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Modeling Biological Nitrogen Fixation And Nitrogen Pollution Potentials At Watershed Scale
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Book Synopsis Modeling Biological Nitrogen Fixation and Nitrogen Pollution Potentials at Watershed Scale by : Christopher Joseph Post
Download or read book Modeling Biological Nitrogen Fixation and Nitrogen Pollution Potentials at Watershed Scale written by Christopher Joseph Post and published by . This book was released on 2001 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Nitrogen Cycle at Regional to Global Scales by : Elizabeth W. Boyer
Download or read book The Nitrogen Cycle at Regional to Global Scales written by Elizabeth W. Boyer and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: This issue is the final report from the International SCOPE Project on Nitrogen Transport and Transformations: A Regional and Global Analysis. SCOPE (the Scientific Committee on Problems of the Environment, ICSU) authorized the Nitrogen Project as an 8-year effort between 1994 and 2002 because of the need to better understand how humans have altered nitrogen cyc1ing globally and at the scale of large regions. Human activity has more than doubled the rate of formation of reactive nitrogen on the land surface of the earth, and the nitrogen cyc1e continues to accelerate. The distribution of this reactive nitrogen is not uniform, though, and some regions such as Europe and Asia have seen massive increases in reactive nitrogen, while other regions have seen little change. The SCOPE Nitrogen Project has synthesized detailed information on the nature of the human alteration of the nitrogen cyc1e through aseries of workshops over the past 8 years. These cumulatively have involved over 250 of previous workshops scientists from over 20 different nations. The results have been published in aseries of special journal issues and reports that synthesize information on nitrogen in the North Atlantic Ocean and its water sheds (Howarth 1996), nitrogen cycling in Asia (Hong-Chi Lin et al. 1996; Mosier et al.
Download or read book Nitrogen Pollution written by and published by . This book was released on 2003 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The European Nitrogen Assessment by : Mark A. Sutton
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.
Book Synopsis Predicting Nutrient Loadings and Fate and Transport of Nitrogen Derived from On-site Systems by :
Download or read book Predicting Nutrient Loadings and Fate and Transport of Nitrogen Derived from On-site Systems written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The potential nitrogen loadings from on-site wastewater treatment systems (septic systems) to North Carolina's river basins have long been ignored. Yet the potential for these systems to have significant impact on surface water exists. This study assessed nitrogen inputs from septic systems on macro (large watershed) and micro (small watershed) scales. Cumulative potential nitrogen loadings from on-site systems to North Carolina's 17 river basins and 134 major sub-basins were estimated using census 1990 data. The soil and water assessment tool (SWAT) model was used to predict the fate and transport nitrogen derived from on-site systems as well as nitrogen exports to surface waters in small watersheds. The sensitivity of the SWAT model output to sources and resolutions of Digital Elevation Model (DEM) inputs on a micro scale was assessed for small watersheds. A Geographic Information System (GIS) based area-driven normalization procedure was developed and implemented to estimate potential nitrogen loadings on the macro scale. Septic system density ranged from 5 to 20 systems/sq. km at a river basin level and 2 to 115 at a sub-basin level. Total potential nitrogen loading from on-site systems was approximately 14 million kg statewide. A small watershed in the lower Coastal Plain was modeled using SWAT to quantify the nitrogen export to the watershed outlet on a micro scale. Over 95% of the septic system derived nitrogen was removed prior to stream discharge. Both the source and resolution of the DEM inputs affected the size of the watershed delineated, flow volume and predicted nitrogen export to the watershed outlet.
Book Synopsis Nitrogen Cycling in the Americas: Natural and Anthropogenic Influences and Controls by : Luiz A. Martinelli
Download or read book Nitrogen Cycling in the Americas: Natural and Anthropogenic Influences and Controls written by Luiz A. Martinelli and published by Springer Science & Business Media. This book was released on 2007-01-19 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in our understanding of the nitrogen cycle and the impact of anthropogenic activities on regional to global scales depend on the expansion of scientific studies to these fast-developing regions. This book presents a series of studies from across the Americas whose aim is to highlight key natural processes that control nitrogen cycling as well as discuss the main anthropogenic influences on the nitrogen cycle in both the tropical and temperate regions of the Americas.
Book Synopsis Achieving Nutrient and Sediment Reduction Goals in the Chesapeake Bay by : National Research Council
Download or read book Achieving Nutrient and Sediment Reduction Goals in the Chesapeake Bay written by National Research Council and published by National Academies Press. This book was released on 2011-09-26 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Chesapeake Bay is North America's largest and most biologically diverse estuary, as well as an important commercial and recreational resource. However, excessive amounts of nitrogen, phosphorus, and sediment from human activities and land development have disrupted the ecosystem, causing harmful algae blooms, degraded habitats, and diminished populations of many species of fish and shellfish. In 1983, the Chesapeake Bay Program (CBP) was established, based on a cooperative partnership among the U.S. Environmental Protection Agency (EPA), the state of Maryland, and the commonwealths of Pennsylvania and Virginia, and the District of Columbia, to address the extent, complexity, and sources of pollutants entering the Bay. In 2008, the CBP launched a series of initiatives to increase the transparency of the program and heighten its accountability and in 2009 an executive order injected new energy into the restoration. In addition, as part of the effect to improve the pace of progress and increase accountability in the Bay restoration, a two-year milestone strategy was introduced aimed at reducing overall pollution in the Bay by focusing on incremental, short-term commitments from each of the Bay jurisdictions. The National Research Council (NRC) established the Committee on the Evaluation of Chesapeake Bay Program Implementation for Nutrient Reduction in Improve Water Quality in 2009 in response to a request from the EPA. The committee was charged to assess the framework used by the states and the CBP for tracking nutrient and sediment control practices that are implemented in the Chesapeake Bay watershed and to evaluate the two-year milestone strategy. The committee was also to assess existing adaptive management strategies and to recommend improvements that could help CBP to meet its nutrient and sediment reduction goals. The committee did not attempt to identify every possible strategy that could be implemented but instead focused on approaches that are not being implemented to their full potential or that may have substantial, unrealized potential in the Bay watershed. Because many of these strategies have policy or societal implications that could not be fully evaluated by the committee, the strategies are not prioritized but are offered to encourage further consideration and exploration among the CBP partners and stakeholders.
Book Synopsis Nitrogen Overload by : Brian G. Katz
Download or read book Nitrogen Overload written by Brian G. Katz and published by John Wiley & Sons. This book was released on 2020-06-16 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Finalist for the 2021 PROSE Award for Environmental Science! An integrated approach to understanding and mitigating the problem of excess nitrogen Human activities generate large amounts of excess nitrogen, which has dramatically altered the nitrogen cycle. Reactive forms of nitrogen, especially nitrate and ammonia, are particularly detrimental. Given the magnitude of the problem, there is an urgent need for information on reactive nitrogen and its effective management. Nitrogen Overload: Environmental Degradation, Ramifications, and Economic Costs presents an integrated, multidisciplinary review of alterations to the nitrogen cycle over the past century and the wide-ranging consequences of nitrogen-based pollution, especially to aquatic ecosystems and human health. Volume highlights include: Comprehensive background information on the nitrogen cycle Detailed description of anthropogenic nitrogen sources Review of the environmental, economic, and health impacts of nitrogen pollution Recommendations and strategies for reducing humanity's nitrogen footprint Discussion of national nitrogen footprints and worldwide examples of mitigation policies The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals. Read the Editors' Vox: https://eos.org/editors-vox/exploring-the-widespread-impacts-of-ongoing-nitrogen-pollution
Book Synopsis Global Implications of the Nitrogen Cycle by : Trelita de Sousa
Download or read book Global Implications of the Nitrogen Cycle written by Trelita de Sousa and published by Cambridge Scholars Publishing. This book was released on 2020-07-16 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrogen constitutes 78% of the Earth’s atmosphere and inevitably occupies a predominant role in marine and terrestrial nutrient biogeochemistry and the global climate. Callous human activities, like the excessive industrial nitrogen fixation and the incessant burning of fossil fuels, have caused a massive acceleration of the nitrogen cycle, which has, in turn, led to an increasing trend in eutrophication, smog formation, acid rain, and emission of nitrous oxide, which is a potent greenhouse gas, 300 times more powerful in warming the Earth’s atmosphere than carbon dioxide. This book comprehensively reviews the biotransformation of nitrogen, its ecological significance and the consequences of human interference. It will appeal to environmentalists, ecologists, marine biologists, and microbiologists worldwide, and will serve as a valuable guide to graduates, post-graduates, research scholars, scientists, and professors.
Book Synopsis The Nitrogen Legacy by : Kimberly Van Meter
Download or read book The Nitrogen Legacy written by Kimberly Van Meter and published by . This book was released on 2016 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Global population has seen a more than threefold increase over the last 100 years, accompanied by rapid changes in land use and a dramatic intensification of agriculture. Such changes have been driven by a great acceleration of the global nitrogen (N) cycle, with N fertilizer use now estimated to be 100 Tg/year globally. Excess N commonly finds its way into both groundwater and surface water, leading to long-term problems of hypoxia, aquatic toxicity and drinking water contamination. Despite ongoing efforts to improve water quality in agroecosystems, results have often been disappointing, with significant lag times between adoption of accepted best management practices (BMPs) and measurable improvements in water quality. It has been hypothesized that such time lags are a result of the buildup of legacy N within the landscape over decades of fertilizer application and agricultural intensification. The central theme of my research has been an exploration of this N legacy, including (1) an investigation of the form, locations and magnitudes of legacy N stores within intensively managed catchments; (2) development of a parsimonious, process-based modeling framework for quantifying catchment-scale time lags based on both soil nutrient accumulations (biogeochemical legacy) and groundwater travel time distributions (hydrologic legacy); and (3) use of a statistical approach to both quantifying N-related time lags at the watershed scale, and identifying the primary physical and management controls on these lags. As a result of these explorations I am able to provide the first direct, large-scale evidence of N accumulation in the root zones of agricultural soils, accumulation that may account for much of the 'missing N' identified in mass balance studies of heavily impacted watersheds. My analysis of long-term soil data (1957-2010) from 206 sites throughout the Mississippi River Basin (MRB) revealed N accumulation in cropland of 25-70 kg ha-1 y-1, a total of 3.8 ± 1.8 Mt y-1 at the watershed scale. A simple modeling framework was then used to show that the observed accumulation of soil organic N (SON) in the MRB over a 30-year period (142 Tg N) would lead to a biogeochemical lag time of 35 years for 99% of legacy SON, even with a complete cessation of fertilizer application. A parsimonious, process-based model, ELEMeNT (Exploration of Long-tErM Nutrient Trajectories), was then developed to quantify catchment-scale time lags based on both soil N accumulation (biogeochemical legacy) and groundwater travel time distributions (hydrologic legacy). The model allowed me to predict the time lags observed in a 10 km2 Iowa watershed that had undergone a 41% conversion of area from row crop to native prairie. The model results showed that concentration reduction benefits are a function of the spatial pattern of implementation of conservation measures, with preferential conversion of land parcels having the shortest catchment-scale travel times providing greater concentration reductions as well as faster response times. This modeling framework allows for the quantification of tradeoffs between costs associated with implementation of conservation measures and the time needed to see the desired concentration reductions, making it of great value to decision makers regarding optimal implementation of watershed conservation measures. To better our understanding of long-term N dynamics, I expanded the ELEMeNT modeling framework described above to accommodate long-term N input trajectories and their impact on N loading at the catchment scale. In this work, I synthesized data from a range of sources to develop a comprehensive, 214-year (1800-2104) trajectory of N inputs to the land surface of the continental United States. The ELEMeNT model was used to reconstruct historic nutrient yields at the outlets of two major U.S. watersheds, the Mississippi River and Susquehanna River Basins, which are the sources of significant nutrient contamination to the Gulf of Mexico and Chesapeake Bay, respectively. My results show significant N loading above baseline levels in both watersheds before the widespread use of commercial N fertilizers, largely due to 19th-century conversion of natural forest and grassland areas to row-crop agriculture. The model results also allowed me to quantify the magnitudes of legacy N in soil and groundwater pools, thus highlighting the dominance of soil N legacies in the MRB and groundwater legacies in the SRB. It was found that approximately 85% of the annual N load in the MRB can be linked to inputs from previous years, while only 47% of SRB N loading is associated with “older” N. In addition, it was found that the dominant sources of current N load in the MRB are fertilizer, atmospheric deposition, and biological N fixation, while manure and atmospheric deposition account for approximately 64% of the current loads in the SRB. Finally, long-term N surplus trajectories were paired with long-term flow-averaged nitrate concentration data to as means of quantifying N-related lag times across an intensively managed watershed in Southern Ontario. In this analysis, we found a significant linear relationship between current flow-averaged concentrations and current N surplus values across the study watersheds. Temporal analysis, however, showed significant nonlinearity between N inputs and outputs, with a strong hysteresis effect indicative of decadal-scale lag times between changes in N surplus values and subsequent changes in flow-averaged nitrate concentrations. Annual lag times across the study watersheds ranged from 15-33 years, with a mean lag of 24.5 years. A seasonal analysis showed a distribution of lag times across the year, with fall lags being the shortest and summer lags the longest, likely due to differences in N delivery pathways. Multiple linear regression analysis of dominant controls showed tile drainage to be a strong determinant of differences in lag times across watersheds in both fall and spring, with a watershed's fractional area under tile drainage being significantly linked to shorter lag times. In summer, tile drainage was found to be an insignificant factor in driving lag times, while a significant relationship was found between the percent soil organic matter and longer N-related lag times. By moving beyond the traditional focus on nutrient concentrations and fluxes, and instead working towards quantification of the spatio-temporal dynamics of non-point source nutrient legacies and their current and future impacts on water quality, we make a significant contribution to the science of managing human impacted landscapes. Due to the strong impacts of nutrient legacies on the time scales for recovery in at-risk landscapes, my work will enable a more accurate assessment of the outcomes of alternative management approaches in terms of both short- and long-term costs and benefits, and the evaluation of temporal uncertainties associated with different intervention strategies.
Book Synopsis Dissertation Abstracts International by :
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2007 with total page 924 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis CO-OCCURRENCE OF NITROGEN FIXATION AND DENITRIFICATION ACROSS A STREAM NITROGEN GRADIENT IN A WESTERN WATERSHED by :
Download or read book CO-OCCURRENCE OF NITROGEN FIXATION AND DENITRIFICATION ACROSS A STREAM NITROGEN GRADIENT IN A WESTERN WATERSHED written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : It is frequently assumed that N2 fixation and denitrification do not co-occur in streams because each process should be favored under different concentrations of reactive nitrogen. Yet, both N2 fixation and denitrification have been found to co-occur in marine and coastal ecosystems despite their differences in nitrogen requirements, and we cannot evaluate this assumption for streams because both processes are rarely quantified together. We asked if these processes could co-exist by measuring rates of N2 fixation using acetylene reduction, denitrification using acetylene block, and N2 flux using membrane inlet mass spectrometry on rocks and sediment in 8 southeastern Idaho streams encompassing a dissolved inorganic nitrogen (DIN) gradient of 6-615 μg/L. N2 flux rates on rocks had a mean of -12,000 ± 4,900 μg/m2/h and on sediment of -2,400 ± 12,000 μg/m2/h, which were significantly different. N2 fixation rates were not significantly different among rock and sediment substrate with means of 22.9 ± 54.4 and 2.2 ± 2.0 μg/m2/h, respectively. Unamended denitrification rates were significantly different among rock and sediment substrates with means of 3 ± 7 and 2248 ± 1565 μg/m2/h, respectively. Amended denitrification rates were also significantly different among substrates with a mean of 352 ± 690 μg/m2/h on rocks and 18,100 ± 6287 μ/m2/h on sediment. DIN concentration was not a significant predictor of unamended denitrification rates, but was a significant predictor of N2 flux and N2 fixation rates on rocks in 2016, and amended denitrification rates on sediments in 2015 and 2016, indicating that DIN concentration alone cannot predict occurrence of processes on all substrates at all times. Multiple linear regression models relating environmental variables to measured rates showed that carbon and phosphorus availability were important predictors of denitrification rates and phosphorus, carbon, and light availability were important predictors of N2 flux rates across all sites. No significant model was produced for N2 fixation rates. Environmental characteristics measured at the scale of entire stream-reaches may not be at a fine enough spatial scale to characterize and predict the co-occurrence of these processes within stream reaches. N2 flux is balanced by the rates of N2 fixation and denitrification, and in order to better understand the fluxes and cycling of N through stream ecosystems we need to examine the co-occurrence of these processes.
Book Synopsis Clean Coastal Waters by : National Research Council
Download or read book Clean Coastal Waters written by National Research Council and published by National Academies Press. This book was released on 2000-08-17 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental problems in coastal ecosystems can sometimes be attributed to excess nutrients flowing from upstream watersheds into estuarine settings. This nutrient over-enrichment can result in toxic algal blooms, shellfish poisoning, coral reef destruction, and other harmful outcomes. All U.S. coasts show signs of nutrient over-enrichment, and scientists predict worsening problems in the years ahead. Clean Coastal Waters explains technical aspects of nutrient over-enrichment and proposes both immediate local action by coastal managers and a longer-term national strategy incorporating policy design, classification of affected sites, law and regulation, coordination, and communication. Highlighting the Gulf of Mexico's "Dead Zone," the Pfiesteria outbreak in a tributary of Chesapeake Bay, and other cases, the book explains how nutrients work in the environment, why nitrogen is important, how enrichment turns into over-enrichment, and why some environments are especially susceptible. Economic as well as ecological impacts are examined. In addressing abatement strategies, the committee discusses the importance of monitoring sites, developing useful models of over-enrichment, and setting water quality goals. The book also reviews voluntary programs, mandatory controls, tax incentives, and other policy options for reducing the flow of nutrients from agricultural operations and other sources.
Book Synopsis Sources, Fate, and Transport of Nitrogen and Phosphorus in the Chesapeake Bay Watershed by : Scott W. Ator
Download or read book Sources, Fate, and Transport of Nitrogen and Phosphorus in the Chesapeake Bay Watershed written by Scott W. Ator and published by Geological Survey (USGS). This book was released on 2011 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spatially Referenced Regression on Watershed Attributes (SPARROW) was used to provide empirical estimates of the sources, fate, and transport of total nitrogen (TN) and total phosphorus (TP) in the Chesapeake Bay watershed, and the mean annual TN and TP flux to the bay and in each of 80,579 nontidal tributary stream reaches. Restoration efforts in recent decades have been insufficient to meet established standards for water quality and ecological conditions in Chesapeake Bay. The bay watershed includes 166,000 square kilometers of mixed land uses, multiple nutrient sources, and variable hydrogeologic, soil, and weather conditions, and bay restoration is complicated by the multitude of nutrient sources and complex interacting factors affecting the occurrence, fate, and transport of nitrogen and phosphorus from source areas to streams and the estuary. Effective and efficient nutrient management at the regional scale in support of Chesapeake Bay restoration requires a comprehensive understanding of the sources, fate, and transport of nitrogen and phosphorus in the watershed, which is only available through regional models. The current models, Chesapeake Bay nutrient SPARROW models, version 4 (CBTN_v4 and CBTP_v4), were constructed at a finer spatial resolution than previous SPARROW models for the Chesapeake Bay watershed (versions 1, 2, and 3), and include an updated timeframe and modified sources and other explantory terms.
Book Synopsis Nitrogen in the Environment: Sources, Problems and Management by : R.F. Follett
Download or read book Nitrogen in the Environment: Sources, Problems and Management written by R.F. Follett and published by Gulf Professional Publishing. This book was released on 2001-12-03 with total page 539 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrogen in the Environment: Sources, Problems, and Management is the first volume to provide a holistic perspective and comprehensive treatment of nitrogen from field, to ecosystem, to treatment of urban and rural drinking water supplies, while also including a historical overview, human health impacts and policy considerations. It provides a worldwide perspective on nitrogen and agriculture. Nitrogen is one of the most critical elements required in agricultural systems for the production of crops for feed, food and fiber. The ever-increasing world population requires increasing use of nitrogen in agriculture to supply human needs for dietary protein. Worldwide demand for nitrogen will increase as a direct response to increasing population. Strategies and perspectives are considered to improve nitrogen-use efficiency. Issues of nitrogen in crop and human nutrition, and transport and transformations along the continuum from farm field to ground water, watersheds, streams, rivers, and coastal marine environments are discussed. Described are aerial transport of nitrogen from livestock and agricultural systems and the potential for deposition and impacts. The current status of nitrogen in the environment in selected terrestrial and coastal environments and crop and forest ecosystems and development of emerging technologies to minimize nitrogen impacts on the environment are addressed. The nitrogen cycle provides a framework for assessing broad scale or even global strategies to improve nitrogen use efficiency. Growing human populations are the driving force that requires increased nitrogen inputs. These increasing inputs into the food-production system directly result in increased livestock and human-excretory nitrogen contribution into the environment. The scope of this book is diverse, covering a range of topics and issues from furthering our understanding of nitrogen in the environment to policy considerations at both farm and national scales.
Book Synopsis Properties and Management of Soils in the Tropics by : Pedro A. Sanchez
Download or read book Properties and Management of Soils in the Tropics written by Pedro A. Sanchez and published by Cambridge University Press. This book was released on 2019-01-10 with total page 685 pages. Available in PDF, EPUB and Kindle. Book excerpt: Long-awaited second edition of classic textbook, brought completely up to date, for courses on tropical soils, and reference for scientists and professionals.
Book Synopsis Selected Water Resources Abstracts by :
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1990 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt:
