Due to frequent soil Cd contamination and wide use of butachlor in China,there is a need to assess their combined toxicity to soil microorganisms.The combined effects of cadmium(Cd,10 mg kg-1 soil) and herbicide butac...Due to frequent soil Cd contamination and wide use of butachlor in China,there is a need to assess their combined toxicity to soil microorganisms.The combined effects of cadmium(Cd,10 mg kg-1 soil) and herbicide butachlor(10,50,and 100 mg kg-1 soil) on enzyme activities and microbial community structure in a paddy soil were assessed using the traditional enzyme assays and random amplified polymorphic DNA(RAPD) analysis.The results showed that urease and phosphatase activities were significantly reduced by high butachlor concentration(100 mg kg-1 soil).When the concentrations of Cd and butachlor added were at a ratio of 1:10,urease and phosphatase activities were significantly decreased whereas enzyme activities were greatly improved at the ratio of 1:5,which indicated that the combined effects of Cd and butachlor on soil urease and phosphatase activities depended largely on their addition concentration ratios.Random amplified polymorphic DNA(RAPD) analysis showed loss of original bands and appearance of new bands when compared with the control soil.Random amplified polymorphic DNA fingerprints suggested substantial differences between the control and treated soil samples,with apparent changes in the number and size of amplified DNA fragments.The addition of high concentration butachlor and the combined impacts of Cd and butachlor significantly affected the diversity of the microbial community.RAPD analysis in conjunction with other biomarkers such as soil enzyme parameters would prove a powerful ecotoxicological tool.Further investigations should be carried out to understand the clear link between RAPD patterns and enzyme activity.展开更多
Alpine ecosystems in permafrost region are extremely sensitive to climate changes.To determine spatial pattern variations in alpine meadow and alpine steppe biomass dynamics in the permafrost region of the Qinghai-Tib...Alpine ecosystems in permafrost region are extremely sensitive to climate changes.To determine spatial pattern variations in alpine meadow and alpine steppe biomass dynamics in the permafrost region of the Qinghai-Tibet Plateau,China,calibrated with historical datasets of above-ground biomass production within the permafrost region's two main ecosystems,an ecosystem-biomass model was developed by employing empirical spatialdistribution models of the study region's precipitation,air temperature and soil temperature.This model was then successfully used to simulate the spatio-temporal variations in annual alpine ecosystem biomass production under climate change.For a 0.44°C decade-1 rise in air temperature,the model predicted that the biomasses of alpine meadow and alpine steppe remained roughly the same if annual precipitation increased by 8 mm per decade-1,but the biomasses were decreased by 2.7% and 2.4%,respectively if precipitation was constant.For a 2.2°C decade-1 rise in air temperature coupled with a 12 mm decade-1 rise in precipitation,the model predicted that the biomass of alpine meadow was unchanged or slightly increased,while that of alpine steppe was increased by 5.2%.However,in the absence of any rise in precipitation,the model predicted 6.8% and 4.6% declines in alpine meadow and alpine steppe biomasses,respectively.The response of alpine steppe biomass to the rising air temperatures and precipitation was significantly lesser and greater,respectively than that of alpine meadow biomass.A better understanding of the difference in alpine ecosystem biomass production under climate change is greatly significant with respect to the influence of climate change on the carbon and water cycles in the permafrost regions of the Qinghai-Tibet Plateau.展开更多
With rapid economic growth in China,anthropogenic reactive nitrogen(Nr) emissions have more than doubled over the last two or three decades.Atmospheric Nr pollution is an environmental concern in China especially in m...With rapid economic growth in China,anthropogenic reactive nitrogen(Nr) emissions have more than doubled over the last two or three decades.Atmospheric Nr pollution is an environmental concern in China especially in megacities such as Beijing.In order to identify the impact of emission sources on atmospheric Nr pollution,we measured atmospheric Nr concentrations and their isotopic composition(δ^(15)N) dynamics at three typical sites:landfill,pig farm and road traffic sites in Beijing from April 2010 to March 2011.Passive samplers were used for monitoring ammonia(NH_3) and nitrogen dioxide(NO_2),two major Nr species,while their δ^(15)N values were measured by a diffusion method combined with mass spectrometer approach.The raw water pool of the landfill and fattening house of the pig farm were important NH_3 sources with mean NH_3 concentrations being 2,829 and 2,369 μg/m^3,respectively,while the road traffic site was a minor NH_3 source(10.6 μg/m^3).NH_3 concentrations at sites besides the landfill and roads were high in summer and low in winter due to the annual variation of temperature and the change of emission source intensity.In contrast,the NH_3 concentrations inside the pig farm house were high in winter and low in summer,for the barn windows were open in summer and closed in winter.The mean NO_2 concentrations were 89.8,32.9 and 23.0 μg/m^3 at the road traffic,the landfill and pig farm sites,respectively.Due to vehicle fuel combustion,NO_2 concentration at the road traffic was the highest among the three sources,and the road traffic was a main NO_2 emission source.PM10,p NH4+ and p NO3– concentrations in particulate matter were higher in summer than in winter(except PM10 for the pig farm).The δ^(15)NH_3 values ranged from –19.14‰ to 7.82‰,with an average of –0.05‰ for the landfill site,and the lowest values were observed in June and July.The δ^(15)NH_3 values for the pig farm site ranged from –29.78‰ to –14.05‰ with an average of –24.51‰,and the δ^(15)NH_3 values were more negative in summer than in the other seasons.The δ^(15)NO_2 values were –9.63‰ to 7.04‰ with an average of –3.72‰ for the road traffic site.The δ^(15)NO_2 values were more negative in summer than those in the other seasons.The different δ^(15)N values for the various Nr species in different sources may serve as important indicators for identifying atmospheric Nr sources in megacities.The results may also provide the theoretical basis for research on the atmospheric N deposition and its sources.展开更多
According to the observational data of viscous debris flows with hyper-concentration, debris flows can be classified into three types:high-viscous, viscous, and sub-viscous debris flows.Distinct formation mechanism of...According to the observational data of viscous debris flows with hyper-concentration, debris flows can be classified into three types:high-viscous, viscous, and sub-viscous debris flows.Distinct formation mechanism of different graded bedding structures in deposits of viscous debris flows was analyzed in this paper by using their yield-stress ratio and flow plug ratio.This paper specially analyzed the effect of Weissenberg which the gravels in squirm condition of hyper-concentration viscous flows would tend to move vertically, and the formation mechanism of the gravels accumulated at surface was also studied.The analysis in this paper can establish a foundation for the studies on differentiation of bedding structures of debris flow deposits and studies on dynamic parameters of debris flows.展开更多
By using geography quantitative methods and Arc GIS,the spatial distribution characteristics,types,rules and influencing factors of 20 representative rural tourism attractions in Yangzhou City were analyzed.The result...By using geography quantitative methods and Arc GIS,the spatial distribution characteristics,types,rules and influencing factors of 20 representative rural tourism attractions in Yangzhou City were analyzed.The results show that the traffic accessibility of various regions in Yangzhou City correlated positively with the spacial distribution of rural tourist attractions in quantity in these regions.The rural tourist attractions were dense in regions 10-20 km away from the center of the city;there was only one rural tourist attraction in regions 40-70 km away from the center of the city;some big rural tourist attractions were distributed in regions 70-90 km away from the center of the city;market orientation influenced the spatial distribution of the rural tourist attractions obviously.In regions 0-30 km away from the center of the city,most rural tourist attractions mainly provided recreation and entertainment services for tourists;in regions more than 70 km away from the center of the city,most rural tourist attractions mainly provided health and recuperation services for tourists;in regions 30-50 km away from the center of the city,the service functions of the rural tourist attractions were compound and diversified.展开更多
Carbon nanotube encapsulated nickel nanorods were catalytic grown via pyrolysis of oil on a bulk nickel wire substrate. X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy...Carbon nanotube encapsulated nickel nanorods were catalytic grown via pyrolysis of oil on a bulk nickel wire substrate. X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy were employed to characterize the as-prepared sample. The results show that, carbon nanotubes possess several microns in length, the filled metallic nickel nanorods with a uniform diameter of 35 nm were tightly encapsulated by the carbon capsules. The detailed formation mechanism for the carbon nanotubes encapsulated nickel nanorods were discussed briefly.展开更多
Taking Pingshuo West Dump (247.91 hm2) for example, an evaluating model of water-soil safety was set up according to 8 disaster factors of soil erosion: 30 min rainfall intensity, surface material, landform and slope ...Taking Pingshuo West Dump (247.91 hm2) for example, an evaluating model of water-soil safety was set up according to 8 disaster factors of soil erosion: 30 min rainfall intensity, surface material, landform and slope gradient, cover-degree, topographic, engineering measure grade of conservation of water-soil, volume weight and irregular subsidence. In new stage, early stage and later stage of reclamation, the degree of safety and the different site conditions were analyzed by the model. The results indicat that the dump belongs to middle danger, low danger and low safety in new stage, early stage and later stage of reclamation respectively. But at the same stage, different site conditions lead to different safety class because of the different disaster factors.展开更多
To figure out water pollution of the Qinhuang River in Binzhou City,broad bean root-tip micronucleus technique was applied to test water quality,water sample from different sampling points was taken to detect the cont...To figure out water pollution of the Qinhuang River in Binzhou City,broad bean root-tip micronucleus technique was applied to test water quality,water sample from different sampling points was taken to detect the contamination of broad bean root tips,so as to reflect water pollution using the pol ution indexes.The results showed that water in the Qinhuang River was polluted in different degrees,and water pollution grew more serious from the upper to the lower reaches.Water pollution sources include domestic sewage and solid waste,thus pollution discharge into the river must be strictly controlled to restore the polluted water and the ecological functions of waterscapes.展开更多
Improving and validating land surface models based on integrated observations in deserts is one of the challenges in land modeling. Particularly, key parameters and parameterization schemes in desert regions need to b...Improving and validating land surface models based on integrated observations in deserts is one of the challenges in land modeling. Particularly, key parameters and parameterization schemes in desert regions need to be evaluated in-situ to improve the models. In this study, we calibrated the land-surface key parameters and evaluated several formulations or schemes for thermal roughness length (z 0h ) in the common land model (CoLM). Our parameter calibration and scheme evaluation were based on the observed data during a torrid summer (29 July to 11 September 2009) over the Taklimakan Desert hinterland. First, the importance of the key parameters in the experiment was evaluated based on their physics principles and the significance of these key parameters were further validated using sensitivity test. Second, difference schemes (or physics-based formulas) of z 0h were adopted to simulate the variations of energy-related variables (e.g., sensible heat flux and surface skin temperature) and the simulated variations were then compared with the observed data. Third, the z 0h scheme that performed best (i.e., Y07) was then selected to replace the defaulted one (i.e., Z98); the revised scheme and the superiority of Y07 over Z98 was further demonstrated by comparing the simulated results with the observed data. Admittedly, the revised model did a relatively poor job of simulating the diurnal variations of surface soil heat flux, and nighttime soil temperature was also underestimated, calling for further improvement of the model for desert regions.展开更多
Eutrophication in the Three Gorges Reservoir has become a serious issue, and phosphorus (P) is the nutrient thought to be primarily responsible although there are few studies about P loss from the mostly sloping farml...Eutrophication in the Three Gorges Reservoir has become a serious issue, and phosphorus (P) is the nutrient thought to be primarily responsible although there are few studies about P loss from the mostly sloping farmlands of the area. This work investigated the amounts and forms of P loss from 9 farmlands with the slopes of 4°, 9°, and 17° in a small watershed, Wangjiagou in Fuling District, Chongqing of China. The slope of the relationship between runoff and rainfall increased with field slope; i.e., there was a significant interaction between the effects of rainfall and field slope on water export. For sediment export by surface runoff, there was no interaction between field slope and rainfall, and the intercept of the relationship between rainfall and sediment loss was significantly different for the 3 slopes. The main P loss was from sediments, regardless of slope. In the runoff water, particulate P was the largest P fraction, and its loss was greatest from the steepest land and least from the flattest. The release of total P and available P from sediments followed the same trend. The P loss during May to July in Wangjiagou was more than 60% of the annual total.展开更多
基金supported by the National Key Basic Research Program of China (No.2004CB418503)the National Natural Science Foundation of China (No.40801203)
文摘Due to frequent soil Cd contamination and wide use of butachlor in China,there is a need to assess their combined toxicity to soil microorganisms.The combined effects of cadmium(Cd,10 mg kg-1 soil) and herbicide butachlor(10,50,and 100 mg kg-1 soil) on enzyme activities and microbial community structure in a paddy soil were assessed using the traditional enzyme assays and random amplified polymorphic DNA(RAPD) analysis.The results showed that urease and phosphatase activities were significantly reduced by high butachlor concentration(100 mg kg-1 soil).When the concentrations of Cd and butachlor added were at a ratio of 1:10,urease and phosphatase activities were significantly decreased whereas enzyme activities were greatly improved at the ratio of 1:5,which indicated that the combined effects of Cd and butachlor on soil urease and phosphatase activities depended largely on their addition concentration ratios.Random amplified polymorphic DNA(RAPD) analysis showed loss of original bands and appearance of new bands when compared with the control soil.Random amplified polymorphic DNA fingerprints suggested substantial differences between the control and treated soil samples,with apparent changes in the number and size of amplified DNA fragments.The addition of high concentration butachlor and the combined impacts of Cd and butachlor significantly affected the diversity of the microbial community.RAPD analysis in conjunction with other biomarkers such as soil enzyme parameters would prove a powerful ecotoxicological tool.Further investigations should be carried out to understand the clear link between RAPD patterns and enzyme activity.
基金funded by the National Basic Research Program (also called 973 Program) (Grant No.2007CB411504)the National Natural Science Foundation of China (Grant No.40925002 and No.40730634)
文摘Alpine ecosystems in permafrost region are extremely sensitive to climate changes.To determine spatial pattern variations in alpine meadow and alpine steppe biomass dynamics in the permafrost region of the Qinghai-Tibet Plateau,China,calibrated with historical datasets of above-ground biomass production within the permafrost region's two main ecosystems,an ecosystem-biomass model was developed by employing empirical spatialdistribution models of the study region's precipitation,air temperature and soil temperature.This model was then successfully used to simulate the spatio-temporal variations in annual alpine ecosystem biomass production under climate change.For a 0.44°C decade-1 rise in air temperature,the model predicted that the biomasses of alpine meadow and alpine steppe remained roughly the same if annual precipitation increased by 8 mm per decade-1,but the biomasses were decreased by 2.7% and 2.4%,respectively if precipitation was constant.For a 2.2°C decade-1 rise in air temperature coupled with a 12 mm decade-1 rise in precipitation,the model predicted that the biomass of alpine meadow was unchanged or slightly increased,while that of alpine steppe was increased by 5.2%.However,in the absence of any rise in precipitation,the model predicted 6.8% and 4.6% declines in alpine meadow and alpine steppe biomasses,respectively.The response of alpine steppe biomass to the rising air temperatures and precipitation was significantly lesser and greater,respectively than that of alpine meadow biomass.A better understanding of the difference in alpine ecosystem biomass production under climate change is greatly significant with respect to the influence of climate change on the carbon and water cycles in the permafrost regions of the Qinghai-Tibet Plateau.
基金supported by the National Basic Research Program of China(2014CB954202)the National Natural Science Foundation of China(40425007,41071151,31421092)the Suzhou University Startup Foundation for Doctor(2015jb04)
文摘With rapid economic growth in China,anthropogenic reactive nitrogen(Nr) emissions have more than doubled over the last two or three decades.Atmospheric Nr pollution is an environmental concern in China especially in megacities such as Beijing.In order to identify the impact of emission sources on atmospheric Nr pollution,we measured atmospheric Nr concentrations and their isotopic composition(δ^(15)N) dynamics at three typical sites:landfill,pig farm and road traffic sites in Beijing from April 2010 to March 2011.Passive samplers were used for monitoring ammonia(NH_3) and nitrogen dioxide(NO_2),two major Nr species,while their δ^(15)N values were measured by a diffusion method combined with mass spectrometer approach.The raw water pool of the landfill and fattening house of the pig farm were important NH_3 sources with mean NH_3 concentrations being 2,829 and 2,369 μg/m^3,respectively,while the road traffic site was a minor NH_3 source(10.6 μg/m^3).NH_3 concentrations at sites besides the landfill and roads were high in summer and low in winter due to the annual variation of temperature and the change of emission source intensity.In contrast,the NH_3 concentrations inside the pig farm house were high in winter and low in summer,for the barn windows were open in summer and closed in winter.The mean NO_2 concentrations were 89.8,32.9 and 23.0 μg/m^3 at the road traffic,the landfill and pig farm sites,respectively.Due to vehicle fuel combustion,NO_2 concentration at the road traffic was the highest among the three sources,and the road traffic was a main NO_2 emission source.PM10,p NH4+ and p NO3– concentrations in particulate matter were higher in summer than in winter(except PM10 for the pig farm).The δ^(15)NH_3 values ranged from –19.14‰ to 7.82‰,with an average of –0.05‰ for the landfill site,and the lowest values were observed in June and July.The δ^(15)NH_3 values for the pig farm site ranged from –29.78‰ to –14.05‰ with an average of –24.51‰,and the δ^(15)NH_3 values were more negative in summer than in the other seasons.The δ^(15)NO_2 values were –9.63‰ to 7.04‰ with an average of –3.72‰ for the road traffic site.The δ^(15)NO_2 values were more negative in summer than those in the other seasons.The different δ^(15)N values for the various Nr species in different sources may serve as important indicators for identifying atmospheric Nr sources in megacities.The results may also provide the theoretical basis for research on the atmospheric N deposition and its sources.
基金supported by the National Natural Science Foundation of China (Grant No.40671026)
文摘According to the observational data of viscous debris flows with hyper-concentration, debris flows can be classified into three types:high-viscous, viscous, and sub-viscous debris flows.Distinct formation mechanism of different graded bedding structures in deposits of viscous debris flows was analyzed in this paper by using their yield-stress ratio and flow plug ratio.This paper specially analyzed the effect of Weissenberg which the gravels in squirm condition of hyper-concentration viscous flows would tend to move vertically, and the formation mechanism of the gravels accumulated at surface was also studied.The analysis in this paper can establish a foundation for the studies on differentiation of bedding structures of debris flow deposits and studies on dynamic parameters of debris flows.
基金Sponsored by Science Foundation for Young Scholars of Hunan Agricultural University(14QN25)
文摘By using geography quantitative methods and Arc GIS,the spatial distribution characteristics,types,rules and influencing factors of 20 representative rural tourism attractions in Yangzhou City were analyzed.The results show that the traffic accessibility of various regions in Yangzhou City correlated positively with the spacial distribution of rural tourist attractions in quantity in these regions.The rural tourist attractions were dense in regions 10-20 km away from the center of the city;there was only one rural tourist attraction in regions 40-70 km away from the center of the city;some big rural tourist attractions were distributed in regions 70-90 km away from the center of the city;market orientation influenced the spatial distribution of the rural tourist attractions obviously.In regions 0-30 km away from the center of the city,most rural tourist attractions mainly provided recreation and entertainment services for tourists;in regions more than 70 km away from the center of the city,most rural tourist attractions mainly provided health and recuperation services for tourists;in regions 30-50 km away from the center of the city,the service functions of the rural tourist attractions were compound and diversified.
基金Funded by the National Natural Science Foundation (No.50774071/ E0402)the Fund from the Science Research Plan of Hubei Province Department of Education (No.D20091505)China National Science & Technology Pillar Plan Project (No.2008BAE60B08)
文摘Carbon nanotube encapsulated nickel nanorods were catalytic grown via pyrolysis of oil on a bulk nickel wire substrate. X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy were employed to characterize the as-prepared sample. The results show that, carbon nanotubes possess several microns in length, the filled metallic nickel nanorods with a uniform diameter of 35 nm were tightly encapsulated by the carbon capsules. The detailed formation mechanism for the carbon nanotubes encapsulated nickel nanorods were discussed briefly.
文摘Taking Pingshuo West Dump (247.91 hm2) for example, an evaluating model of water-soil safety was set up according to 8 disaster factors of soil erosion: 30 min rainfall intensity, surface material, landform and slope gradient, cover-degree, topographic, engineering measure grade of conservation of water-soil, volume weight and irregular subsidence. In new stage, early stage and later stage of reclamation, the degree of safety and the different site conditions were analyzed by the model. The results indicat that the dump belongs to middle danger, low danger and low safety in new stage, early stage and later stage of reclamation respectively. But at the same stage, different site conditions lead to different safety class because of the different disaster factors.
基金Sponsored by Natural Science Foundation of Shandong Province(ZR2014EEP009)Doctoral Scientific Research Foundation of Binzhou University(2014Y17)+3 种基金Science and Technology Plan of Shandong Higher Education Institution(J16LD03)National Undergraduate Training Programs for Innovation and Entrepreneurship(201610449064)University Scientific Research Development Program of Shandong Province(J15LD04)Key Scientific Research Projects of Binzhou University(BZXYG1502)
文摘To figure out water pollution of the Qinhuang River in Binzhou City,broad bean root-tip micronucleus technique was applied to test water quality,water sample from different sampling points was taken to detect the contamination of broad bean root tips,so as to reflect water pollution using the pol ution indexes.The results showed that water in the Qinhuang River was polluted in different degrees,and water pollution grew more serious from the upper to the lower reaches.Water pollution sources include domestic sewage and solid waste,thus pollution discharge into the river must be strictly controlled to restore the polluted water and the ecological functions of waterscapes.
基金jointly funded by the National Natural Science Foundation of China(GrantNo40775019)Desert Meteorology Science Foundation of China(Grant NoSqj2009012)Project of Key Laboratory of Oasis Ecology(Xinjiang University)Ministry of Education(Grant NoXJDX0206-2009-08)
文摘Improving and validating land surface models based on integrated observations in deserts is one of the challenges in land modeling. Particularly, key parameters and parameterization schemes in desert regions need to be evaluated in-situ to improve the models. In this study, we calibrated the land-surface key parameters and evaluated several formulations or schemes for thermal roughness length (z 0h ) in the common land model (CoLM). Our parameter calibration and scheme evaluation were based on the observed data during a torrid summer (29 July to 11 September 2009) over the Taklimakan Desert hinterland. First, the importance of the key parameters in the experiment was evaluated based on their physics principles and the significance of these key parameters were further validated using sensitivity test. Second, difference schemes (or physics-based formulas) of z 0h were adopted to simulate the variations of energy-related variables (e.g., sensible heat flux and surface skin temperature) and the simulated variations were then compared with the observed data. Third, the z 0h scheme that performed best (i.e., Y07) was then selected to replace the defaulted one (i.e., Z98); the revised scheme and the superiority of Y07 over Z98 was further demonstrated by comparing the simulated results with the observed data. Admittedly, the revised model did a relatively poor job of simulating the diurnal variations of surface soil heat flux, and nighttime soil temperature was also underestimated, calling for further improvement of the model for desert regions.
基金Supported by the National Key Technologies Research and Development Program of the Ministry of Science and Technology of China during the 12th Five-Year Plan Period (No. 2012BAD141318)
文摘Eutrophication in the Three Gorges Reservoir has become a serious issue, and phosphorus (P) is the nutrient thought to be primarily responsible although there are few studies about P loss from the mostly sloping farmlands of the area. This work investigated the amounts and forms of P loss from 9 farmlands with the slopes of 4°, 9°, and 17° in a small watershed, Wangjiagou in Fuling District, Chongqing of China. The slope of the relationship between runoff and rainfall increased with field slope; i.e., there was a significant interaction between the effects of rainfall and field slope on water export. For sediment export by surface runoff, there was no interaction between field slope and rainfall, and the intercept of the relationship between rainfall and sediment loss was significantly different for the 3 slopes. The main P loss was from sediments, regardless of slope. In the runoff water, particulate P was the largest P fraction, and its loss was greatest from the steepest land and least from the flattest. The release of total P and available P from sediments followed the same trend. The P loss during May to July in Wangjiagou was more than 60% of the annual total.
