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101.
Rien E. van Wijk Michael Schaub Steffen Hahn Natalia Juárez-García-Pelayo Björn Schäfer Lukáš Viktora Manuel Martín-Vivaldi Marko Zischewski Silke Bauer 《Die Naturwissenschaften》2018,105(7-8):42
The annual cycle of migrating birds is shaped by their seasonal movements between breeding and non-breeding sites. Studying how migratory populations are linked throughout the annual cycle—migratory connectivity, is crucial to understanding the population dynamics of migrating bird species. This requires the consideration not only of spatial scales as has been the main focus to date but also of temporal scales: only when both aspects are taken into account, the degree of migratory connectivity can be properly defined. We investigated the migration behaviour of hoopoes (Upupa epops) from four breeding populations across Europe and characterised migration routes to and from the breeding grounds, location of non-breeding sites and the timing of key migration events. Migration behaviour was found to vary both within and amongst populations, and even though the spatial migratory connectivity amongst the populations was weak, temporal connectivity was strong with differences in timing amongst populations, but consistent timing within populations. The combination of diverse migration routes within populations and co-occurrence on the non-breeding grounds between populations might promote exchange between breeding populations. As a result, it might make hoopoes and other migrating bird species with similar strategies more resilient to future habitat or climatic changes and stabilise population trends. 相似文献
102.
Rui Wang Zhaofei Liu Liguang Jiang Zhijun Yao Junbo Wang Jianting Ju 《环境科学学报(英文版)》2016,28(3):183-194
The geochemistry of natural waters in the Changtang Nature Reserve,northern Tibet,can help us understand the geology of catchments,and provide additional insight in surface processes that influence water chemistry such as rock weathering on the Qinghai–Tibet Plateau.However,severe natural conditions are responsible for a lack of scientific data for this area.This study represents the first investigation of the chemical composition of surface waters and weathering effects in two lake basins in the reserve(Lake Dogaicoring Qiangco and Lake Longwei Co).The results indicate that total dissolved solids(TDS)in the two lakes are significantly higher than in other gauged lakes on the Qinghai–Tibet Plateau,reaching 20–40 g/L,and that TDS of the tectonic lake(Lake Dogaicoring Qiangco)is significantly higher than that of the barrier lake(Lake Longwei Co).Na+and Cl-are the dominant ions in the lake waters as well as in the glacier-fed lake inflows,with chemical compositions mainly affected by halite weathering.In contrast,ion contents of inflowing rivers fed by nearby runoff are lower and concentrations of dominant ions are not significant.Evaporite,silicate,and carbonate weathering has relatively equal effects on these rivers.Due to their limited scope,small streams near the lakes are less affected by carbonate than by silicate weathering. 相似文献
103.
中国政府以2005年为基年提出了碳减排指标,确定各省碳减排基数对于明确各省碳减排责任具有重要意义.本文结合“十一五”期间节能指标分解过程中存在的问题,分析了省际贸易中隐含的碳排放对于确定各省碳减排基数的影响,并分别基于生产者负责原则和消费者负责原则计算了“十二五”期间各省碳减排基数.计算结果表明:①将工业部门拆分为23个部门能够更加充分反映省际贸易结构差异对于隐含碳排放计算的影响;②省际贸易中隐含碳排放不仅在各省间有较大差异而且呈现出从中西部地区调往东部地区的整体转移方向;③不同原则下各省碳减排基数计算结果存在较大差异,消费者负责原则更加真实地反映了各地区实际减排责任,避免了部分省份通过省际调进代替本省生产的方式实现碳减排目标. 相似文献
104.
Toxic heavy metal contamination and risk assessment of street dust in small towns of Shanghai suburban area, China 总被引:4,自引:0,他引:4
Ju Zhang Huanguang Deng Dongqi Wang Zhenlou Chen Shiyuan Xu 《Environmental science and pollution research international》2013,20(1):323-332
The aims of this paper were to quantify the heavy metal concentrations in street dust of small towns in Shanghai suburban area compared with those in urban area, and examine their seasonal and spatial variations, and to assess their risks to water environment and local populations. Street dust samples were collected from three small towns and urban area in Shanghai in different seasons. Levels of heavy metals were determined by atomic adsorption spectrophotometer analyzer. The method of potential ecological risk index and the health risk assessment model were used to evaluate the potential risks to water bodies and local residents, respectively. The mean metal concentrations in street dust of small towns were far above soil background values but still lower than those in the urban area. No significant seasonal change was observed except for Cr, Ni, and Zn concentrations. Higher metal concentrations tended to be located in central area of towns and township roads. The integrated metal contamination was high and posed a strong potential ecological risk. Children had greater health risk than adults. The carcinogenic risk probabilities were under the acceptable level. The hazard index values to children were close to the safe level. Street dust from the studied area has been contaminated by heavy metals. The contamination of these elements is related more to the pollution source than seasonal change. The combination of the six metals may threaten the water environment and has non-cancer health risk to children, but not to adults. 相似文献
105.
Praveen Linga Rajnish Kumar Ju Dong Lee John Ripmeester Peter Englezos 《International Journal of Greenhouse Gas Control》2010,4(4):630-637
A new apparatus employing a modular, mechanically agitated gas-inducing crystallizer is used to demonstrate the capture of CO2 via hydrate crystallization. The crystallizer enhances the contact of hydrate forming gases with water and thus the rate of hydrate crystallization increases. Flue gas (CO2/N2) and fuel gas (CO2/H2) mixtures were used to represent post- and precombustion capture. A comparison between the rates of hydrate formation in different crystallizers is presented by defining a metric called the normalized rate of hydrate formation. The gas uptake and the separation efficiency for the fuel and flue gas mixtures were found to be greater compared to the results obtained in a smaller scale stirred tank reactor (Kumar et al., 2009c, Linga et al., 2008). The gas uptake and CO2 recovery for flue gas mixture in the presence of THF obtained in this work was higher than that reported in the literature with tetra-n-butyl ammonium bromide and tetra-n-butyl ammonium fluoride (Fan et al., 2009, Li et al., 2009). Although hydrate crystallization is able to capture CO2, the power required for mechanical agitation was found to be very significant. If the hydrate process is to be used industrially then hydrate crystallization must be carried out without mechanical agitation. 相似文献
106.
Analysis and evaluation of chlorinated persistent organic compounds and PAHs in sludge in Korea 总被引:4,自引:0,他引:4
The concentrations of 12 POPs listed in the Stockholm convention, chlorophenols (CPs) and PAHs were investigated in sludge samples from wastewater and sewage treatment plants (WWTPs and STPs). The concentrations of PCDD/Fs in the wastewater sludge ranged from 0.189 to 1092 ng-TEQkg(-1) dry wt., and most of the sludge samples had levels below the EU guideline for the land application of PCDD/Fs (<100 ng-TEQkg(-1) dry wt.) except one sample. Co-PCB congeners were analyzed from four WWTPs, with total concentrations ranging from 0.265 to 26.6 ng-TEQkg(-1) dry wt., which were similar to the results obtained from previous studies. The levels of PCDD/Fs and Co-PCBs varied according to the main source of the influent to each WWTP and the paper industry was the main source of these compounds in the sludge due to the chlorine bleaching process. In case of OCPs, HCB and p,p'-DDE were detected at relatively high levels in the sludge samples compared to other target compounds, ranging from 1.30 to 21.5 microg kg(-1) dry wt. and 0.758 to 14.8 microg kg(-1) dry wt., respectively. Different OCP distribution patterns were observed according to sludge types, with HCB and DDTs being dominant in the sludge from WWTPs and STPs, respectively. The total levels of PAHs and CPs ranged from 1.24 to 44.9 mg kg(-1) dry wt. and 0.340 to 3.85 mg kg(-1) dry wt., respectively. The PAHs and CPs were also shown to have various distribution patterns, possibly due to the different wastewater sources to the WWTPs. 相似文献
107.
通过调查海门市城区所有NOX和NO2排放源,从排放情况和NO2月浓度变化情况分析,得出了海门市城区NO2污染物浓度呈上升趋势的结果。 相似文献
108.
109.
上海市典型城市河岸带不同植被类型下土壤反硝化作用研究 总被引:2,自引:0,他引:2
为了解城市河岸带不同植被类型下土壤的反硝化速率及其影响因子,在上海市城市河岸带的长风绿地选择了熊掌木、硕苞蔷薇和矮生百慕大草3种植被类型,于2012年3月(春初)、5月(春季)、7月(夏季)、11月(秋季)测定了其下不同深度(2~5 cm、12~15 cm、22~25 cm和32~35 cm)土壤的反硝化速率和土壤的粒度、含水率、SOC、NH4+和NO3-含量等基本理化性质。结果表明:长风绿地3种植被类型下土壤理化性质和反硝化速率具有一定的差异性,但均表现为2~5 cm深度土壤反硝化速率显著高于其他深度;熊掌木和硕苞蔷薇2~5 cm深度土壤反硝化速率均为春初显著高于其他季节,而草地2~5 cm深度反硝化速率在春夏季显著高于春初和秋季;其他深度土壤均不存在显著的季节性差异;植被类型、深度和季节对反硝化速率的单一和综合影响效应(除植被类型*深度外)均显著;反硝化速率与土壤的SOC、NH4+和NO3-含量呈极显著正相关(p<001),而与土壤含水率和气温没有显著相关关系 相似文献
110.
This study analyzed the concentrations of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS) in maternal and umbilical cord sera at delivery from the general population in Korea. Seventy samples were analyzed with ion-pairing and LC/MS/MS. PFOS, PFOA and PFHxS were detected in both maternal and umbilical cord sera. There was a high correlation of PFC concentrations between maternal and cord serum samples, implying transplacental transport. Ranking of transplacental transfer efficiency was PFOA > PFHxS > PFOS. Student’s t-tests revealed that concentrations of maternal PFOA were related with decreases in birth weight, birth length and ponderal index, suggesting a possible impact on fetal growth. With multiple logistic regression models, maternal PFOS concentration showed a significant inverse association with ponderal index (OR = 0.22; 95% CI, 0.05–0.90). Umbilical cord PFHxS concentration showed a significant inverse association with birth weight (OR = 0.26; 95% CI, 0.08–0.85) or a marginally significant inverse association with birth length (OR = 0.33; 95% CI, 0.09–1.17). This is the first report demonstrating an inverse association of birth outcomes with PFHxS exposure. Concentrations of maternal PFOA were decreased with parity, implying that delivery is one of the major routes for PFOA elimination in women. This study demonstrated prenatal exposure of PFCs through placental transfer which could result in possible developmental effects in the population sampled. Our results may provide data basis to conduct a larger scale investigation into developmental effects of PFCs in the future and contribute to understanding levels of PFC contaminations from a variety of populations in the globe. 相似文献