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151.
Joshua Olusegun Okeniyi Uchechuckwu Eric Obiajulu Adedamola Oluwafisayo Ogunsanwo Nosadeba Wisdom Odiase Elizabeth Toyin Okeniyi 《Mitigation and Adaptation Strategies for Global Change》2013,18(3):325-335
The potential of CH4 (methane) greenhouse gas (GHG) emissions based on a model of prevailing behavioural pattern of livestock waste management in Nigerian local farms was investigated in this paper. Livestock waste, from Sus domesticus, pig, and Gallus domesticus, poultry, were employed as substrates in the study which uses water from a fish rearing farm as the matrix medium to simulate wastewater pool/river environment. A substrate to fish-water ratio of 1:3 by mass was used in developed laboratory-size digesting reactor system with U-tube water displacement, to facilitate volumetric readings of gas production, for each mix of the livestock waste. Volumetric readings from these, at ambient temperature conditions in the retention time of 32 days, follow the Normal probability density function, in accordance with Kolmogorov-Smirnov goodness-of-fit criteria. These readings showed that CH4-containing gas as high as 67.3?×?10?3 dm3 was produced on the 14th day from the pig and 86.8?×?10?3 dm3 on the 13th day from the poultry substrates. The overall CH4-containing gas productions of 255.4?×?10?3 dm3/kg and 323.58?×?10?3 dm3/kg were observed for the pig and the poultry substrates, respectively. A 70% scale-up analysis, modelled from these results, for the nation yield potential emission of about 4 kg CH4 (that could be as potent as 84 kg CO2-equivalent) annually. The environmental implications on global warming and possible prospects of recoverable domestic benefits from the waste through the adoption of sustainable policy of livestock waste managements for mitigating the CH4 emissions in Nigerian local farms are presented. 相似文献
152.
Faulkner JW Zhang W Geohring LD Steenhuis TS 《Journal of environmental management》2011,92(3):587-595
Silage bunker runoff can be a very polluting substance and is increasingly being treated by vegetative treatment areas (VTAs), but little information exists regarding nutrient removal performance of systems receiving this wastewater. Nutrient transport through the shallow subsurface of three VTAs (i.e. one VTA at Farm WNY and two VTAs at Farm CNY) in glaciated soils containing a restrictive layer (i.e., fragipan) was assessed using a mass balance approach. At Farm WNY, the mass removal of ammonium was 63%, nitrate was 0%, and soluble reactive phosphorus (SRP) was 39%. At Farm CNY, the mass removal of ammonium was 79% in the West VTA, but nitrate and SRP increased by 200% and 533%, respectively. Mass removal of ammonium was 67% in the East VTA at Farm CNY; nitrate removal was 86% and SRP removal was 88%. The East VTA received a much higher nutrient loading, which was attributed to a malfunctioning low-flow collection apparatus within the settling basin. Results demonstrate that nutrient reduction mechanisms other than vegetative uptake can be significant within VTAs. Even though increases in nitrate mass were observed, concentrations in 1.65m deep wells indicated that groundwater impairment from leaching of nitrate was not likely. These results offer one of the first evaluations of VTAs treating silage bunker runoff, and highlight the importance of capturing concentrated low flows in VTA systems. 相似文献
153.
Joshua B. Johnson J. Edward Gates Nicolas P. Zegre 《Environmental monitoring and assessment》2011,173(1-4):685-699
Research on effects of wind turbines on bats has increased dramatically in recent years because of significant numbers of bats killed by rotating wind turbine blades. Whereas most research has focused on the Midwest and inland portions of eastern North America, bat activity and migration on the Atlantic Coast has largely been unexamined. We used three long-term acoustic monitoring stations to determine seasonal bat activity patterns on the Assateague Island National Seashore, a barrier island off the coast of Maryland, from 2005 to 2006. We recorded five species, including eastern red bats (Lasiurus borealis), big brown bats (Eptesicus fuscus), hoary bats (Lasiurus cinereus), tri-colored bats (Perimyotis subflavus), and silver-haired bats (Lasionycteris noctivagans). Seasonal bat activity (number of bat passes recorded) followed a cosine function and gradually increased beginning in April, peaked in August, and declined gradually until cessation in December. Based on autoregressive models, inter-night bat activity was autocorrelated for lags of seven nights or fewer but varied among acoustic monitoring stations. Higher nightly temperatures and lower wind speeds positively affected bat activity. When autoregressive model predictions were fitted to the observed nightly bat pass totals, model residuals >2 standard deviations from the mean existed only during migration periods, indicating that periodic increases in bat activity could not be accounted for by seasonal trends and weather variables alone. Rather, the additional bat passes were attributable to migrating bats. We conclude that bats, specifically eastern red, hoary, and silver-haired bats, use this barrier island during migration and that this phenomenon may have implications for the development of near and offshore wind energy. 相似文献
154.
Russell J. Qualls Joshua M. Scott William B. DeOreo 《Journal of the American Water Resources Association》2001,37(3):547-559
ABSTRACT: Granular matrix soil moisture sensors were used to control urban landscape irrigation in Boulder, Colorado, during 1997. The purpose of the study was to evaluate the effectiveness and reliability of the technology for water conservation. The 23 test sites included a traffic median, a small city park, and 21 residential sites. The results were very good. The system limited actual applications to an average of 73 percent of the theoretical requirement. This resulted in an average saving of $331 per installed sensor. The sensors were highly reliable. All 23 sensors were placed in service at least three years prior to the 1997 study during earlier studies. Of these, only two had failed by the beginning of the 1997 study, both due to external factors. Including replacement of these failed sensors, the total repair cost for the 1997 irrigation season was less than $270. The effort required to maintain each system was small, only about 6–7 minutes per visit. Each site was visited weekly for this study, but less frequent visits could be made in practice. The sensors observed in this study performed well, significantly reduced water consumption, and were easy to monitor and maintain. Soil moisture sensors appear to be a useful and economical tool for urban water conservation. 相似文献
155.
Examining relationships between climate change and mental health in the Circumpolar North 总被引:1,自引:0,他引:1
156.
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158.
Joseph P. Dudley § Joshua R. Ginsberg † rew J. Plumptre † John A. Hart † Liliana C. Campos‡ 《Conservation biology》2002,16(2):319-329
159.
Large logs, important agents of biophysical heterogeneity in temperate floodplain rivers, have been virtually eliminated from modified systems. Our purpose was to quantify the sources and dynamics of large logs (> or = 1 m diameter) in the mainstem of a nearly pristine system: the Queets River, Washington, USA. Erosion of forests by the river supplies 0.40 logs x (100 m)(-1) x yr(-1) to the channel. Most (72%) are new logs entering the river for the first time as the river undercuts mature fluvial terraces dominated by large conifers. Retrospective airphoto analyses demonstrate that, over 63 years, the Queets River recruits 95% of new logs from a riparian corridor extending 265 m laterally on both banks, mostly through channel meandering. However, input rates are patchy, with 10% of the valley length supplying 38% of the new logs. As the river moves laterally, remnant logs are left on channel surfaces that later develop riparian forests and reenter the river when those forests erode. Remnant logs lying on the floodplain forest floor surface or buried in alluvium constitute 21% and 7% of the annual inputs from bank erosion, respectively. We estimate that 50% of logs deposited in the channel in a given year, including those underpinning logjams, are transported downriver within five years. Over the next 55 years, bank erosion reclaims an additional 23%, leaving 27% of the logs stable for > 60 years. Simulations indicate that recurrent transport is common, with half of the large conifers being deposited in > or = 3 locations and transported > or = 1.5 km prior to disintegrating. One in ten logs links distant reaches by occupying > or = 7 locations spanning > or = 12.0 km. Instream supplies are therefore a mixture of new and old logs from nearby and upstream forests, sustained by the recapture and transport of stockpiled remnant logs during periods when new inputs are low. We propose that patchy input rates and the periodic rearrangement of large logs are important drivers of temporal variation in river valley habitats, adding to the spatial complexity created by stable logs. These findings underscore the importance of extensive mature forests and connectivity in temperate floodplain rivers. 相似文献