Coupled organic and inorganic carbon cycling in the deep subseafloor sediment of the northeastern Bering Sea Slope (IODP Exp. 323)
We studied microbially mediated diagenetic processes driven by carbon mineralization in subseafloor sediment of the northeastern Bering Sea Slope to a depth of 745meters below seafloor (mbsf). Sites U1343, U1344 and U1345 were drilled during Integrated Ocean Drilling Program (IODP) Expedition 323 at...
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ftunivrhodeislan:oai:digitalcommons.uri.edu:gsofacpubs-2121 2023-12-03T10:20:19+01:00 Coupled organic and inorganic carbon cycling in the deep subseafloor sediment of the northeastern Bering Sea Slope (IODP Exp. 323) Wehrmann, Laura M. Risgaard-Petersen, Nils Schrum, Heather N. Walsh, Emily A. Huh, Youngsook Ikehara, Minoru Pierre, Catherine D'Hondt, Steven Ferdelman, Timothy G. Ravelo, Ana Christina Takahashi, Kozo Zarikian, Carlos Alvarez 2011-05-24T07:00:00Z https://digitalcommons.uri.edu/gsofacpubs/1152 https://doi.org/10.1016/j.chemgeo.2011.03.002 unknown DigitalCommons@URI https://digitalcommons.uri.edu/gsofacpubs/1152 doi:10.1016/j.chemgeo.2011.03.002 https://doi.org/10.1016/j.chemgeo.2011.03.002 Graduate School of Oceanography Faculty Publications Bering Sea Deep subseafloor sediment Diagenetic carbonate formation Integrated Ocean Drilling Program Microbially mediated diagenetic processes Organic carbon mineralization text 2011 ftunivrhodeislan https://doi.org/10.1016/j.chemgeo.2011.03.002 2023-11-06T19:09:56Z We studied microbially mediated diagenetic processes driven by carbon mineralization in subseafloor sediment of the northeastern Bering Sea Slope to a depth of 745meters below seafloor (mbsf). Sites U1343, U1344 and U1345 were drilled during Integrated Ocean Drilling Program (IODP) Expedition 323 at water depths of 1008 to 3172m. They are situated in the high productivity "Green Belt" region, with organic carbon burial rates typical of the high-productivity upwelling domains on western continental margins. The three sites show strong geochemical similarities. The downward sequence of microbially mediated processes in the sediment encompasses (1) organoclastic sulfate reduction, (2) anaerobic oxidation of methane (AOM) coupled to sulfate reduction, and (3) methanogenesis. The sediment contains two distinct zones of diagenetic carbonate formation, located at the sulfate-methane transition zone (SMTZ) and between 300 and 400mbsf. The SMTZ at the three sites is located between 6 and 9mbsf. The upward methane fluxes into the SMTZ are similar to fluxes in SMTZs underlying high-productivity surface waters off Chile and Namibia. Our Bering Sea results show that intense organic carbon mineralization drives high ammonium and dissolved inorganic carbon (DIC) production rates (>4.2mmolm-3y-1) in the uppermost 10mbsf and strongly imprints on the stable carbon isotope composition of DIC, driving it to a minimum value of -27‰ (VPDB) at the SMTZ. Pore-water calcium and magnesium profiles demonstrate formation of diagenetic Mg-rich calcite in the SMTZ. Below the SMTZ, methanogenesis results in 13C-enrichment of pore-water DIC, with a maximum value of +11.9‰ The imprint of methanogenesis on the DIC carbon isotope composition is evident down to a depth of 150mbsf. Below this depth, slow or absent microbially mediated carbon mineralization leaves DIC isotope composition unaffected. Ongoing carbonate formation between 300 and 400 mbsf strongly influences pore-water DIC and magnesium concentration profiles. The linked succession ... Text Bering Sea University of Rhode Island: DigitalCommons@URI Bering Sea Chemical Geology 284 3-4 251 261 |
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Open Polar |
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University of Rhode Island: DigitalCommons@URI |
op_collection_id |
ftunivrhodeislan |
language |
unknown |
topic |
Bering Sea Deep subseafloor sediment Diagenetic carbonate formation Integrated Ocean Drilling Program Microbially mediated diagenetic processes Organic carbon mineralization |
spellingShingle |
Bering Sea Deep subseafloor sediment Diagenetic carbonate formation Integrated Ocean Drilling Program Microbially mediated diagenetic processes Organic carbon mineralization Wehrmann, Laura M. Risgaard-Petersen, Nils Schrum, Heather N. Walsh, Emily A. Huh, Youngsook Ikehara, Minoru Pierre, Catherine D'Hondt, Steven Ferdelman, Timothy G. Ravelo, Ana Christina Takahashi, Kozo Zarikian, Carlos Alvarez Coupled organic and inorganic carbon cycling in the deep subseafloor sediment of the northeastern Bering Sea Slope (IODP Exp. 323) |
topic_facet |
Bering Sea Deep subseafloor sediment Diagenetic carbonate formation Integrated Ocean Drilling Program Microbially mediated diagenetic processes Organic carbon mineralization |
description |
We studied microbially mediated diagenetic processes driven by carbon mineralization in subseafloor sediment of the northeastern Bering Sea Slope to a depth of 745meters below seafloor (mbsf). Sites U1343, U1344 and U1345 were drilled during Integrated Ocean Drilling Program (IODP) Expedition 323 at water depths of 1008 to 3172m. They are situated in the high productivity "Green Belt" region, with organic carbon burial rates typical of the high-productivity upwelling domains on western continental margins. The three sites show strong geochemical similarities. The downward sequence of microbially mediated processes in the sediment encompasses (1) organoclastic sulfate reduction, (2) anaerobic oxidation of methane (AOM) coupled to sulfate reduction, and (3) methanogenesis. The sediment contains two distinct zones of diagenetic carbonate formation, located at the sulfate-methane transition zone (SMTZ) and between 300 and 400mbsf. The SMTZ at the three sites is located between 6 and 9mbsf. The upward methane fluxes into the SMTZ are similar to fluxes in SMTZs underlying high-productivity surface waters off Chile and Namibia. Our Bering Sea results show that intense organic carbon mineralization drives high ammonium and dissolved inorganic carbon (DIC) production rates (>4.2mmolm-3y-1) in the uppermost 10mbsf and strongly imprints on the stable carbon isotope composition of DIC, driving it to a minimum value of -27‰ (VPDB) at the SMTZ. Pore-water calcium and magnesium profiles demonstrate formation of diagenetic Mg-rich calcite in the SMTZ. Below the SMTZ, methanogenesis results in 13C-enrichment of pore-water DIC, with a maximum value of +11.9‰ The imprint of methanogenesis on the DIC carbon isotope composition is evident down to a depth of 150mbsf. Below this depth, slow or absent microbially mediated carbon mineralization leaves DIC isotope composition unaffected. Ongoing carbonate formation between 300 and 400 mbsf strongly influences pore-water DIC and magnesium concentration profiles. The linked succession ... |
format |
Text |
author |
Wehrmann, Laura M. Risgaard-Petersen, Nils Schrum, Heather N. Walsh, Emily A. Huh, Youngsook Ikehara, Minoru Pierre, Catherine D'Hondt, Steven Ferdelman, Timothy G. Ravelo, Ana Christina Takahashi, Kozo Zarikian, Carlos Alvarez |
author_facet |
Wehrmann, Laura M. Risgaard-Petersen, Nils Schrum, Heather N. Walsh, Emily A. Huh, Youngsook Ikehara, Minoru Pierre, Catherine D'Hondt, Steven Ferdelman, Timothy G. Ravelo, Ana Christina Takahashi, Kozo Zarikian, Carlos Alvarez |
author_sort |
Wehrmann, Laura M. |
title |
Coupled organic and inorganic carbon cycling in the deep subseafloor sediment of the northeastern Bering Sea Slope (IODP Exp. 323) |
title_short |
Coupled organic and inorganic carbon cycling in the deep subseafloor sediment of the northeastern Bering Sea Slope (IODP Exp. 323) |
title_full |
Coupled organic and inorganic carbon cycling in the deep subseafloor sediment of the northeastern Bering Sea Slope (IODP Exp. 323) |
title_fullStr |
Coupled organic and inorganic carbon cycling in the deep subseafloor sediment of the northeastern Bering Sea Slope (IODP Exp. 323) |
title_full_unstemmed |
Coupled organic and inorganic carbon cycling in the deep subseafloor sediment of the northeastern Bering Sea Slope (IODP Exp. 323) |
title_sort |
coupled organic and inorganic carbon cycling in the deep subseafloor sediment of the northeastern bering sea slope (iodp exp. 323) |
publisher |
DigitalCommons@URI |
publishDate |
2011 |
url |
https://digitalcommons.uri.edu/gsofacpubs/1152 https://doi.org/10.1016/j.chemgeo.2011.03.002 |
geographic |
Bering Sea |
geographic_facet |
Bering Sea |
genre |
Bering Sea |
genre_facet |
Bering Sea |
op_source |
Graduate School of Oceanography Faculty Publications |
op_relation |
https://digitalcommons.uri.edu/gsofacpubs/1152 doi:10.1016/j.chemgeo.2011.03.002 https://doi.org/10.1016/j.chemgeo.2011.03.002 |
op_doi |
https://doi.org/10.1016/j.chemgeo.2011.03.002 |
container_title |
Chemical Geology |
container_volume |
284 |
container_issue |
3-4 |
container_start_page |
251 |
op_container_end_page |
261 |
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1784267738657587200 |