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511.
Ren W Tian H Chen G Liu M Zhang C Chappelka AH Pan S 《Environmental pollution (Barking, Essex : 1987)》2007,149(3):327-335
Our simulations with the Dynamic Land Ecosystem Model (DLEM) indicate that the combined effect of ozone, climate, carbon dioxide and land use have caused China's grasslands to act as a weak carbon sink during 1961-2000. This combined effect on national grassland net primary productivity (NPP) and carbon storage was small, but changes in annual NPP and total carbon storage across China's grasslands showed substantial spatial variation, with the maximum total carbon uptake reduction of more than 400gm(-2) in some places of northeastern China. The grasslands in the central northeastern China were more sensitive and vulnerable to elevated ozone pollution than other regions. The combined effect excluding ozone could potentially lead to an increase of 14Tg C in annual NPP and 0.11Pg C in total carbon storage for the same time period. This implies that improvement in air quality could significantly increase productivity and carbon storage in China's grassland ecosystems. 相似文献
512.
Use of ethylenediurea (EDU) to ameliorate ozone effects on purple coneflower (Echinacea purpurea) 总被引:2,自引:0,他引:2
Szantoi Z Chappelka AH Muntifering RB Somers GL 《Environmental pollution (Barking, Essex : 1987)》2007,150(2):200-208
Purple coneflower plants (Echinacea purpurea) were placed into open-top chambers (OTCs) for 6 and 12 weeks in 2003 and 2004, respectively, and exposed to charcoal-filtered air (CF) or twice-ambient (2x) ozone (O3) in 2003, and to CF, 2x or non-filtered (NF), ambient air in 2004. Plants were treated with ethylenediurea (EDU) weekly as a foliar spray. Foliar symptoms were observed in >95% of the plants in 2x-treated OTCs in both years. Above-ground biomass was not affected by 2x treatments in 2003, but root and total-plant biomass decreased in 2004. As a result of higher concentrations of select cell wall constituents (% ADF, NDF and lignin) nutritive quality was lower for plants exposed to 2x-O3 in 2003 and 2004 (26% and 17%, respectively). Significant EDU x O3 interactions for concentrations of cell wall constituents in 2003 indicated that EDU ameliorated O3 effects on nutritive quality. Interactions observed in 2004 were inconsistent. 相似文献
513.
The IMPROVE_A temperature protocol for thermal/optical carbon analysis: maintaining consistency with a long-term database 总被引:7,自引:0,他引:7
Chow JC Watson JG Chen LW Chang MC Robinson NF Trimble D Kohl S 《Journal of the Air & Waste Management Association (1995)》2007,57(9):1014-1023
Thermally derived carbon fractions including organic carbon (OC) and elemental carbon (EC) have been reported for the U.S. Interagency Monitoring of PROtected Visual Environments (IMPROVE) network since 1987 and have been found useful in source apportionment studies and to evaluate quartz-fiber filter adsorption of organic vapors. The IMPROVE_A temperature protocol defines temperature plateaus for thermally derived carbon fractions of 140 degrees C for OC1, 280 degrees C for OC2, 480 degrees C for OC3, and 580 degrees C for OC4 in a helium (He) carrier gas and 580 degrees C for EC1, 740 degrees C for EC2, and 840 degrees C for EC3 in a 98% He/2% oxygen (O2) carrier gas. These temperatures differ from those used previously because new hardware used for the IMPROVE thermal/optical reflectance (IMPROVE_TOR) protocol better represents the sample temperature than did the old hardware. A newly developed temperature calibration method demonstrates that these temperatures better represent sample temperatures in the older units used to quantify IMPROVE carbon fractions from 1987 through 2004. Only the thermal fractions are affected by changes in temperature. The OC and EC by TOR are insensitive to the change in temperature protocol, and therefore the long-term consistency of the IMPROVE database is conserved. A method to detect small quantities of O2 in the pure He carrier gas shows that O2 levels above 100 ppmv also affect the comparability of thermal carbon fractions but have little effect on the IMPROVE_TOR split between OC and EC. 相似文献
514.
Edward M. Jhee Keri L. Dandridge Arthur M. Christy Jr. A. Joseph Pollard 《Chemoecology》1999,9(2):93-95
515.
Problem
Limited literature suggests that gasoline prices have substantial effects on reducing fatal crashes. However, the literature focuses only on fatal crashes and does not examine the effects on all traffic crashes.Methods
Mississippi traffic crash data from April 2004–December 2008 from the Mississippi Highway Patrol and regular-grade unleaded gasoline price data from the Energy Information Administration of the U.S. Department of Energy were used to investigate the effects of gasoline prices on traffic safety by age, gender, and race.Results
Gasoline prices have both short-term and intermediate-term effects on reducing total traffic crashes and crashes of females, whites, and blacks. The intermediate-term effects are generally stronger than the short-term effects. Gasoline prices also have short-term effects on reducing crashes of younger drivers and intermediate-term effects on older drivers and male drivers.Impact on Industry
Higher gasoline taxes reduce traffic crashes and may result in additional societal benefits. 相似文献516.
Anne-Sophie Bonnet-Lebrun Thomas Larsen Thorkell Lindberg Thrarinsson Yann Kolbeinsson Morten Frederiksen Tim I. Morley Derren Fox Aude Boutet Fabrice le Bouard Tanguy Deville Erpur Snr Hansen Thomas Hansen Patrick Roberts Norman Ratcliffe 《Ambio》2022,51(2):345
Climate change alters species distributions by shifting their fundamental niche in space through time. Such effects may be exacerbated by increased inter-specific competition if climate alters species dominance where competitor ranges overlap. This study used census data, telemetry and stable isotopes to examine the population and foraging ecology of a pair of Arctic and temperate congeners across an extensive zone of sympatry in Iceland, where sea temperatures varied substantially. The abundance of Arctic Brünnich’s guillemot Uria lomvia declined with sea temperature. Accessibility of refugia in cold water currents or fjords helped support higher numbers and reduce rates of population decline. Competition with temperate Common guillemots Uria aalge did not affect abundance, but similarities in foraging ecology were sufficient to cause competition when resources are limiting. Continued warming is likely to lead to further declines of Brünnich’s guillemot, with implications for conservation status and ecosystem services.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01650-7. 相似文献
517.
Keller WB Heneberry J Leduc J Gunn J Yan N 《Environmental monitoring and assessment》2006,115(1-3):419-431
We used multiple linear regression analysis to investigate relationships between late-summer epilimnion thickness, transparency, lake area, acidity and summer weather conditions in a large ($n = 116$) multi-year data set for 9 small Boreal Shield lakes. Dissolved organic carbon (DOC) was the best individual predictor of late summer epilimnion thickness ($r^{2} = 0.69$). Total chlorophyll~$a$, the number of days between ice-out and late-summer stratification, and lake area collectively explained an additional 14% of the variation in epilimnion thickness. The three attributes of summer weather that we examined, mean daily temperature, mean daily wind speed, and mean daily hours of bright sunshine, did not add to the predictive ability of our regression model. Lake acidity also did not add directly to the predictive ability of the model, likely because DOC concentrations already reflected the effects of pH. Our study supports an increasing body of evidence indicating that the dominant effects of climate change on lake thermal structure in small lakes will be through effects on processes that affect lake transparency. 相似文献
518.
Robert D. ARTHUR Jagadish TORLAPATI Kyung-Hee SHIN Daniel K. CHA Yeomin YOON Ahjeong SON 《Frontiers of Environmental Science & Engineering》2014,8(3):386-393
Process control parameters influencing microbial perchlorate reduction via a flow-through zero-valent iron (ZVI) column reactor were investigated in order to optimize perchlorate removal from water. Mixed perchlorate reducers were obtained from a wastewater treatment plant and inoculated into the reactor without further acclimation. Examined parameters included hydraulic residence time (HRT), pH, nutrients requirement, and perchlorate reduction kinetics. The minimum HRT for the system was concluded to be 8 hr. The removal efficiency of 10 mg. L-1 influent perchlorate concentration was reduced by 20%-80% without control to the neutral pH (HRT = 8 hr). Therefore pH was determined to be an important parameter for microbial perchlorate reduction. Furthermore, a viable alternative to pH buffer was discussed. The microbial perchlorate reduction followed the first order kinetics, with a rate constant (K) of 0.761 hr-1. The results from this study will contribute to the implementation of a safe, cost effective, and efficient system for perchlorate reduction to below regulated levels. 相似文献
519.
Arthur P.J. Mol 《国际发展与全球生态学杂志》2013,20(4):303-318
Most globalization scholars identify negative consequences for the environment in the neo-liberal orientation in current economic globalization processes. But at the same time, we can witness constant efforts at the supra-national level to institutionalize environmental interests and considerations in new institutions, arrangements and regimes. Many of the multilateral environmental arrangements give evidence of such developments. This paper aims to analyze the nature, substance and place of institutional clashes that take place between these emerging environmental institutions and the more established economic institutions linked to liberalization of trade and investment. The paper finds that (i) current globalization processes cannot be defined as giving only leeway to capital without taking care of the environment, (ii) the clashes between the economic and environmental institutions are more than only a clash between economic priorities versus environmental interests, and (iii) the pacification of these clashes will not happen in a fortnight, as the environmental advocates especially are unlikely to move towards an integration of the two kind of institutions in the short term. 相似文献
520.
Since the original formulation of the notion of safety climate, many people have developed safety climate measures and conducted factor analyses to identify distinct dimensions. Typically, these analyses were based on samples of workers in a limited number of workplaces, but since they did not allow for the non-independence of the data, they are incorrect. An appropriate analysis should use a multi-level method. This flaw in the analyses to date may at least partly explain the different factor structures of safety climate reported in the literature. 相似文献