Download or read book Fractionation of Organic Matter from Arctic Soils in Alaska written by Wendy Marie Loya and published by . This book was released on 1996 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Size fractionation and Characterization of Cryoturbated Soil Organic Matter in Arctic Tundra Alaska written by Chunhao Xu and published by . This book was released on 2005 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Recent studies indicated a second layer of organic matter often accumulates in the lower active layer and upper permafrost in arctic tundra soils due to cryoturbation. The objective of this study is to characterize cryoturbated organic matter by the combination of physical size-fractionation approaches with modern analytical techniques. The results of elemental composition (C, N), stable isotope (13C, 15N), radiocarbon age (14C), and molecular fingerprints (Py-GC/MS) analysis indicated cryoturbated organic matters are little humified and highly bioavailable. SOM (soil organic matter) associated with fine sand size particles was considered to be the organic carbon pool most sensitive to the changing climate. Clay minerals stabilize less humifed organic matter than those in temperate and tropical soils. The bioavailable soluble organics extracted from cryoturbated organic matter were found to have significant long-term accumulated effects on carbon cycling. The similar molecular compositions between cryoturbated and surface organic matter suggest vegetation covers haven't changed since the early Holocene. Furthermore, the quality of SOM in moist acidic tundra is higher than that of wet nonacidic tundra. With the deepening active layer followed by thawing permafrost, cryoturbated organic matter could reenter the biogeochemical cycles in the Arctic, resulting in a positive feedback to climate change"--Leaf iii.

Download or read book Pathways of Anaerobic Organic Matter Decomposition in Tundra Soils from Barrow Alaska written by and published by . This book was released on 2015 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Arctic tundra soils store a large quantity of organic carbon that is susceptible to decomposition and release to the atmosphere as methane (CH4) and carbon dioxide (CO2) under a warming climate. Anaerobic processes that generate CH4 and CO2 remain unclear because previous studies have focused on aerobic decomposition pathways. To predict releases of CO2 and CH4 from tundra soils, it is necessary to identify pathways of soil organic matter decomposition under the anoxic conditions that are prevalent in Arctic ecosystems. Here molecular and spectroscopic techniques were used to monitor biological degradation of water-extractable organic carbon (WEOC) during anoxic incubation of tundra soils from a region of continuous permafrost in northern Alaska. Organic and mineral soils from the tundra active layer were incubated at -2, +4, or +8°C for up to 60 days to mimic the short-term thaw season. Results suggest that, under anoxic conditions, fermentation converted complex organic molecules into simple organic acids that were used in concomitant Fe-reduction and acetoclastic methanogenesis reactions. Nonaromatic compounds increased over time as WEOC increased. Organic acid metabolites initially accumulated in soils but were mostly depleted by day 60 because organic acids were consumed to produce Fe(II), CO2, and CH4. We conclude that fermentation of nonprotected organic matter facilitates methanogenesis and Fe reduction reactions, and that the proportion of organic acids consumed by methanogenesis increases relative to Fe reduction with increasing temperature. As a result, the decomposition pathways observed in this study are important to consider in numerical modeling of greenhouse gas production in the Arctic.

Download or read book Assessment Methods for Soil Carbon written by John M. Kimble and published by CRC Press. This book was released on 2000-12-28 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since carbon sequestration in soils reduces the amount of carbon available to the atmosphere, the Kyoto Protocols have heightened interest in soil carbon pools and their effect on carbon fluxes. Assessment Methods for Soil Carbon addresses many of the questions related to the measurement, monitoring, and verification of organic and inorganic carbon in soils. The major topics covered are: carbon pools; soil sampling and preparation, analytical techniques for soil carbon; soil erosion and sedimentation; remote sensing, GIS and modeling; procedures for scaling carbon data from point and local measurements to regional and even national scales; and economic and policy issues. In Assessment Methods for Soil Carbon, leading researchers show that we now have the ability to measure, monitor, and verify changes to soil carbon. The book establishes the need for standardized methods that can be used by anyone, and helps us better understand the link between the pedosphere (soils) and the atmosphere. It also shows the importance of developing links between the economics of carbon sequestration and the amounts sequestered, and highlights the need for scientists and policy makers to interact to ensure that policies fit within the scope of present technologies.

Download or read book Fractionation and Characterization of Natural Organic Matter from Certain Rivers and Soils by Free flow Electrophoresis written by J. A. Leenheer and published by . This book was released on 1973 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissolved Organic Matter in Wetland Soils and Streams of Southeast Alaska written by Jason B. Fellman and published by . This book was released on 2008 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Dissolved organic matter (DOM) transported from terrestrial to aquatic ecosystems is an important source of C, N and energy for the metabolism of aquatic heterotrophic bacteria. I examined the concentration and chemical quality of DOM exported from coastal temperate watersheds in southeast Alaska to determine if wetland soils are an important source of biodegradable dissolved organic carbon (BDOC) to aquatic ecosystems. I addressed this question through a combination of high resolution temporal and spatial field measurements in three watersheds near Juneau, Alaska by using a replicated experimental design that characterized DOM export from three different soil types (bog, forested wetland and upland forest) within each of the watersheds. PARAFAC modeling of fluorescence excitation-emission spectroscopy and BDOC incubations were used to evaluate the chemical quality and lability of DOM. Overall, my findings show that wetland soils contribute substantial biodegradable DOM to streams and the response in BDOC delivery to streams changes seasonally, with soil type, and during episodic events such as stormflows. In particular, the chemical quality of DOM in streamwater and soil solution was similar during the spring runoff and fall wet season, as demonstrated by the similar contribution of protein-like fluorescence in soil solution and in streams. These findings indicate a tight coupling between wetland DOM source pools and streams is responsible for the export of BDOC from terrestrial ecosystems. Thus, seasonal changes in soil-stream linkages can have a major influence on watershed biogeochemistry with important implications for stream metabolism and the delivery of labile DOM to coastal ecosystems. Soil DOM additions in small streams draining the three soil types showed that DOM leached from watershed soils is readily used as a substrate by stream heterotrophs and at the same time modified in composition by the selective degradation of the proteinaceous fraction of DOM. These findings indicate terrestrial DOM inputs to streams are an important source of C to support stream heterotrophic production. Thus, the production of protein-rich, labile DOM and subsequent loss in stream runoff has the potential to be an important loss of C and N from coastal temperate watersheds"--Leaf iii.

Download or read book Global Climate Change and Cold Regions Ecosystems written by John M. Kimble and published by CRC Press. This book was released on 2000-06-28 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Global Climate Change and Cold Regions Ecosystems provides information on soil processes and the carbon cycle in cold ecoregions as well as the soil carbon pool and its fluxes in the soils of cold ecoregions. Filling a void in this area of soil science, this resource explains soil processes influencing C dynamics under natural and disturbed ecosystems. The soils of the cold region ecosystems serve as a net sink of atmospheric C. However, an increase in global temperature could render them a net source. In the event of global warming, the cold regions ecosystems-arctic, sub-arctic, alpine, Antarctic, boreal forests, and peatlands-will undergo radical changes. Potential environmental change could drastically increase the active soil layer and influence the large C pool found in them. Topics include: soil C pools in different cold ecoregions, the impact of natural and anthropogenic disturbances on the soil C pool, the method of assessment of C and other properties of soils of the cold regions ecosytems while focusing on the fate of C in permafrost soils. Global Climate Change and Cold Regions Ecosystems covers the current and possible future effects of the cold ecoregions soil C pool on the global carbon pool.

Download or read book Bioavailability and Chemical Characterization of Soil Organic Matter in Arctic Soils written by Xiaoyan Dai and published by . This book was released on 2001 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The purpose of this research was to evaluate bioavailability and chemical characteristics of soil organic matter (SOM) in Arctic tundra soils. Five soil horizons in three different sites located in the Arctic Slope of Alaska were used for this research. This thesis comprises five chapters, each of which described a method that can be used to study the bioavailability and chemcial characteristics of SOM in these samples. Chapter One used laboratory incubation technique to determine CO2 evolution from the soils. The cumulative CO2 respired from the samples during the incubation period was used as index of bioavailability of SOM. Chapter Two utilized cross polarization magic angle spinning (CPMAS) 13C NMR and liquid-state 13C NMR techniques to evaluate the chemical composition of SOM. Chapter Three described how pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was used to characterize SOM. Chapter Four summarized different approaches for characterizing SOM, and Chapter Five usedd amino sugar contents in soils to assess the microbial contribution to SOM. The laboratory incubation study indicated that temperature had a positive effect on the CO2 evolution from these samples, and the tundra soils would have higher potential to contribute to greenhouse gas emissions with elevated temperature. Among the extractable soil organic fractions, neutrals such as hyrophilic neutrals (HIN), hydrophobic neutrals (HON) and low-molecular-weight neutrals (LMN) are more bioavailable than these such as humic acid (HA) and fulvic acid. (FA). Liquid-state and solid state 13C NMR and Py-GC/MS techniques exhibited more potential for evaluating the relative quality of SOM compared to the wet chemical analysis method. Together with the laboratory incubation method, these techniques can be used to identity the chemical composition of SOM, and to establish correlations between the chemical composition and bioavailability of SOM. Amino sugars in soil can provide insights into the microbial contribution to SOM and to the quality and bioavailability of SOM due to their microbial origin. Bacterial-derived muramic acid and fungal-derived glucosamine can be used to differentiate between bacterial and fungal contributions to SOM. Coupled with chemical composition changes resulted from incubation at different temperatures, these results can be used to interpret the dynamics of microbial population"--Leaves iii-iv.

Download or read book Mass Spectrometry of Soils written by Thomas Boutton and published by CRC Press. This book was released on 1996-05-30 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work provides detailed coverage of the applications of proven spectometric techniques in soil science. It presents analytical approaches important in the study of pool sizes and the dynamics of macro- and micronutrients, the structure and function of soil organic matter, and the co-evolution of soils, plant communities and climate. Interdisciplinary perspectives from soil science, ecology, geology, chemistry, biogeochemistry, agronomy and physics, are offered.

Download or read book Soil Processes and the Carbon Cycle written by Rattan Lal and published by CRC Press. This book was released on 2018-02-06 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: World soils contain about 1500 gigatons of organic carbon. This large carbon reserve can increase atmospheric concentrations of CO2 by soil misuse or mismanagement, or it can reverse the 'greenhouse' effect by judicious land use and proper soil management. Soil Processes and the Carbon Cycle describes soil processes and their effects on the global carbon cycle while relating soil properties to soil quality and potential and actual carbon reserves in the soil. In addition, this book deals with modeling the carbon cycle in soil, and with methods of soil carbon determinations.

Download or read book Soil Organic Matter and its Role in Crop Production written by and published by Elsevier. This book was released on 1973-01-01 with total page 647 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil Organic Matter and its Role in Crop Production

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 Standard Soil Methods for Long Term Ecological Research written by G. Philip Robertson and published by Oxford University Press. This book was released on 1999-10-28 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Standardized methods and measurements are crucial for ecological research, particularly in long-term ecological studies where the projects are by nature collaborative and where it can be difficult to distinguish signs of environmental change from the effects of differing methodologies. This second volume in the Long-Term Ecological Research (LTER) Network Series addresses these issues directly by providing a comprehensive standardized set of protocols for measuring soil properties. The goal of the volume is to facilitate cross-site synthesis and evaluation of ecosystem processes. Chapters cover methods for studying physical and chemical properties of soils, soil biological properties, and soil organisms, and they include work from many leaders in the field. The book is the first broadly based compendium of standardized soil measurement methods and will be an invaluable resource for ecologists, agronomists, and soil scientists.

Download or read book Fractionation and characterization of organic matter in wastewater from a swine waste retention basin written by and published by DIANE Publishing. This book was released on with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Agronomy Abstracts written by and published by . This book was released on 1993 with total page 976 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes abstracts of the annual meetings of the American Society of Agronomy; Soil Science Society of America; Crop Science Society of America ( - of its Agronomic Education Division).

Download or read book Fractionation of Soil Organic Matter written by Everett Douglas Cann and published by . This book was released on 1946 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Up to the present, investigations of the organic matter characteristic of soils have not yielded much specific information respecting the major components. Individual organic compounds of a considerable variety have been isolated in small amounts. From the study of decomposing plant residues, of synthetic mixtures of isolated lignin fractions and proteins and of soil organic matter itself , it has been inferred that the major part of the latter consists of a complex of protein-like and lignin-like materials, and that a carbohydrate-like compound occurs next in amount. [...]" --