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Author: Xiaoyi Zhang Publisher: ISBN: Category : Languages : en Pages : 61
Book Description
Over the last century, human activities have dramatically increased the inputs of nitrogen (N) and phosphorus (P) to land, resulting in increased eutrophication of aquatic systems, and degradation of drinking water quality. Although many changes in management have been adopted to mitigate these impacts, little improvement has been observed in water quality. Multiple N and P mass balance studies have indicated imbalances between inputs and outputs of N and P in anthropogenic landscapes. In this work, historical (1901-2011) N and P budgets for the Grand River Watershed (GRW) in southwestern Ontario were developed using the NANI/NAPI (net anthropogenic N/P input) framework. NANI was calculated as the sum of four different components: commercial fertilizer N application, atmospheric N deposition, net food and feed imports, and biological N fixation. A similar budgeting method was used to estimate NAPI, which includes fertilizer P application, net food and feed imports and detergent P use by humans. Relevant data was obtained from the Canadian agricultural census, Environment Canada, and literature estimates. Our results showed that annual NANI and NAPI values increased approximate 2-fold since 1901, with peak net inputs in 1986 and 1976, respectively. Increases in NANI over time can primarily be attributed to high atmospheric N deposition, fertilizer N application and biological N fixation, while increases in NAPI are primarily due to increased fertilizer P application. Spatially, the hotspots for both NANI and NAPI have since the early 1950s shifted to the central sub-watersheds of the GRW, which can be attributed to greater urbanization and agricultural intensification in the central area. The historical NANI and NAPI estimates obtained for the GRW provide insights into the spatio-temporal patterns in NANI and NAPI, and can facilitate better N and P management strategies.
Author: Xiaoyi Zhang Publisher: ISBN: Category : Languages : en Pages : 61
Book Description
Over the last century, human activities have dramatically increased the inputs of nitrogen (N) and phosphorus (P) to land, resulting in increased eutrophication of aquatic systems, and degradation of drinking water quality. Although many changes in management have been adopted to mitigate these impacts, little improvement has been observed in water quality. Multiple N and P mass balance studies have indicated imbalances between inputs and outputs of N and P in anthropogenic landscapes. In this work, historical (1901-2011) N and P budgets for the Grand River Watershed (GRW) in southwestern Ontario were developed using the NANI/NAPI (net anthropogenic N/P input) framework. NANI was calculated as the sum of four different components: commercial fertilizer N application, atmospheric N deposition, net food and feed imports, and biological N fixation. A similar budgeting method was used to estimate NAPI, which includes fertilizer P application, net food and feed imports and detergent P use by humans. Relevant data was obtained from the Canadian agricultural census, Environment Canada, and literature estimates. Our results showed that annual NANI and NAPI values increased approximate 2-fold since 1901, with peak net inputs in 1986 and 1976, respectively. Increases in NANI over time can primarily be attributed to high atmospheric N deposition, fertilizer N application and biological N fixation, while increases in NAPI are primarily due to increased fertilizer P application. Spatially, the hotspots for both NANI and NAPI have since the early 1950s shifted to the central sub-watersheds of the GRW, which can be attributed to greater urbanization and agricultural intensification in the central area. The historical NANI and NAPI estimates obtained for the GRW provide insights into the spatio-temporal patterns in NANI and NAPI, and can facilitate better N and P management strategies.
Author: Kristin Kiara Gardner Publisher: ISBN: Category : Bayesian statistical decision theory Languages : en Pages : 454
Book Description
Anthropogenic activity has greatly increased watershed export of bioavailable nitrogen. Escalating levels of bioavailable nitrogen can deteriorate aquatic ecosystems by promoting nuisance algae growth, depleting dissolved oxygen levels, altering biotic communities, and expediting eutrophication. Despite these potential detrimental impacts, there is notable lack of understanding of the linkages between anthropogenic nitrogen inputs and the spatial and seasonal heterogeneity of stream network concentrations and watershed nitrogen export. This dissertation research seeks to more accurately define these linkages by investigating the roles of landscape position and spatial distribution of anthropogenic nitrogen inputs on the magnitude and speciation of watershed nitrogen export and retention and how these roles vary seasonally across contrasting landscapes in a 212 km 2 mountainous watershed in southwest Montana. Results indicate localized inputs of anthropogenic nitrogen occurring in watershed areas with quick transport times to streams had disproportionate effects on watershed nitrogen export compared to spatially distributed or localized inputs of nitrogen to areas with longer transport times. In lower elevation alluvial streams, these effects varied seasonally and were most evident during the dormant winter season by amplified nitrate peaks, elevated dissolved organic nitrogen:dissolved organic nitrogen (DIN:DON) ratios and lower dissolved organic carbon (DOC):total dissolved nitrogen (DOC:TDN). During the summer growing season, biologic uptake of nitrogen masked anthropogenic influences on watershed nitrogen export; however, endmember mixing analysis of nitrate isotopes revealed significant anthropogenic influence during the growing season, despite low nitrate concentrations and DIN:DON ratios. In contrast, streams draining alpine environments consisting of poorly developed, shallow soils and small riparian areas exhibited yearlong elevated nitrate concentrations compared to other sites, suggesting these areas were highly nitrogen enriched. Watershed modeling revealed the majority of watershed nitrogen retention occurred in the upland environment, most likely from biological uptake or lack of hydrologic connectivity. This work has critical implications for watershed management, which include: 1) developing flexible strategies that address varying landscape characteristics and nitrogen loading patterns across a watershed, 2) avoiding clustering nitrogen loading in areas with quick travel times to surface waters, 3) seasonal monitoring to accurately gauge watershed nitrogen saturation status, and 4) incorporating spatial relationships into streamwater nitrogen models.
Author: Nicolas Flipo Publisher: Springer Nature ISBN: 3030542602 Category : Science Languages : en Pages : 430
Book Description
This open access book reviews the water-agro-food and socio-eco-system of the Seine River basin (76,000 km2), and offers a historical perspective on the river’s long-term contamination. The Seine basin is inhabited by circa 17 million people and is impacted by intensive agricultural practices and industrial activities. These pressures have gradually affected its hydrological, chemical and ecological functioning, leading to a maximum chemical degradation between the 1960s and the 1990s. Over the last three decades, while major water-quality improvements have been observed, new issues (e.g. endocrine disruptors, microplastics) have also emerged. The state of the Seine River network, from the headwaters to estuary, is increasingly controlled by the balance between pressures and social responses. This socio-ecosystem provides a unique example of the functioning of a territory under heavy anthropogenic pressure during the Anthropocene era. The achievements made were possible due to the long-term PIREN Seine research program, established in 1989 and today part of the French socio-ecological research network “Zones Ateliers”, itself part of the international Long-term Socio-economic and Ecological Research Network (LTSER). Written by experts in the field, the book provides an introduction to the water budget and the territorial metabolism of the Seine basin, and studies the trajectories and impact of various pollutants in the Seine River. It offers insights into the ecological functioning, the integration of agricultural practices, the analysis of aquatic organic matter, and the evolution of fish assemblages in the Seine basin, and also presents research perspectives and approaches to improve the water quality of the Seine River. Given its scope, it will appeal to environmental managers, scientists and policymakers interested in the long-term contamination of the Seine River.
Author: National Research Council Publisher: National Academies Press ISBN: 0309210828 Category : Political Science Languages : en Pages : 258
Book Description
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.
Author: National Research Council Publisher: National Academies Press ISBN: 0309072549 Category : Nature Languages : en Pages : 107
Book Description
Scientists have long sought to unravel the fundamental mysteries of the land, life, water, and air that surround us. But as the consequences of humanity's impact on the planet become increasingly evident, governments are realizing the critical importance of understanding these environmental systemsâ€"and investing billions of dollars in research to do so. To identify high-priority environmental science projects, Grand Challenges in Environmental Sciences explores the most important areas of research for the next generation. The book's goal is not to list the world's biggest environmental problems. Rather it is to determine areas of opportunity thatâ€"with a concerted investmentâ€"could yield significant new findings. Nominations for environmental science's "grand" challenges were solicited from thousands of scientists worldwide. Based on their responses, eight major areas of focus were identifiedâ€"areas that offer the potential for a major scientific breakthrough of practical importance to humankind, and that are feasible if given major new funding. The book further pinpoints four areas for immediate action and investment.
Author: K. Ramesh Reddy Publisher: CRC Press ISBN: 0429531931 Category : Science Languages : en Pages : 926
Book Description
The globally important nature of wetland ecosystems has led to their increased protection and restoration as well as their use in engineered systems. Underpinning the beneficial functions of wetlands are a unique suite of physical, chemical, and biological processes that regulate elemental cycling in soils and the water column. This book provides an in-depth coverage of these wetland biogeochemical processes related to the cycling of macroelements including carbon, nitrogen, phosphorus, and sulfur, secondary and trace elements, and toxic organic compounds. In this synthesis, the authors combine more than 100 years of experience studying wetlands and biogeochemistry to look inside the black box of elemental transformations in wetland ecosystems. This new edition is updated throughout to include more topics and provide an integrated view of the coupled nature of biogeochemical cycles in wetland systems. The influence of the elemental cycles is discussed at a range of scales in the context of environmental change including climate, sea level rise, and water quality. Frequent examples of key methods and major case studies are also included to help the reader extend the basic theories for application in their own system. Some of the major topics discussed are: Flooded soil and sediment characteristics Aerobic-anaerobic interfaces Redox chemistry in flooded soil and sediment systems Anaerobic microbial metabolism Plant adaptations to reducing conditions Regulators of organic matter decomposition and accretion Major nutrient sources and sinks Greenhouse gas production and emission Elemental flux processes Remediation of contaminated soils and sediments Coupled C-N-P-S processes Consequences of environmental change in wetlands# The book provides the foundation for a basic understanding of key biogeochemical processes and its applications to solve real world problems. It is detailed, but also assists the reader with box inserts, artfully designed diagrams, and summary tables all supported by numerous current references. This book is an excellent resource for senior undergraduates and graduate students studying ecosystem biogeochemistry with a focus in wetlands and aquatic systems.
Author: Xiaoyi Zhang
Author: Xiaoyi Zhang
Author: Kristin Kiara Gardner
Author: Nicolas Flipo
Author: National Research Council
Author: National Research Council
Author: Vijay P. Singh
Author: K. Ramesh Reddy
Author: Henning Steinfeld
Author: Ignacio Rodríguez-Iturbe
Author: