Download or read book Sources and Controls of Reactive Nitrogen Gas Emissions from a Mojave Desert Ecosystem written by Carmody K. McCalley and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This body of work considerably expands our understanding of gaseous nitrogen (N) loss dynamics in arid ecosystems, a process that directly affects longterm N bioavailability and the release of chemically important gas species into the atmosphere. Chapter one focuses on identifying controls over biological sources of reactive N gas emissions, especially the pulse of NO and NH3 that occurs following precipitation. This research shows a two-step response of reactive N gas emissions to pulsed water additions. First, there is a large transient NH3 pulse. Second, biological activity is stimulated leading to NO production by nitrifying bacteria. Results indicate that biological sources of NO and NH3 efflux respond primarily to the addition of water; however, fluxes are modulated by temperature and nutrient constraints on microbial activity. Chapter two explores the role of non-biological processes in reactive N gas emissions from desert soils. Combination of laboratory and field measurements show that abiotic reactions are a key component of N loss from desert soils, both under dry conditions and during post-wetting periods. It is hypothesized that during the summer, extreme surface soil temperatures caused by direct exposure to incoming solar radiation result in thermal decomposition of N-containing compounds, yielding elevated rates of reactive N gas efflux. Chapter three focuses on the effects of elevated CO2 on soil fluxes of reactive N gases. Under soil conditions optimal for biological activity, long-term fumigation with elevated CO2 reduces reactive N gas losses in the islands of fertility created by the dominant shrub Larea tridentata. These results provide supporting evidence that elevated CO2 alters soil N dynamics in arid ecosystems, including increased N immobilization and decreased N mineralization and nitrification. Chapter four provides a robust estimate of annual reactive N gas emissions for a Mojave Desert ecosystem, accounting for daily, seasonal and yearly variation in environmental conditions. This annual estimate of 0.1 to 0.6 kg N ha-1 y-1 includes considerable variation, reflecting inter-annual variability in summer precipitation and growing season moisture conditions. These results demonstrate the strong impact that alterations in precipitation patterns under future climate scenarios will have on N dynamics in water limited ecosystems.
Download or read book Final Technical Report written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to anticipate the effects of global change on ecosystem function, it is essential that predictive relationships be established linking ecosystem function to global change scenarios. The Mojave Desert is of considerable interest with respect to global change. It contains the driest habitats in North America, and thus most closely approximates the world's great arid deserts. In order to examine the effects of climate and land use changes, in 2001 we established a long-term manipulative global change experiment, called the Mojave Global Change Facility. Manipulations in this study include the potential effects of (1) increased summer rainfall (75 mm over three discrete 25 mm events), (2) increased nitrogen deposition (10 and 40 kg ha-1), and (3) the disturbance of biological N-fixing crusts . Questions addressed under this grant shared the common hypothesis that plant and ecosystem performance will positively respond to the augmentation of the most limiting resources to plant growth in the Mojave Desert, e.g., water and nitrogen. Specific hypotheses include (1) increased summer rainfall will significantly increase plant production through an alleviation of moisture stress in the dry summer months, (2) N-deposition will increase plant production in this N-limited system, particularly in wet years or in concert with added summer rain, and (3) biological crust disturbance will gradually decrease bio-available N, with concomitant long-term reductions in photosynthesis and ANPP. Individual plant and ecosystem responses to global change may be regulated by biogeochemical processes and natural weather variability, and changes in plant and ecosystem processes may occur rapidly, may occur only after a time lag, or may not occur at all. During the first PER grant period, we observed changes in plant and ecosystem processes that would fall under each of these time-response intervals: plant and ecosystem processes responded rapidly to added summer rain, whereas most processes responded slowly or in a lag fashion to N-deposition and with no significant response to crust disturbance. Therefore, the primary objectives of this renewal grant were to: (1) continue ongoing measurements of soil and plant parameters that assess primary treatment responses; (2) address the potential heterogeneity of soil properties and (3) initiate a new suite of measurements that will provide data necessary for scaling/modeling of whole-plot to ecosystem-level responses. Our experimental approach included soil plant-water interactions using TDR, neutron probe, and miniaturized soil matric potential and moisture sensors, plant ecophysiological and productivity responses to water and nitrogen treatments and remote sensing methodologies deployed on a radio control platform. We report here the most significant findings of our study.
Download or read book Biological Soil Crusts An Organizing Principle in Drylands written by Bettina Weber and published by Springer. This book was released on 2016-05-21 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume summarizes our current understanding of biological soil crusts (biocrusts), which are omnipresent in dryland regions. Since they cover the soil surface, they influence, or even control, all surface exchange processes. Being one of the oldest terrestrial communities, biocrusts comprise a high diversity of cyanobacteria, algae, lichens and bryophytes together with uncounted bacteria, and fungi. The authors show that biocrusts are an integral part of dryland ecosystems, stabilizing soils, influencing plant germination and growth, and playing a key role in carbon, nitrogen and water cycling. Initial attempts have been made to use biocrusts as models in ecological theory. On the other hand, biocrusts are endangered by local disruptions and global change, highlighting the need for enhanced recovery methods. This book offers a comprehensive overview of the fascinating field of biocrust research, making it indispensable not only for scientists in this area, but also for land managers, policy makers, and anyone interested in the environment.
Download or read book Review and Integration of Biosphere Atmosphere Modelling of Reactive Trace Gases and Volatile Aerosols written by Raia Silvia Massad and published by Springer. This book was released on 2015-07-16 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: When considering biosphere–atmosphere exchange of trace gases and volatile aerosols, significant advances have been made both from an experimental and modelling point of view and on several scales. This was particularly stimulated by the availability of new datasets generated from improvements in analytical methods and flux measurement techniques. Recent research advances allow us, not only to identify major mechanisms and factors affecting the exchanges between the biosphere and the atmosphere, but also to recognize several gaps in the methodologies used in accounting for emissions and deposition in landscape and global scale models. This work aims at (i) reviewing exchange processes and modelling schemes, parameterisations and datasets, (ii) presenting a common conceptual framework to model soil-vegetation-atmosphere exchange of reactive trace gases and aerosols accounting for in-canopy transfer chemical interactions and (iii) discussing the key elements of the agreed framework.
Download or read book The European Nitrogen Assessment written by Mark A. Sutton and published by Cambridge University Press. This book was released on 2011-04-14 with total page 665 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presenting the first continental-scale assessment of reactive nitrogen in the environment, this book sets the related environmental problems in context by providing a multidisciplinary introduction to the nitrogen cycle processes. Issues of upscaling from farm plot and city to national and continental scales are addressed in detail with emphasis on opportunities for better management at local to global levels. The five key societal threats posed by reactive nitrogen are assessed, providing a framework for joined-up management of the nitrogen cycle in Europe, including the first cost-benefit analysis for different reactive nitrogen forms and future scenarios. Incorporating comprehensive maps, a handy technical synopsis and a summary for policy makers, this landmark volume is an essential reference for academic researchers across a wide range of disciplines, as well as stakeholders and policy makers. It is also a valuable tool in communicating the key environmental issues and future challenges to the wider public.
Download or read book Dryland Ecohydrology written by Paolo D'Odorico and published by Springer Science & Business Media. This book was released on 2006-01-09 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecohydrology emerges as a new field of research aiming at furthering our understanding of the earth system through the study of the interactions between the water cycle and vegetation. By combining the analysis of biotic and abiotic components of terrestrial ecosystems, this volume provides a synthesis of material on arid and semiarid landscapes, which is currently spread in a number of books and journal articles. The focus on water-limited ecosystems is motivated by their high sensitivity to daily, seasonal, and decadal perturbations in water availability, and by the ecologic, climatic, and economic significance of most of the drylands around the world. Conceived as a tool for scientists working in the area of the earth and environmental sciences, this book presents the basic principles of eco-hydrology as well as a broad spectrum of topics and advances in this research field. The chapters collected in this book have been contributed by authors with different expertise, who work in several arid areas around the World. They describe the various interactions among the biological and physical dynamics in dryland ecosystems, starting from basic processes in the soil-vegetation-climate system, to landscape-scale hydrologic and geomorphic processes, ecohydrologic controls on soil nutrient dynamics, and multiscale analyses of disturbances and patterns.
Download or read book Environment Abstracts Annual written by and published by . This book was released on 1990 with total page 2142 pages. Available in PDF, EPUB and Kindle. Book excerpt: This database encompasses all aspects of the impact of people and technology on the environment and the effectiveness of remedial policies and technologies, featuring more than 950 journals published in the U.S. and abroad. The database also covers conference papers and proceedings, special reports from international agencies, non-governmental organizations, universities, associations and private corporations. Other materials selectively indexed include significant monographs, government studies and newsletters.
Download or read book Biological Soil Crusts Structure Function and Management written by Jayne Belnap and published by Springer Science & Business Media. This book was released on 2013-12-01 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: In arid lands, where vegetation is sparse or absent, the open ground is not bare but generally covered by a community of small, highly specialized organisms. Cyanobacteria, algae, microfungi, lichens, and bryophytes aggregate soil particles to form a coherent skin - the biological soil crust. It stabilizes and protects the soil surface from erosion by wind and water, influences water runoff and infiltration, and contributes nitrogen and carbon to desert soils. Soil surface disturbance, such as heavy livestock grazing, human trampling or off-road vehicles, breaks up the fragile soil crust, thus compromising its stability, structure, and productivity. This book is the first synthesis of the biology of soil crusts and their importance as an ecosystem component. Composition and functioning of different soil-crust types are discussed, and case studies are used to show the impact of crusts on landscape hydrology, soil stability, nutrient cycles, and land management.
Download or read book Physiological Ecology of North American Desert Plants written by Stanley D. Smith and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: Following a description of the physical and biological characterization of the four North American deserts together with the primary adaptations of plants to environmental stress, the authors go on to present case studies of key species. They provide an up-to-date and comprehensive review of the major patterns of adaptation in desert plants, with one chapter devoted to several important exotic plants that have invaded these deserts. The whole is rounded off with a synthesis of the resource requirements of desert plants and how they may respond to global climate change.
Download or read book Agronomy Abstracts written by and published by . This book was released on 1995 with total page 1348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes abstracts of the annual meetings of the American Society of Agronomy; Soil Science Society of America; Crop Science Society of America ( - of its Agronomic Education Division).
Download or read book Crop ecology cultivation and uses of cactus pear written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Org.. This book was released on 2018-06-05 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cactus plants are precious natural resources that provide nutritious food for people and livestock, especially in dryland areas. Originally published in 1995, this extensively revised edition provides fresh insights into the cactus plant’s genetic resources, physiological traits, soil preferences and vulnerability to pests. It provides invaluable guidance on managing the resource to support food security and offers tips on how to exploit the plant’s culinary qualities.
Download or read book The Environment Index written by and published by . This book was released on 1981 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Compilation of Minimum and Maximum Isotope Ratios of Selected Elements in Naturally Occurring Terrestrial Materials and Reagents written by Tyler B. Coplen and published by . This book was released on 2002 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Documented variations in the isotopic compositions of some chemical elements are responsible for expanded uncertainties in the standard atomic weights published by the Commission on Atomic Weights and Isotopic Abundances of the International Union of Pure and Applied Chemistry. This report summarizes reported variations in the isotopic compositions of 20 elements that are due to physical and chemical fractionation processes (not due to radioactive decay) and their effects on the standard atomic weight uncertainties. For 11 of those elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, silicon, sulfur, chlorine, copper, and selenium), standard atomic weight uncertainties have been assigned values that are substantially larger than analytical uncertainties because of common isotope abundance variations in materials of natural terrestrial origin. For 2 elements (chromium and thallium), recently reported isotope abundance variations potentially are large enough to result in future expansion of their atomic weight uncertainties. For 7 elements (magnesium, calcium, iron, zinc, molybdenum, palladium, and tellurium), documented isotope-abundance variations in materials of natural terrestrial origin are too small to have a significant effect on their standard atomic weight uncertainties.
Download or read book Trees in a Changing Environment written by Michael Tausz and published by Springer. This book was released on 2014-08-26 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book delivers current state-of-the-science knowledge of tree ecophysiology, with particular emphasis on adaptation to a novel future physical and chemical environment. Unlike the focus of most books on the topic, this considers air chemistry changes (O3, NOx, and N deposition) in addition to elevated CO2 effects and its secondary effects of elevated temperature. The authors have addressed two systems essential for plant life: water handling capacity from the perspective of water transport; the coupling of xylem and phloem water potential and flow; water and nutrition uptake via likely changes in mycorrhizal relationships; control of water loss via stomata and its retention via cellular regulation; and within plant carbon dynamics from the perspective of environmental limitations to growth, allocation to defences, and changes in partitioning to respiration. The authors offer expert knowledge and insight to develop likely outcomes within the context of many unknowns. We offer this comprehensive analysis of tree responses and their capacity to respond to environmental changes to provide a better insight in understanding likelihood for survival, as well as planning for the future with long-lived, stationary organisms adapted to the past: trees.
Download or read book The Carbon Cycle written by T. M. L. Wigley and published by Cambridge University Press. This book was released on 2005-08-22 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reducing carbon dioxide (CO2) emissions is imperative to stabilizing our future climate. Our ability to reduce these emissions combined with an understanding of how much fossil-fuel-derived CO2 the oceans and plants can absorb is central to mitigating climate change. In The Carbon Cycle, leading scientists examine how atmospheric carbon dioxide concentrations have changed in the past and how this may affect the concentrations in the future. They look at the carbon budget and the "missing sink" for carbon dioxide. They offer approaches to modeling the carbon cycle, providing mathematical tools for predicting future levels of carbon dioxide. This comprehensive text incorporates findings from the recent IPCC reports. New insights, and a convergence of ideas and views across several disciplines make this book an important contribution to the global change literature.
Download or read book Renewable and Efficient Electric Power Systems written by Gilbert M. Masters and published by John Wiley & Sons. This book was released on 2005-01-03 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a comprehensive textbook for the new trend of distributed power generation systems and renewable energy sources in electric power systems. It covers the complete range of topics from fundamental concepts to major technologies as well as advanced topics for power consumers. An Instructor's Manual presenting detailed solutions to all the problems in the book is available from the Wiley editorial department -- to obtain the manual, send an email to [email protected]
Download or read book Electricity from Renewable Resources written by National Research Council and published by National Academies Press. This book was released on 2010-04-05 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: A component in the America's Energy Future study, Electricity from Renewable Resources examines the technical potential for electric power generation with alternative sources such as wind, solar-photovoltaic, geothermal, solar-thermal, hydroelectric, and other renewable sources. The book focuses on those renewable sources that show the most promise for initial commercial deployment within 10 years and will lead to a substantial impact on the U.S. energy system. A quantitative characterization of technologies, this book lays out expectations of costs, performance, and impacts, as well as barriers and research and development needs. In addition to a principal focus on renewable energy technologies for power generation, the book addresses the challenges of incorporating such technologies into the power grid, as well as potential improvements in the national electricity grid that could enable better and more extensive utilization of wind, solar-thermal, solar photovoltaics, and other renewable technologies.
