Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard)
Arctic fjord sediments of Svalbard receive terrestrial material from glacial runoff and organic matter from marine primary productivity. Organic carbon mineralization proceeds primarily through sulfate and iron reduction in the fjord sediment. The ongoing retreat of glaciers in the high Arctic is al...
Published in: | Geochimica et Cosmochimica Acta |
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Format: | Article in Journal/Newspaper |
Language: | English |
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2020
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Online Access: | https://pure.au.dk/portal/en/publications/fa47057e-7ff3-4fd3-b300-be8e52c7cb42 https://doi.org/10.1016/j.gca.2019.12.033 http://www.scopus.com/inward/record.url?scp=85078849197&partnerID=8YFLogxK |
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ftuniaarhuspubl:oai:pure.atira.dk:publications/fa47057e-7ff3-4fd3-b300-be8e52c7cb42 2024-02-11T09:59:34+01:00 Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard) Michaud, Alexander B. Laufer, Katja Findlay, Alyssa Pellerin, André Antler, Gilad Turchyn, Alexandra V. Røy, Hans Wehrmann, Laura M. Jørgensen, Bo Barker 2020 https://pure.au.dk/portal/en/publications/fa47057e-7ff3-4fd3-b300-be8e52c7cb42 https://doi.org/10.1016/j.gca.2019.12.033 http://www.scopus.com/inward/record.url?scp=85078849197&partnerID=8YFLogxK eng eng https://pure.au.dk/portal/en/publications/fa47057e-7ff3-4fd3-b300-be8e52c7cb42 info:eu-repo/semantics/restrictedAccess Michaud , A B , Laufer , K , Findlay , A , Pellerin , A , Antler , G , Turchyn , A V , Røy , H , Wehrmann , L M & Jørgensen , B B 2020 , ' Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard) ' , Geochimica et Cosmochimica Acta , vol. 280 , pp. 423-440 . https://doi.org/10.1016/j.gca.2019.12.033 Arctic Fjord Glacier Iron reactivity Sulfate reduction Sulfide oxidation Svalbard article 2020 ftuniaarhuspubl https://doi.org/10.1016/j.gca.2019.12.033 2024-01-24T23:59:49Z Arctic fjord sediments of Svalbard receive terrestrial material from glacial runoff and organic matter from marine primary productivity. Organic carbon mineralization proceeds primarily through sulfate and iron reduction in the fjord sediment. The ongoing retreat of glaciers in the high Arctic is altering the input of glacial material to the fjords, with unknown consequences for the iron and sulfur cycles in the fjord sediments. We measured sulfate reduction rates in sediment cores and analyzed porewater geochemistry, then compared these results to long-term sediment incubations to determine the rates of iron reduction and sulfide oxidation in three glacially influenced fjords on the west coast of Spitsbergen, Svalbard. Despite an abundance of glacially-sourced Fe(III)-oxide minerals, active sulfate reduction took place throughout the sediment. Analyses of the sulfur and oxygen isotopic composition of porewater sulfate and sulfate concentrations suggest that sulfide produced from biological sulfate reduction is reoxidized to sulfate. Long-term sediment incubations indicated sulfide oxidation at all three stations. The rate of sulfide oxidation was controlled by both the rate of sulfate reduction and the quantity and reactivity of Fe(III)-oxides. In our experimental incubations, we detected a decrease in Fe(III) content of the 0.5 M HCl and ascorbate-extractable fractions, but not in the 6 M HCl fraction, indicating that the highly reactive Fe(III) fraction is utilized by microorganisms and serves as the oxidant for sulfide oxidation. Our results show that sulfide oxidation in glacially-influenced fjord sediments is a wide-spread geochemical process. Further warming will drive glacial retreat onto land, where sediment-laden glacial meltwater will be altered during flow through proglacial streams and lakes before entering the marine environment. Fjord sediments will likely become more sulfidic, as glaciers deliver less particulate, highly-reactive metal oxides to the marine environment. Article in Journal/Newspaper Arctic Arctic glacier Svalbard Spitsbergen Aarhus University: Research Arctic Svalbard Geochimica et Cosmochimica Acta 280 423 440 |
institution |
Open Polar |
collection |
Aarhus University: Research |
op_collection_id |
ftuniaarhuspubl |
language |
English |
topic |
Arctic Fjord Glacier Iron reactivity Sulfate reduction Sulfide oxidation Svalbard |
spellingShingle |
Arctic Fjord Glacier Iron reactivity Sulfate reduction Sulfide oxidation Svalbard Michaud, Alexander B. Laufer, Katja Findlay, Alyssa Pellerin, André Antler, Gilad Turchyn, Alexandra V. Røy, Hans Wehrmann, Laura M. Jørgensen, Bo Barker Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard) |
topic_facet |
Arctic Fjord Glacier Iron reactivity Sulfate reduction Sulfide oxidation Svalbard |
description |
Arctic fjord sediments of Svalbard receive terrestrial material from glacial runoff and organic matter from marine primary productivity. Organic carbon mineralization proceeds primarily through sulfate and iron reduction in the fjord sediment. The ongoing retreat of glaciers in the high Arctic is altering the input of glacial material to the fjords, with unknown consequences for the iron and sulfur cycles in the fjord sediments. We measured sulfate reduction rates in sediment cores and analyzed porewater geochemistry, then compared these results to long-term sediment incubations to determine the rates of iron reduction and sulfide oxidation in three glacially influenced fjords on the west coast of Spitsbergen, Svalbard. Despite an abundance of glacially-sourced Fe(III)-oxide minerals, active sulfate reduction took place throughout the sediment. Analyses of the sulfur and oxygen isotopic composition of porewater sulfate and sulfate concentrations suggest that sulfide produced from biological sulfate reduction is reoxidized to sulfate. Long-term sediment incubations indicated sulfide oxidation at all three stations. The rate of sulfide oxidation was controlled by both the rate of sulfate reduction and the quantity and reactivity of Fe(III)-oxides. In our experimental incubations, we detected a decrease in Fe(III) content of the 0.5 M HCl and ascorbate-extractable fractions, but not in the 6 M HCl fraction, indicating that the highly reactive Fe(III) fraction is utilized by microorganisms and serves as the oxidant for sulfide oxidation. Our results show that sulfide oxidation in glacially-influenced fjord sediments is a wide-spread geochemical process. Further warming will drive glacial retreat onto land, where sediment-laden glacial meltwater will be altered during flow through proglacial streams and lakes before entering the marine environment. Fjord sediments will likely become more sulfidic, as glaciers deliver less particulate, highly-reactive metal oxides to the marine environment. |
format |
Article in Journal/Newspaper |
author |
Michaud, Alexander B. Laufer, Katja Findlay, Alyssa Pellerin, André Antler, Gilad Turchyn, Alexandra V. Røy, Hans Wehrmann, Laura M. Jørgensen, Bo Barker |
author_facet |
Michaud, Alexander B. Laufer, Katja Findlay, Alyssa Pellerin, André Antler, Gilad Turchyn, Alexandra V. Røy, Hans Wehrmann, Laura M. Jørgensen, Bo Barker |
author_sort |
Michaud, Alexander B. |
title |
Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard) |
title_short |
Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard) |
title_full |
Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard) |
title_fullStr |
Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard) |
title_full_unstemmed |
Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard) |
title_sort |
glacial influence on the iron and sulfur cycles in arctic fjord sediments (svalbard) |
publishDate |
2020 |
url |
https://pure.au.dk/portal/en/publications/fa47057e-7ff3-4fd3-b300-be8e52c7cb42 https://doi.org/10.1016/j.gca.2019.12.033 http://www.scopus.com/inward/record.url?scp=85078849197&partnerID=8YFLogxK |
geographic |
Arctic Svalbard |
geographic_facet |
Arctic Svalbard |
genre |
Arctic Arctic glacier Svalbard Spitsbergen |
genre_facet |
Arctic Arctic glacier Svalbard Spitsbergen |
op_source |
Michaud , A B , Laufer , K , Findlay , A , Pellerin , A , Antler , G , Turchyn , A V , Røy , H , Wehrmann , L M & Jørgensen , B B 2020 , ' Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard) ' , Geochimica et Cosmochimica Acta , vol. 280 , pp. 423-440 . https://doi.org/10.1016/j.gca.2019.12.033 |
op_relation |
https://pure.au.dk/portal/en/publications/fa47057e-7ff3-4fd3-b300-be8e52c7cb42 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.gca.2019.12.033 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
280 |
container_start_page |
423 |
op_container_end_page |
440 |
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1790595412591116288 |