scholarly journals Yucca Mountain Area Saturated Zone Dissolved Organic Carbon Isotopic Data

2007 ◽  
Author(s):  
James Thomas ◽  
David Decker ◽  
Gary Patterson ◽  
Zell Peterman ◽  
Todd Mihevc ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Yucca Mountain ◽  
Saturated Zone ◽  
Isotopic Data ◽  
Mountain Area ◽  
Carbon Isotopic

scholarly journals Isotopic and chromatographic fingerprinting of the sources of dissolved organic carbon in a shallow coastal aquifer

2020 ◽  
Vol 24 (4) ◽  
pp. 2167-2178 ◽  
Author(s):  
Karina T. Meredith ◽  
Andy Baker ◽  
Martin S. Andersen ◽  
Denis M. O'Carroll ◽  
Helen Rutlidge ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Coastal Aquifer ◽  
Carbon Isotopic Composition ◽  
Median Concentration ◽  
Carbon Isotopic ◽  
Groundwater Samples ◽  
Doc Concentration ◽  
Geochemical Analyses ◽  
Terrestrial Subsurface

Abstract. The terrestrial subsurface is the largest source of freshwater globally. The organic carbon contained within it and processes controlling its concentration remain largely unknown. The global median concentration of dissolved organic carbon (DOC) in groundwater is low compared to surface waters, suggesting significant processing in the subsurface. Yet the processes that remove this DOC in groundwater are not fully understood. The purpose of this study was to investigate the different sources and processes influencing DOC in a shallow anoxic coastal aquifer. Uniquely, this study combines liquid chromatography organic carbon detection with organic (δ13CDOC) carbon isotope geochemical analyses to fingerprint the various DOC sources that influence the concentration, carbon isotopic composition, and character with respect to distance from surface water sources, depth below surface, and inferred groundwater residence time (using 3H activities) in groundwater. It was found that the average groundwater DOC concentration was 5 times higher (5 mg L−1) than the global median concentration and that the concentration doubled with depth at our site, but the chromatographic character did not change significantly. The anoxic saturated conditions of the aquifer limited the rate of organic matter processing, leading to enhanced preservation and storage of the DOC sources from peats and palaeosols contained within the aquifer. All groundwater samples were more aromatic for their molecular weight in comparison to other lakes, rivers and surface marine samples studied. The destabilization or changes in hydrology, whether by anthropogenic or natural processes, could lead to the flux of up to 10 times more unreacted organic carbon from this coastal aquifer compared to deeper inland aquifers.

The Distribution and Stable Carbon Isotopic Composition of Dissolved Organic Carbon in Estuaries

Estuaries ◽  
1994 ◽  
Vol 17 (1) ◽  
pp. 111 ◽  
Author(s):  
Bruce Peterson ◽  
Brian Fry ◽  
Meredith Hullar ◽  
Susan Saupe ◽  
Richard Wright
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Isotopic Composition ◽  
Carbon Isotopic Composition ◽  
Stable Carbon ◽  
Carbon Isotopic

scholarly journals Isotopic and chromatographic fingerprinting of the sources of dissolved organic carbon in a shallow coastal aquifer

2019 ◽  
Author(s):  
Karina T. Meredith ◽  
Andy Baker ◽  
Martin S. Andersen ◽  
Denis M. O'Carroll ◽  
Helen Rutlidge ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Coastal Aquifer ◽  
Carbon Isotopic Composition ◽  
Natural Processes ◽  
Median Concentration ◽  
Carbon Isotopic ◽  
Groundwater Samples ◽  
Doc Concentration ◽  
Geochemical Analyses

Abstract. The terrestrial sub-surface is the largest source of freshwater globally. The organic carbon contained within it and processes controlling its concentration remain largely unknown. The global median concentration of dissolved organic carbon in groundwater is low compared to surface waters suggesting significant processing in the subsurface. Yet the processes that remove this dissolved organic carbon (DOC) in groundwater are not fully understood. The purpose of this study was to investigate the different sources and processes influencing DOC in a shallow anoxic coastal aquifer. Uniquely, this study combines liquid chromatography organic carbon detection with inorganic (δ13CDIC) and organic (δ13CDOC) carbon isotope geochemical analyses, to fingerprint the various DOC sources that influence the concentration, carbon isotopic composition and character with distance from surface water sources, depth below surface and groundwater residence time (using 3H) in groundwater. It was found that the average groundwater DOC concentration was five times higher (5 mg L−1) than the global median concentration and it doubled with depth, but the chromatographic character did not change significantly. The anoxic saturated conditions of the aquifer have limited the rate of organic matter processing leading to enhanced preservation and storage of the sources such as peats and palaeosols. All groundwater samples are more aromatic for their molecular weight in comparison to lakes and rivers and surface marine samples. The destabilisation or changes in hydrology, whether by anthropogenic or natural processes could lead to the flux of up to ten times more unreacted organic carbon from this coastal aquifer than compared to deeper inland aquifers.

UV Photochemical Oxidation and Extraction of Marine Dissolved Organic Carbon at UC Irvine: Status, Surprises, and Methodological Recommendations

Radiocarbon ◽  
2019 ◽  
Vol 61 (5) ◽  
pp. 1603-1617 ◽  
Author(s):  
Brett D Walker ◽  
Steven R Beaupré ◽  
Sheila Griffin ◽  
Ellen R M Druffel
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Small Sample ◽  
Photochemical Oxidation ◽  
Comparison Study ◽  
Trap Design ◽  
Design Efficiency ◽  
System Parameters ◽  
Carbon Isotopic ◽  
Overall Efficiency

ABSTRACTThe first ultraviolet photochemical oxidation (UVox) extraction method for marine dissolved organic carbon (DOC) as CO2 gas was established by Armstrong and co-workers in 1966. Subsequent refinement of the UVox technique has co-evolved with the need for high-precision isotopic (Δ14C, δ13C) analysis and smaller sample size requirements for accelerator mass spectrometry radiocarbon (AMS 14C) measurements. The UVox line at UC Irvine was established in 2004 and the system reaction kinetics and efficiency for isolating seawater DOC rigorously tested for quantitative isolation of ∼1 mg C for AMS 14C measurements. Since then, improvements have been made to sampling, storage, and UVox methods to increase overall efficiency. We discuss our progress, and key UVox system parameters for optimizing precision, accuracy, and efficiency, including (1) ocean to reactor: filtration, storage and preparation of DOC samples, (2) cryogenic trap design, efficiency and quantification of CO2 break through, and (3) use of isotopic standards, blanks and small sample graphitization techniques for the correction of DOC concentrations and Fm values with propagated uncertainties. New DOC UVox systems are in use at many institutions. However, rigorous assessment of quantitative UVox DOC yields and blank contributions, DOC concentrations and carbon isotopic values need to be made. We highlight the need for a community-wide inter-comparison study.

scholarly journals Flux and age of dissolved organic carbon exported to the Arctic Ocean: A carbon isotopic study of the five largest arctic rivers

2007 ◽  
Vol 21 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Peter A. Raymond ◽  
J. W. McClelland ◽  
R. M. Holmes ◽  
A. V. Zhulidov ◽  
K. Mull ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Arctic Ocean ◽  
The Arctic ◽  
Isotopic Study ◽  
Carbon Isotopic ◽  
The Arctic Ocean ◽  
Arctic Rivers

Carbon isotopic characterization of hydrophobic dissolved organic carbon in rainwater

2013 ◽  
Vol 68 ◽  
pp. 230-234 ◽  
Author(s):  
G. Brooks Avery ◽  
K. Farhana Biswas ◽  
Ralph Mead ◽  
Melissa Southwell ◽  
Joan D. Willey ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Carbon Isotopic ◽  
Isotopic Characterization
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