Journal ArticleDOI
Evaluation of specific ultraviolet absorbance as an indicator of the chemical composition and reactivity of dissolved organic carbon.
James L Weishaar,George R. Aiken,Brian A. Bergamaschi,Miranda S. Fram,Roger Fujii,Kenneth Mopper +5 more
TLDR
Data indicate that SUVA, determined at 254 nm, is strongly correlated with percent aromaticity as determined by 13C NMR for 13 organic matter isolates obtained from a variety of aquatic environments and is shown to be a useful parameter for estimating the dissolved aromatic carbon content in aquatic systems.Abstract:
Specific UV absorbance (SUVA) is defined as the UV absorbance of a water sample at a given wavelength normalized for dissolved organic carbon (DOC) concentration. Our data indicate that SUVA, determined at 254 nm, is strongly correlated with percent aromaticity as determined by 13C NMR for 13 organic matter isolates obtained from a variety of aquatic environments. SUVA, therefore, is shown to be a useful parameter for estimating the dissolved aromatic carbon content in aquatic systems. Experiments involving the reactivity of DOC with chlorine and tetra- methylammonium hydroxide (TMAH), however, show a wide range of reactivity for samples with similar SUVA values. These results indicate that, while SUVA measurements are good predictors of general chemical characteristics of DOC, they do not provide information about reactivity of DOC derived from different types of source materials. Sample pH, nitrate, and iron were found to influence SUVA measurements.read more
Citations
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Journal ArticleDOI
Absorption spectral slopes and slope ratios as indicators of molecular weight, source, and photobleaching of chromophoric dissolved organic matter
John R. Helms,Aron Stubbins,Jason D. Ritchie,Elizabeth C. Minor,David J. Kieber,Kenneth Mopper +5 more
TL;DR: In this article, a new approach for parameterizing dissolved organic matter (DOM) ultraviolet-visible absorption spectra is presented, where two distinct spectral slope regions (275-295 nm and 350-400 nm) within log-transformed absorption spectras were used to compare DOM from contrasting water types, ranging from wetlands (Great Dismal Swamp and Suwannee River) to photobleached oceanic water (Atlantic Ocean).
Book
Biogeochemistry of marine dissolved organic matter
TL;DR: The second edition of the Biogeochemistry of Marine Dissolved Organic Matter (Second Edition) as discussed by the authors provides a comprehensive overview of 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.
Journal ArticleDOI
Optical properties of dissolved organic matter (DOM): Effects of biological and photolytic degradation
Angela M. Hansen,Tamara E.C. Kraus,Brian A. Pellerin,Jacob A. Fleck,Bryan D. Downing,Brian A. Bergamaschi +5 more
TL;DR: In this article, the authors measured changes in commonly used optical properties and indices in DOM leached from peat soil, plants, and algae following biological and photochemical degradation to determine whether they provide unique signatures that can be linked to original DOM source.
Journal ArticleDOI
Measurement of Dissolved Organic Matter Fluorescence in Aquatic Environments: An Interlaboratory Comparison
Kathleen R. Murphy,Kenna D. Butler,Robert G. M. Spencer,Colin A. Stedmon,Jennifer Boehme,George R. Aiken +5 more
TL;DR: In an effort to reduce future occurrences of similar problems, algorithms for correcting and calibrating EEMs are described in detail, and MATLAB scripts for implementing the study's protocol are provided, and this approach will serve to increase the intercomparability of DOM fluorescence studies.
Journal ArticleDOI
Unraveling the role of land use and microbial activity in shaping dissolved organic matter characteristics in stream ecosystems
TL;DR: This article used absorbance and fluorescence spectroscopy with parallel factor analysis (PARAFAC) to characterize dissolved organic matter (DOM) in 43 streams distributed throughout watersheds of mixed land use in southern Ontario, Canada.
References
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Book
Spectrometric identification of organic compounds
TL;DR: In this paper, a sequence of procedures for identifying an unknown organic liquid using mass, NMR, IR, and UV spectroscopy is presented, along with specific examples of unknowns and their spectra.
Book
Study and Interpretation of the Chemical Characteristics of Natural Water
TL;DR: The chemical composition of natural water is derived from many different sources of solutes, including gases and aerosols from the atmosphere, weathering and erosion of rocks and soil, solution or precipitation reactions occurring below the land surface, and cultural effects resulting from human activities.
Journal ArticleDOI
Spectrofluorometric characterization of dissolved organic matter for indication of precursor organic material and aromaticity
Diane M. McKnight,Elizabeth W. Boyer,Paul Westerhoff,Peter T. Doran,Thomas Kulbe,Dale T. Andersen +5 more
TL;DR: In this article, the authors studied the fluorescence properties of fulvic acids isolated from streams and rivers receiving predominantly terrestrial sources of organic material and from lakes with microbial sources, and showed that the ratio of the emission intensity at a wavelength of 450 nm to that at 500 nm, obtained with an excitation of 370 nm, can serve as a simple index to distinguish sources of isolated aquatic fulvic acid.
Journal ArticleDOI
Characterization of lignin by gas capillary chromatography of cupric oxide oxidation products
John I. Hedges,John R. Ertel +1 more
TL;DR: In this paper, a reproducible method for the characterization of lignin in untreated plant and geochemical samples containing 10 mg or less organic matter is described, where the whole sample is treated with alkaline cupric oxide at 170 degrees to produce simple lignins derived phenols that are extracted with ethyl oxide and analyzed by gas capillary chromatography on fused silica columns.