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Natural and anthropogenic sources of lead, zinc, and nickel in sediments of Lake Izabal, Guatemala

Journal of Environmental Sciences 2020年第10期32卷 117-126页

作者： Elisandra Hernandez Jonathan Obrist-Farner Mark Brenner William F.Kenney Jason H.Curtis Edward Duarte Geosciences and Geological and Petroleum Engineering Department Missouri Uniuersity of Science and Technology.RollaMO 65409USA. Department of Geological Sciences University of FloridaGainesvilleFL 32611USA land use and enuironmental change institute Uniuersity of FloridaGainesvilleFL 32611USA Escuela de Quimica Universidad de San Carlos de Guatemala01012Guatermala

Sediments in Lake Izabal,Guatemala,contain substantial lead (Pb),zinc (Zn),and nickel (Ni).The lack of historical data for heavy metal concentrations in the sediments makes it difficult to determine the sources or evaluate whether inputs of metals to the lake have changed through *** measured the relative abundances and concentrations of Pb,Zn,and Ni by X-Ray Fluorescence core scanning and by Inductively Coupled Plasma Optical Emission Spectrometry in three sediment cores to explore stratigraphic distributions of metals in the lake *** amounts of Pb and Zn in the core taken near the Polochic Delta suggest that galena and sphalerite mining increased Pb and Zn delivery to Lake Izabal between ~1945 and 1965 *** up-core Ni increase in the core taken near a different mine on the north shore of Lake Izabal suggests that recent nickel mining operations led to an increase in Ni concentrations in the local sediments,but amounts in the other cores indicate that Ni is not widely distributed throughout the *** cores from Lake Izabal are reliable recorders of heavy metal input to the lake,and were measured to establish background metal levels,which would otherwise be *** of Pb,Zn,and Ni in older,pre-20th-century Lake Izabal sediments reflect input from natural erosion of *** results provide previously unavailable estimates of background metal concentrations in Lake Izabal before the onset of *** results are necessary for future monitoring related to mining contamination of the lake ecosystem.

关键词： Lake Izabal Heavy metals Lead contamination Anthropogenic impacts Mining Guatemala

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Nitrate removal and extracellular polymeric substances of autohydrogenotrophic bacteria under various pH and hydrogen flow rates

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Journal of Environmental Sciences 2018年第1期30卷 50-57页

作者： Tran-Ngoc-Phu Nguyen Pei-Chung Chen Chihpin Huang institute of enuironmental Engineering National Chiao Tung UniuersityHsinchu 300Chinese Taipei

In recent years there has been an increasing interest in the use of autohydrogenotrophic bacteria to treat nitrate from wastewater. However, our knowledge about the characteristics of extracellular polymeric substances（EPS） releasing by these activities is not yet very advanced. This study aimed to investigate the change in EPS compositions under various p H values and hydrogen flow rates, taking into consideration nitrogen removal. Results showed that p H 7.5 and a hydrogen flow rate of 90 m L/min were the optimal operating conditions, resulting in 100% nitrogen removal after 6 hr of operation. Soluble and bound polysaccharides decreased, while bound proteins increased with increasing p H. Polysaccharides increased with increasing hydrogen flow rate. No significant change of bound proteins was observed at various hydrogen flow rates.

关键词： Autohydrogenotrophic bacteria Nitrate removal Extracellular polymeric substances Polysaccharides Proteins

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Open land-use map:a regional land-use mapping strategy for incorporating OpenStreetMap with earth observations

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Geo-Spatial Information Science 2017年第3期20卷 269-281页

作者： Di Yang Chiung-Shiuan Fu Audrey C.Smith Qiang Yu Department of Geography University of FloridaGainesvilleFLUSA land use and Environmental change institute University of FloridaGainesvilleFLUSA Beijing Key Laboratory of Precision Forestry Beijing Forestry UniversityBeijingChina

A land-use map at the regional scale is a heavy computation task yet is critical to most landowners,researchers,and decision-makers,enabling them to make informed decisions for varying *** are two major difficulties in generating land classification maps at the regional scale:the necessity of large data-sets of training points and the expensive computation cost in terms of both money and *** Geographic Information opens a new era in mapping and visualizing the physical world by providing an open-access database valuable georeferenced information collected by volunteer *** one of the most well-known VGI initiatives,OpenStreetMap(OSM),contributes not only to road network distribution information but also to the potential for using these data to justify and delineate land ***,most large-scale mapping approaches-including regional and national scales–confuse“land cover”and“land-use”,or build up the land-use database based on modeled land cover data-sets,in this study,we clearly distinguished and differentiated land-use from land *** focusing on our prime objective of mapping land-use and management practices,a robust regional land-use mapping approach was developed by integrating OSM data with the earth observation remote sensing *** novel approach incorporates a vital temporal component to large-scale land-use mapping while effectively eliminating the typically burdensome computation and time/money demands of such ***,our novel approach in regional scale land-use mapping produced robust results in our study area:the overall internal accuracy of the classifier was 95.2%and the external accuracy of the classifier was measured at 74.8%.

关键词： OpenStreetMap(OSM) Volunteered Geographic Information(VGI) crowdsourced data Random Forest Google Earth Engine(GEE)

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changes and Effecting Factors of Grain Production in China

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Chinese Geographical Science 2011年第6期21卷 676-684页

作者： CHEN Yuqi LI Xiubin WANG Jing Key Laboratory of land use Ministry of Land and Resource Beijing 100035 Chin~ institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China）

Based on the data from the Cost-benefit Data of Farm Produce and the China Agricultural Yearbook, this paper aims to examine the spatial and temporal change characteristics of total grain production and its affecting factors. The results show that： 1） During 1980 to 2007, total grain production increased from 3.20 ~ 108 t to 5.02 x 108 t in China, with annual increasing rate of 1.68%. From the regional disparities, most of the regions present increasing trend of total grain production except for several regions with higher level of economic development; 2） Grain sown area decreased from 1.17 × 108 ha in 1980 to 1.06 x 108 ha in 2007, which has negative effect on total grain production; 3） The increase of grain yield per unit area caused by land use intensity changes contributed to the increase of total grain yield greatly. However, as the land use intensity showed that farmers pay more attention to labor-saving input but not yield-increasing input, the less enthusiasm of farmers in grain production may become an important constraint on fu- ture grain production increase in China; 4） Based on the results, this paper proposed different land management poli- cies in different regions, for example, the government should protect cultivated land, promote large scale production. As to the less developed regions, the government should pay more attention to agricultural subsidies to promote farm- ers＇ enthusiasm in grain production.

关键词： grain production grain yield per unit area grain sown area land use intensity

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Heterogeneity of water-retention capacity of forest and its influencing factors based on meta-analysis in the Beijing-Tianjin-Hebei region

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Journal of Geographical Sciences 2021年第1期31卷 69-90页

作者： SHI Xiaoli DU Chenliang GUO Xudong SHI Wenjiao Hebei Key Laboratory of Environmental change and Ecological Construction College of Resources and Environmental SciencesHebei Normal UniversityShijiazhuang 050024China Key Laboratory of land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China Hebei Technology Innovation Center for Remote Sensing Identification of Environmental change Shijiazhuang 050024China land Surveying and Planning institute Key Laboratory of Land UseMinistry of Natural ResourcesBeijing 100035China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

Water retention is important in forest ecosystem services. The heterogeneity analysis of water-retention capacity and its influencing factors is of great significance for the construction of water-retention functional areas, restoration of vegetation, and the protection of forest ecosystems in the Beijing-Tianjin-Hebei region. A total of 1366 records concerning water-retention capacity in the canopy layer, litter layer, and soil layer of forest ecosystem in this region were obtained from 193 literature published from 1980 to 2017. The influencing factors of water-retention capacity in each layer were analyzed, and path analysis was used to investigate the contribution of the factors to the water-retention capacity of the three layers. The results showed that mixed forests had the highest water-retention capacity, followed by broad-leaved forests, coniferous forests, and shrub forests. In addition, no matter the forest type, the ranking of the water-retention capacity was soil layer, canopy layer, and litter layer from high to low. The main influencing factors of water-retention capacity in forest canopy were leaf area index and maximum daily precipitation(R2=0.49), and the influencing coefficients were 0.34 and 0.30, respectively. The main influencing factors of water-retention capacity in the litter layer were semi-decomposed litter(R2=0.51), and the influencing coefficient was 0.51. The main influencing factors of water-retention capacity in the soil layer were non-capillary porosity and soil depth(R2=0.61), the influencing coefficients were 0.60 and 0.38, respectively. This study verifies the simulation of the water balance model or inversion of remote sensing of the water-retention capacity at the site scale, and provides scientific basis for further study of the impact of global change on water retention.

关键词： meta-analysis path analysis water retention Beijing-Tianjin-Hebei region

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Salt-affected marginal lands:a solution for biochar production

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Biochar 2023年第1期5卷 381-390页

作者： Yang Wang Qimei Lin Zhongzhen Liu Kesi Liu Xiang Wang Jianying Shang institute of Agricultural Resources and Environment Guangdong Academy of Agricultural SciencesGuangdong 510640China Department of land use and Engineering College of Land Science and TechnologyChina Agricultural UniversityBeijing 100193China Department of Grassland Science College of Grassland Science and TechnologyChina Agricultural UniversityBeijing 100193China

The literature has shown that biochar can serve as potential amendment to achieve sustainable agriculture and *** accessibility and availability of cheap feedstock are considered as important constraint factors for the widespread application of biochar in *** lands are widely distributed globally,several times larger than arable land,and hold little value for food production due to poor soil ***,these lands are suitable for growing plants,which can be used as feedstock for biochar *** salt-affected lands,as one of the main marginal lands,are particularly suitable for cultivating diverse varieties of halophytes that can be pyrolyzed into biochar,bio-gas,and *** halophyte-derived biochar is useful to produce a desirable acid soil conditioner due to its high ash and rich bases,and improves soil characteristics under extreme saline ***,syngas and bio-oil hold potential benefits as fuels and industrial raw *** study introduces an innovative management technique for marginal lands such as salt-affected land,which can provide all-round benefits in food production,land management,vegetation coverage,carbon sequestration,and climate change mitigation.

关键词： Marginal lands Salt-affected soils Halophytes Biochar Soil amendment

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Distribution and effects of tree leaf litter on vegetation composition and biomass in a forest–grassland ecotone

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Journal of Plant Ecology 2014年第3期7卷 264-275页

作者： Alejandro Loydi Kerstin Lohse Annette Otte Tobias W.Donath R.Lutz Eckstein institute of landscape Ecology and Resource Management Research Center for BiosystemsLand Use and Nutrition(IFZ)Justus-Liebig University GiessenHeinrich-Buff-Ring 26-32DE-35392GiessenGermany

Aims After abandonment of grasslands,secondary succession leads to the invasion by woody *** process begins with the accumulation of tree litter in the forest–grassland *** objectives were to determine the relationships between litter amounts and vegetation composition and cover along natural forest–grassland ecotones and to experimentally study the initial effects of tree litter accumulation on grassland vegetation and on microsite *** We established 11 transects varying from 12 to 15 m in length in different forest–grassland ecotones in the Lahn-Dill highlands,Germany,and measured the mass and cover of tree litter and the cover and composition of vegetation at five sequential positions along each transect by using 1 m2 plots with five *** a field experiment,we established plots subjected to different litter amounts(0,200 and 600g m^(−2))and evaluated changes in grassland vegetation,soil temperature and soil nutrient availability below the litter *** Findings Tree litter amounts decrease from 650 to 65g m^(−2) across the forest–grassland *** changed from shrubs and annual species(adapted to more stressful conditions)in the forests edge to grasses,rosettes and hemirosette species(with higher competitive abilities)in the *** anthropogenic forest–grassland ecotones showed abrupt edges,and the two adjacent ecosystems were characterized by different species pools and functional *** the field experiment,the presence of a litter layer reduced vegetation biomass and cover;the species richness was only reduced in the treatment with high litter(600g m^(−2)).Additionally,adding litter on top of vegetation also reduced thermal amplitude and the number of frost days,while increasing the availability of some nutrients,such as nitrogen and aluminium,the latter being an indicator of soil *** a tree litter layer of 600g m^(−2) in grassland areas had strong effects on the compos

关键词： forest edge land abandonment land use change litter oak(Quercus robur) semi-natural grassland tree invasion

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Modeling the impact of dam removal on channel evolution and sediment delivery in a multiple dam setting

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International Journal of Sediment Research 2019年第6期34卷 537-549页

作者： R.E.Poeppl T.Coulthard S.D.Keesstra M.Keiler Department of Geography and Regional Research University of Vienna School of Environmental Sciences University of Hull Wageningen Environmental Research Team SoilWater and Land Use 4. University of BernInstitute of Geography

Dam removal can generate geomorphic disturbances,including channel bed and bank erosion and associated abrupt/pulsed release and downstream transfer of reservoir sediment,but the type and rate of geomorphic response often are hard to *** situation gets even more complex in systems which have been impacted by multiple dams and a long and complex engineering *** previous studies one-dimensional(1-D) models were used to predict aspects of post-removal channel ***,these models do not consider two-dimensional(2-D) effects of dam removal such as bank erosion processes and lateral *** the current study the impacts of multiple dams and their removal on channel evolution and sediment delivery were modeled by using a 2-D landscape evolution model(CAESAR-Lisflood) focusing on the following aspects:patterns,rates,and processes of geomorphic change and associated sediment delivery on annual to decadal *** current modeling study revealed that geomorphic response to dam removal(i.e.,channel evolution and associated rates of sediment delivery) in multiple dam settings is variable and complex in space and *** in geomorphic system response is related to differences in dam size,the proximity of upstream dams,related buffering effects and associated rates of upstream sediment supply,and emerging feedback processes as well as to the presence of channel stabilization *** types and rates of geomorphic adjustment,using the 2-D landscape evolution model CAESAR-Lisflood,are similar to those reported in previous ***,the use of a 2-D method showed some advantages compared to1-D models,generating spatially varying patterns of erosion and deposition before and after dam removal that provide morphologies that are more readily comparable to field data as well as features like the lateral re-working of past reservoir deposits which further enables the maintenance of sediment delivery downstream.

关键词： Reservoir and river management landscape evolution modeling Sediment pulses River engineering Legacy effects Complexity

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Numerical Simulation of Fluxes Generated by Inhomogeneities of the Underlying Surface over the Jinta Oasis in Northwestern China

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Advances in Atmospheric Sciences 2011年第4期28卷 887-906页

作者：李万莉吕世华傅慎明孟宪红 H.C.NNAMCHI Key Laboratory of land Surface Process and Climate change in Cold and Arid Regions Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences institute of Atmospheric Physics Chinese Academy of Sciences Department of Geography University of Nigeria

Using land-use types derived from satellite remote sensing data collected by the EOS Moderate Resolution Imaging Spectroradiometer （EOS/MODIS）, the mesoscale and turbulent fluxes generated by inhomogeneities of the underlying surface over the Jinta Oasis, northwestern China, were simulated using the Regional Atmospheric Modeling System （RAMS4.4）. The results indicate that mesoscale circulation generated by land-surface inhomogeneities over the Jinta Oasis is more important than turbulence. Vertical heat fluxes and water vapor are transported to higher levels by mesoscale circulation. Mesoscale circulation also produces mesoscale synoptic systems and prevents water vapor over the oasis from running off. Mesoscale circulation transports moisture to higher atmospheric levels as the land-surface moisture over the oasis increases, favoring the formation of clouds, which sometimes leads to rainfall. Large-scale wind speed has a significant impact on mesoscale heat fluxes. During the active phase of mesoscale circulation, the stronger large-scale winds are associated with small mesoscale fluxes; however, background wind seems to intensify the turbulent sensible heat flux and turbulent latent heat flux. If the area of oasis is enlarged properly, mesoscale circulation will be able to transport moisture to higher levels, favoring the formation of rainfall in the oasis and protecting its ＂cold island＂ effect. The impact of irrigation on rainfall is important, and increasing irrigation across the oasis is necessary to protect the oasis.

关键词： inhomogeneities RAMS mesoscale circulation turbulence heat flux

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Allometric models for estimating aboveground biomass in the tropical woodlands of Ghana, West Africa

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Forest Ecosystems 2020年第3期7卷 539-561页

作者： Raymond Aabeyir Stephen Adu-Bredu Wilson Agyei Agyare Michael J.C.Weir Department of Environment and Resource Studies UDS-Wa CampusWaGhana WASCAL Graduate Research Programme on Climate change and land use KNUSTKumasiGhana Biodiversity Conservation and Ecosystem Division CSIR-Forestry Research Institute of GhanaKumasiGhana Department of Agricultural and Biosystems Engineering KNUSTKumasiGhana Department of Natural Resources Faculty of Geoinformation Science and Earth Observation(ITC)University of TwenteEnschedethe Netherlands

Background: Modelling aboveground biomass(AGB) in forest and woodland ecosystems is critical for accurate estimation of carbon stocks. However, scarcity of allometric models for predicting AGB remains an issue that has not been adequately addressed in Africa. In particular, locally developed models for estimating AGB in the tropical woodlands of Ghana have received little attention. In the absence of locally developed allometric models, Ghana will continue to use Tier 1 biomass data through the application of pantropic models. Without local allometric models it is not certain how Ghana would achieve Tier 2 and 3 levels under the United Nations programme for reducing emissions from deforestation and forest degradation. The objective of this study is to develop a mixedspecies allometric model for use in estimating AGB for the tropical woodlands in Ghana. Destructive sampling was carried out on 745 trees(as part of charcoal production) for the development of allometric equations. Diameter at breast height(dbh, i.e. 1.3 m above ground level), total tree height(H) and wood density(ρ) were used as predictors for the models. Seven models were compared and the best model selected based on model efficiency,bias(%) and corrected Akaike Information Criterion. The best model was validated by comparing its results with those of the pantropic model developed by Chave et al.(Glob Chang Biol 20:3177–3190, 2014) using equivalence test and conventional paired ***: The results revealed that the best model for estimating AGB in the tropical woodlands is AGB =0.0580ρ((dbh)2 H)0.999. The equivalence test showed that this model and the pantropic model developed by Chave et al.(Glob Chang Biol 20:3177–3190, 2014) were equivalent within ±10% of their mean predictions(p-values <0.0001 for one-tailed t-tests for both lower and upper bounds at 5% significant level), while the paired t-test revealed that the mean(181.44 ± 18.25 kg) of the model predictions of the best model of this s

关键词： Charcoal Diameter at breast height Tree height Wood density Savannah woodland

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