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Paleo-shoreline changes in moraine dammed lake Khagiin Khar, Khentey Mountains, Central Mongolia
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作者 OH Jeong-Sik SEONG Yeong Bae +1 位作者 HONG Seongchan YU Byung Yong 《山地科学学报:英文版》 SCIE CSCD 2019年第6期1215-1230,共16页
The formation and evolution of glacier moraine-dammed lakes are closely related to past glacier expansion and retreat. Geomorphic markers such as lacustrine terraces and beach ridges observed in these lakes provide im... The formation and evolution of glacier moraine-dammed lakes are closely related to past glacier expansion and retreat. Geomorphic markers such as lacustrine terraces and beach ridges observed in these lakes provide important evidence for regional paleoenvironment reconstruction. We document the magnitude of paleo-shoreline fluctuations and timings of highstands of lake water by using cosmogenic 10Be surface exposure dating and optically stimulated luminescence(OSL) dating on samples collected from lacustrine sediment and bedrock strath in Lake Khagiin Khar. The lake was initially impounded by glacier moraine at the Global Last Glacial maximum(gLGM;21–19 ka), and the lake reached its maximum paleo-shoreline level of 1840 m at sea level(a.s.l.). At that time, the stored lake water amount was up to seven times greater and the surface area was three times larger than the present values. The paleolake experienced higher shoreline levels at 1832, 1822, and 1817 m a.s.l. and reached the present lake level after 0.4 ka. We interpret that decrease in the paleolake level was caused by spillover. The increase in melt water after the gLGM and the Late Glacial exceeded the storage threshold of the lake, and the paleolake water overflowed across the lowest drainage divides. The lake spilled over across the lowest bedrock ridge at 15.9 ± 0.6 ka, and the outlet was incised since that time at a rate of 3.72 ± 0.15 mm/yr. The initial stream of the Khiidiin Pass River was disturbed by LGM moraine damming and was rerouted into the present course running through moraine after the spillover at 15.9 ± 0.6 ka. 展开更多
关键词 Moraine-dammed LAKE LAKE Khagiin Khar SHORELINE SPILLOVER 10Be exposure DATING
Dynamic changes in lakes in the Hoh Xil region before and after the 2011 outburst of Zonag Lake
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作者 LIU Wen-hui XIE Chang-wei +6 位作者 ZHAO Lin WU Tong-hua WANG Wu ZHANG Yu-xin YANG Gui-qian ZHU Xiao-fan YUE Guang-yang 《山地科学学报:英文版》 SCIE CSCD 2019年第5期1098-1110,共13页
Zonag, Kusai, Hedin Noel and Yanhu Lakes are independent inland lakes in the Hoh Xil region on the Qinghai-Tibet Plateau. In September2011, Zonag Lake burst after the water level had increased for many years. Floods f... Zonag, Kusai, Hedin Noel and Yanhu Lakes are independent inland lakes in the Hoh Xil region on the Qinghai-Tibet Plateau. In September2011, Zonag Lake burst after the water level had increased for many years. Floods flowed through Kusai and Hedin Noel Lakes into Yanhu Lake;since then, the four small endorheic catchments merged into one larger catchment. This hydrological process caused the rapid shrinkage of Zonag Lake and continuous expansion of Yanhu Lake. In this study,based on satellite images, meteorological data and field investigations, we examined the dynamic changes in the four lakes and analyzed the influencing factors. The results showed that before 2011, the trends in the four lake areas were similar and displayed several stages. The change in the area of Zonag Lake corresponded well to the change in annual precipitation(AP), but the magnitude of the change was less than that of a non-glacier-fed lake. Although increased precipitation was the dominant factor that caused Zonag Lake to expand, increased glacier melting and permafrost thawing due to climate warming also had significant effects. After the 2011 outburst of Zonag Lake, due to the increasing AP and accelerating glacier melting, the increases in water volume of the three lakes were absorbed by Yanhu Lake, and Yanhu Lake expanded considerably. According to the rapid growth rates in water level and lake area, Yanhu Lake is likely to burst in 1-2 years. 展开更多
关键词 Dynamic CHANGE LAKE areas Influencing factors GLACIER CHANGE PERMAFROST thawing Zonag LAKE
我国湖泊环境司法之检视与完善--以洞庭湖环境资源法庭为中心 预览
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作者 彭中遥 《华侨大学学报:哲学社会科学版》 CSSCI 北大核心 2019年第3期102-113,共12页
我国湖泊环境司法保障之关键在于推进其环境司法专门化,切入点为构建专门的、针对特定湖泊的环境资源审判机构。为顺应新时代洞庭湖环境司法之现实需求,湖南省于2017年成立了专门的洞庭湖环境资源法庭。然而在实践中,洞庭湖环境资源法... 我国湖泊环境司法保障之关键在于推进其环境司法专门化,切入点为构建专门的、针对特定湖泊的环境资源审判机构。为顺应新时代洞庭湖环境司法之现实需求,湖南省于2017年成立了专门的洞庭湖环境资源法庭。然而在实践中,洞庭湖环境资源法庭存在法律依据缺失、司法资源匮乏、案件来源不足、跨行政区域管辖困难等挑战。亟需通过明确法律依据、优化资源配置、拓宽案件来源、规范跨区域管辖等措施来应对上述挑战。洞庭湖环境资源法庭之探索经验与运行实践,既可助力于湖南省生态文明建设与环境司法改革,亦可为全国其他湖泊环境资源审判机构之专门化建设提供可资借鉴的范本。 展开更多
关键词 湖泊 洞庭湖环境资源法庭 环境司法 跨区域集中管辖
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Denitrification and the controlling factors in Yunnan Plateau Lakes (China): Exploring the role of enhanced internal nitrogen cycling by algal blooms
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作者 Sifeng Wu Zhen Wu +2 位作者 Zhongyao Liang Yong Liu Yilin Wang 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第2期349-358,共10页
Denitrification plays an important role in nitrogen (N) removal in freshwater ecosystems. This internal process regulates the fluctuations of N concentration, especially for lakes with high nutrients concentrations an... Denitrification plays an important role in nitrogen (N) removal in freshwater ecosystems. This internal process regulates the fluctuations of N concentration, especially for lakes with high nutrients concentrations and long residence time. Lakes in Yunnan plateau (southwestern China) provide typical cases, while studies in this region have been rare. Therefore, we studied denitrification of two lakes (Lake Dianchi in hypereutrophic state and Lake Erhai in mesotrophic) in this region. We used acetylene inhibition technique to quantify potential denitrification rate (PDR) of these lakes in April and August, 2015 and 2016. PDR of the sediments ranged 0–1.21μmol/(N·m^2·hr), and that of overlying water ranged 0–0.24μmol/(N·L·hr). Then, we used Least Angle Regression to determine the controlling factors for denitrification. Nutrients controlled PDR from two aspects: providing essential nitrogen sources;and affecting the richness and metabolism of denitrifying bacteria. In April, both aspects limited PDR;while only nitrogen sources limited PDR in August, due to depleted nitrate and enhanced denitrifying bacteria activity. Ammonia was most significant to denitrification, indicating that nitrate from nitrification transported to the bottom of well-mixed lake provide major N source by denitrification. The high PDR and low nitrate concentrate in August were evidence of an enhanced internal N cycling by algal blooms. 展开更多
关键词 DENITRIFICATION Controlling factors LAKE Dianchi LAKE Erhai ALGAL bloom INTERNAL CYCLING
Modelling Chorabari Lake outburst flood, Kedarnath, India
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作者 Mohammd RAFIQ Shakil Ahmad ROMSHOO +1 位作者 Anoop Kumar MISHRA Faizan JALAL 《山地科学学报:英文版》 SCIE CSCD 2019年第1期64-76,共13页
In this study,the Glacier Lake Outburst Flood(GLOF)that occurred over Kedarnath in June 2013 was modeled using integrated observations from the field and Remote Sensing(RS).The lake breach parameters such as area,dept... In this study,the Glacier Lake Outburst Flood(GLOF)that occurred over Kedarnath in June 2013 was modeled using integrated observations from the field and Remote Sensing(RS).The lake breach parameters such as area,depth,breach,and height have been estimated from the field observations and Remote Sensing(RS)data.A number of modelling approaches,including Snow Melt Runoff Model(SRM),Modified Single Flow model(MSF),Watershed Management System(WMS),Simplified Dam Breach Model(SMPDBK)and BREACH were used to model the GLOF.Estimations from SRM produced a runoff of about 22.7 m3 during 16–17,June 2013 over Chorabari Lake.Bathymetry data reported that the lake got filled to its maximum capacity(3822.7 m3)due to excess discharge.Hydrograph obtained from the BREACH model revealed a peak discharge of about 1699 m3/s during an intense water flow episode that lasted for 10–15 minutes on 17 th June 2013.Excess discharge from heavy rainfall and snowmelt into the lake increased its hydrostatic pressure and the lake breached cataclysmically. 展开更多
关键词 GLACIER LAKE OUTBURST FLOOD GIS MODELLING Snow Melt RUNOFF Kedarnath GLACIER LAKE
Remotely sensed estimation and mapping of soil moisture by eliminating the effect of vegetation cover 预览
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作者 WU Cheng-yong CAO Guang-chao +6 位作者 CHEN Ke-long E Chong-yi MAO Ya-hui ZHAO Shuang-kai WANG Qi SU Xiao-yi WEI Ya-lan 《农业科学学报:英文版》 SCIE CAS CSCD 2019年第2期316-327,共12页
Soil moisture(SM), which plays a crucial role in studies of the climate, ecology, agriculture and the environment, can be estimated and mapped by remote sensing technology over a wide region. However, remotely sensed ... Soil moisture(SM), which plays a crucial role in studies of the climate, ecology, agriculture and the environment, can be estimated and mapped by remote sensing technology over a wide region. However, remotely sensed SM is constrained by its estimation accuracy, which mainly stems from the influence of vegetation cover on soil spectra information in mixed pixels. To overcome the low-accuracy defects of existing surface albedo method for estimating SM, in this paper, Qinghai Lake Basin, an important animal husbandry production area in Qinghai Province, China, was chosen as an empirical research area. Using the surface albedo computed from moderate resolution imaging spectroradiometer(MODIS) reflectance products and the actual measured SM data, an albedo/vegetation coverage trapezoid feature space was constructed. Bare soil albedo was extracted from the surface albedo mainly containing information of soil, vegetation, and both albedo models for estimating SM were constructed separately. The accuracy of the bare soil albedo model(root mean square error=4.20, mean absolute percent error=22.75%, and theil inequality coefficient=0.67) was higher than that of the existing surface albedo model(root mean square error=4.66, mean absolute percent error=25.46% and theil inequality coefficient=0.74). This result indicated that the bare soil albedo greatly improved the accuracy of SM estimation and mapping. As this method eliminated the effect of vegetation cover and restored the inherent soil spectra, it not only quantitatively estimates and maps SM at regional scales with high accuracy, but also provides a new way of improving the accuracy of soil organic matter estimation and mapping. 展开更多
关键词 SOIL moisture remote sensing BARE SOIL ALBEDO TRAPEZOID feature space QINGHAI Lake Basin
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Editorial: Effects of metal contamination on ammonia-oxidizing microorganisms in a freshwater reservoir
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作者 Wei Feng Xiaowen Yan Chris Le 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第5期364-366,共3页
Ammonia-oxidizing microorganisms,including ammoniaoxidizing bacteria(AOB)and archaea(AOA),are important to the global nitrogen cycle.These microbes catalyze the oxidization of ammonia(NH3)to nitrite(NO2-),the ratelimi... Ammonia-oxidizing microorganisms,including ammoniaoxidizing bacteria(AOB)and archaea(AOA),are important to the global nitrogen cycle.These microbes catalyze the oxidization of ammonia(NH3)to nitrite(NO2-),the ratelimiting step in the biogeochemical cycling of nitrogen(Stahl and de la Torre,2012). 展开更多
关键词 ACCIDENTAL metal SPILL Ammonia-oxidizing ARCHAEA Ammonia-oxidizing bacteria AMOA gene Arsenic cadmium copper lead zinc Lake sediment Nitrogen cycling
对湖(库)不同深度下五日生化需氧量含量变化的研究
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作者 李国栋 《黑龙江环境通报》 2019年第2期37-39,共3页
五日生化需氧量(BOD5)是一种表示水体中可被微生物氧化的物质的含量,是衡量水中有机物含量的重要参数。以尼尔基水库水样为研究样本,研究了自然水体湖(库)不同深度下BOD5含量随水深的变化趋势。研究表明:自然水体中,湖(库)的BOD5含量随... 五日生化需氧量(BOD5)是一种表示水体中可被微生物氧化的物质的含量,是衡量水中有机物含量的重要参数。以尼尔基水库水样为研究样本,研究了自然水体湖(库)不同深度下BOD5含量随水深的变化趋势。研究表明:自然水体中,湖(库)的BOD5含量随深度的增加而降低。 展开更多
关键词 五日生化需氧量 水库 趋势 水质监测
Impact of Drain Effluent on Surficial Sediments in theMediterranean Coastal Wetland: SedimentologicalCharacteristics and Metal PollutionStatus at Lake Manzala, Egypt 预览
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作者 FARHAT Hassan I 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第4期834-848,共15页
Surface sediments were collected from Lake Manzala, the Mediterranean coastal wetland located to the east of the Nile Delta, Egypt, to assess the effect of drain effluent on the spatial variations of sedimentary chara... Surface sediments were collected from Lake Manzala, the Mediterranean coastal wetland located to the east of the Nile Delta, Egypt, to assess the effect of drain effluent on the spatial variations of sedimentary characteristics and heavy metal pollution. Grain-size compositions, textures, and heavy metal distribution patterns in sediments are presented using GIS technique. Results of the analysis of the sediment showed a clear effect of drain effluent, with an increase in fine fractions and homogeneous suspensions in transportation mode. Lake sediments were dominated by sandy mud textures, and mode of transportation was homogeneous sus- pension and rolling. Spatial distribution of heavy metals (Fe, Mn, Zn, Cu, Ni, Cr, and Pb) was studied in the lake’s surficial sediments, along with their relationship to drain effluent and their contamination status in the ecological system. Heavy metal pollution status was assessed by means of accepted sediment quality guidelines and contamination assessment methods (contamination factor, con- tamination degree, modified contamination degree, geo-accumulation, and enrichment factor). Among the determined heavy metals, Pb had the most ecological risk. Generally, the heavy metals in the surface sediments indicated pollution risk ranging from moderate to considerable, particularly, in those sites facing drains and inlets that had the highest toxic effluent. The results were interpreted by statistical means. A cluster analysis defined areas facing drain discharge and inlets as separated groups. ANOVA indicated that most of the sedimentation and studied metals directed this clustering. 展开更多
关键词 LAKE Manzala Mediterranean WETLAND metal POLLUTION sedimentological characteristics
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Microbial diversity in Huguangyan Maar Lake of China revealed by high-throughput sequencing 预览
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作者 HOU Qinghua FANG Zhou +1 位作者 ZHU Qingmei DONG Hongpo 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第4期1245-1257,共13页
Huguangyan Maar Lake is a typical maar lake in the southeast of China. It is well preserved and not disturbed by anthropogenic activities. In this study, microbial community structures in sediment and water samples fr... Huguangyan Maar Lake is a typical maar lake in the southeast of China. It is well preserved and not disturbed by anthropogenic activities. In this study, microbial community structures in sediment and water samples from Huguangyan Maar Lake were investigated using a high-throughput sequencing method. We found significant differences between the microbial community compositions of the water and the sediment. The sediment samples contained more diverse Bacteria and Archaea than did the water samples. Actinobacteria, Betaproteobacteria, Cyanobacteria, and Deltaproteobacteria predominated in the water samples while Deltaproteobacteria, Anaerolineae, Nitrospira, and Dehalococcoidia were the major bacterial groups in the sediment. As for Archaea, Woesearchaeota (DHVEG-6), unclassified Archaea, and Deep Sea Euryarchaeotic Group were detected at higher abundances in the water, whereas the Miscellaneous Crenarchaeotic Group, Thermoplasmata, and Methanomicrobia were significantly more abundant in the sediment. Interactions between Bacteria and Archaea were common in both the water column and the sediment. The concentrations of major nutrients (NO^3-, PO4^3-, SiO3^2- and NH4^+) shaped the microbial population structures in the water. At the higher phylogenetic levels including phylum and class, many of the dominant groups were those that were also abundant in other lakes;however, novel microbial populations (unclassified) were often seen at the lower phylogenetic levels. Our study lays a foundation for examining microbial biogeochemical cycling in sequestered lakes or reservoirs. 展开更多
关键词 Huguangyan MAAR LAKE HIGH-THROUGHPUT SEQUENCING MICROBIAL diversity
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Evaluation of SWAT Model performance on glaciated and non-glaciated subbasins of Nam Co Lake, Southern Tibetan Plateau, China
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作者 Muhammad ADNAN KANG Shi-chang +3 位作者 ZHANG Guo-shuai Muhammad Naveed ANJUM Muhammad ZAMAN ZHANG Yu-qing 《山地科学学报:英文版》 SCIE CSCD 2019年第5期1075-1097,共23页
This paper presents an assessment of the Soil and Water Assessment Tool(SWAT) on a glaciated(Qugaqie) and a non-glaciated(Niyaqu) subbasin of the Nam Co Lake. The Nam Co Lake is located in the southern Tibetan Plateau... This paper presents an assessment of the Soil and Water Assessment Tool(SWAT) on a glaciated(Qugaqie) and a non-glaciated(Niyaqu) subbasin of the Nam Co Lake. The Nam Co Lake is located in the southern Tibetan Plateau, two subbasins having catchment areas of 59 km~2 and 388 km~2, respectively. The scores of examined evaluation indices(i.e., R~2, NSE, and PBIAS) established that the performance of the SWAT model was better on the monthly scale compared to the daily scale. The respective monthly values of R~2, NSE, and PBIAS were 0.94, 0.97, and 0.50 for the calibration period while 0.92, 0.88, and -8.80 for the validation period. Glacier melt contribution in the study domain was simulated by using the SWAT model in conjunction with the Degree Day Melt(DDM) approach. The conjunction of DDM with the SWAT Model ensued improved results during both calibration(R~2=0.96, NSE=0.95, and PBIAS=-13.49) and validation (R~2=0.97, NSE=0.96, and PBIAS=-2.87) periods on the monthly time scale. Average contribution(in percentage) of water balance components to the total streamflow of Niyaqu and Qugaqie subbasins was evaluated. We found that the major portion(99.45%) of the streamflow in the Niyaqu subbasin was generated by snowmelt or rainfall surface runoff(SURF_Q), followed by groundwater(GW_Q, 0.47%), and lateral(LAT_Q, 0.06%) flows. Conversely, in the Qugaqie subbasin, major contributor to the streamflow(79.63%) was glacier melt(GLC_Q), followed by SURF_Q(20.14%), GW_Q(0.13%), and LAT_Q(0.089%). The contribution of GLC_Q was the highest(86.79%) in July and lowest(69.95%) in September. This study concludes that the performance of the SWAT model in glaciated catchment is weak without considering glacier component in modeling;however, it performs reasonably well in non-glaciated catchment. Furthermore, the temperature index approach with elevation bands is viable in those catchments where streamflows are driven by snowmelt. Therefore, it is recommended to use the SWAT Model in conjunction with DDM or energy base model to simulat 展开更多
关键词 SWAT MODEL NAM Co Lake DEGREE-DAY MELT MODEL Streamflow HYDROLOGICAL Response Unit
A Historical Sedimentary Record of Mercury in a Shallow Eutrophic Lake: Impacts of Human Activities and Climate Change 预览
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作者 Hanxiao Zhang Shouliang Huo +3 位作者 Kevin M. Yeager Beidou Xi Jingtian Zhang Fengchang Wu 《工程(英文)》 2019年第2期296-304,共9页
Mercury and its derivatives are hazardous environmental pollutants and could affect the aquatic ecosystems and human health by biomagnification. Lake sediments can provide important historical information regarding ch... Mercury and its derivatives are hazardous environmental pollutants and could affect the aquatic ecosystems and human health by biomagnification. Lake sediments can provide important historical information regarding changes in pollution levels and thus trace anthropogenic or natural influences. This research investigates the 100-year history of mercury (Hg) deposition in sediments from Chao Lake, a shallow eutrophic lake in China. The results indicate that the Hg deposition history can be separated into three stages (pre-1960s, 1960s–1980s, and post-1980s) over the last 100 years. Before the 1960s, Hg concentrations in the sediment cores varied little and had no spatial difference. Since the 1960s, the concentration of Hg began to increase gradually, and showed a higher concentration of contamination in the western half of the lake region than in the eastern half of the lake region due to all kinds of centralized human-input sources. The influences of anthropogenic factors and hydrological change are revealed by analyzing correlations between Hg and heavy metals (Fe, Co, Cr, Cu, Mn, Pb, and Zn), stable carbon and nitrogen isotopes (d13C and d15N), nutrients, particle sizes, and meteorological factors. The results show that Hg pollution intensified after the 1960s, mainly due to hydrological change, rapid regional development and urbanization, and the proliferation of anthropogenic Hg sources. Furthermore, the temperature, wind speed, and evaporation are found to interactively influence the environmental behaviors and environmental fate of Hg. 展开更多
关键词 Lake sediment MERCURY Vertical distribution ANTHROPOGENIC activities
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Evaluating the efficiency of the Dong model in determining fire vulnerability in Iran’s Zagros forests 预览
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作者 Sabri Baqer Rasooli Amir Eslam Bonyad 《林业研究:英文版》 CAS CSCD 2019年第4期1447-1458,共12页
Recent fires in Iran’s Zagros forests have inflicted heavy,extensive losses to the environment,forests,villages,and forest inhabitants,resulting in a huge financial loss to the country.With the increasing risk of fir... Recent fires in Iran’s Zagros forests have inflicted heavy,extensive losses to the environment,forests,villages,and forest inhabitants,resulting in a huge financial loss to the country.With the increasing risk of fire and the resulting losses,it has become ever more necessary to design and develop efficient fire control and prediction procedures.The present study utilizes the Dong model to develop a map of areas vulnerable to fire in the Zarivar lake forests as a representative sample of Zagros forests.The model uses as its inputs some of the most significant factors(such as vegetation,physiographic features,and the human component)that affect the fire occurrence and spread.Having assigned weights to each factor based on the model,all maps were overlapped in the ArcMap and then the region was divided into five zones.The results showed that 74%of the region was located in three classes:highly vulnerable,vulnerable,and medially vulnerable.To validate the proposed zoning map it was compared with a map based on real data obtained from previous fires.The results showed that 81%of fire incidents were located in highly vulnerable,vulnerable and medially vulnerable zones.Furthermore,the findings indicated a medium to a high degree of fire vulnerability in Zarivar Lake forests. 展开更多
关键词 Dong MODEL FIRE incidents Zarivar lake ZONING
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Mercury bioaccumulation in fish in an artificial lake used to carry out cage culture
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作者 Yongmin Wang Qing Xie +3 位作者 Qinqin Xu Jinping Xue Cheng Zhang Dingyong Wang 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第4期352-359,共8页
As a global toxic pollutant,mercury(Hg)bioaccumulation within food chain could be influenced by human disturbance.Ten typical fish species were collected from Changshou Lake,an artificial lake used to carry out cage f... As a global toxic pollutant,mercury(Hg)bioaccumulation within food chain could be influenced by human disturbance.Ten typical fish species were collected from Changshou Lake,an artificial lake used to carry out cage fish culture,to investigate the C/N isotopic compositions and Hg bioaccumulation in fish.The results showed that the total Hg(THg)and methylmercury(MeHg)levels in fish muscles((56.03±43.96)and(32.35±29.57)ng/g,wet weight),comparable with those in most studies in China,were significantly lower than the international marketing limit(0.5 mg/kg).Past human input for cage culture in this lake led to abnormal15N enrichment in food chain,as the quantitative trophic levels based onδ15N were different with that classified by feeding behaviors.This phenomenon subsequently demonstrated that it should be considered thoughtfully with respect to the application of the traditional method for understanding Hg bioaccumulation power by the slope of log10[Hg]withδ15N regression in specific water body(i.e.,Changshou Lake).In addition,no significant linear correlation between Hg and body weight or length of some fish species was observed,suggesting that the fish growth in the eutrophic environment was disproportionate with Hg bioaccumulation,and fish length or weight was not the main factor affecting Hg transfer with food web.The occurrence of human disturbance in aquatic system presents a challenge to a better understanding of the Hg bioaccumulation and biomagnification within the food chain. 展开更多
关键词 MERCURY METHYLMERCURY Human disturbed lake BIOACCUMULATION N ENRICHMENT
Distribution of geochemical fractions of phosphorus and its ecological risk in sediment cores of a largest brackish water lake,South Asia 预览
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作者 Saroja Kumar Barik Satyanarayan Bramha +3 位作者 Tapan Kumar Bastia Dibakar Behera Pratap Kumar Mohanty Prasanta Rath 《国际泥沙研究:英文版》 SCIE 2019年第3期251-261,共11页
The current study focuses on the vertical profile of different geochemical fractions of phosphorus-loosely bound(Lo–P),aluminium bound(Al–P),iron bound(Fe–P),calcium bound(Ca–P),and organic bound phosphorus(O–P)a... The current study focuses on the vertical profile of different geochemical fractions of phosphorus-loosely bound(Lo–P),aluminium bound(Al–P),iron bound(Fe–P),calcium bound(Ca–P),and organic bound phosphorus(O–P)along with ecological risk assessment of sediment cores from Chilika Lake,eastcoast of India.The percentage contribution of the different fractions to the sedimentary phosphorus in the sediment column of the whole lake are on the order:O–P(33.2%)>Ca–P(20.3%)>Fe–P(18%)>Al–P(6.7%)>Lo–P(0.35%).The Phosphorus Pollution Index(PPI)revealed the contamination of lake sediment with phosphorus.The principal component and cluster analyses highlighted the anthropogenic contribution of phosphorus.The negative loading of Ca–P with Ca points towards its origin from marine shells.The discriminate analysis showed that the variables like Ca–P,bio-available phosphorus(BAP),and pH were able to effectively discriminate the sectors in a significant manner. 展开更多
关键词 PHOSPHORUS FRACTIONS ECOLOGICAL risk SEDIMENT core Chilika LAKE
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Urban recreational water – potential breeding ground for antibiotic resistant bacteria?
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作者 Jing Yang Xu Connie Le +1 位作者 Baowei Chen Hongquan Zhang 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第7期1-3,共3页
The emergence of multidrug-resistant bacteria, or'superbugs,' has become an urgent and worldwide concern.Antibiotic-resistant bacteria (ARB) cause significant morbidity and mortality (O’Neill, 2016). It has b... The emergence of multidrug-resistant bacteria, or'superbugs,' has become an urgent and worldwide concern.Antibiotic-resistant bacteria (ARB) cause significant morbidity and mortality (O’Neill, 2016). It has been estimated that ARB cause at least 23,000 deaths annually in the United States alone and hundreds of thousands of deaths in developing countries (Bougnom and Piddock, 2017). 展开更多
关键词 Antibiotic RESISTANCE genes (ARGs) MULTIDRUG RESISTANCE in bacteria MICROBIAL PATHOGENS LAKE water and sediment
Wintering Swan Geese maximize energy intake through substrate foraging depth when feeding on buried Vallisneria natans tubers 预览
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作者 Yan Chen Yong Zhang +2 位作者 Lei Cao Willem F.de Boer Anthony D.Fox 《鸟类学研究:英文版》 CSCD 2019年第2期163-170,共8页
Background: Foraging theory predicts that animals select patches that offer the highest net rate of energy gain. Hence, prey distribution patterns and spatiotemporal heterogeneity play important roles in determining a... Background: Foraging theory predicts that animals select patches that offer the highest net rate of energy gain. Hence, prey distribution patterns and spatiotemporal heterogeneity play important roles in determining animal feeding patch selection. For waterfowl foraging on buried aquatic plant tubers, the distribution and biomass of these plant organs vary with depth in the substrate. Since excavation costs also increase with depth, the energy intake of the animals foraging on these plants is highly sediment depth dependent. Methods: Here, using observations of Swan Geese (Anser cygnoides) foraging on Vallisneria natans tubers, we test our hypothesis that geese feeding on tubers buried at intermediate sediment depth maximize their daily energy intake because of the interaction between tuber size and abundance with depth. To do this, we measured the distribution patterns of buried Vallisneria tubers under both undisturbed conditions and post-exploitation by geese (i.e. giving-up conditions). We investigated the relationship between tuber size and burial depth, and total tuber biomass within each sediment layer in undisturbed and exploited plots. Finally, we compared modelled Swan Goose daily energy intake feeding on Vallisneria tubers buried at different sediment layers (1–10, 11–20 and 21–30 cm below the surface). Results: Dry weight of Vallisneria tubers linearly increased with burial depth, while average total dry weight density of tubers showed a unimodal relationship, peaking at intermediate levels. Not surprisingly, Swan Geese foraged most intensively on tubers buried at intermediate sediment depths, where they maximize their daily energy intake. Our results support our hypothesis that Swan Geese feeding on tubers at intermediate depths maximize their daily energy intake. Conclusions: Our study is the first to quantify foraging strategies of Swan Geese during the wintering period, emphasizing the importance of plant traits on foraging selection of belowground foragers. 展开更多
关键词 Energetic trade-off Optimal FORAGING Shengjin Lake SUBSTRATE Tuber burial DEPTH Yangtze River
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宋代长江沿线的水系变迁:基于主要河道与湖泊的考察
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作者 谭静怡 《深圳大学学报:人文社会科学版》 CSSCI 北大核心 2019年第4期152-160,共9页
在自然环境和人文社会因素综合作用下,宋代长江沿线的水系发生变迁。长江沿线的水系变迁着重反映在河道与湖泊两方面。在河道层面,主要表现在川江、荆江、城陵矶-湖口、湖口-扬州、扬子江等主干段线河床、岸线、河面、水量的变化上,其... 在自然环境和人文社会因素综合作用下,宋代长江沿线的水系发生变迁。长江沿线的水系变迁着重反映在河道与湖泊两方面。在河道层面,主要表现在川江、荆江、城陵矶-湖口、湖口-扬州、扬子江等主干段线河床、岸线、河面、水量的变化上,其中以城陵矶至扬州波动最为明显,岸线频动,矶头较多,且出现了一些新的沙洲。在湖泊层面,则集中体现在太湖、鄱阳湖、洞庭湖等重要湖泊水体深度、湖面广度的改变上,太湖水网不畅面积渐趋缩小,鄱阳湖基本上奠定了今天的形态,洞庭湖不断向西拓展且持续沉降为历史时期水体最深的阶段。如是,运用环境史学的相关研究方法考察宋代长江沿线主要河道与湖泊的发展状貌,不仅可以了解当时长江沿线水环境的发展状况,还有助于为该地区的经济开发与水环境保护提供宝贵的历史经验。 展开更多
关键词 宋代 长江沿线 水系变迁 河道 湖泊
Magnetic mineral diagenesis in sediments of saline lake Lop Nur
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作者 LI Wen MU Gui-jin +1 位作者 LIN Yong-chong SONG Hao-ze 《山地科学学报:英文版》 SCIE CSCD 2019年第3期548-560,共13页
Saline lakes are useful repositories for paleo-climatic records. In recent years, magnetic properties of saline lake sediments have been widely applied to establish paleo-climatic change. However,the influence factors... Saline lakes are useful repositories for paleo-climatic records. In recent years, magnetic properties of saline lake sediments have been widely applied to establish paleo-climatic change. However,the influence factors of magnetic properties in saline lakes have not been fully understood, which complicates the paleoenvironmental interpretation.Here, we present a rock magnetic analyses result of LOP1 profile(40°26′09″′N, 90°21′23″E) from Lop Nur, a well-known saline lake, located in the eastern Tarim Basin in northwestern China. We combined the particle size, total organic content, and mineral characteristics analysis to assess the influence factors of magnetic properties in Lop Nur and its environmental significance. The results indicate that early diagenesis is the major influence factor on magnetic properties of Lop Nur saline sediments.Authigenic greigite and pyrite are identified within organic-rich sediments, which produce zones with high and low magnetic susceptibilities, respectively.The different authigenic iron sulfide contents in different layers are related to sedimentary environment changes. Sufficient supplies of organic matter and sulphate and low sedimentation rates favour the pyritization process. Moreover, if pyritization was constrained, intermediate greigite formed and was preserved. In oxidizing environments, sediment magnetic properties are consistent with those of source materials from Tarim Basin and are mainly controlled by particle size and hydrodynamic sorting of mainly detrital magnetite is largely unaffected by early diagenesis. Our study demonstrates that magnetic properties can provide a robust approach for studying depositional environment change in saline lake. In addition, the information obtained in this study would also provide insights into the geochemical processes of iron element in saline lakes. 展开更多
关键词 EARLY DIAGENESIS MAGNETIC properties SALINE LAKE Lop Nur
Palaeoenvironmental setting of lacustrine stromatolites in the Miocene Wudaoliang Group, northern Tibetan Plateau
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作者 Ling-Qi Zeng Hai-Sheng Yi +3 位作者 Guo-Qing Xia Klaus Simon Christine Heim Gernot Arp 《古地理学报:英文版》 CSCD 2019年第3期270-284,共15页
Lacustrine stromatolites were widespread in the Miocene Wudaoliang Group(stromatolites of the Wudaoliang Group), northern Tibetan Plateau;but only at one location nearby the Wudaoliang Town, they occurred intensively ... Lacustrine stromatolites were widespread in the Miocene Wudaoliang Group(stromatolites of the Wudaoliang Group), northern Tibetan Plateau;but only at one location nearby the Wudaoliang Town, they occurred intensively in thick, laterally traceable beds(Wudaoliang stromatolites). Although deposited in lacustrine environment, the lack of fossils in these rocks hampers determining whether the stromatolites formed in freshwater or saline conditions.To address this problem, and in an attempt to identify criteria to distinguish differences of freshwater and saline conditions, we studied the laminae microfabrics, stable carbon and oxygen isotope ratios, rare earth element patterns and biomarkers of the stromatolites. These stromatolites can be divided into fenestral stromatolites and agglutinated stromatolites. The fabric of fenestral stromatolites is formed by microcrystalline carbonate enclosing spar-cemented, angular crystal traces. Essentially, this fabric is interpreted as pseudomorph after former formed evaporite crystals. Faecal pel ets identical to that of the present-day brine shrimp Artemia, lack of other eukaryotic fossils,and stable isotopic signals point to a shal ow, evaporation-dominated hypersaline lake setting. Covariation of carbon and oxygen isotopes indicates hydrological y closed conditions of the Miocene lake on northern Tibetan Plateau.However, if compared to other lacustrine carbonates of the Wudaoliang Group, the high δ13 C values of the investigated Wudaoliang stromatolites reveal an additional photosynthetic effect during the deposition of the stromatolites.Furthermore, although no direct evidence is available from field observations and microfabrics, a positive europium anomaly of Wudaoliang stromatolites indicates that a palaeo-hydrothermal inflow system had existed in the outcrop area.These new results favour a hypersaline lake setting subject to hot spring inflow for the Wudaoliang stromatolites, in contrast to earlier interpretations suggesting a freshwater lake setting(e.g. Yi et al., Jo 展开更多
关键词 LACUSTRINE STROMATOLITES MIOCENE Wudaoliang GROUP HYPERSALINE lake HYDROTHERMAL Northern Tibetan plateau
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