-03)the Ocean Public Welfare Scientific Research Project (No. 201005029)
文摘Twenty-nine samples of surface sediments from tidal flats in the Northern Shandong Province were collected for grain size, heavy metal(Hg, Cu, Pb, Zn, Cd, and Cr), and oil pollution analyses. The geoaccumulation index(Igeo) and factor analysis were introduced to evaluate sediment quality and source of contaminants. The mean concentrations of Hg, Cu, Pb, Zn, Cd, Cr, and oil in the surface sediments in the study area are 0.033, 17.756, 19.121, 55.700, 0.291, 59.563, and 14.213 μg g-1, respectively. The heavy metal contamination in the old delta lobe is slightly higher than that in the abandoned delta lobe; however, the opposite was observed for oil pollution. The Igeo results revealed that the overall quality of the surface sediments in the study area is in good condition. The heavy metal pollution levels show a descending order: Cd> Hg> Cr> Cu> Zn> Pb, Cd being the main pollutant. The contamination level for in the study area is relatively lower than those for China's other tidal flats. Heavy metals are mainly derived from natural sources of rock weathering and erosion, partly influenced by industrial and agricultural discharge. However, oil pollution is mainly from runoff input, motorized fishing boat sewage, and oil exploitation.
文摘The Nanhui tidal flat is located in the area of slow current where the ebb currents from the Changjiang Estuaryand the Hangzhou Bay converge and the flood current from the sea diverges into the estuary and the bay. The flat extends seaward in tongue shape and has a wide and gentle surface with a marked difference of tidal levels on its two sides, which results in the sediment longitudinal transport on the flat. The water-sediment conditions are diverse at different locations. The velocity and sediment concentration in intertidal zone are higher during the flood tide than those during the ebb tide. The net sediment transport is landward, resulting in a large amount of deposition of sediments on the shoal. However, the ebb current is the dominant one in deep-water area where the net sediment transport is seaward. There exist two circulation systems in plane view on the shoal and in its adjacent deep-water area, which results in the sediment exchanges between the flat and channel and between the estuary and the bay. The landward storm waves erode shoal face, causing the rise of water level on the flat, originating the formation of the vertical circulation system of the sediment transport, and consequently * accelerating the evolution process of the tidal flat.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.40131020 and 40173030)the Science&Technology Department of Shanghai(Grant Nos.05DZ120007+1 种基金05JC14059)the Environment Protection Department of Shanghai and the PhD Program Scholarship Fund of ECNU 2005.
文摘From July 2003 to July 2004,samples were collected on Chongming Island east tidal flat every two months.The research showed that the nitrous oxide(N2O)production rate was very low in the water,Chongming east tidal flat(CM)sediment was the N2O source of the water.Sediment N2O natural production rate was between-0.08 and 1.74μmolN·m-2·h-1.N2O natural production rate was higher in the summer.The difference of the N2O natural production rate in the different tidal flats,the correlation between the N2O natural production rate and the denitrification rate,and those with the temperature and DO indicate that middle tidal flat sediment denitrification was the main process of the N2O production,while in the low tidal flat sediment,the production of the N2O came from several processes of the nitrogen cycling.Tidal flat sediment denitrification reaction was stronger in summer and winter but relatively lower in the late autumn and early spring.Seasonal change of the sediment denitrification rate was wide,from 1.12 to 33.34μmolN·m-2·h-1.Temperature,DO and the coactions of them had the prominent effect on the tidal flat sediment denitrification.
基金Supported by the National Natural Science Foundation of China(Grant Nos.40173030,40571006 and 40131020)the Science&Technology Department of Shanghai(Grant Nos.05DZ120007 and 05JC14059)China Postdoctoral Science Foundation
文摘Sediment denitrification rates at six Yangtze River estuary tidal flat locations(mudflats and salt marshes)were measured from July 2003 to October 2004.In winter and summer,spatial distribution of denitrification rates was not great in the Yangtze estuary,while in spring and autumn,denitrification rates had a great spatial distribution because of the human activity effect.The temporal change of denitrification rates was greater.They ranged from 0.2 to 36.4 umolN·m^(-2)·h^(-1),and were higher in the summertime.The annual average of sediment denitrification rate was 18.2±12.3 mu molN·m^(-2)·h^(-1)in the middle tidal flat and 15.1±9.45 mu molN·m^(-2)·h^(-1)in the low tidal flat in the Yangtze estuary.Data analysis indicated that the temperature was the primary factor controlling the process of denitrification(significant positive correlation,P<0.01);at the same time,the content of sediment total nitrogen(TN)and the molar ratio of sediment carbon and nitrogen(C/N)had significant positive correlation(P<0.05)and negative correlation(P<0.05)with denitrification rates,respectively.In the Yangtze estuary,increasing of water salinity had no significant inhibition of denitrification because of the wide change range of water salinity.
基金This research was supported by project of China Geological Survey(DD20190725)Innovative Special Project of Sino-US Intergovernmental Cooperation in Science and Technology(2017YFE0106300)。
文摘The sequence stratigraphic framework of Shanxi Formation in the northeast Zhoukou Depression was established based on detailed sequence stratigraphical and sedimentological analysis by utilizing the logging and core data of six wells drilled in the eastern tectonic unit of Zhoukou Depression.It was divided into three third-order sequences,namely SQs1,SQs2,and SQs3 from bottom to top.Each sequence can be divided into a transgressive system tract(TST)and a highstand system tract(HST).Furthermore,four sequence boundaries and three maximum flooding surfaces were identified,and they are the bottom interface SBs and maximum flooding surface mfss1 of SQs1,the bottom interface SBs1 and maximum flooding surface mfss2 of SQs2,the bottom interface SBs3 and maximum flooding surface mfss3 of SQs3,and the top interface SBx from bottom to top.Carbonate tidal flat–clastic tidal flat sedimentary system developed in Shanxi Formation in the northeast Zhoukou Depression(also referred to as the study area)under the control of regression.Meanwhile,four sedimentary microfacies were identified in the sedimentary system,which are lime-mud flats,sand flats,mixed flats,and mud flats.The transgression in the study area occurred from the southeast to the northwest.Therefore,the northwestern part is the seaward side,and the southeastern part is the landward side.As revealed by relevant drilling data,SQs1 of the Shanxi Formation is characterized by the development of limestone and carbonaceous mudstone,with limestone,dark mudstone,and carbonaceous mudstone mainly developing.Meanwhile,lime-mud flats were mainly deposited in it.During the periods of SQs2 and SQs3,the sedimentary environment of the study area changed from the carbonate tidal flats to clastic tidal flats as the coastline migrated towards the sea.In these periods,sand flats mainly developed near the maximum flooding surfaces and were relatively continuous in the eastern and southern parts of the transgressive system tract;mixed flats were relatively continuous in the western and northern parts of the transgressive system tract as well as the eastern and southern parts of the highstand system tract;mud flats widely developed in the highstand system tract.Peat flats mainly developed in the period of HSTs2,with coal seams relatively developing in the southeastern part of the study area as revealed by drilling data.The peat flats in SQs2 are favorable hydrocarbon source layers,the lime-mud flats in SQs1 and sand flats formed in the transgression periods of SQs2 and SQs3 constitute favorable hydrocarbon reservoirs,and the mud flats form in the transgressions periods serve as favorable cap rocks.Therefore,the study area features a reservoir-cap assemblage for self-generating and self-storing of hydrocarbon,and the southeastern part of the study area can be taken as a favorable exploration area.
