Physical controls on the storage of methane in landfast sea ice
We report on methane (CH<sub>4</sub>) dynamics in landfast sea ice, brine and under-ice seawater at Barrow in 2009. The CH<sub>4</sub> concentrations in under-ice water ranged from 25.9 to 116.4 nmol L<sup>−1</sup><sub>sw</sub>, indicating a...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-06-01
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| Series: | The Cryosphere |
| Online Access: | http://www.the-cryosphere.net/8/1019/2014/tc-8-1019-2014.pdf |
| _version_ | 1811194374878396416 |
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| author | J. Zhou J.-L. Tison G. Carnat N.-X. Geilfus B. Delille |
| author_facet | J. Zhou J.-L. Tison G. Carnat N.-X. Geilfus B. Delille |
| author_sort | J. Zhou |
| collection | DOAJ |
| description | We report on methane (CH<sub>4</sub>) dynamics in landfast sea ice, brine and
under-ice seawater at Barrow in 2009. The CH<sub>4</sub> concentrations in
under-ice water ranged from 25.9 to 116.4 nmol L<sup>−1</sup><sub>sw</sub>,
indicating a supersaturation of 700 to 3100% relative to the atmosphere.
In comparison, the CH<sub>4</sub> concentrations in sea ice ranged from 3.4 to
17.2 nmol L<sup>−1</sup><sub>ice</sub> and the deduced CH<sub>4</sub> concentrations in
brine from 13.2 to 677.7 nmol L<sup>−1</sup><sub>brine</sub>. We investigated the processes underlying the difference in CH<sub>4</sub> concentrations between
sea ice, brine and under-ice water and suggest that biological controls
on the storage of CH<sub>4</sub> in ice were minor in comparison to the physical
controls. Two physical processes regulated the storage of CH<sub>4</sub> in our
landfast ice samples: bubble formation within the ice and sea ice
permeability. Gas bubble formation due to brine concentration and solubility decrease favoured the
accumulation of CH<sub>4</sub> in the ice at the beginning of ice growth. CH<sub>4</sub>
retention in sea ice was then twice as efficient as that of salt; this also
explains the overall higher CH<sub>4</sub> concentrations in brine than in the
under-ice water. As sea ice thickened, gas bubble formation became less
efficient, CH<sub>4</sub> was then mainly trapped in the dissolved state. The
increase of sea ice permeability during ice melt marked the end of CH<sub>4</sub>
storage. |
| first_indexed | 2024-04-12T00:24:57Z |
| format | Article |
| id | doaj.art-d2e2cfa4ebc54cfe892f521a88fbdd8a |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-04-12T00:24:57Z |
| publishDate | 2014-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-d2e2cfa4ebc54cfe892f521a88fbdd8a2022-12-22T03:55:34ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242014-06-01831019102910.5194/tc-8-1019-2014Physical controls on the storage of methane in landfast sea iceJ. Zhou0J.-L. Tison1G. Carnat2N.-X. Geilfus3B. Delille4Laboratoire de glaciologie, DSTE, Université Libre de Bruxelles, Brussels, BelgiumLaboratoire de glaciologie, DSTE, Université Libre de Bruxelles, Brussels, BelgiumLaboratoire de glaciologie, DSTE, Université Libre de Bruxelles, Brussels, BelgiumArctic Research Center, Aarhus University, Aarhus, DenmarkUnité d'Océanographie chimique, MARE, Université de Liège, Liège, BelgiumWe report on methane (CH<sub>4</sub>) dynamics in landfast sea ice, brine and under-ice seawater at Barrow in 2009. The CH<sub>4</sub> concentrations in under-ice water ranged from 25.9 to 116.4 nmol L<sup>−1</sup><sub>sw</sub>, indicating a supersaturation of 700 to 3100% relative to the atmosphere. In comparison, the CH<sub>4</sub> concentrations in sea ice ranged from 3.4 to 17.2 nmol L<sup>−1</sup><sub>ice</sub> and the deduced CH<sub>4</sub> concentrations in brine from 13.2 to 677.7 nmol L<sup>−1</sup><sub>brine</sub>. We investigated the processes underlying the difference in CH<sub>4</sub> concentrations between sea ice, brine and under-ice water and suggest that biological controls on the storage of CH<sub>4</sub> in ice were minor in comparison to the physical controls. Two physical processes regulated the storage of CH<sub>4</sub> in our landfast ice samples: bubble formation within the ice and sea ice permeability. Gas bubble formation due to brine concentration and solubility decrease favoured the accumulation of CH<sub>4</sub> in the ice at the beginning of ice growth. CH<sub>4</sub> retention in sea ice was then twice as efficient as that of salt; this also explains the overall higher CH<sub>4</sub> concentrations in brine than in the under-ice water. As sea ice thickened, gas bubble formation became less efficient, CH<sub>4</sub> was then mainly trapped in the dissolved state. The increase of sea ice permeability during ice melt marked the end of CH<sub>4</sub> storage.http://www.the-cryosphere.net/8/1019/2014/tc-8-1019-2014.pdf |
| spellingShingle | J. Zhou J.-L. Tison G. Carnat N.-X. Geilfus B. Delille Physical controls on the storage of methane in landfast sea ice The Cryosphere |
| title | Physical controls on the storage of methane in landfast sea ice |
| title_full | Physical controls on the storage of methane in landfast sea ice |
| title_fullStr | Physical controls on the storage of methane in landfast sea ice |
| title_full_unstemmed | Physical controls on the storage of methane in landfast sea ice |
| title_short | Physical controls on the storage of methane in landfast sea ice |
| title_sort | physical controls on the storage of methane in landfast sea ice |
| url | http://www.the-cryosphere.net/8/1019/2014/tc-8-1019-2014.pdf |
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