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151.
Benjamin S. Rashford Richard M. Adams JunJie Wu Richard A. Voldseth Glenn R. Guntenspergen Brett Werner W. Carter Johnson 《Regional Environmental Change》2016,16(2):515-526
Wetland productivity in the Prairie Pothole Region (PPR) of North America is closely linked to climate. A warmer and drier climate, as predicted, will negatively affect the productivity of PPR wetlands and the services they provide. The effect of climate change on wetland productivity, however, will not only depend on natural processes (e.g., evapotranspiration), but also on human responses. Agricultural land use, the predominant use in the PPR, is unlikely to remain static as climate change affects crop yields and prices. Land use in uplands surrounding wetlands will further affect wetland water budgets and hence wetland productivity. The net impact of climate change on wetland productivity will therefore depend on both the direct effects of climate change on wetlands and the indirect effects on upland land use. We examine the effect of climate change and land-use response on semipermanent wetland productivity by combining an economic model of agricultural land-use change with an ecological model of wetland dynamics. Our results suggest that the climate change scenarios evaluated are likely to have profound effects on land use in the North and South Dakota PPR, with wheat displacing other crops and pasture. The combined pressure of land-use and climate change significantly reduces wetland productivity. In a climate scenario with a +4 °C increase in temperature, our model predicts that almost the entire region may lack the wetland productivity necessary to support wetland-dependent species. 相似文献
152.
D. F. Adams R. K. Koppe 《Journal of the Air & Waste Management Association (1995)》2013,63(3):161-165
A new bromine, microcoulometric titration cell has been used with a commercially-available microcoulometer for the detection and analysis of sulfur-containing gases in various kraft mill emissions. Separation of the constituents of the gaseous mixtures emitted from mill sources including the recovery furnace, digestors, evaporators, lime kiln, and dissolvers was accomplished on an 8-ft, 3/16 in. stainless steel column packed with 10% Triton X-305 on 60–80 mesh Chromosorb G, DMCS-treated. The column was isothermally operated at 30°C for 4–6 mins and then rapidly raised to 70°C The exact program was varied with the type of sample analyzed. Each source gas was initially screened by direct injection of 0.01–0.1 ml of gas to determine whether or not disproportionately large concentrations of one or more components were present. Appropriate sample volumes were then selected to provide “on-scale” recorder peaks for the major constituents. Elution times for the major constituents were observed so that these compounds could be vented at the proper time following injection of large sample volumes (up to 10 ml) for detection and analysis of minor constituents. Venting of the high concentration compounds was necessary when analyzing large volume samples to maintain near equilibrium titration conditions in the microtitration cell. 相似文献
153.
Donald F. Adams 《Journal of the Air & Waste Management Association (1995)》2013,63(9):963-968
This paper presents initial measurement data on the emission of volatile, reduced sulfur-containing gases from flue gas desulfurization (FGD) storage ponds. Several different types of FGD stored sludges were studied including lime, limestone, and mixtures of fly ash and lime or limestone residues, some of which had been chemically stabilized. The volatile sulfur gas emissions were cryogenically concentrated and determined by wall-coated, open-tubular capillary column gas chromatography using a flame photometric detector. Hydrogen sulfide, carbonyl sulfide, dimethyl sulfide, carbon disulfide, and an unusual, unidentified sulfur-containing compound were found in the gaseous pond flux. Benzene, toluene, and α-pinene were also identified by gas chromatography-single ion monitoring mass spectrometry. The total reduced sulfur gas emission from a 100 acre pond approximated 2.0 kg day?1 (as sulfur). 相似文献
154.
Donald F. Adams 《Journal of the Air & Waste Management Association (1995)》2013,63(4):434-438
ABSTRACT The temporal and longitudinal characteristics of volatile organic compound (VOC) emissions from the aeration units of a publicly owned treatment works (POTWs) have been investigated by systematic monitoring and mathematical modeling. Field tests have been conducted at a 120-mgd wastewater treatment plant to investigate the hourly, weekly, and seasonal changes of VOC emissions. Variations of VOC emissions along the length of the aeration units have been tested and modeled. Most VOCs have decreasing concentration profiles. Henry's law coefficients and biodegradation constants for the detected compounds have been validated with the improved models and the field test data. More than one-half of the emissions were found to have been generated from the first one-third of the aeration unit length. 相似文献
155.
James W. Mjelde Richard M. Adams Bruce L. Dixon Philip Garcia 《Journal of the Air & Waste Management Association (1995)》2013,63(4):360-364
The effects of ozone on the profitability of Illinois cash grain farms is investigated by utilizing a profit function framework. This approach uses individual farms as the observational unit so the data are generated under field conditions. Hence, experimental plot data are not used although results from past biological experiments are utilized to frame initial hypotheses and for evaluation of the estimated model. This study demonstrates the benefits of combining economic data and biological science results to estimate the economic reactions of producers in terms of input and output (production) response to an ambient environmental characteristic. A time series of cross sectional data on cash grain farms in Illinois is used to estimate two profit functions. Ozone data are measured on a growing season basis by county. The estimated model shows ozone has a negative effect on profits. Increases in ozone levels tend to depress output levels and lessen the demand for variable inputs. Additionally, a production function is derived from one of the profit functions. The impact of ozone is found to be in general agreement with dose-response data obtained in Illinois by plant scientists. 相似文献
156.
Frank S. Gilliam Mary Beth Adams 《Journal of the Air & Waste Management Association (1995)》2013,63(10):978-984
Abstract Although extensive research on acidic deposition has been directed toward spruce-fir forests, less research has been done on the impacts of air pollution on eastern montane hardwood forests. The purpose of this study was to describe precipitation chemistry for several Appalachian hardwood forest sites at or near the Fernow Experimental Forest (FEF) to assess the potential for problems associated with acidic deposition. Emphasis was placed on seasonal patterns of ionic concentrations (H+, Ca++, NH4+; NO3-, and SO4=) and spatial variability of ionic concentrations and deposition among sites. Seasonal patterns of most ions showed highest concentrations during the summer months and deposition of H+ was especially pronounced during this time. Deposition of all ions was generally greater (related to greater precipitation) at three montane forested sample sites compared to a nonforested riverbottom site. Precipitation chemistry at FEF was similar to other sites throughout the eastern United States and contrasted sharply with mid-western and western sites. Eastern sites, including means for FEF sites, were uniformly 3-4 times higher in H+ and SO4= concentration than the mid-western and western sites. Precipitation at FEF was chronically acidic, more so during the growing season, and highest at higher elevations where environmental stresses can be most severe. Furthermore, there were occasional large discrepancies between the low-elevation site and the higher-elevation forested sites for precipitation chemistry and acidic deposition. These results suggest that synoptic-scale (network) data may greatly underestimate the pollutant conditions to which highelevation forest trees are exposed, since network data rarely take elevation into account and typically are based on annual ionic concentration and deposition means that may be considerably lower than those of the growing season. 相似文献
157.
Walter R. Hill Michael G. Ryon John G. Smith S. Marshall Adams Harry L. Boston Arthur J. Stewart 《Environmental management》2010,45(3):563-576
The effects of pollutants on primary producers ramify through ecosystems because primary producers provide food and structure
for higher trophic levels and they mediate the biogeochemical cycling of nutrients and contaminants. Periphyton (attached
algae) were studied as part of a long-term biological monitoring program designed to guide remediation efforts by the Department
of Energy’s Y-12 National Security Complex on East Fork Poplar Creek (EFPC) in Oak Ridge, Tennessee. High concentrations of
nutrients entering EFPC were responsible for elevated periphyton production and placed the stream in a state of eutrophy.
High rates of primary production at upstream locations in EFPC were associated with alterations in both invertebrate and fish
communities. Grazers represented >50% of the biomass of invertebrates and fish near the Y-12 Complex but <10% at downstream
and reference sites. An index of epilithic periphyton production accounted for 95% of the site-to-site variation in biomass
of grazing fish. Analyses of heavy metals in EFPC periphyton showed that concentrations of zinc, cadmium, copper and nickel
in periphyton decreased exponentially with distance downstream from Y-12. Zinc uptake by periphyton was estimated to reduce
the concentration of this metal in stream water ~60% over a 5-km reach of EFPC. Management options for mitigating eutrophy
in EFPC include additional reductions in nutrient inputs and/or allowing streamside trees to grow and shade the stream. However,
reducing periphyton growth may lead to greater downstream transport of contaminants while simultaneously causing higher concentrations
of mercury and PCBs in fish at upstream sites. 相似文献
158.
Some researches studied the removal of steroid estrogens by enzymatic treatment, however none verified the residual estrogenicity after the enzymatic treatment at environmental conditions. In this study, the residual estrogenic activities of the key natural and synthetic steroid estrogens were investigated following enzymatic treatment with horseradish peroxidase (HRP) and laccase from Trametes versicolor. Synthetic water and municipal wastewater containing environmental concentrations of estrone, 17beta-estradiol, estriol, and 17alpha-ethinylestradiol were treated. Liquid chromatography-mass spectrometry analysis demonstrated that the studied steroid estrogens were completely oxidized in the wastewater reaction mixture after a 1-h treatment with either HRP (8-10 U ml(-1)) or laccase (20 U ml(-1)). Using the recombinant yeast assay, it was also confirmed that both enzymatic treatments were very efficient in removing the estrogenic activity of the studied steroid estrogens. The laccase-catalyzed process seemed to present great advantages over the HRP-catalyzed system for up-scale applications for the treatment of municipal wastewater. 相似文献
159.
Susan A. Weiner David A. Galbraith Dean C. Adams Nicole Valenzuela Fernando B. Noll Christina M. Grozinger Amy L. Toth 《Die Naturwissenschaften》2013,100(8):795-799
DNA methylation plays an important role in the epigenetic control of developmental and behavioral plasticity, with connections to the generation of striking phenotypic differences between castes (larger, reproductive queens and smaller, non-reproductive workers) in honeybees and ants. Here, we provide the first comparative investigation of caste- and life stage-associated DNA methylation in several species of bees and vespid wasps displaying different levels of social organization. Our results reveal moderate levels of DNA methylation in most bees and wasps, with no clear relationship to the level of sociality. Strikingly, primitively social Polistes dominula paper wasps show unusually high overall DNA methylation and caste-related differences in site-specific methylation. These results suggest DNA methylation may play a role in the regulation of behavioral and physiological differences in primitively social species with more flexible caste differences. 相似文献
160.
Nathalie Butt Alienor L.M. Chauvenet Vanessa M. Adams Maria Beger Rachael V. Gallagher Danielle F. Shanahan Michelle Ward James E.M. Watson Hugh P. Possingham 《Conservation biology》2021,35(3):775-783
Species that cannot adapt or keep pace with a changing climate are likely to need human intervention to shift to more suitable climates. While hundreds of articles mention using translocation as a climate-change adaptation tool, in practice, assisted migration as a conservation action remains rare, especially for animals. This is likely due to concern over introducing species to places where they may become invasive. However, there are other barriers to consider, such as time-frame mismatch, sociopolitical, knowledge and uncertainty barriers to conservationists adopting assisted migration as a go-to strategy. We recommend the following to advance assisted migration as a conservation tool: attempt assisted migrations at small scales, translocate species with little invasion risk, adopt robust monitoring protocols that trigger an active response, and promote political and public support. 相似文献