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Dissolved Organic Matter Sources And Dynamics In An Agricultural Watershed
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Book Synopsis Dissolved Organic Matter Sources and Dynamics in an Agricultural Watershed by : Sandrine Journet Matiasek
Download or read book Dissolved Organic Matter Sources and Dynamics in an Agricultural Watershed written by Sandrine Journet Matiasek and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Agriculture is a dominant land use on Earth, but its impacts on dissolved organic matter (DOM) sources, processing, and fate remain relatively unclear. The goal of this research was to study DOM sources and dynamics in an irrigated agricultural watershed of Central Valley, California by 1) assessing the quantitative and qualitative impacts of organic matter (OM) desorption from sediments and soils, and by 2) generating an amino acids time series to link seasonal processes (natural and anthropogenic) to changes in stream DOM chemistry and reactivity. Abiotic desorption experiments revealed that mineral-bound organic carbon (OC) desorption is a predictable and finite process in agricultural surface waters, contributing 5 - 7% of the annual dissolved OC (DOC) export, with local maxima up to 50% of typical field runoff concentrations and 20% of winter storm DOC concentrations. The relevance of OM desorption was even more evident at the molecular level. Relative to mineral-bound OM, desorbed DOM was nitrogen-poor and depleted in amino acids and lignin. Distinct fractionation patterns of amino acids and lignin phenols led to a more acidic DOM pool that appeared substantially more degraded than particulate OM, with decreased mole fractions of basic amino acids, increased molar contributions of non-protein amino acids, decreased degradation index values, and increased proportions of acidic lignin phenols. If unaccounted for, the profound alteration of DOM composition incurred by desorption could lead to misinterpretations of indicators commonly used to assess the diagenetic state of OM. At the watershed scale, the role of land use and hydrologic controls on labile DOM dynamics was evidenced by elevated total hydrolyzable amino acid (THAA) concentrations throughout the low-discharge irrigation season and by seasonal compositional differences. DOM during winter baseflow was the most degraded, with the lowest THAA content and the lowest degradation index (DI), while winter storms and summer irrigation were two critical hydrologic regimes for DOM cycling with the largest amino acid contents, the largest proportions of basic amino acids, and the largest DI values, indicative of a relatively fresh DOM pool. The biogeochemical relevance of irrigation practices was therefore demonstrated by the mobilization of DOM similar in concentration and reactivity to DOM during winter storms.
Book Synopsis Hydrologic Dynamics Control Dissolved Organic Matter Export from Watersheds by : Rebecca Anne Bellmore
Download or read book Hydrologic Dynamics Control Dissolved Organic Matter Export from Watersheds written by Rebecca Anne Bellmore and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolved organic matter (DOM) is an important component of nutrient cycling and energy transfer within and between ecosystems. Understanding controls over the magnitude and quality of DOM that is transferred from soils to surface water is needed to better characterize the terrestrial-aquatic carbon flux and effects of terrestrial DOM on downstream ecosystems. A meta-analysis of the response of in-stream dissolved organic nitrogen concentration (DON) to high flow events indicates that DON typically increases with flow across a wide range of ecosystem types, likely as novel DOM sources in the landscape are mobilized and transported to streams and rivers. Mechanisms controlling DOM export, including dissolved organic carbon (DOC) and DON concentrations and the quality of DOM, were examined in a small agricultural catchment in eastern Washington State. In the soil column, DOC concentration declined and source of DOM shifted from humic-like and plant-derived to microbially-derived with depth through the profile. Across seasons and years, DOM exported via drain discharge during low flows resembled that found deep in the soil profile, and DOM exported during high flows suggests topsoil and litter sources contribute to export. A simple mixing model suggests that litter leachate can contribute over 50% of DOM during peak flow. Based on modeled contributions of litter, topsoil and subsoil DOM during storm events, DOC concentration is over-predicted, except for peak flows, suggesting removal via sorption and/or microbial decomposition in the soil column control DOC export on the timescale of events. Although the character of exported DOM shifts with flow conditions, laboratory incubations suggest bioavailability to the stream sediment microbial community is consistently low, with a maximum of 7% loss over 6 days, indicating exported DOM is likely transported beyond the immediate stream reach. An analysis of anticipated effects of climate change on the flow regime in the catchment projects the wettest years to become more variable, with non-linear effects on the magnitude of DOC export. Finally I explore how climate change assessments can be incorporated into nonpoint source nutrient management plans, despite current uncertainty about the magnitude and timeframe of climate effects on nutrient loading.
Book Synopsis Source Tracing of Dissolved Organic Matter (DOM) in Watersheds Using UV and Fluorescence Spectroscopy by : Jessica Wong
Download or read book Source Tracing of Dissolved Organic Matter (DOM) in Watersheds Using UV and Fluorescence Spectroscopy written by Jessica Wong and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In aquatic ecosystems, dissolved organic matter (DOM) is an important source of detrital energy on which microorganisms rely. However, its dynamics are not well understood in an ecological context. By isolating watershed sources, the work reported in this thesis has attempted to characterize the seasonal patterns of DOM in the hyporheic zone of a temperate stream and to find the likely sources that contribute to this pool of organic carbon. Hyporheic DOM characteristics described by UV spectroscopy indicated temporal rather than spatial dependence. Excitation-emission matrices (EEMs) showed that hyporheic DOM was mainly comprised of fulvic- and humic-like fluorescence with small amounts of protein-like fluorescence. Increases in dissolved organic carbon (DOC) concentrations from birch litter isolates were greater than those from cedar litter in early autumn, but less in late autumn. Although streambed biofilm was not significant in increasing DOC concentrations, it was also a source of protein-like fluorescence.
Book Synopsis Source Tracing of Dissolved Organic Matter (DOM) in Watersheds Using UV and Fluorescence Spectroscopy by : Jessica Chi Ying Wong
Download or read book Source Tracing of Dissolved Organic Matter (DOM) in Watersheds Using UV and Fluorescence Spectroscopy written by Jessica Chi Ying Wong and published by . This book was released on 2009 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: In aquatic ecosystems, dissolved organic matter (DOM) is an important source of detrital energy on which microorganisms rely. However, its dynamics are not well understood in an ecological context. By isolating specific watershed sources, the work reported in this thesis has attempted to characterize the seasonal patterns of DOM in the hyporheic zone of a temperate stream and to find the likely sources that contribute to this abundant pool of organic carbon. Hyporheic DOM characteristics described by UV spectroscopy indicated temporal rather than spatial dependence in relative allochthonous/autochthonous source in the fall. Excitation-emission matrices (EEMs) showed that hyporheic DOM was mainly comprised of fulvic- and humic-like fluorescence with small amounts of protein-like fluorescence. Cedar needles appeared to be an important and consistent source of this protein-like fluorescence in autumn. In contrast, DOM leached from birch litter was more dynamic in that its quality as an energy source decreased as the season progressed. Increases in dissolved organic carbon (DOC) concentrations from birch litter isolates were greater than those from cedar litter in early autumn, but less in late autumn. Although streambed biofilm was not significant in increasing DOC concentrations, it was also a source of protein-like fluorescence.
Book Synopsis Advances in the Physicochemical Characterization of Dissolved Organic Matter by : Fernando Rosario-Ortiz
Download or read book Advances in the Physicochemical Characterization of Dissolved Organic Matter written by Fernando Rosario-Ortiz and published by ACS Symposium. This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of dissolved organic matter (DOM) has fascinated scientists and engineers for at least 60 years - from the initial efforts focused on measuring the concentrations of carbon in marine and aquatic systems, to the discovery of the role of DOM in the formation of disinfection byproducts, all the way to the new emphasis on the detailed understanding of the different functional groups and basic structural features which are the basis for the physicochemical properties of the material. After 50 years of work in the area, there are still many questions regarding DOM. The study of dissolved organic matter (DOM) has fascinated researchers in different fields of science and engineering for many decades. The impact that DOM has on a wide array of environmental processes has resulted in the development of a multidisciplinary community of researchers all focusing on using different analytical techniques and experimental design to better understand DOM. This book offers select case studies focusing on the advanced characterization of DOM in different environments and with respect to different processes. It results from the conclusion of a symposium that E. M. Thurman and I had organized for the 245th meeting of the American Chemical Society, which was held on April 7-11, 2013 in New Orleans, Louisiana.
Book Synopsis Hydrological Regulation on Dissolved Organic Carbon Transport from Agricultural and Forest Soils to Streams by : Yi Mei
Download or read book Hydrological Regulation on Dissolved Organic Carbon Transport from Agricultural and Forest Soils to Streams written by Yi Mei and published by . This book was released on 2013 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Predicting Rainfall Erosion Losses by : Walter H. Wischmeier
Download or read book Predicting Rainfall Erosion Losses written by Walter H. Wischmeier and published by . This book was released on 1978 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Universal Soil Loss Equation (USLE) enables planners to predict the average rate of soil erosion for each feasible alternative combination of crop system and management practices in association with a specified soil type, rainfall pattern, and topography. When these predicted losses are compared with given soil loss tolerances, they provide specific guidelines for effecting erosion control within specified limits. The equation groups the numerous interrelated physical and management parameters that influence erosion rate under six major factors whose site-specific values can be expressed numerically. A half century of erosion research in many States has supplied information from which at least approximate values of the USLE factors can be obtained for specified farm fields or other small erosion prone areas throughout the United States. Tables and charts presented in this handbook make this information readily available for field use. Significant limitations in the available data are identified.
Book Synopsis Soil Erosion and Carbon Dynamics by : Eric J. Roose
Download or read book Soil Erosion and Carbon Dynamics written by Eric J. Roose and published by CRC Press. This book was released on 2005-12-09 with total page 443 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most complete, nonpartisan source of information on this hot agronomic topic available today, this book brings together a diverse group of papers and data to resolve the debate between sedimentologists and soil scientists and agronomists over whether the effects of soil erosion on carbon and atmospheric CO2 is beneficial or destructive. Divided
Book Synopsis Field Book for Describing and Sampling Soils by : Philip J. Schoeneberger
Download or read book Field Book for Describing and Sampling Soils written by Philip J. Schoeneberger and published by Government Printing Office. This book was released on 2012 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: NOTE: NO FURTHER DISCOUNT FOR THIS PRINT PRODUCT-- OVERSTOCK SALE -- Significantly reduced list price USDA-NRCS. Issued in spiral ringboundbinder. By Philip J. Schoeneberger, et al. Summarizes and updates the current National Cooperative SoilSurvey conventions for describing soils. Intended to be both currentand usable by the entire soil science community."
Book Synopsis Aquatic Organic Matter Fluorescence by : Paula G. Coble
Download or read book Aquatic Organic Matter Fluorescence written by Paula G. Coble and published by Cambridge University Press. This book was released on 2014-07-14 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: A core text on principles, laboratory/field methodologies, and data interpretation for fluorescence applications in aquatic science, for advanced students and researchers.
Book Synopsis Dissolved Organic Carbon Release from Mineral Soils and Sediments in an Irrigated Agricultural System by : Sandrine J. Matiasek
Download or read book Dissolved Organic Carbon Release from Mineral Soils and Sediments in an Irrigated Agricultural System written by Sandrine J. Matiasek and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water interactions with soil and vegetation are greatly altered in agricultural watersheds compared to natural landscapes, which impacts sources and fates of organic carbon (OC). While mineral soil horizons in natural ecosystems primarily act as filters for dissolved organic carbon (DOC) leached from organic surface horizons, tilled soils largely lack an organic horizon and their mineral horizons therefore act as a source for both DOC and sediment to surface waters. Irrigated watersheds highlight this difference, as DOC and total suspended sediment (TSS) concentrations simultaneously increase during the low-discharge irrigation season, suggesting that sediment-associated OC may constitute a significant source of DOC. While DOC solubilized from sediments and soils has been found to be compositionally similar to stream DOC, the contributions of mineral-bound OC solubilization to agricultural streams remain poorly quantified. To address this, we conducted abiotic solubilization experiments using sediments (suspended and bed) and soils from an irrigated agricultural watershed in northern California, USA. Sediments (R2 > 0.99) and soils (0.74
Book Synopsis Dissolved Organic Matter in Freshwater Ecosystems by : Penny J. Johnes
Download or read book Dissolved Organic Matter in Freshwater Ecosystems written by Penny J. Johnes and published by . This book was released on 2023-11-23 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Dissolved Organic Carbon Dynamics During the Snowmelt Period in a Small Urban Watershed by : Jaclyn L. O'Riley
Download or read book Dissolved Organic Carbon Dynamics During the Snowmelt Period in a Small Urban Watershed written by Jaclyn L. O'Riley and published by . This book was released on 2012 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Dissolved Organic Matter (DOM) Concentrations and Quality for Watershed Compartments in a Forested Mid-Atlantic Watershed, USA by : Nina Finger
Download or read book Dissolved Organic Matter (DOM) Concentrations and Quality for Watershed Compartments in a Forested Mid-Atlantic Watershed, USA written by Nina Finger and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: While the importance of dissolved organic matter (DOM) constituents is well recognized we know very little about how these constituents vary across watershed compartments, influence the transport of dissolved organic carbon (DOC) and nitrogen (DON), and determine the mobility and bioavailability of DOM. We explore the concentrations and quality of DOM for ten watershed sources in a 12 ha forested catchment over a two-year period. DOM was evaluated for throughfall, litter leachate, soil water, shallow and deep groundwater, groundwater discharged from seeps, stream water and water in the hyporheic zone. Soil water samples included both free flowing soil water (using zero tension lysimeters) as well as soil pore water (using tension lysimeters). DOM quality was characterized using a suite of indices derived from UV-visible absorbance and parallel factor analysis (PARAFAC) modeling of fluorescence excitation-emission matrices (EEMs). DOM quality displayed a pronounced trend in watershed compartments especially as a function of soil depth. The humic, aromatic, and high molecular weight constituents of DOM decreased with soil depth while there was a concomitant percent increase in the protein-like DOM moieties. Principal component analyses (PCA) revealed that the differences in surficial watershed compartments were dictated by humic components while differences in groundwater sources were dictated by % total proteins. The increase in % total proteins with increasing soil depth indicated that in groundwater a greater fraction of DOM may be bioavailable compared to DOM in litter leachate and soil water. We did not find any conclusive evidence for C or N enrichment in any particular DOM quality pools. In addition, DOM quality displayed pronounced spatial differences. DOM in wetland groundwater was more aromatic and humic than that at the riparian location. This study also suggested that some spectrofluorometric indices (e.g. the humification index, HIX) may be preferable over others (e.g. specific UV absorbance, SUVA) for characterizing DOM quality.
Book Synopsis Field Measurements for Forest Carbon Monitoring by : Coeli M Hoover
Download or read book Field Measurements for Forest Carbon Monitoring written by Coeli M Hoover and published by Springer Science & Business Media. This book was released on 2008-10-20 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the summer of 2003, a workshop was held in Portsmouth, NH, to discuss land measurement techniques for the North American Carbon Program. Over 40 sci- tists representing government agencies, academia and nonprofit research organi- tions located in Canada, the US and Mexico participated. During the course of the workshop a number of topics were discussed, with an emphasis on the following: • The need for an intermediate tier of carbon measurements. This level of study would be more extensive than state-level inventories of the US Forest Service Forest Inventory and Analysis Program, but less detailed than intensive ecos- tem studies sites such as those in Long Term Ecological Research network. This tier would ideally provide a basis to link and scale remote sensing measurements and inventory data, and supply data required to parameterize existing models (see Wofsy and Harriss 2002, Denning et al. 2005). • The design criteria that such a network of sites should meet. The network and s- pling design should be standardized, but flexible enough to be applied across North America. The design also needs to be efficient enough to be implemented without the need for large field crews, yet robust enough to provide useful information. Finally, the spatial scale must permit easy linkage to remotely sensed data. • The key variables that should be measured at each site, and the frequency of measurement.
Book Synopsis Aquatic Ecosystems: Interactivity of Dissolved Organic Matter by : Stuart Findlay
Download or read book Aquatic Ecosystems: Interactivity of Dissolved Organic Matter written by Stuart Findlay and published by Academic Press. This book was released on 2003 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: Overviews of the source, supply and variability of DOM, surveys of the processes that mediate inputs to microbial food webs, and syntheses consolidating research findings provide a comprehensive review of what is known of DOM in freshwater. This book will be important to anyone interested in understanding the fundamental factors associated with DOM that control aquatic ecosystems."--BOOK JACKET.
Book Synopsis Watershed Export of Dissolved Organic Matter in Response to Anthropogenic and Hydroclimatic Drivers in Subtropical Streams and Rivers by : Shuo Chen
Download or read book Watershed Export of Dissolved Organic Matter in Response to Anthropogenic and Hydroclimatic Drivers in Subtropical Streams and Rivers written by Shuo Chen and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolved organic matter (DOM) is an assemblage of heterogeneous organic compounds that play important roles in terrestrial and aquatic ecosystems. In this dissertation, I investigated changes in the amount, source, composition, lability, and ecological functions of stream water DOM in response to agricultural land use, hydrological events, and downstream transport and transformation in the southeastern United States. The dissertation includes three stand-alone studies presented in Chapters 2, 3 and 4, respectively. In Chapter 2, I evaluated the effects of hurricane-induced storm events on the quantity and quality of DOM exported from ten watersheds of various physical and land-use characteristics within five Gulf and South Atlantic states. We found that large storms can significantly enhance the concentrations and yields of terrestrially-derived dissolved organic carbon (DOC) and nutrients in streams and rivers but decrease the percentage bioreactive DOC. This study demonstrates that extreme weather and climate events can lead to rapid, ecosystem-level disturbances that significantly shift energy and nutrient availability within drainage networks. The objective of Chapter 3 was to quantify the relative importance of agricultural land use and natural hydroclimatic drivers in affecting the quality and quantity of DOM in a group of 15 streams draining watersheds of a gradient of agricultural land use. The partial least square path modeling (PLS-PM) identified that agricultural land use increased stream water DOM quantity primarily through increasing allochthonous carbon sources. This study demonstrates that structural equation modeling is a powerful tool that should be more widely adopted to distinguish among multiple drivers and mechanisms regulating freshwater biogeochemistry. Chapter 4 investigated the longitudinal transformations of DOM in relation to ecosystem metabolism along a fluvial section including 3rd order, 7th and 8th order streams. From upstream to downstream, DOC concentrations and the relative contributions of freshly-produced DOM increased. The gross primary productivity was positively correlated with the contributions of autochthonous DOM, yet the ecosystem respiration did not vary with the quantity or quality of DOM. This study highlights the complexity of DOM transformations in relation to stream metabolism along the river continuum. Collectively, the three independent but connected studies reveal the complexity and sensitivity of inland water DOM in response to hydroclimatic and anthropogenic drivers. The findings provide new insights into potential shifts in energy and substrates exported across the terrestrial-aquatic boundary due to human activities and climate change and how these shifts can alter water quality and fluvial biogeochemical functions.
