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 |
---|---|
Main Authors: | , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Elsevier
2020
|
Subjects: | |
Online Access: | http://eprints.esc.cam.ac.uk/4642/ http://eprints.esc.cam.ac.uk/4642/1/1-s2.0-S0016703720300016-main.pdf http://eprints.esc.cam.ac.uk/4642/2/1-s2.0-S0016703720300016-mmc1.docx https://doi.org/10.1016/j.gca.2019.12.033 |
id |
ftucambridgeesc:oai:eprints.esc.cam.ac.uk:4642 |
---|---|
record_format |
openpolar |
spelling |
ftucambridgeesc:oai:eprints.esc.cam.ac.uk:4642 2023-05-15T14:27:27+02:00 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 text http://eprints.esc.cam.ac.uk/4642/ http://eprints.esc.cam.ac.uk/4642/1/1-s2.0-S0016703720300016-main.pdf http://eprints.esc.cam.ac.uk/4642/2/1-s2.0-S0016703720300016-mmc1.docx https://doi.org/10.1016/j.gca.2019.12.033 en eng Elsevier http://eprints.esc.cam.ac.uk/4642/1/1-s2.0-S0016703720300016-main.pdf http://eprints.esc.cam.ac.uk/4642/2/1-s2.0-S0016703720300016-mmc1.docx Michaud, Alexander B. and Laufer, Katja and Findlay, Alyssa and Pellerin, André and Antler, Gilad and Turchyn, Alexandra V. and Røy, Hans and Wehrmann, Laura M. and Jørgensen, Bo Barker (2020) Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard). Geochimica et Cosmochimica Acta. ISSN 00167037 DOI https://doi.org/10.1016/j.gca.2019.12.033 <https://doi.org/10.1016/j.gca.2019.12.033> 01 - Climate Change and Earth-Ocean Atmosphere Systems Article PeerReviewed 2020 ftucambridgeesc https://doi.org/10.1016/j.gca.2019.12.033 2020-08-27T18:10:05Z 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 Climate change Svalbard Spitsbergen University of Cambridge, Department of Earth Sciences: ESC Publications Arctic Svalbard Geochimica et Cosmochimica Acta 280 423 440 |
institution |
Open Polar |
collection |
University of Cambridge, Department of Earth Sciences: ESC Publications |
op_collection_id |
ftucambridgeesc |
language |
English |
topic |
01 - Climate Change and Earth-Ocean Atmosphere Systems |
spellingShingle |
01 - Climate Change and Earth-Ocean Atmosphere Systems 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 |
01 - Climate Change and Earth-Ocean Atmosphere Systems |
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) |
publisher |
Elsevier |
publishDate |
2020 |
url |
http://eprints.esc.cam.ac.uk/4642/ http://eprints.esc.cam.ac.uk/4642/1/1-s2.0-S0016703720300016-main.pdf http://eprints.esc.cam.ac.uk/4642/2/1-s2.0-S0016703720300016-mmc1.docx https://doi.org/10.1016/j.gca.2019.12.033 |
geographic |
Arctic Svalbard |
geographic_facet |
Arctic Svalbard |
genre |
Arctic Arctic Climate change Svalbard Spitsbergen |
genre_facet |
Arctic Arctic Climate change Svalbard Spitsbergen |
op_relation |
http://eprints.esc.cam.ac.uk/4642/1/1-s2.0-S0016703720300016-main.pdf http://eprints.esc.cam.ac.uk/4642/2/1-s2.0-S0016703720300016-mmc1.docx Michaud, Alexander B. and Laufer, Katja and Findlay, Alyssa and Pellerin, André and Antler, Gilad and Turchyn, Alexandra V. and Røy, Hans and Wehrmann, Laura M. and Jørgensen, Bo Barker (2020) Glacial influence on the iron and sulfur cycles in Arctic fjord sediments (Svalbard). Geochimica et Cosmochimica Acta. ISSN 00167037 DOI https://doi.org/10.1016/j.gca.2019.12.033 <https://doi.org/10.1016/j.gca.2019.12.033> |
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 |
_version_ |
1766301207908843520 |