Download or read book Fluxes of Dissolved Organic Matter from Urban Catchments in the Neuse River Basin written by Sarah Ellen Johnston and published by . This book was released on 2015 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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:
Download or read book Hydrologic and Land Cover Effects on Sources and Fate of In Stream Fluorescent Dissolved Organic Matter written by Baek Soo P. Lee and published by . This book was released on 2015 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolved organic matter (DOM) is a critical component of the carbon cycle linking terrestrial and aquatic ecosystems. Although many factors influence DOM fluxes and quality in rivers, controls on DOM compositions in catchments of the western U.S. are poorly understood. UV and fluorescent spectroscopy is a simpler, faster, and less expensive DOM fingerprinting technique compared to techniques, such as nuclear magnetic resonance (NMR) spectroscopy or wet chemical fractionation, and could be useful for characterizing complex DOM chemistry. However, only 1 % of DOM is estimated to be fluorescent, and the utility of UV and fluorescent spectroscopy for DOM characterization needs to be further investigated. This dissertation applied UV and fluorescent spectroscopy to examine hydrologic and land cover controls on DOM chemistry in streams of 45 catchments in the forested headwaters and a mixed landscape of the Willamette River Basin, Oregon, based on two years of monitoring. This dissertation contributes three major findings. First, freezing of water alters DOM chemistry by preferentially precipitating aromatic DOM. Second, UV and fluorescent spectroscopy was able to discriminate DOM delivered from highly processed, proteinrich deep subsurface sources during dry seasons especially in forested headwater streams of the H. J. Andrews Experimental Forest (HJA), where nitrogen inputs are very low. In addition, fluorescent DOM chemistry differed among watersheds with varying forest management history. Third, although fluorescent DOM in a headwater forested system differed among land use history, fluorescent DOM composition did not vary among streams draining a well-mixed landscape of urban, pasture/hay, forest, and agricultural land cover types in the central Willamette River Basin, where nitrogen inputs to streams are relatively high. Dissolved organic carbon (DOC) concentration decreased and the fluorescent index indicated an increase in terrestrial sources of DOM from small (1st and 2nd order) to large (4th to 6th order) streams. A protein-like DOM component that was detected in the headwater forested study site (HJA) was not detected in stream samples from the middle basin study site. These findings indicate that in-stream respiration, fueled by nutrient additions from agriculture runoff, consumes bioavailable, labile DOM (proteins) preferentially relative to more recalcitrant, terrestrial sources of DOM along water flow paths from headwater streams to major rivers. This study shows the clear applicability of the fluorescent characterization of DOM in identifying hydrologic and landscape controls as well as varying DOM chemistry and functions throughout watershed ecosystems.
Download or read book Dissolved Organic Matter in Arctic Watersheds and Coastal Waters written by Craig Thomas Connolly and published by . This book was released on 2019 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Arctic warming is already affecting the movement of freshwater and dissolved organic matter (DOM) from watersheds to the coastal ocean in the Arctic. Improved understanding of DOM in freshwater sources and linkages to DOM characteristics in Arctic coastal waters is needed to assess responses to and feedbacks with climate change. This work focuses on DOM characteristics that couple watershed and coastal systems in the Arctic, with specific considerations of river and groundwater inputs to lagoon ecosystems along the eastern Alaska Beaufort Sea coast. We found that spring and summer river-borne concentrations of dissolved organic carbon and nitrogen (DOC and DON) are strongly linked to variations in watershed slope and soil organic matter coverage across space and scale in the Arctic. The quantities and composition of DOM in lagoons of the eastern Alaska Beaufort Sea coast vary markedly between seasons. Specifically, lagoons experience a shift from high to low DOC and DON concentrations between the late spring sea ice break-up and winter ice-covered periods, but these concentrations are more variable during the summer open water period. Distinct seasonal transitions in ice coverage, runoff from land, and water exchange with the Beaufort Sea strongly influence the availability of lagoon DOM. During the summer, concentrations of DOC and DON in supra-permafrost groundwater (SPGW) inputs to lagoons are much higher than those found in local rivers and lagoons. Late-summer fluxes of SPGW DOM to the northern Alaska coastline are substantial and may be the principal source of DOM to lagoons without river inputs. This SPGW DOM is sourced from readily leachable organic matter in surface soils and deeper soil horizons that likely extend into thawing permafrost. SPGW DOM contains aromatic carbon compounds that are largely resistant to microbial degradation on the order of days to months. While nearby river and lagoon water DOM has a similar composition and degradability, SPGW contains a portion of bioavailable and reactive DOM that is not present in river and lagoon waters. Inputs of SPGW DOM provide a potentially important source of energy for lagoon food webs along the Alaskan Beaufort Sea coast during the late summer
Download or read book Study of the Aquatic Dissolved Organic Matter from the Seine River Catchment France by Optical Spectroscopy Combined to Asymmetrical Flow Field flow Fractionation written by Phuong Thanh Nguyen (chimiste).) and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main goal of this thesis was to investigate the characteristics of dissolvedorganic matter (DOM) within the Seine River catchment in the Northern part of France. ThisPhD thesis was performed within the framework of the PIREN-Seine research program. Theapplication of UV/visible absorbance and EEM fluorescence spectroscopy combined toPARAFAC and PCA analyses allowed us to identify different sources of DOM andhighlighted spatial and temporal variations of DOM properties. The Seine River wascharacterized by the strongest biological activity. DOM from the Oise basin seemed to havemore "humic" characteristics, while the Marne basin was characterized by a third specifictype of DOM. For samples collected during low-water periods, the distributions of the 7components determined by PARAFAC treatment varied between the studied sub-basins,highlighting different organic materials in each zone. A homogeneous distribution of thecomponents was obtained for the samples collected in period of flood.Then, a semi-quantitative asymmetrical flow field-flow fractionation (AF4) methodology wasdeveloped to fractionate DOM. The following optimized parameters were determined: across-flow rate of 2 ml min-1 during the focus step with a focusing time of 2 min and anexponential gradient of cross-flow from 3.5 to 0.2 ml min-1 during the elution step. Thefluorescence properties of various size-based fractions of DOM were evaluated by applyingthe optimized AF4 methodology to fractionate 13 samples, selected from the three sub-basins.The fluorescence properties of these fractions were analysed, allowing us to discriminatebetween the terrestrial or autochthonous origin of DOM.
Download or read book Changes in Fluxes of Dissolved Organic Carbon DOC from Small Catchments in Central Scotland written by Catherine Louise Wearing and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Concentrations of dissolved organic carbon (DOC) measured within water bodies have been increasing on a global scale over the last two decades. Changes in temperature and rainfall have been shown to increase the production and export of DOC from catchments with peat soils in the UK (Freeman et al., 2001). However it is not clear whether increases in DOC concentrations are caused by production increases induced by temperature changes or by a greater incidence of high flows induced by rainfall changes. Increases in both temperature and rainfall have been predicted in Scotland over the next few decades (Kerr et al., 1999) which may further increase current DOC concentrations and exports. The implications of this include both a decrease in water quality and an increase in mobility of metals in upland water bodies. The overall aim of the thesis is to determine if the relationship between dissolved organic carbon (DOC) concentrations and discharge has changed over a 20 year period in small stream catchments in Scotland, in order to better understand the role of hydrology, in driving changes in DOC concentration. To achieve this streams draining two coniferous forest sites and one moorland site were monitored intensively between June 2004 and February 2006. Analysis of the relationship between DOC and discharge, within the catchments, identified the importance of the amount of precipitation falling on the catchment, antecedent precipitation and season, on the concentration of DOC that was measured within the stream. Models were then developed using variables to represent these drivers in terms of both the production (seasonal sine values and 14 day average temperatures) and movement (log of discharge (log Q), days since previous storm event and rising or falling stage) of DOC. In the Ochil Hills catchment, the best predictive model, used 4 hour average discharge and 1 day average 30cm soil temperatures (R2= 0.88). In the Duchray and Elrig catchments, the best predictive models produced used discharge and seasonal sine values; the strength of the model was greater in the Elrig (R2= 0.80) than the Duchray (R2= 0.48) catchment. The strength of the regression models produced highlighted the importance of precipitation in the movement of DOC to the stream and temperature variables representing production in the surrounding catchment. To determine if dissolved organic carbon (DOC) concentrations had changed within the three study catchments, since previous research was conducted at the same sites in the early 1980s and 1990s (Grieve, 1984a; Grieve, 1994), then regression analysis conducted in the previous research was repeated, so changes in the DOC and discharge relationship could be identified. Analysis of the Ochil Hills regression equations identified higher log of discharge and lower temperature and seasonal sine values in the present study (2004-06), when compared to the previous study (1982-83). This suggests that more DOC is now available for movement from the soil, and that the difference between winter and summer DOC production has decreased, potentially because of increasing temperatures. This would explain the limited increase in DOC concentration within the Ochil Hills stream. In the Duchray and Elrig streams, a large increase in DOC was identified at all discharges when all the models produced were compared between the two sampling periods (1989-90 and 2004-06). The increasing trend in DOC concentrations is too large to have been produced by change in temperature alone and it is suggested that the measured reduction in acidic deposition has resulted in the increased DOC concentrations measured in the Duchray and Elrig. The results from this research have identified that concentrations of DOC have increased in Scottish streams over the last 20 years and that the increases in DOC have been induced, potentially by temperature changes in climate. However, changes in temperature are not the only driver of this change as the reduction in acidic deposition is potentially more important, specifically in areas with base poor geology such as the Duchray and Elrig catchments.
Download or read book Sources and Fates of Dissolved Organic Carbon in Rural and Urban Watersheds in Brazos County Texas written by Danielle Cioce and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Bryan/College Station (B/CS) region has been reported to have elevated concentrations of dissolved organic carbon (DOC) in surface water. Increased DOC concentrations are worrisome as DOC has been shown to be an energy source for the recovery and regrowth of E. coli and many watersheds are impaired by high bacteria levels. To examine the sources and fates of DOC in rural and urban regions to better understand DOC movement though the environment, seven watersheds were studied. To investigate source, streams were analyzed using diffuse reflectance near infrared spectroscopy (DR-NIR) and carbon isotopes. Fate of DOC was determined through monthly streams samples, gathered between March 2011 and February 2012, which were incubated for biodegradable DOC (BDOC). Soil in the region was sampled based on land use categories. Soil was analyzed for DOC and BDOC as well as DOC adsorption, the other major fate of DOC. Above ground vegetation was sampled in conjunction with soil and analyzed for BDOC. Data indicated that fecal matter from cliff swallows provided considerable organic material to streams in the B/CS region as shown through DR-NIR. Carbon isotope values in streams ranged from -23.5 +/- 0.7% to -26.8 +/- 0.5%. Stream spectra may be able to predict carbon isotope values in streams (Adj. R2 = 0.88). Mean annual stream DOC concentrations ranged from 11 +/- 3 mg/L to 31 +/- 12 mg/L, which represents a significant decrease in DOC between 2007 and 2011. Concurrent increases in pH and conductivity were also recorded. The decrease in DOC and the increases in pH and conductivity may be due to impacts of high sodium irrigation tap water. Biodegradable DOC was low in streams, which is likely due to DOC being present in streams in refractory forms that are resistant to microbial breakdown. Soil chemistry, including soil adsorption, was greatly influenced by sodium. The elevated adsorption coefficients and release values seen in highly developed and urban open areas can be attributed to frequent exposure to high sodium irrigation water. The results indicate that sodium is a major driver of DOC in the system. Sound management decisions concerning irrigation water chemistry and urban development might eventually emerge to protect water quality as a result of this research.
Download or read book Dissolved Organic Matter in the Anthropogenically Impacted Grand River and Natural Burnt River Watersheds written by Ryan H. S. Hutchins and published by . This book was released on 2011 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolved organic carbon (DOM) is one of the largest cycled organic carbon pools on Earth and an important biogeochemical factor in aquatic systems. DOM can act as an energy source for microorganisms, alter the depth of the photic zone for photosynthesis, absorb harmful ultraviolet radiation, as well as alter the transport and toxicity of contaminants. The purpose of this research project was to characterize DOM in the Grand River watershed in Ontario, Canada using a wide range of qualitative and quantitative techniques and determine the impact of anthropogenic activities as well as seasonal and longitudinal changes on DOM processes. To reach the study objectives, historical data was analyzed to determine the seasonal cycle in the Grand River watershed. Intensive longitudinal sampling surveys were undertaken to evaluate the DOM characteristics and processes in the Grand River. Surveys of the less impacted Burnt River watershed were used as a comparison watershed to the Grand River to evaluate allochthonous and autochthonous indicators of DOM source and human impacts on DOM processes. Drinking water surveillance data was used to evaluate the effect of DOM in the Grand River on formation of disinfection by-products (DBPs). Different trends were seen in the Grand River in terms of longitudinal area and season. The headwaters of the river showed more autochthonous DOM in the spring and winter compared to the fall and summer. The lower-central river peaked in autochthonous DOM in the summer and was more allochthonous in the winter. DOM generally became more autochthonous downstream in the Grand River and was most autochthonous below the large sewage treatment plants (STPs) in the central portion. Protein content, measured as protein-like fluorescence normalized to DOC concentration, was strongly related to [delta]15N of DON; both are associated with autochthonous DOM in the Grand River and show the effects of the major STPs. The increase in autochthonous DOM below the STPs is likely associated with nutrient enrichment stimulating primary production and macrophyte growth. Based on the comparison of the Burnt River with the more impacted Grand River, the effect of lakes and photodegradation can make discrimination of autochthonous and allochthonous DOM more difficult. The ratio of DOC/DON and protein-like fluorescence proved to be robust indicators despite photodegradation. Human impacts on the Grand River watershed result in a greater seasonal cycle, high primary production in the summer and a downstream trend of increasing autochthonous DOM compared to the Burnt River. Based on drinking water surveillance data and literature review, autochthonous DOM caused greater DBPs in the drinking waters fed by the Grand River. This is currently a threat to human health and DBPs in sewage treatment plant effluent may be a threat to ecosystem health.
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 Watershed Management for Potable Water Supply written by National Research Council and published by National Academies Press. This book was released on 2000-02-17 with total page 569 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1997, New York City adopted a mammoth watershed agreement to protect its drinking water and avoid filtration of its large upstate surface water supply. Shortly thereafter, the NRC began an analysis of the agreement's scientific validity. The resulting book finds New York City's watershed agreement to be a good template for proactive watershed management that, if properly implemented, will maintain high water quality. However, it cautions that the agreement is not a guarantee of permanent filtration avoidance because of changing regulations, uncertainties regarding pollution sources, advances in treatment technologies, and natural variations in watershed conditions. The book recommends that New York City place its highest priority on pathogenic microorganisms in the watershed and direct its resources toward improving methods for detecting pathogens, understanding pathogen transport and fate, and demonstrating that best management practices will remove pathogens. Other recommendations, which are broadly applicable to surface water supplies across the country, target buffer zones, stormwater management, water quality monitoring, and effluent trading.
Download or read book Drinking Water from Forests and Grasslands written by and published by . This book was released on 2000 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 2005 Joint Assembly written by American Geophysical Union. Joint Assembly and published by . This book was released on 2005 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
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.
Download or read book The Riverine Ecosystem Synthesis written by James H. Thorp and published by Elsevier. This book was released on 2010-07-27 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the most comprehensive model yet for describing the structure and functioning of running freshwater ecosystems. Riverine Ecosystems Synthesis (RES) is a result of combining several theories published in recent decades, dealing with aquatic and terrestrial systems. New analyses are fused with a variety of new perspectives on how river network ecosystems are structured and function, and how they change along longitudinal, lateral, and temporal dimensions. Among these novel perspectives is a dramatically new view of the role of hydrogeomorphic forces in forming functional process zones from headwaters to the mouths of great rivers. Designed as a useful tool for aquatic scientists worldwide whether they work on small streams or great rivers and in forested or semi-arid regions, this book will provide a means for scientists to understand the fundamental and applied aspects of rivers in general and includes a practical guide and protocols for analyzing individual rivers. Specific examples of rivers in at least four continents (Africa, Australia, Europe and North America) serve to illustrate the power and utility of the RES concept. Develops the classic, seminal article in River Research and Applications, "A Model of Biocomplexity in River Networks Across Space and Time" which introduced the RES concept for the first time A guide to the practical analysis of individual rivers, extending its use from pristine ecosystems to modern, human-modified rivers An essential aid both to the study fundamental and applied aspects of rivers, such as rehabilitation, management, monitoring, assessment, and flow manipulation of networks
Download or read book Hydrology for Urban Land Planning written by Luna Bergere Leopold and published by . This book was released on 1968 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biogeochemistry of Marine Dissolved Organic Matter written by Dennis A. Hansell and published by Academic Press. This book was released on 2014-10-02 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine dissolved organic matter (DOM) is a complex mixture of molecules found throughout the world's oceans. It plays a key role in the export, distribution, and sequestration of carbon in the oceanic water column, posited to be a source of atmospheric climate regulation. Biogeochemistry of Marine Dissolved Organic Matter, Second Edition, focuses on the chemical constituents of DOM and its biogeochemical, biological, and ecological significance in the global ocean, and provides a single, unique source for the references, information, and informed judgments of the community of marine biogeochemists. Presented by some of the world's leading scientists, this revised edition reports on the major advances in this area and includes new chapters covering the role of DOM in ancient ocean carbon cycles, the long term stability of marine DOM, the biophysical dynamics of DOM, fluvial DOM qualities and fate, and the Mediterranean Sea. Biogeochemistry of Marine Dissolved Organic Matter, Second Edition, is an extremely useful resource that helps people interested in the largest pool of active carbon on the planet (DOC) get a firm grounding on the general paradigms and many of the relevant references on this topic. Features up-to-date knowledge of DOM, including five new chapters The only published work to synthesize recent research on dissolved organic carbon in the Mediterranean Sea Includes chapters that address inputs from freshwater terrestrial DOM
