Sediment transport in estuarine systems has been of increasing interest for scientists during the past few decades. However, the mechanisms for sediment redistribution remain unclear. We characterized in detail sedime...Sediment transport in estuarine systems has been of increasing interest for scientists during the past few decades. However, the mechanisms for sediment redistribution remain unclear. We characterized in detail sediment transport in the Xiaoqing River estuary using the mathematical Weibull function to partition grain-size components of surface sediments in the southwestern Laizhou Bay, Northeast China. Four partitioned components: finer than 4,4.6-12.5, 23.4-63.3, and 67.1-132.6 μm were interpreted in terms of hydrodynamic conditions. During sediment transport, silt grains were suspended and moved seaward from three depositional centers, whereas fine-grained sands moved generally landward. Overall, sediments are transported clockwise in a generally NNE direction near shore and then turn eastward offshore. The mathematical partitioning method showed a great potential for future estuarine environmental studies.展开更多
Detrital minerals of 137 offshore and 22 river sediment samples collected from Qingdao coastal areas have been analyzed. Four mineral assemblage provinces can be classified by Q-mode cluster analysis. Factor analysis ...Detrital minerals of 137 offshore and 22 river sediment samples collected from Qingdao coastal areas have been analyzed. Four mineral assemblage provinces can be classified by Q-mode cluster analysis. Factor analysis identifies two major factors that account for the total variability in most common minerals: 1) based on the relationship of quartz, hornblende, actinolite, micas, and authigenic pyrite, 41.55% of the variability is related to sediment sources; 2) based on the relationship of epidote, garnet, sphere, and ilmenite, 23.21% can be related to strong hydrodynamic conditions that control transport and sedimentation. By comparing mineral compositions of river waters in the study area, the following four mineral provenances can be identified. The Qingdao-Laoshan nearshore area has a quartz-feldspar-epidote-hornblende-limenite-limonite-sphene assemblage, which is largely attributed to relict sediment and coastal erosion. The Jimo-Haiyang nearshore area has a quartz-feldspar-hornblende-epidote-limonite-mica-actinolite assemblage, derived largely from the Wulong River and Rushan River, and is also affected by the Huanghe River, while the Qianliyan Island area in the deeper offshore area separated by a mud belt has a similar assemblage. The Haiyang-Rushan nearshore area has a quartz-feldspar-hornblende-epidote-micas-limonite assemblage, indicating multiple sources from the Rushan River, the Wulong River, the Huanghe River, and coastal erosion. The central area, located in an eddy center, has a mica-authigenic pyrite-hornblende-quartz-feldspar assemblage, indicating multiple sources dominated by Huanghe River distal sediments.展开更多
China is experiencing rapid urbanization that has changed the water quality of rivers, especially nutrient loads. In this study, a typical urban river located in a karst area, Chengguan River, was chosen to explore th...China is experiencing rapid urbanization that has changed the water quality of rivers, especially nutrient loads. In this study, a typical urban river located in a karst area, Chengguan River, was chosen to explore the influence of urbanization on river ecosystems based on nutrient concentration and nitrate isotopes. The results show monthly variability of water chemistry and nutrient concentration. Nutrient concentration in two tributaries and the mainstem showed significant spatial variability, with heavy N and P pollution in one tributary near a suburban area,indicating a response to different levels of urbanization.Measurements of nitrate dual isotopes suggest thatvolatilization, assimilation, nitrification, and denitrification all occur in the polluted river. Water chemistry and nitrate isotopes show that major nitrogen sources included domestic waste and agricultural input, such as chemical fertilizer and manure. The results suggest that urbanization increases nutrient concentrations and accelerates the riverine nitrogen dynamic, and point to the need to manage point sources of sewage effluents to improve the water quality of urban rivers in southwestern China.展开更多
This enchanting delicacy made from world-renowned Jinhua Ham is a traditional dish in southeastern Jiangsu and Zhejiang provinces.The story of its conception dates back to the year 1127 when the Jurchen troops invaded...This enchanting delicacy made from world-renowned Jinhua Ham is a traditional dish in southeastern Jiangsu and Zhejiang provinces.The story of its conception dates back to the year 1127 when the Jurchen troops invaded and overturned the Northern Song Dynasty(960-1127).Zhao Gou,younger brother of the last Northern Song emperor,established the Southern Song Dynasty(1127-1279),and declared Shangqiu,Henan Province,the new capital.展开更多
The purpose of this paper was to implement ＂Soil and Water Assessment Tool （SWAT）＂ model and Geographic Information System （GIS） to evaluate the impact of land use changes on stream discharge in Nghinh Tuong wat...The purpose of this paper was to implement ＂Soil and Water Assessment Tool （SWAT）＂ model and Geographic Information System （GIS） to evaluate the impact of land use changes on stream discharge in Nghinh Tuong watershed （a brand of Cau River） in Northern Vietnam. The watershed was coverd by 56% forestry land, 30% agricultural land and the remain 14% for others. Stream discharge observed data from 2002 to 2007 were used for calibration period and from 2008 to 2012 for validation period. The result showed that two coefficients （NSE and PBIAS） to evaluate model performance were 0.76 and 6.54% for calibration period and 0.87 and 4.74% for validation period, respectively. Stream discharge strongly depends not only on quantity of precipitation but also on land use change. Through the scenario 1, agricultural land （corn, orchard and tea） increases 9,782.67 ha （2.45%）, meanwhile forest （forest-mixed） decreases 1,091.77 ha （2.75%） as compared to baseline scenario. Additionally, precipitation increases 3.74% in mean wet season, but decreases 0.5% in mean dry season with respect to baseline period. SWAT model was able to simulate stream discharge and sediment yield for Nghinh Tuong watershed successfully not only for baseline scenario but also for scenario 1. In brief, SWAT proves its ability in simulation stream discharge in subwatershed level. It is a useful tool to assist water quantity and quality management process in Nghinh Tuong watershed. This work one more time indicated that SWAT is useful tool for resources and environment management.展开更多
The sequence stratigraphy and geochronology of the terrestrial dinosaur-bearing strata,i.e.,the Qiupa Formation,were poorly studied in the Luanchuan-Tantou Basin in western Henan,China.This study shows that these stra...The sequence stratigraphy and geochronology of the terrestrial dinosaur-bearing strata,i.e.,the Qiupa Formation,were poorly studied in the Luanchuan-Tantou Basin in western Henan,China.This study shows that these strata represent a complete succession from the Late Cretaceous to the early Paleogene,including the K/T boundary,in this area.Here we report a detailed study of the K/T boundary,especially its stratigraphic sequence,sedimentary characteristics,integrity,continuity,and geological implications.展开更多
Tidally induced resuspension processes play an important role in the release of mercury (Hg) into the water column, which increases the risk of Hg exposure to estuarine eco-systems. In order to further understand the ...Tidally induced resuspension processes play an important role in the release of mercury (Hg) into the water column, which increases the risk of Hg exposure to estuarine eco-systems. In order to further understand the geochemical activities of Hg in the intertidal area, the temporal variations of dissolved Hg (Hg D ) and particulate Hg (Hg P ) in the water column during the course of a tidal cycle and its geochemical processes were studied in the southern intertidal zone of the Yangtze Estuary, China. The concentrations of Hg D and Hg P varied between 37-612 ng/L and 51-638 ng/L respectively during the tidal cycle. The increase of Hg D was distinguished at the early flood tide and late ebb tide when the water flow rates were higher. The Hg D concentrations were negatively correlated with Hg P (r = 0.523, p < 0.05) and positively correlated with dissolved organic carbon (DOC) (r = 0.605, p < 0.05) in the bottom water, indicating that the Hg D released from the sediments into the overlying water was associated with the simultaneously released colloidal material in the bottom water. The main pathways for the translocation of Hg from the sediments to the overlying water include the processes of desorption from resuspended particles, advection or diffusion from sediments, and the oxidation of resuspended sulfide. The results of principal components analysis (PCA) and Pearson correlation analysis showed that the combined effects of the total suspended substrate (TSS), DOC, pH and dissolved oxygen (DO) influenced the geochemical activities of Hg in the water column during the course of a tidal cycle.展开更多
Archaea play an important role in global carbon and nitrogen cycles. Archaeal lipids, such as isoprenoid glycerol diakyl glycerol tetraethers(i GDGTs), are important biomarkers tracing change in archaeal community str...Archaea play an important role in global carbon and nitrogen cycles. Archaeal lipids, such as isoprenoid glycerol diakyl glycerol tetraethers(i GDGTs), are important biomarkers tracing change in archaeal community structure and biogeochemical processes in the natural environments. In this research, the spatial distributions of archaeal lipids in the surface sediments of the Jiulong River(JR) and the Jiulong River estuary(JRE) were examined. GDGT-0(containing zero cyclopentyl ring) and crenarchaeol were the most abundant i GDGTs in the JR and JRE. From the rivers to the estuary, the total i GDGTs, GDGT-0, crenarchaeol and archaeol concentrations showed significant spatial variation; in particular, GDGT-0 and archaeol in the river may be predominantly derived in situ from methanogens, whereas crenarchaeol in the estuary mainly derived in situ from Thaumarchaeota. We inferred that archaeal community was dominated by methanogens in the Jiulong River and by Thaumarchaeota in the Jiulong River estuary, which are consistent with change in archaeal community structure observed in other estuarine environments.展开更多
基金Supported by the China Postdoctoral Science Foundation (No.2012M520369)the National Natural Science Foundation of China (Nos.40906047,41076031,40925012)+1 种基金the State Oceanic Research Project for Public Benefit of China (No.201105020)the National Basic Research Program of China (973 Program) (Nos.2010CB951201,2012CB821900)
文摘Sediment transport in estuarine systems has been of increasing interest for scientists during the past few decades. However, the mechanisms for sediment redistribution remain unclear. We characterized in detail sediment transport in the Xiaoqing River estuary using the mathematical Weibull function to partition grain-size components of surface sediments in the southwestern Laizhou Bay, Northeast China. Four partitioned components: finer than 4,4.6-12.5, 23.4-63.3, and 67.1-132.6 μm were interpreted in terms of hydrodynamic conditions. During sediment transport, silt grains were suspended and moved seaward from three depositional centers, whereas fine-grained sands moved generally landward. Overall, sediments are transported clockwise in a generally NNE direction near shore and then turn eastward offshore. The mathematical partitioning method showed a great potential for future estuarine environmental studies.
基金the National Natural Science Foundation of China (Nos. 41376079, 41406081 and 41506107)Marine Geology Survey Project (Nos. GZH200900501 and GZH201100203)the Basic Fund of Ministry of Science Foundation of China (No. 2013FY112200)
文摘Detrital minerals of 137 offshore and 22 river sediment samples collected from Qingdao coastal areas have been analyzed. Four mineral assemblage provinces can be classified by Q-mode cluster analysis. Factor analysis identifies two major factors that account for the total variability in most common minerals: 1) based on the relationship of quartz, hornblende, actinolite, micas, and authigenic pyrite, 41.55% of the variability is related to sediment sources; 2) based on the relationship of epidote, garnet, sphere, and ilmenite, 23.21% can be related to strong hydrodynamic conditions that control transport and sedimentation. By comparing mineral compositions of river waters in the study area, the following four mineral provenances can be identified. The Qingdao-Laoshan nearshore area has a quartz-feldspar-epidote-hornblende-limenite-limonite-sphene assemblage, which is largely attributed to relict sediment and coastal erosion. The Jimo-Haiyang nearshore area has a quartz-feldspar-hornblende-epidote-limonite-mica-actinolite assemblage, derived largely from the Wulong River and Rushan River, and is also affected by the Huanghe River, while the Qianliyan Island area in the deeper offshore area separated by a mud belt has a similar assemblage. The Haiyang-Rushan nearshore area has a quartz-feldspar-hornblende-epidote-micas-limonite assemblage, indicating multiple sources from the Rushan River, the Wulong River, the Huanghe River, and coastal erosion. The central area, located in an eddy center, has a mica-authigenic pyrite-hornblende-quartz-feldspar assemblage, indicating multiple sources dominated by Huanghe River distal sediments.
基金financially supported by National Natural Science Foundation of China(Grant Nos.41571130072 and41130536)the Ministry of Science and Technology of China through Grant Nos.2016YFA0601000 and 2013CB956700
文摘China is experiencing rapid urbanization that has changed the water quality of rivers, especially nutrient loads. In this study, a typical urban river located in a karst area, Chengguan River, was chosen to explore the influence of urbanization on river ecosystems based on nutrient concentration and nitrate isotopes. The results show monthly variability of water chemistry and nutrient concentration. Nutrient concentration in two tributaries and the mainstem showed significant spatial variability, with heavy N and P pollution in one tributary near a suburban area,indicating a response to different levels of urbanization.Measurements of nitrate dual isotopes suggest thatvolatilization, assimilation, nitrification, and denitrification all occur in the polluted river. Water chemistry and nitrate isotopes show that major nitrogen sources included domestic waste and agricultural input, such as chemical fertilizer and manure. The results suggest that urbanization increases nutrient concentrations and accelerates the riverine nitrogen dynamic, and point to the need to manage point sources of sewage effluents to improve the water quality of urban rivers in southwestern China.
文摘This enchanting delicacy made from world-renowned Jinhua Ham is a traditional dish in southeastern Jiangsu and Zhejiang provinces.The story of its conception dates back to the year 1127 when the Jurchen troops invaded and overturned the Northern Song Dynasty(960-1127).Zhao Gou,younger brother of the last Northern Song emperor,established the Southern Song Dynasty(1127-1279),and declared Shangqiu,Henan Province,the new capital.
文摘The purpose of this paper was to implement ＂Soil and Water Assessment Tool （SWAT）＂ model and Geographic Information System （GIS） to evaluate the impact of land use changes on stream discharge in Nghinh Tuong watershed （a brand of Cau River） in Northern Vietnam. The watershed was coverd by 56% forestry land, 30% agricultural land and the remain 14% for others. Stream discharge observed data from 2002 to 2007 were used for calibration period and from 2008 to 2012 for validation period. The result showed that two coefficients （NSE and PBIAS） to evaluate model performance were 0.76 and 6.54% for calibration period and 0.87 and 4.74% for validation period, respectively. Stream discharge strongly depends not only on quantity of precipitation but also on land use change. Through the scenario 1, agricultural land （corn, orchard and tea） increases 9,782.67 ha （2.45%）, meanwhile forest （forest-mixed） decreases 1,091.77 ha （2.75%） as compared to baseline scenario. Additionally, precipitation increases 3.74% in mean wet season, but decreases 0.5% in mean dry season with respect to baseline period. SWAT model was able to simulate stream discharge and sediment yield for Nghinh Tuong watershed successfully not only for baseline scenario but also for scenario 1. In brief, SWAT proves its ability in simulation stream discharge in subwatershed level. It is a useful tool to assist water quantity and quality management process in Nghinh Tuong watershed. This work one more time indicated that SWAT is useful tool for resources and environment management.
基金supported by National Natural Science Foundation of China(Grant Nos.90914003,40872017)National Basic Research Program of China(Grant No.2006CB70145)
文摘The sequence stratigraphy and geochronology of the terrestrial dinosaur-bearing strata,i.e.,the Qiupa Formation,were poorly studied in the Luanchuan-Tantou Basin in western Henan,China.This study shows that these strata represent a complete succession from the Late Cretaceous to the early Paleogene,including the K/T boundary,in this area.Here we report a detailed study of the K/T boundary,especially its stratigraphic sequence,sedimentary characteristics,integrity,continuity,and geological implications.
基金supported by the National Natural Science Foundation of China (40701164, 40971259)the National Key Water Special Project of China (2009ZX07317-006)the Program of Shanghai Subject Chief Scientist (10XD1401600)
文摘Tidally induced resuspension processes play an important role in the release of mercury (Hg) into the water column, which increases the risk of Hg exposure to estuarine eco-systems. In order to further understand the geochemical activities of Hg in the intertidal area, the temporal variations of dissolved Hg (Hg D ) and particulate Hg (Hg P ) in the water column during the course of a tidal cycle and its geochemical processes were studied in the southern intertidal zone of the Yangtze Estuary, China. The concentrations of Hg D and Hg P varied between 37-612 ng/L and 51-638 ng/L respectively during the tidal cycle. The increase of Hg D was distinguished at the early flood tide and late ebb tide when the water flow rates were higher. The Hg D concentrations were negatively correlated with Hg P (r = 0.523, p < 0.05) and positively correlated with dissolved organic carbon (DOC) (r = 0.605, p < 0.05) in the bottom water, indicating that the Hg D released from the sediments into the overlying water was associated with the simultaneously released colloidal material in the bottom water. The main pathways for the translocation of Hg from the sediments to the overlying water include the processes of desorption from resuspended particles, advection or diffusion from sediments, and the oxidation of resuspended sulfide. The results of principal components analysis (PCA) and Pearson correlation analysis showed that the combined effects of the total suspended substrate (TSS), DOC, pH and dissolved oxygen (DO) influenced the geochemical activities of Hg in the water column during the course of a tidal cycle.
基金supported by the National Key Basic Research Program of China (Grant No. 2013CB955703)the South China Sea-Deep Program of the National Natural Science Foundation of China (Grant Nos. 91028005 & 91428308)+3 种基金the National Natural Science Foundation of China (Grant Nos. 41276125 & 31470539)the "National Thousand Talents Program" at the State Key Laboratory of Marine Geology of Tongji Universitythe Expenses for Chinese University Basic Researchinterdisciplinary Programs (Grant No. 1350219165)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. IUEQN201307)
文摘Archaea play an important role in global carbon and nitrogen cycles. Archaeal lipids, such as isoprenoid glycerol diakyl glycerol tetraethers(i GDGTs), are important biomarkers tracing change in archaeal community structure and biogeochemical processes in the natural environments. In this research, the spatial distributions of archaeal lipids in the surface sediments of the Jiulong River(JR) and the Jiulong River estuary(JRE) were examined. GDGT-0(containing zero cyclopentyl ring) and crenarchaeol were the most abundant i GDGTs in the JR and JRE. From the rivers to the estuary, the total i GDGTs, GDGT-0, crenarchaeol and archaeol concentrations showed significant spatial variation; in particular, GDGT-0 and archaeol in the river may be predominantly derived in situ from methanogens, whereas crenarchaeol in the estuary mainly derived in situ from Thaumarchaeota. We inferred that archaeal community was dominated by methanogens in the Jiulong River and by Thaumarchaeota in the Jiulong River estuary, which are consistent with change in archaeal community structure observed in other estuarine environments.
