Download or read book Polarity related Molecular Characterization of marine Dissolved Organic Matter DOM written by Marc Einsporn and published by . This book was released on 2011 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Characterization of Dissolved Organic Matter DOM in Seawater written by Jasper Daniel Hendrik van Heemst and published by . This book was released on 2000 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wunderli Karl 1881 1961 written by and published by . This book was released on 1901 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Zeitungsausschnitte.

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 Molecular Characterization and Photochemical Transformation of Dissolved Organic Matter from Land to Ocean written by Hongmei Chen and published by . This book was released on 2014 with total page 344 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 Molecular Characterization of Dissolved Organic Matter by Ultrahigh resolution Mass Spectrometry written by Vanessa-Nina Roth and published by . This book was released on 2013 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamics and Characterization of Marine Organic Matter written by N. Handa and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past decade the scientific activities of the Joint Global Ocean Flux Study (JGOFS), which focuses on the role of the oceans in controlling climate change via the transport and storage of greenhouse gases and organic matter, have led to an increased interest in the study of the biogeochemistry of organic matter. There is also a growing interest in global climate fluctuations. This, and the need for a precise assessment of the dynamics of carbon and other bio-elements, has led to a demand for an improved understanding of biogeochemical processes and the chemical characteristics of both particulate and dissolved organic matter in the ocean. A large amount of proxy data has been published describing the changes of the oceanic environment, but qualitative and quantitative estimates of the vertical flux of (proxy) organic compounds have not been well documented. There is thus an urgent need to pursue this line of study and, to this end, this book starts with several papers dealing with the primary production of organic matter in the upper ocean. Thereafter, the book goes on to follow the flux and characterization of particulate organic matter, discussed in relation to the primary production in the euphotic zone and resuspension in the deep waters, including the vertical flux of proxy organic compounds. It goes on to explain the decomposition and transformation of organic matter in the ocean environment due to photochemical and biological agents, and the reactivity of bulk and specific organic compounds, including the air-sea interaction of biogenic gases. The 22 papers in the book reflect the interests of JGOFS and will thus serve as a valuable reference source for future biogeochemical investigations of both bio-elements and organic matter in seawater, clarifying the role of the ocean in global climate change.

Download or read book Elemental and Molecular Characterization and Bioavailability of Dissolved Organic Matter in the Mediterranean Sea written by Alba María Martínez Pérez and published by . This book was released on 2018 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Introduction to Organic Geochemistry written by Stephen D. Killops and published by John Wiley & Sons. This book was released on 2013-04-16 with total page 673 pages. Available in PDF, EPUB and Kindle. Book excerpt: An Introduction to Organic Geochemistry explores the fate of organic matter of all types, biogenic and man-made, in the Earth System. investigates the variety of pathways and biogeochemical transformations that carbon compounds can experience over a range of time scales and in different environments scope widened to provide a broad and up-to-date background - structured to accommodate readers with varied scientific backgrounds essential terminology is defined fully and boxes are used to explain concepts introduced from other disciplines further study aided by the incorporation of carefully selected literature references It investigates the variety of pathways and biogeochemical transformations that carbon compounds can experience over a range of time scales and in different environments.

Download or read book Chemical Characterization of Refractory Dissolved Organic Matter written by Neal Ken Arakawa and published by . This book was released on 2016 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of this thesis was to combine a chemical degradation technique together with an analytical framework centered primarily around gas chromatography (GC) to more fully interrogate the composition of aquatic dissolved organic matter (DOM). Previous studies had suggested that aliphatic compounds could represent a significant fraction of refractory organic matter isolated by solid phase extraction (SPE). These studies had also uncovered the vast complexity of DOM. Gas chromatography coupled to mass spectrometry provides superior separation capability and is ideal for examining complex mixtures of lipid-derived molecules. As such I sought to develop a comprehensive GC analysis methods to provide molecular level information for DOM isolated by solid phase extraction (SPE) onto a hydrophobic resin- PPL (Agilent Bond Elut). In Chapter II, a comprehensive chemical reduction procedure was developed and first applied to the environmental DOM standard Suwannee River Fulvic Acid (SRFA) as a proxy for marine DOM. The resulting hydrocarbons were amenable to comprehensive gas chromatography time-of-flight mass spectrometry (GCxGC-TOF-MS), and effectively resolved into multiple series of alicyclic, unsaturated compounds. This was the first direct demonstration of the isomeric complexity of aquatic DOM. Similar alicyclic compounds were recovered from the reduction of terrestrial source material, implicating resin acids and sterols as potential precursors of SRFA. In Chapter III the reduction process was applied to marine surface DOM from the Scripps Institution of Oceanography Pier, and similar alicylic compounds were found. The GCxGC-TOF-MS identified carbon backbones closely resembling carotenoids, implicating these ubiquitous and highly reactive biomolecules as the source of a significant fraction of DOM accumulating in the marine water column. The structural assignment was supported by the identification of carotenoid derived resonances in two dimensional nuclear magnetic resonance (NMR) spectra, which indicated that these molecules were highly oxidized compared to the parent molecules consistent with their present in DOM. Following up on this work in Chapter IV the carotenoid [beta]-carotene was irradiated with natural sunlight to test the hypothesis that photodegradation was one pathway that converted carotenoids into water-soluble degradation products. The first finding was that the reaction produced a series of compounds identical to compounds isolated from marine DOM. The second important result was that the reaction produced a complex mixture of isomers from a single compound that helps to at least partly explain the compositional diversity in marine DOM. Together, the data in Chapters III and IV allowed us to link a large fraction of DOM to a ubiquitous biomolecule that can now serve as a model for studies examining the formation and fate of DOM that accumulates in the ocean on long timescales. Finally, in Chapter V we sought to examine how the composition of DOM -- both the complex alicyclic fraction and small, polar biomolecules, which are considered a "fresher" signal of biological input -- evolved across a salinity gradient. Although core biochemical classes were present in all regions the data supported in situ production of compositionally similar material rather than mixing across the gradients as proposed in some studies. Together, the chapters in my thesis provide new insight in the composition of dissolved organic matter in marine and terrestrial environments. The thesis also represents the most comprehensive molecular level characterization of DOM isolated by this solid phase extraction method, which is the most commonly used isolation method in the field. My findings also provide an important foundation for future lab-based mechanistic studies of DOM cycling in the marine environment.

Download or read book Structural Characterization of Freshwater Dissolved Organic Matter from Arctic and Temperate Climates Using Novel Analytical Approaches written by Gwen C. Woods and published by . This book was released on 2012 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Molecular Weight HMW Dissolved Organic Matter DOM in Seawater written by Lihini I. Aluwihare and published by . This book was released on 1999 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this thesis was to use high resolution analytical techniques coupled with molecular level analyses to chemically characterize high molecular weight (> 1 k Da (HMW)) dissolved organic matter (DOM) isolated from seawater in an attempt to provide new insights in to the cycling of DOM in the ocean. While a variety of sites spanning different environments (fluvial, coastal and oceanic) and ocean basins were examined, the chemical structure of the isolated HMW DOM varied little at both the polymer and monomer levels. All samples show similar ratios of carbohydrate:acetate:lipid carbon (80±4:10±2:9±4) indicating that these biochemicals are present within a family of related polymers. The carbohydrate fraction shows a characteristic distribution of seven major neutral monosaccharides: rhamnose, fucose, arabinose, xylose, mannose, glucose and galactose; and additionally contains Nacetylated amino sugars as seen by Nuclear Magnetic Resonance Spectroscopy (NMR). This family of compounds, consisting of a specifically linked polysaccharide backbone that is acylated at several positions, has been termed acylated polysaccharides (APS) by our laboratory. APS accounts for 50% of the carbon in HMW DOM isolated from the surface ocean and 20% of the carbon in HMW DOM isolated from the deep ocean. In order to identify a possible source for APS three species of phytoplankton, Thalassiossira weissflogii, Emiliania huxleyi and Phaeocystis, were cultured in seawater and their HMW DOM exudates examined by variety of analytical techniques. Both the T. weissflogii and E. huxleyi exudates contain compounds that resemble APS indicating that phytoplankton are indeed a source of APS to the marine environment. Furthermore, the degradation of the T. weissflogii exudate by a natural assemblage of microorganisms indicates that the component resembling APS is more resistant to microbial degradation compared to other polysaccharides present in the culture. Molecular level analyses show the distribution of monosaccharides to be conservative in surface and deep waters suggesting that APS is present throughout the water column. In order to determine the mechanism by which APS is delivered to the deep ocean the [delta]14C value of APS in the deep ocean was compared to the A14C value of the dissolved inorganic carbon (DIC) at the same depth. If the formation of deep water is the dominant mode of transport then both the DIC and APS will have similar [delta]14C values. However, if APS is injected into the deep ocean from particles or marine snow then the [delta]14C value of APS will be higher than the DIC at the same depth. Our results indicate that APS in the deep Pacific Ocean carries a modem [delta]14C value and is substantially enriched in 14C relative to the total HMW DOM and the DIC at that depth. Thus, particle dissolution appears to be the most important pathway for the delivery of APS to the deep ocean.

Download or read book Black Sea Oceanography written by E. Izdar and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Research Workshop, Çesme, Izmir, Turkey, October 23-27, 1989

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 Marine Biotechnology Revealing an Ocean of Opportunities written by Ana Rotter and published by Frontiers Media SA. This book was released on 2022-03-18 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Natural Organic Matter in Drinking Water written by Jean-Phillipe Croue and published by American Water Works Association. This book was released on 2000 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research reported on here sought to characterize natural organic matter (NOM) in dilute solutions and to isolate it without altering its properties, so that the effect of NOM in drinking water may be considered. Several NOM isolation methods were evaluated, including evaporation, reverse osmosis, nanofiltration, and adsorption. The effects of such isolation procedures on NOM's chemical composition and reactivity were considered. Based on these studies, the report presents conclusions regarding the feasibility and adequacy of in situ and ex situ techniques. Croue is affiliated with Laboratoire de Chimie de l'Eau de l'Environment, Universite de Poiters. Annotation copyrighted by Book News, Inc., Portland, OR.