Organic sulfur fluxes and geomorphic control of sulfur isotope ratios in rivers
Pyrite oxidation plays a critical role in the relationship between weathering and climate, and its impact on the global carbon cycle has previously been constrained through inversion models utilizing observations of river sulfate ($SO^{2–}_{4}$) and its 34 S/ 32 S isotope ratio (δ 34 S SO4 ). Howeve...
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Online Access: | http://www.osti.gov/servlets/purl/1786349 https://www.osti.gov/biblio/1786349 https://doi.org/10.1016/j.epsl.2021.116838 |
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ftosti:oai:osti.gov:1786349 2023-07-30T04:04:28+02:00 Organic sulfur fluxes and geomorphic control of sulfur isotope ratios in rivers Kemeny, Preston C. Torres, Mark A. Lamb, Michael P. Webb, Samuel M. Dalleska, Nathan Cole, Trevor Hou, Yi Marske, Jared Adkins, Jess F. Fischer, Woodward W. 2022-09-26 application/pdf http://www.osti.gov/servlets/purl/1786349 https://www.osti.gov/biblio/1786349 https://doi.org/10.1016/j.epsl.2021.116838 unknown http://www.osti.gov/servlets/purl/1786349 https://www.osti.gov/biblio/1786349 https://doi.org/10.1016/j.epsl.2021.116838 doi:10.1016/j.epsl.2021.116838 54 ENVIRONMENTAL SCIENCES 2022 ftosti https://doi.org/10.1016/j.epsl.2021.116838 2023-07-11T10:03:59Z Pyrite oxidation plays a critical role in the relationship between weathering and climate, and its impact on the global carbon cycle has previously been constrained through inversion models utilizing observations of river sulfate ($SO^{2–}_{4}$) and its 34 S/ 32 S isotope ratio (δ 34 S SO4 ). However, measurements from some rivers have suggested that SSO4 can be substantially impacted by processes such as microbial sulfate reduction and/or sulfur assimilation and cycling, rather than simply reflecting a weighted mixture of lithologic sulfur sources. To study the prevalence and controls on $SO^{2–}_{4}$ transformations, in this study we measured dissolved major element concentrations and δ 34 S SO4 in river water samples from throughout western Iceland. Our analyses focused on samples from a small catchment hosting the Efri Haukadalsá river, a system with relatively uniform and isotopically constrained basaltic bedrock. We also measured sediment δ 34 S and sulfur speciation using sulfur K-edge X-ray absorption spectroscopy on sediment and vegetation samples from this catchment. Values of dissolved δ 34 S SO4 in the Efri Haukadalsá ranged from 2.5‰ to 23.7‰ and had a linear relationship with Cl – /$SO^{2–}_{4}$ ratios, indicating that $SO^{2–}_{4}$ predominantly derived from basalt weathering and meteoric precipitation. The lower δ 34 S SO4 values were found in fluvial valleys with V-shaped cross sections, while higher values of δ 34 S SO4 occurred in U-shaped, glacially eroded valleys with thick alluvial fills blanketing the valley floor. Spectroscopic observations identified organic sulfur phases in suspended river sediment, floodplain deposits, and vegetation. Mass balance calculations quantified the organic sulfur flux as less than 10% of $SO^{2–}_{4}$ export, and sediment δ 34 S values were comparable to river δ 34 S SO4 . We interpreted these isotopic and chemical patterns as reflecting differences in the availability of unweathered bedrock across the Efri Haukadalsá catchment, with V-shaped valleys having ... Other/Unknown Material Iceland SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Haukadalsá ENVELOPE(-21.737,-21.737,65.041,65.041) Earth and Planetary Science Letters 562 116838 |
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Open Polar |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
op_collection_id |
ftosti |
language |
unknown |
topic |
54 ENVIRONMENTAL SCIENCES |
spellingShingle |
54 ENVIRONMENTAL SCIENCES Kemeny, Preston C. Torres, Mark A. Lamb, Michael P. Webb, Samuel M. Dalleska, Nathan Cole, Trevor Hou, Yi Marske, Jared Adkins, Jess F. Fischer, Woodward W. Organic sulfur fluxes and geomorphic control of sulfur isotope ratios in rivers |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
Pyrite oxidation plays a critical role in the relationship between weathering and climate, and its impact on the global carbon cycle has previously been constrained through inversion models utilizing observations of river sulfate ($SO^{2–}_{4}$) and its 34 S/ 32 S isotope ratio (δ 34 S SO4 ). However, measurements from some rivers have suggested that SSO4 can be substantially impacted by processes such as microbial sulfate reduction and/or sulfur assimilation and cycling, rather than simply reflecting a weighted mixture of lithologic sulfur sources. To study the prevalence and controls on $SO^{2–}_{4}$ transformations, in this study we measured dissolved major element concentrations and δ 34 S SO4 in river water samples from throughout western Iceland. Our analyses focused on samples from a small catchment hosting the Efri Haukadalsá river, a system with relatively uniform and isotopically constrained basaltic bedrock. We also measured sediment δ 34 S and sulfur speciation using sulfur K-edge X-ray absorption spectroscopy on sediment and vegetation samples from this catchment. Values of dissolved δ 34 S SO4 in the Efri Haukadalsá ranged from 2.5‰ to 23.7‰ and had a linear relationship with Cl – /$SO^{2–}_{4}$ ratios, indicating that $SO^{2–}_{4}$ predominantly derived from basalt weathering and meteoric precipitation. The lower δ 34 S SO4 values were found in fluvial valleys with V-shaped cross sections, while higher values of δ 34 S SO4 occurred in U-shaped, glacially eroded valleys with thick alluvial fills blanketing the valley floor. Spectroscopic observations identified organic sulfur phases in suspended river sediment, floodplain deposits, and vegetation. Mass balance calculations quantified the organic sulfur flux as less than 10% of $SO^{2–}_{4}$ export, and sediment δ 34 S values were comparable to river δ 34 S SO4 . We interpreted these isotopic and chemical patterns as reflecting differences in the availability of unweathered bedrock across the Efri Haukadalsá catchment, with V-shaped valleys having ... |
author |
Kemeny, Preston C. Torres, Mark A. Lamb, Michael P. Webb, Samuel M. Dalleska, Nathan Cole, Trevor Hou, Yi Marske, Jared Adkins, Jess F. Fischer, Woodward W. |
author_facet |
Kemeny, Preston C. Torres, Mark A. Lamb, Michael P. Webb, Samuel M. Dalleska, Nathan Cole, Trevor Hou, Yi Marske, Jared Adkins, Jess F. Fischer, Woodward W. |
author_sort |
Kemeny, Preston C. |
title |
Organic sulfur fluxes and geomorphic control of sulfur isotope ratios in rivers |
title_short |
Organic sulfur fluxes and geomorphic control of sulfur isotope ratios in rivers |
title_full |
Organic sulfur fluxes and geomorphic control of sulfur isotope ratios in rivers |
title_fullStr |
Organic sulfur fluxes and geomorphic control of sulfur isotope ratios in rivers |
title_full_unstemmed |
Organic sulfur fluxes and geomorphic control of sulfur isotope ratios in rivers |
title_sort |
organic sulfur fluxes and geomorphic control of sulfur isotope ratios in rivers |
publishDate |
2022 |
url |
http://www.osti.gov/servlets/purl/1786349 https://www.osti.gov/biblio/1786349 https://doi.org/10.1016/j.epsl.2021.116838 |
long_lat |
ENVELOPE(-21.737,-21.737,65.041,65.041) |
geographic |
Haukadalsá |
geographic_facet |
Haukadalsá |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
http://www.osti.gov/servlets/purl/1786349 https://www.osti.gov/biblio/1786349 https://doi.org/10.1016/j.epsl.2021.116838 doi:10.1016/j.epsl.2021.116838 |
op_doi |
https://doi.org/10.1016/j.epsl.2021.116838 |
container_title |
Earth and Planetary Science Letters |
container_volume |
562 |
container_start_page |
116838 |
_version_ |
1772815929617416192 |