Silicate weathering in anoxic marine sediments
Two sediment cores retrieved at the northern slope of Sakhalin Island, Sea of Okhotsk, were analyzed for biogenic opal, organic carbon, carbonate, sulfur, major element concentrations, mineral contents, and dissolved substances including nutrients, sulfate, methane, major cations, humic substances,...
Published in: | Geochimica et Cosmochimica Acta |
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Online Access: | https://oceanrep.geomar.de/id/eprint/6736/ https://oceanrep.geomar.de/id/eprint/6736/1/110_Wallmann_2008_SilicateWeatheringInAnoxicMarine_Artzeit_pubid9429.pdf https://doi.org/10.1016/j.gca.2008.03.026 |
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ftoceanrep:oai:oceanrep.geomar.de:6736 2023-05-15T18:09:18+02:00 Silicate weathering in anoxic marine sediments Wallmann, Klaus Aloisi, Giovanni Haeckel, Matthias Tishchenko, P. Pavlova, G. Greinert, Jens Kutterolf, Steffen Eisenhauer, Anton 2008 text https://oceanrep.geomar.de/id/eprint/6736/ https://oceanrep.geomar.de/id/eprint/6736/1/110_Wallmann_2008_SilicateWeatheringInAnoxicMarine_Artzeit_pubid9429.pdf https://doi.org/10.1016/j.gca.2008.03.026 en eng Elsevier https://oceanrep.geomar.de/id/eprint/6736/1/110_Wallmann_2008_SilicateWeatheringInAnoxicMarine_Artzeit_pubid9429.pdf Wallmann, K. , Aloisi, G., Haeckel, M. , Tishchenko, P., Pavlova, G., Greinert, J. , Kutterolf, S. and Eisenhauer, A. (2008) Silicate weathering in anoxic marine sediments. Geochimica et Cosmochimica Acta, 72 (12). pp. 2895-2918. DOI 10.1016/j.gca.2008.03.026 <https://doi.org/10.1016/j.gca.2008.03.026>. doi:10.1016/j.gca.2008.03.026 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2008 ftoceanrep https://doi.org/10.1016/j.gca.2008.03.026 2023-04-07T14:53:24Z Two sediment cores retrieved at the northern slope of Sakhalin Island, Sea of Okhotsk, were analyzed for biogenic opal, organic carbon, carbonate, sulfur, major element concentrations, mineral contents, and dissolved substances including nutrients, sulfate, methane, major cations, humic substances, and total alkalinity. Down-core trends in mineral abundance suggest that plagioclase feldspars and other reactive silicate phases (olivine, pyroxene, volcanic ash) are transformed into smectite in the methanogenic sediment sections. The element ratios Na/Al, Mg/Al, and Ca/Al in the solid phase decrease with sediment depth indicating a loss of mobile cations with depth and producing a significant down-core increase in the chemical index of alteration. Pore waters separated from the sediment cores are highly enriched in dissolved magnesium, total alkalinity, humic substances, and boron. The high contents of dissolved organic carbon in the deeper methanogenic sediment sections (50–150 mg dm−3) may promote the dissolution of silicate phases through complexation of Al3+ and other structure-building cations. A non-steady state transport-reaction model was developed and applied to evaluate the down-core trends observed in the solid and dissolved phases. Dissolved Mg and total alkalinity were used to track the in-situ rates of marine silicate weathering since thermodynamic equilibrium calculations showed that these tracers are not affected by ion exchange processes with sediment surfaces. The modeling showed that silicate weathering is limited to the deeper methanogenic sediment section whereas reverse weathering was the dominant process in the overlying surface sediments. Depth-integrated rates of marine silicate weathering in methanogenic sediments derived from the model (81.4–99.2 mmol CO2 m−2 year−1) are lower than the marine weathering rates calculated from the solid phase data (198–245 mmol CO2 m−2 year−1) suggesting a decrease in marine weathering over time. The production of CO2 through reverse weathering in surface ... Article in Journal/Newspaper Sakhalin OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Okhotsk Geochimica et Cosmochimica Acta 72 12 2895 2918 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
Two sediment cores retrieved at the northern slope of Sakhalin Island, Sea of Okhotsk, were analyzed for biogenic opal, organic carbon, carbonate, sulfur, major element concentrations, mineral contents, and dissolved substances including nutrients, sulfate, methane, major cations, humic substances, and total alkalinity. Down-core trends in mineral abundance suggest that plagioclase feldspars and other reactive silicate phases (olivine, pyroxene, volcanic ash) are transformed into smectite in the methanogenic sediment sections. The element ratios Na/Al, Mg/Al, and Ca/Al in the solid phase decrease with sediment depth indicating a loss of mobile cations with depth and producing a significant down-core increase in the chemical index of alteration. Pore waters separated from the sediment cores are highly enriched in dissolved magnesium, total alkalinity, humic substances, and boron. The high contents of dissolved organic carbon in the deeper methanogenic sediment sections (50–150 mg dm−3) may promote the dissolution of silicate phases through complexation of Al3+ and other structure-building cations. A non-steady state transport-reaction model was developed and applied to evaluate the down-core trends observed in the solid and dissolved phases. Dissolved Mg and total alkalinity were used to track the in-situ rates of marine silicate weathering since thermodynamic equilibrium calculations showed that these tracers are not affected by ion exchange processes with sediment surfaces. The modeling showed that silicate weathering is limited to the deeper methanogenic sediment section whereas reverse weathering was the dominant process in the overlying surface sediments. Depth-integrated rates of marine silicate weathering in methanogenic sediments derived from the model (81.4–99.2 mmol CO2 m−2 year−1) are lower than the marine weathering rates calculated from the solid phase data (198–245 mmol CO2 m−2 year−1) suggesting a decrease in marine weathering over time. The production of CO2 through reverse weathering in surface ... |
format |
Article in Journal/Newspaper |
author |
Wallmann, Klaus Aloisi, Giovanni Haeckel, Matthias Tishchenko, P. Pavlova, G. Greinert, Jens Kutterolf, Steffen Eisenhauer, Anton |
spellingShingle |
Wallmann, Klaus Aloisi, Giovanni Haeckel, Matthias Tishchenko, P. Pavlova, G. Greinert, Jens Kutterolf, Steffen Eisenhauer, Anton Silicate weathering in anoxic marine sediments |
author_facet |
Wallmann, Klaus Aloisi, Giovanni Haeckel, Matthias Tishchenko, P. Pavlova, G. Greinert, Jens Kutterolf, Steffen Eisenhauer, Anton |
author_sort |
Wallmann, Klaus |
title |
Silicate weathering in anoxic marine sediments |
title_short |
Silicate weathering in anoxic marine sediments |
title_full |
Silicate weathering in anoxic marine sediments |
title_fullStr |
Silicate weathering in anoxic marine sediments |
title_full_unstemmed |
Silicate weathering in anoxic marine sediments |
title_sort |
silicate weathering in anoxic marine sediments |
publisher |
Elsevier |
publishDate |
2008 |
url |
https://oceanrep.geomar.de/id/eprint/6736/ https://oceanrep.geomar.de/id/eprint/6736/1/110_Wallmann_2008_SilicateWeatheringInAnoxicMarine_Artzeit_pubid9429.pdf https://doi.org/10.1016/j.gca.2008.03.026 |
geographic |
Okhotsk |
geographic_facet |
Okhotsk |
genre |
Sakhalin |
genre_facet |
Sakhalin |
op_relation |
https://oceanrep.geomar.de/id/eprint/6736/1/110_Wallmann_2008_SilicateWeatheringInAnoxicMarine_Artzeit_pubid9429.pdf Wallmann, K. , Aloisi, G., Haeckel, M. , Tishchenko, P., Pavlova, G., Greinert, J. , Kutterolf, S. and Eisenhauer, A. (2008) Silicate weathering in anoxic marine sediments. Geochimica et Cosmochimica Acta, 72 (12). pp. 2895-2918. DOI 10.1016/j.gca.2008.03.026 <https://doi.org/10.1016/j.gca.2008.03.026>. doi:10.1016/j.gca.2008.03.026 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.gca.2008.03.026 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
72 |
container_issue |
12 |
container_start_page |
2895 |
op_container_end_page |
2918 |
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1766181787992588288 |