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Title: Composition of Dissolved Organic Matter in Pore Waters of Anoxic Marine Sediments Analyzed by 1H Nuclear Magnetic Resonance Spectroscopy

Abstract

Marine sediments are globally significant sources of dissolved organic matter (DOM) to the oceans, but the biogeochemical role of pore-water DOM in the benthic and marine carbon cycles remains unclear due to a lack of understanding about the molecular composition of DOM. To help fill this knowledge gap, we used 1H nuclear magnetic resonance (NMR) spectroscopy to examine depth variability in the composition of pore-water DOM in anoxic sediments of Santa Barbara Basin, California Borderland. Proton detected spectra were acquired on whole samples without pre-concentration to avoid preclusion of any DOM components from the analytical window. Broad unresolved resonance (operationally assigned to carboxyl-rich alicyclic molecules, or CRAM) dominated all spectra. Most of the relatively well-resolved peaks (attributed to biomolecules or their derivatives) appeared at chemical shifts similar to those previously reported for marine DOM in the literature, but at different relative intensities. DOM composition changed significantly within the top 50 cm of the sediment column, where the relative intensity of CRAM increased, and the relative intensity of resolved resonances decreased. The composition of CRAM itself also changed throughout the entire length of the 4.5-m profile, as CRAM protons became increasingly aliphatic at the expense of functionalized protons. Given that pore-watermore » DOM is generated from sedimentary organic matter that includes pre-aged and degraded material, and that DOM is theoretically subject to microbial reworking in the pore waters for centuries to millennia, these data suggest that marine sediments may be sources of CRAM that are compositionally unique from CRAM generated in the upper ocean.« less

Authors:
 [1];  [2];  [3];  [4];  [1]
  1. San Francisco State Univ., Tiburon, CA (United States). Estuary & Ocean Science Center
  2. Texas A & M Univ., College Station, TX (United States)
  3. Old Dominion Univ., Norfolk, VA (United States)
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Materials Science Division
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1439111
Alternate Identifier(s):
OSTI ID: 1518565
Report Number(s):
LLNL-JRNL-751233
Journal ID: ISSN 2296-7745; 937031
Grant/Contract Number:  
AC52-07NA27344; OCE-1155562; OCE-1155320; OCE-1155764
Resource Type:
Published Article
Journal Name:
Frontiers in Marine Science
Additional Journal Information:
Journal Volume: 5; Journal Issue: 172; Journal ID: ISSN 2296-7745
Publisher:
Frontiers Research Foundation
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; pore water; DOM; carbon; NMR; sediment; anoxic; marine; Santa Barbara Basin

Citation Formats

Fox, Christina A., Abdulla, Hussain A., Burdige, David J., Lewicki, James P., and Komada, Tomoko. Composition of Dissolved Organic Matter in Pore Waters of Anoxic Marine Sediments Analyzed by 1H Nuclear Magnetic Resonance Spectroscopy. United States: N. p., 2018. Web. doi:10.3389/fmars.2018.00172.
Fox, Christina A., Abdulla, Hussain A., Burdige, David J., Lewicki, James P., & Komada, Tomoko. Composition of Dissolved Organic Matter in Pore Waters of Anoxic Marine Sediments Analyzed by 1H Nuclear Magnetic Resonance Spectroscopy. United States. doi:10.3389/fmars.2018.00172.
Fox, Christina A., Abdulla, Hussain A., Burdige, David J., Lewicki, James P., and Komada, Tomoko. Fri . "Composition of Dissolved Organic Matter in Pore Waters of Anoxic Marine Sediments Analyzed by 1H Nuclear Magnetic Resonance Spectroscopy". United States. doi:10.3389/fmars.2018.00172.
@article{osti_1439111,
title = {Composition of Dissolved Organic Matter in Pore Waters of Anoxic Marine Sediments Analyzed by 1H Nuclear Magnetic Resonance Spectroscopy},
author = {Fox, Christina A. and Abdulla, Hussain A. and Burdige, David J. and Lewicki, James P. and Komada, Tomoko},
abstractNote = {Marine sediments are globally significant sources of dissolved organic matter (DOM) to the oceans, but the biogeochemical role of pore-water DOM in the benthic and marine carbon cycles remains unclear due to a lack of understanding about the molecular composition of DOM. To help fill this knowledge gap, we used 1H nuclear magnetic resonance (NMR) spectroscopy to examine depth variability in the composition of pore-water DOM in anoxic sediments of Santa Barbara Basin, California Borderland. Proton detected spectra were acquired on whole samples without pre-concentration to avoid preclusion of any DOM components from the analytical window. Broad unresolved resonance (operationally assigned to carboxyl-rich alicyclic molecules, or CRAM) dominated all spectra. Most of the relatively well-resolved peaks (attributed to biomolecules or their derivatives) appeared at chemical shifts similar to those previously reported for marine DOM in the literature, but at different relative intensities. DOM composition changed significantly within the top 50 cm of the sediment column, where the relative intensity of CRAM increased, and the relative intensity of resolved resonances decreased. The composition of CRAM itself also changed throughout the entire length of the 4.5-m profile, as CRAM protons became increasingly aliphatic at the expense of functionalized protons. Given that pore-water DOM is generated from sedimentary organic matter that includes pre-aged and degraded material, and that DOM is theoretically subject to microbial reworking in the pore waters for centuries to millennia, these data suggest that marine sediments may be sources of CRAM that are compositionally unique from CRAM generated in the upper ocean.},
doi = {10.3389/fmars.2018.00172},
journal = {Frontiers in Marine Science},
number = 172,
volume = 5,
place = {United States},
year = {2018},
month = {5}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.3389/fmars.2018.00172

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Cited by: 1 work
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