Download or read book Biogeochemical Cycling and Retention of Carbon and Nutrients in a Constructed Wetland Receiving Agricultural Runoff in the San Joaquin Valley California written by Jonathan Maynard and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The biogeochemical cycles of carbon (C) and phosphorus (P) are intricately linked in aquatic systems, as P is often the limiting nutrient for primary productivity. The conversion of flood plain agroecosystems to flow-through wetlands is becoming a popular land-use practice for treating agricultural runoff nation wide, yet little information exists to document how these systems function in California where constructed wetlands dry out in late winter and spring. I examined the biogeochemical cycling of carbon and phosphorus in a small flow-through constructed wetland that receives agricultural runoff from approximately 2,300 ha of irrigated farmland. The first study (Chapter 2) examined the potential for wetland C sequestration via exogenous and endogenous C sources over a 13-year period. Results from this study showed that although surface sediments were enriched with endogenous sources of C (24 g kg−1), the long-term storage of C (~14 g kg−1) was maintained at the same level as inflowing sediment (14 g kg−1) due to fluctuating cycles of flooding and drying. Thus additional C sequestration from endogenous sources may be limited in seasonally-saturated wetlands due to enhanced oxidation during drying cycles. The second study (Chapter 3) quantified wetland metabolism across a range of spatial scales (meters to 100s of meters) to better understand the linkages between ecosystem metabolism and biotic and abiotic factors. Results from this study showed that despite high rates of primary productivity, high respiration rates limited net C production in this wetland, resulting in heterotrophic conditions during most of the season. However, the addition of high C loads in inflowing water and moderate retention efficiencies resulted in a positive C mass balance during most sampling dates. The third study (Chapter 4) quantified the role of sulfides in inducing mobilization of P in constructed wetland soils. This study shows that sulfide induced P flux can play an important role in the retention and cycling of P in wetland soils. However, soils enriched in iron oxides can effectively buffer sulfide concentration in pore water. These studies illustrate the potential role small flow-though wetlands can play in sequestering carbon and improving water quality in agriculturally intensive watersheds.
Download or read book Biogeochemical Cycling of Phosphorus in Constructed Flow through Wetlands Receiving Agricultural Runoff in the San Joaquin Valley California written by Jonathan Maynard and published by . This book was released on 2008 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Biogeochemical Cycling Processes in Walker Branch Watershed written by Dale W Johnson and published by . This book was released on 1988-12-01 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Forest and Rangeland Soils of the United States Under Changing Conditions written by Richard V. Pouyat and published by Springer Nature. This book was released on 2020-09-02 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book synthesizes leading-edge science and management information about forest and rangeland soils of the United States. It offers ways to better understand changing conditions and their impacts on soils, and explores directions that positively affect the future of forest and rangeland soil health. This book outlines soil processes and identifies the research needed to manage forest and rangeland soils in the United States. Chapters give an overview of the state of forest and rangeland soils research in the Nation, including multi-decadal programs (chapter 1), then summarizes various human-caused and natural impacts and their effects on soil carbon, hydrology, biogeochemistry, and biological diversity (chapters 2–5). Other chapters look at the effects of changing conditions on forest soils in wetland and urban settings (chapters 6–7). Impacts include: climate change, severe wildfires, invasive species, pests and diseases, pollution, and land use change. Chapter 8 considers approaches to maintaining or regaining forest and rangeland soil health in the face of these varied impacts. Mapping, monitoring, and data sharing are discussed in chapter 9 as ways to leverage scientific and human resources to address soil health at scales from the landscape to the individual parcel (monitoring networks, data sharing Web sites, and educational soils-centered programs are tabulated in appendix B). Chapter 10 highlights opportunities for deepening our understanding of soils and for sustaining long-term ecosystem health and appendix C summarizes research needs. Nine regional summaries (appendix A) offer a more detailed look at forest and rangeland soils in the United States and its Affiliates.
Download or read book Ecosystems of California written by Harold Mooney and published by Univ of California Press. This book was released on 2016-01-19 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt: This long-anticipated reference and sourcebook for CaliforniaÕs remarkable ecological abundance provides an integrated assessment of each major ecosystem typeÑits distribution, structure, function, and management. A comprehensive synthesis of our knowledge about this biologically diverse state, Ecosystems of California covers the state from oceans to mountaintops using multiple lenses: past and present, flora and fauna, aquatic and terrestrial, natural and managed. Each chapter evaluates natural processes for a specific ecosystem, describes drivers of change, and discusses how that ecosystem may be altered in the future. This book also explores the drivers of CaliforniaÕs ecological patterns and the history of the stateÕs various ecosystems, outlining how the challenges of climate change and invasive species and opportunities for regulation and stewardship could potentially affect the stateÕs ecosystems. The text explicitly incorporates both human impacts and conservation and restoration efforts and shows how ecosystems support human well-being. Edited by two esteemed ecosystem ecologists and with overviews by leading experts on each ecosystem, this definitive work will be indispensable for natural resource management and conservation professionals as well as for undergraduate or graduate students of CaliforniaÕs environment and curious naturalists.
Download or read book Biogeochemistry and Plant Litter Decomposition in Wetlands written by Stephanie Tillson Castle and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Decomposition of plant litter, accumulation and loss of plant litter within the system and nutrient acquisition of plants through epi- and endophytic nitrogen fixation are all processes which have both immediate and long-term implications in the biogeochemical cycling and ecosystem processes of wetland ecosystems. In light of large scale wetland loss and degradation to human impact, restoration has become a large focus in environmental conservation. Plant litter decomposition dynamics play a central role in the functioning of wetland ecosystems, and although many have explored the importance and impact of plant litter in ecosystems, few have linked differences in accumulation and decay rates directly to wetland restoration outcomes. The first of two goals of this dissertation research was to improve understanding of drivers of plant litter decomposition in wetlands, while also exploring how changes in decomposition processes may impact wetland restoration. In this context, three experiments in wetland environments were utilized to explore decomposition dynamics: constructed wetlands in the expansive Sacramento-San Joaquin (SSJ) Delta, spring-fed Amargosa Valley wetlands of the Mojave Desert, and phosphorus (P) limited marshes of Belize. A litter decomposition experiment in the Sacramento-San Joaquin Delta showed significant differences in decay rates between both species and tissue types (leaves, roots, rhizomes), which were shown to compound over long-term time scales resulting in significant differences in overall organic matter. Further, in this study belowground tissues were also shown to be a significant and important source of organic matter accumulation compared to aboveground litter materials, which has implications for restoration outcomes. Decay rates of plant litter can be largely impacted by changes in ecosystem conditions such as water level and temperature. In a study in the Mojave Desert wetlands, disturbance by lowered water level caused a 30-fold reduction in litter decay rate which resulted in accumulation of a extremely dense litter layer and led to shift in ecosystem state. Under these conditions, litter accumulation represented a significant inhibitor of plant regeneration via rhizome resprouts and seedling germination following disturbance. In another study, experimental decay rate data from original lab incubations were combined with a meta-analysis from relevant literature to explore nutrient controls on microbial litter decomposition. Results showed that overall, microbial decomposition via extracellular enzyme production was strongly influenced by nitrogen (N) availability regardless of underlying nutrient limitation (N or P). The second goal of this dissertation research was to improve understanding of nutrient acquisition in an important wetland macrophyte, Schoenoplectus californicus. In regard to nutrient acquisition of plants, we found that S. californicus is able to subsidize a significant proportion of its overall N budget through endo- and epiphytic N2-fixation. In combination, the knowledge derived from these studies increases our understanding of biogeochemical processes in wetlands, and can provide important information to land managers and conservationists to both guide restoration activities in important wetlands systems, while also protecting and conserving ecologically significant wetland resources.
Download or read book Biogeochemical Cycling in Lake Superior Tributaries written by Ashley Anne Coble and published by . This book was released on 2015 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seasonal and spatial variability in environmental factors may affect dissolved organic matter composition and nutrient transformation and retention in streams. The objective of this research was to quantify and describe seasonality, quantity, and quality of nutrient processing and export of ammonium (NH4), soluble reactive phosphate (SRP), and dissolved organic carbon (DOC) into Lake Superior through intensive study in a small 1st order watershed coupled with snapshot measurements across 12 tributaries that varied in size, location, and wetland coverage. Our results suggest biodegradable C is exported from a small headwater stream year-round and that DOC mineralization rates can be stimulated by additions of NH4 and labile C (Chapter 2). We found that biodegradable DOC varied synchronously among 3 rivers that varied in size by three orders of magnitude. Furthermore, these rivers exported 9 to 17% of annual DOC in biodegradable form, which may then fuel biological activity in nearshore zones of Lake Superior. Modeling of historical loads of DOC suggests that spring loads of DOC have increased and fall loads have decreased over a 26 year period, but annual loads have not (Chapter 3). Across eleven tributaries variability in NH4 uptake velocity was explained by watershed area, discharge, and fluorescence index of DOC (indicator of microbial and terrestrial sources; Chapter 4). Temporally detailed measurements (every 2 to 4 weeks for 3 years) of nutrient uptake in a small headwater stream indicated light availability, algal and periphyton biomass, solute concentrations, and pH were important predictors of NH4 uptake velocity (Chapter 5). We found a similar magnitude of NH4 uptake velocity during winter and summer measurements while SRP uptake velocity was greater in summer than winter (Chapter 5). Overall the greatest uptake velocities were observed in spring and fall for NH4, in spring for SRP and in fall for DOC (Chapter 5). Collectively, this research demonstrates the temporally dynamic nature of biodegradable carbon and nutrient uptake, the tight coupling of C and N cycling, and the role of DOM composition in stream nutrient uptake in northern temperate forested streams.
Download or read book Nutrient Removal and Greenhouse Gas Emissions from 20 Year Old Constructed Wetlands Receiving Tile Drainage Water a Biogeochemical Analysis written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Restoration of Aquatic Ecosystems written by National Research Council and published by National Academies Press. This book was released on 1992-01-01 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aldo Leopold, father of the "land ethic," once said, "The time has come for science to busy itself with the earth itself. The first step is to reconstruct a sample of what we had to begin with." The concept he expressedâ€"restorationâ€"is defined in this comprehensive new volume that examines the prospects for repairing the damage society has done to the nation's aquatic resources: lakes, rivers and streams, and wetlands. Restoration of Aquatic Ecosystems outlines a national strategy for aquatic restoration, with practical recommendations, and features case studies of aquatic restoration activities around the country. The committee examines: Key concepts and techniques used in restoration. Common factors in successful restoration efforts. Threats to the health of the nation's aquatic ecosystems. Approaches to evaluation before, during, and after a restoration project. The emerging specialties of restoration and landscape ecology.
Download or read book Biogeochemical Cycling of Carbon Nitrogen and Phosphorus Nutrients in River Delta Marshes of Lavaca Bay Texas written by Texas. Department of Water Resources and published by . This book was released on 1978 with total page 267 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling the Impacts of Climate Change on Hydrology and Agricultural Pollutant Runoff in California s Central Valley written by Darren L. Ficklin and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Soil and Water Assessment Tool (SWAT) and HYDRUS were used to assess the impact of climate change on the hydrologic cycle (streamflow, surface runoff, groundwater recharge, evapotranspiration, and irrigation water use) and agricultural pollutant runoff (sediment, nitrate, phosphorus, chlorpyrifos, and diazinon) in the Sacramento and San Joaquin River watersheds in California's Central Valley. Five separate studies were constructed. For the first three studies, hydrological responses were modeled in the San Joaquin River watershed using variations of atmospheric CO2 (550 and 970 ppm), temperature (+1.1 and +6.4°C), and precipitation (0%, ±10%, and ±20%) based on Intergovernmental Panel on Climate Change projections. The fourth study used a calibration and an uncertainty analysis technique for the calibration of the Sacramento River watershed. This study confirmed that SWAT was able to capture the large amount of uncertainty within the Sacramento River watershed and successfully simulate streamflow, sediment, nitrate, chlorpyrifos and diazinon loads. The final study used a novel stochastic climate change analysis technique to bracket the 95% confidence interval of potential climate changes. For all studies, increases in precipitation generally changed the hydrological cycle and agricultural runoff proportionally, where increases in precipitation resulted in increases in surface runoff and thus agricultural runoff and vice-versa. Also, for all studies, increasing temperature caused a temporal shift in plant growth patterns and redistributed evapotranspiration and irrigation water demand earlier in the year. Increasing atmospheric CO2 resulted in watershed-wide decreases in evapotranspiration, therefore increasing water yield and streamflow while concurrently decreasing irrigation water use. This research improves the understanding between climate change and hydrology and agricultural pollutant runoff within the Central Valley of California. Theses climate change analyses may be used by water resource managers to evaluate the potential effects of climate change.
Download or read book Perturbations to Nutrient and Carbon Cycles by River Damming written by Taylor Maavara and published by . This book was released on 2017 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: The damming of rivers represents one of the most far-reaching human modifications to the flows of water and associated matter from land to sea. Globally there are over 70 000 large dams whose reservoirs store more than seven times as much water as natural rivers. Due to increasing demands for energy, irrigation, drinking water, and flood control, the construction of dams will continue into the foreseeable future. Indeed, there is currently an ongoing boom in dam construction, particularly focused in emerging economies, which is expected to double the fragmentation of rivers on Earth. Essential nutrient elements such as phosphorus (P), nitrogen (N), silicon (Si), and carbon (C) are transported and transformed along the land-ocean aquatic continuum (LOAC), forming the basis for freshwater food webs in lakes, rivers, wetlands, reservoirs, and floodplains, and ultimately for marine food webs in estuarine and coastal environments. The dam-driven fragmentation of the rivers along the LOAC will significantly modify global nutrient and C fluxes via elimination from the water column in reservoirs. In this thesis, I quantify in-reservoir elimination and transformation fluxes for phosphorus (P), silicon (Si), and organic carbon (OC), with the goal of determining (1) how much Si, P, and organic C (OC) are retained or eliminated globally due to river damming, (2) how damming modifies the balance of productivity (heterotrophy vs. autotrophy) in river systems worldwide, (3) to what extent damming changes nutrient speciation or reactivity along the LOAC, and (4) if reservoirs retain or eliminate certain nutrients more efficiently than others, and if so, how this decoupling changes nutrient ratios delivered to coastal zones. I address these research questions at the reservoir scale, by quantifying nutrient elimination in Lake Diefenbaker, Saskatchewan, and through the development of spatially explicit global nutrient and carbon models. In Chapter 2, I present a reservoir-scale field study of reactive silicon dynamics in Lake Diefenbaker, a reservoir in Canada's central prairie province of Saskatchewan. I use a year-round dataset of surface water samples and sediment cores to construct a Si budget for the reservoir, including an estimation of the amount of Si buried in the reservoir annually. I use this study to illustrate the differences in retention of Si relative to N and P, and put forth the hypothesis that river damming results in a decoupling of nutrient cycling. This study acts as an introduction to the concept of differential nutrient retention in reservoirs, which I go on to show at the global scale for Si, P, and C in reservoirs in Chapters 3, 4, and 5. Following Chapter 2, I address my research questions by developing a mechanistic approach to global scale biogeochemical modelling. This approach yields spatially explicit results, which allows for the quantification of regional watershed and coastal trends, as well as lumped continental changes. In Chapter 3, the modelling approach itself is introduced, through application to the Si cycle. I show, via a meta-analysis comparing the distribution of physical and chemical parameters of published reservoir Si budgets to reservoirs worldwide, that the existing literature Si budgets are severely limited in their ability to represent the dataset of global reservoirs. I then introduce the mechanistic approach by developing a biogeochemical box model representing Si dynamics in reservoirs. I assign rate expressions to transformation fluxes and input/output fluxes, which are constrained as uniform distributions between limits that encapsulate possible global ranges. Using a Monte Carlo approach, I allow the model to randomly select each rate constant independently for 6000 iterations, generating a database of hypothetical Si dynamics in reservoirs worldwide. I use this generated dataset to establish expressions relating Si retention to water residence time, which I apply to an existing database of global reservoirs. Ultimately I develop a global estimate of dissolved and reactive Si burial in reservoirs for year 2000. Chapters 4 and 5 use the same modelling approach presented in Chapter 3, but applied to riverine P and organic carbon (OC) fluxes. Because the cycles of P and OC have been studied in more detail than Si in the literature, it is possible to constrain higher order probability density functions (PDFs) for many rate constants. In the case of OC, it also becomes possible to use a statistically significant semi-empirical approach to calculate a number of fluxes, as expressions to predict OC dynamics have been established from globally applicable datasets. Using the upstream-catchment area-normalized Global-NEWS model's watershed yields as input to each reservoir, I use the 1970, 2000, 2030 and 2050 model predictions to estimate historical and predict future P and OC elimination by dams. In Chapter 4, I show that damming retains 12% of the global total P load to watersheds in year 2000, potentially rising to 17% by 2030. In Chapter 5, I show that global OC mineralization in reservoirs exceeds carbon fixation (P
Download or read book Microbial Diversity and Carbon Cycling in San Francisco Bay Wetlands written by and published by . This book was released on 2014 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wetland restoration efforts in San Francisco Bay aim to rebuild habitat for endangered species and provide an effective carbon storage solution, reversing land subsidence caused by a century of industrial and agricultural development. However, the benefits of carbon sequestration may be negated by increased methane production in newly constructed wetlands, making these wetlands net greenhouse gas (GHG) sources to the atmosphere. We investigated the effects of wetland restoration on below-ground microbial communities responsible for GHG cycling in a suite of historic and restored wetlands in SF Bay. Using DNA and RNA sequencing, coupled with real-time GHG monitoring, we profiled the diversity and metabolic potential of wetland soil microbial communities. The wetland soils harbor diverse communities of bacteria and archaea whose membership varies with sampling location, proximity to plant roots and sampling depth. Our results also highlight the dramatic differences in GHG production between historic and restored wetlands and allow us to link microbial community composition and GHG cycling with key environmental variables including salinity, soil carbon and plant species.
Download or read book Agricultural Nonpoint Source Pollution written by William F. Ritter and published by CRC Press. This book was released on 2000-12-15 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: If you work in the water quality management field, you know the challenges of monitoring and controlling pollutants in our water supply. The increasing problem of agricultural nonpoint source pollution requires complex solutions. Agricultural Nonpoint Source Pollution: Watershed Management and Hydrology covers the latest techniques and methods of managing large watershed areas, with an emphasis on controlling non-point source pollution, especially from agricultural run-off. Written by leading experts, the book includes topics such as: nitrate and phosphorus pollution, pesticide contamination, erosion and sedimentation, water-table management, and watershed management. The authors discuss the effects of agricultural run-off - one of the most intransigent problems now faced by environmental engineers and hydrologists. They explore each issue with an eye towards the integrated management of water quality and water resources over a defined area or region. This single-source reference gives you a complete understanding of the whats, whys, and hows of nonpoint source pollution - and more importantly of how to monitor and manage it. Agricultural Nonpoint Source Pollution: Watershed Management and Hydrology provides a broad but detailed overview that helps you to comprehend the intricacies of the problem and puts you on the path to finding the answers.
Download or read book Urban Stormwater Management in the United States written by National Research Council and published by National Academies Press. This book was released on 2009-03-17 with total page 611 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rapid conversion of land to urban and suburban areas has profoundly altered how water flows during and following storm events, putting higher volumes of water and more pollutants into the nation's rivers, lakes, and estuaries. These changes have degraded water quality and habitat in virtually every urban stream system. The Clean Water Act regulatory framework for addressing sewage and industrial wastes is not well suited to the more difficult problem of stormwater discharges. This book calls for an entirely new permitting structure that would put authority and accountability for stormwater discharges at the municipal level. A number of additional actions, such as conserving natural areas, reducing hard surface cover (e.g., roads and parking lots), and retrofitting urban areas with features that hold and treat stormwater, are recommended.
Download or read book Sustainable Intensification written by Jules N. Pretty and published by Routledge. This book was released on 2012-06-25 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Continued population growth, rapidly changing consumption patterns and the impacts of climate change and environmental degradation are driving limited resources of food, energy, water and materials towards critical thresholds worldwide. These pressures are likely to be substantial across Africa, where countries will have to find innovative ways to boost crop and livestock production to avoid becoming more reliant on imports and food aid. Sustainable agricultural intensification - producing more output from the same area of land while reducing the negative environmental impacts - represents a solution for millions of African farmers. This volume presents the lessons learned from 40 sustainable agricultural intensification programmes in 20 countries across Africa, commissioned as part of the UK Government's Foresight project. Through detailed case studies, the authors of each chapter examine how to develop productive and sustainable agricultural systems and how to scale up these systems to reach many more millions of people in the future. Themes covered include crop improvements, agroforestry and soil conservation, conservation agriculture, integrated pest management, horticulture, livestock and fodder crops, aquaculture, and novel policies and partnerships.
Download or read book Toward Sustainable Agricultural Systems in the 21st Century written by National Research Council and published by National Academies Press. This book was released on 2010-07-25 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last 20 years, there has been a remarkable emergence of innovations and technological advances that are generating promising changes and opportunities for sustainable agriculture, yet at the same time the agricultural sector worldwide faces numerous daunting challenges. Not only is the agricultural sector expected to produce adequate food, fiber, and feed, and contribute to biofuels to meet the needs of a rising global population, it is expected to do so under increasingly scarce natural resources and climate change. Growing awareness of the unintended impacts associated with some agricultural production practices has led to heightened societal expectations for improved environmental, community, labor, and animal welfare standards in agriculture. Toward Sustainable Agricultural Systems in the 21st Century assesses the scientific evidence for the strengths and weaknesses of different production, marketing, and policy approaches for improving and reducing the costs and unintended consequences of agricultural production. It discusses the principles underlying farming systems and practices that could improve the sustainability. It also explores how those lessons learned could be applied to agriculture in different regional and international settings, with an emphasis on sub-Saharan Africa. By focusing on a systems approach to improving the sustainability of U.S. agriculture, this book can have a profound impact on the development and implementation of sustainable farming systems. Toward Sustainable Agricultural Systems in the 21st Century serves as a valuable resource for policy makers, farmers, experts in food production and agribusiness, and federal regulatory agencies.
