Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters
A major issue of Arctic marine science is to understand whether the Arctic Ocean is, or will be, a source or sink for air–sea CO2 exchange. This has been complicated by the recent discoveries of ikaite (a polymorph of CaCO3·6H2O) in Arctic and Antarctic sea ice, which indicate that multiple chemical...
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Copernicus Publications
2012
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00024667 2023-05-15T13:36:44+02:00 Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters Rysgaard, S. Glud, R. N. Lennert, K. Cooper, M. Halden, N. Leakey, R. J. G. Hawthorne, F. C. Barber, D. 2012-08 electronic https://doi.org/10.5194/tc-6-901-2012 https://noa.gwlb.de/receive/cop_mods_00024667 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00024622/tc-6-901-2012.pdf https://tc.copernicus.org/articles/6/901/2012/tc-6-901-2012.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-6-901-2012 https://noa.gwlb.de/receive/cop_mods_00024667 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00024622/tc-6-901-2012.pdf https://tc.copernicus.org/articles/6/901/2012/tc-6-901-2012.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2012 ftnonlinearchiv https://doi.org/10.5194/tc-6-901-2012 2022-02-08T22:50:04Z A major issue of Arctic marine science is to understand whether the Arctic Ocean is, or will be, a source or sink for air–sea CO2 exchange. This has been complicated by the recent discoveries of ikaite (a polymorph of CaCO3·6H2O) in Arctic and Antarctic sea ice, which indicate that multiple chemical transformations occur in sea ice with a possible effect on CO2 and pH conditions in surface waters. Here, we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from a melting 1.7 km2 (0.5–1 m thick) drifting ice floe in the Fram Strait during summer. Our findings show that ikaite crystals are present throughout the sea ice but with larger crystals appearing in the upper ice layers. Ikaite crystals placed at elevated temperatures disintegrated into smaller crystallites and dissolved. During our field campaign in late June, melt reduced the ice floe thickness by 0.2 m per week and resulted in an estimated 3.8 ppm decrease of pCO2 in the ocean surface mixed layer. This corresponds to an air–sea CO2 uptake of 10.6 mmol m−2 sea ice d−1 or to 3.3 ton km−2 ice floe week−1. This is markedly higher than the estimated primary production within the ice floe of 0.3–1.3 mmol m−2 sea ice d−1. Finally, the presence of ikaite in sea ice and the dissolution of the mineral during melting of the sea ice and mixing of the melt water into the surface oceanic mixed layer accounted for half of the estimated pCO2 uptake. Article in Journal/Newspaper Antarc* Antarctic Arctic Arctic Ocean Fram Strait Sea ice The Cryosphere Niedersächsisches Online-Archiv NOA Antarctic Arctic Arctic Ocean The Cryosphere 6 4 901 908 |
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Open Polar |
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Niedersächsisches Online-Archiv NOA |
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ftnonlinearchiv |
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English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Rysgaard, S. Glud, R. N. Lennert, K. Cooper, M. Halden, N. Leakey, R. J. G. Hawthorne, F. C. Barber, D. Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters |
topic_facet |
article Verlagsveröffentlichung |
description |
A major issue of Arctic marine science is to understand whether the Arctic Ocean is, or will be, a source or sink for air–sea CO2 exchange. This has been complicated by the recent discoveries of ikaite (a polymorph of CaCO3·6H2O) in Arctic and Antarctic sea ice, which indicate that multiple chemical transformations occur in sea ice with a possible effect on CO2 and pH conditions in surface waters. Here, we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from a melting 1.7 km2 (0.5–1 m thick) drifting ice floe in the Fram Strait during summer. Our findings show that ikaite crystals are present throughout the sea ice but with larger crystals appearing in the upper ice layers. Ikaite crystals placed at elevated temperatures disintegrated into smaller crystallites and dissolved. During our field campaign in late June, melt reduced the ice floe thickness by 0.2 m per week and resulted in an estimated 3.8 ppm decrease of pCO2 in the ocean surface mixed layer. This corresponds to an air–sea CO2 uptake of 10.6 mmol m−2 sea ice d−1 or to 3.3 ton km−2 ice floe week−1. This is markedly higher than the estimated primary production within the ice floe of 0.3–1.3 mmol m−2 sea ice d−1. Finally, the presence of ikaite in sea ice and the dissolution of the mineral during melting of the sea ice and mixing of the melt water into the surface oceanic mixed layer accounted for half of the estimated pCO2 uptake. |
format |
Article in Journal/Newspaper |
author |
Rysgaard, S. Glud, R. N. Lennert, K. Cooper, M. Halden, N. Leakey, R. J. G. Hawthorne, F. C. Barber, D. |
author_facet |
Rysgaard, S. Glud, R. N. Lennert, K. Cooper, M. Halden, N. Leakey, R. J. G. Hawthorne, F. C. Barber, D. |
author_sort |
Rysgaard, S. |
title |
Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters |
title_short |
Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters |
title_full |
Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters |
title_fullStr |
Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters |
title_full_unstemmed |
Ikaite crystals in melting sea ice – implications for pCO2 and pH levels in Arctic surface waters |
title_sort |
ikaite crystals in melting sea ice – implications for pco2 and ph levels in arctic surface waters |
publisher |
Copernicus Publications |
publishDate |
2012 |
url |
https://doi.org/10.5194/tc-6-901-2012 https://noa.gwlb.de/receive/cop_mods_00024667 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00024622/tc-6-901-2012.pdf https://tc.copernicus.org/articles/6/901/2012/tc-6-901-2012.pdf |
geographic |
Antarctic Arctic Arctic Ocean |
geographic_facet |
Antarctic Arctic Arctic Ocean |
genre |
Antarc* Antarctic Arctic Arctic Ocean Fram Strait Sea ice The Cryosphere |
genre_facet |
Antarc* Antarctic Arctic Arctic Ocean Fram Strait Sea ice The Cryosphere |
op_relation |
The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-6-901-2012 https://noa.gwlb.de/receive/cop_mods_00024667 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00024622/tc-6-901-2012.pdf https://tc.copernicus.org/articles/6/901/2012/tc-6-901-2012.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-6-901-2012 |
container_title |
The Cryosphere |
container_volume |
6 |
container_issue |
4 |
container_start_page |
901 |
op_container_end_page |
908 |
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1766083309063897088 |