Download or read book Characterisation of dissolved organic matter in the Vesdre river Belgium using flourescence spectroscopy written by L. Moatlhodi 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 Characterization and Source Identification of Dissolved Organic Matter DOM in the Tha Chin River Basin by Fluorescence Spectroscopy written by Supakit Jewcharoen and published by . This book was released on 2014 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization and Identification of Dissolved Organic Matter Sources in a Drinking Water Reservoir Using Fluorescence Spectroscopy Methods written by 王家緯 and published by . This book was released on 2018 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Linking Optical and Chemical Properties of Dissolved Organic Matter in Natural Waters written by Christopher L. Osburn and published by Frontiers Media SA. This book was released on 2017-01-17 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: A substantial increase in the number of studies using the optical properties (absorbance and fluorescence) of dissolved organic matter (DOM) as a proxy for its chemical properties in estuaries and the coastal and open ocean has occurred during the last decade. We are making progress on finding the actual chemical compounds or phenomena responsible for DOM’s optical properties. Ultrahigh resolution mass spectrometry, in particular, has made important progress in making the key connections between optics and chemistry. But serious questions remain and the last major special issue on DOM optics and chemistry occurred nearly 10 years ago. Controversies remain from the non-specific optical properties of DOM that are not linked to discrete sources, and sometimes provide conflicting information. The use of optics, which is relatively easier to employ in synoptic and high resolution sampling to determine chemistry, is a critical connection to make and can lead to major advances in our understanding of organic matter cycling in all aquatic ecosystems. The contentions and controversies raised by our poor understanding of the linkages between optics and chemistry of DOM are bottlenecks that need to be addressed and overcome.

Download or read book Characterization of dissolved organic matter DOM in the Vesdre river catchment Belgium during autumn leaf fall written by A.K. Weldemariam and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement of Dissolved Organic Matter in the Cape Fear River Estuary by 3 D Fluorescence Spectroscopy written by Tomi Lee Hill and published by . This book was released on 2002 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fluorescence and Size Characterization of Dissolved Organic Matter in Riverine and Sea Waters in the Northern Gulf of Mexico written by Zhengzhen Zhou and published by . This book was released on 2012 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Chromophoric Dissolved Organic Matter CDOM in the Lower Cape Fear River Using Absorbance Spectroscopy and EEM PARAFAC Analysis written by Adam Chase Chase and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Spectroscopic Characterization of Dissolved Organic Matter written by John Robert Helms and published by . This book was released on 2012 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Molecular and Optical Characterization of Dissolved Organic Matter in the Central Arctic Ocean written by Xianyu Kong and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolved organic matter (DOM) in the ocean is a complex mixture of molecules derived from autochthonous (marine) or allochthonous (terrestrial) origins. DOM plays an important role in marine biogeochemical cycles by attenuating light available for primary production, serving as an energy and nutrient source for heterotrophic communities, regulating the ultraviolet and visible light absorption, undergoing photochemical processing, and acting as a trace metal ligand. DOM in the Central Arctic Ocean (CAO) is influenced by increased freshwater input and associated terrestrial materials in recent decades due to rapid climate change. The quantification of DOM sources (terrestrial versus marine) in the water column of the CAO is not well constrained. Few studies have systematically investigated the seasonality and spatial variability of DOM by combining optical and molecular-level analytical techniques in the CAO, especially during winter. State of the art chemical characterization of DOM is subject to major challenges: Solid phase extraction (SPE) that is often used to desalt and pre-concentrate marine DOM introduces chemical fractionation effects, which limits the comparability between analytical results for original samples and those carried out for SPE-DOM. There is no specific method to quantify fractionation effects, nor specific guidelines to avoid fractionation. Using mass spectrometry, quantitative DOM analyses is challenged by selective ionization of molecules and the large number of unresolved structural isomers that prevent classical external calibration. In the first part of this thesis, a method was developed to quantitatively track optical or chemical fractionation during SPE and investigate the potential mechanisms. We found a decrease in extraction efficiency of dissolved organic carbon (DOC), fluorescence and absorbance, and polar organic substances with increasing carbon loading on the SPE column. As the surface loading of the solid-phase increased, the dominant extraction mechanism shifted from PPL physisorption to increased DOM self-assembly, resulting in optical and chemical fractionation. The relative DOC loading (DOCload) was used to assess the carbon loading during SPE, and a double sigmoid model was applied to our online permeate fluorescence data as a function of DOCload, which allowed us to assess the degree of variability induced by DOCload. This finding has ample implications for the future processing and previous interpretation of chemical characteristics in SPE-DOM of aquatic organic matter. For the second part of the thesis, original water samples were acquired from the “Multidisciplinary Drifting Observatory for the Study of Arctic Climate” (MOSAiC) expedition. The water column samples covered a full year (2019 / 2020) and included the regions Amundsen Basin, western Nansen Basin and Yermak Plateau and Fram Strait. Samples were analyzed using optical spectroscopy to determine chromophoric DOM (CDOM) and fluorescent DOM (FDOM). In addition, a new method was applied that used Fourier transform ion cyclotron resonance mass spectrometry hyphenated to high performance liquid chromatography (LC-FTMS). The method allowed DOM analysis in original filtered water and thus avoided the chemical fractionation introduced by SPE. During the MOSAiC expedition, DOC concentrations and CDOM characteristics in the water column were primarily influenced by regional differences. These differences were largely dependent on terrestrially-derived DOM (tDOM) input by the transpolar drift (TPD) as indicative of average 136% and 45% higher aCDOM(350) and DOC concentration, respectively, in the Amundsen compared to the western Nansen Basin and Yermak Plateau, and slightly modified by seasonal changes. Despite the convenient identification of tDOM, optical spectroscopy was not suitable to quantify the contribution of tDOM to bulk DOC or to track sea ice derived DOM in the water column. In contrast, using LC-FTMS, we found quantitative linear correlation between the summed mass peak magnitudes for each sample (intsum) and DOC concentration. By combing LC-FTMS and source identification with optical parameters, we were able to quantify DOM sources (terrestrial versus marine) in the water column: 83% of the summed peak magnitude of all samples could be related to marine or terrestrial sources. tDOM contributed ∼17% (or 8 μmol kg-1) to deep DOC (~2000 m) in the CAO and was more refractory and had a higher state of unsaturation compared to marine DOM. The quantitative characterization of DOM in original seawater from different origin is a major step in the field of research. It provides a unique and new insight into the molecular changes in marine DOM composition and an improved understanding of the terrestrial DOM distribution in the CAO.

Download or read book Comprehensive Characterization of Dissolved Organic Matter by Using Chemical Fractionation and High Resolution Organic Structural Spectroscopy written by Yan Li and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessing the effect of dissolved organic matter DOM quality on degradation kinetics in the Vesdre River Belgium written by D.T. Dibar and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Dissolved Organic Matter in Water Using Fourier Transform Infrared Spectroscopy and X ray Photoelectron Spectroscopy written by Shichen Zhang and published by . This book was released on 2015 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolved organic matter (DOM) from several freshwater sources (Hinkson Creek upstream and downstream of the City of Columbia, Missouri River, landfill leachate, and wastewater treatment plant (WWTP)) was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The goal was to identify major chemical compound classes, such as carboxylic acid, amide, ester, and aliphatic and aromatic characteristics in water samples from different sources. Results showed that samples from the city landfills contained the highest concentration of aromatic and protein-like compounds, while samples from WWTP contained more acids and hydrophilic fraction. It appeared that for freshwaters, the DOM inputs from the surroundings had a significant effect on the DOM chemical composition. The study demonstrated that coupling FTIR with XPS analyses could provide insights into the physicochemical and biogeochemical characteristics of DOM in different aquatic systems, as well as the characteristics of the environments from which the DOMs were derived.

Download or read book Spectroscopic Characterization of Dissolved Organic Matter written by Xiaoyan Cao and published by . This book was released on 2014 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemical Characterization of Dissolved Organic Matter and Its Influence on the Chemistry of River Water written by Johannes Helmut Reuter and published by . This book was released on 1972 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: