Antarctic ice sheet fertilises the Southern Ocean
Southern Ocean (SO) marine primary productivity (PP) is strongly influenced by the availability of iron in surface waters, which is thought to exert a significant control upon atmospheric CO<sub>2</sub> concentrations on glacial/interglacial timescales. The zone bordering the Antarctic I...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-05-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/11/2635/2014/bg-11-2635-2014.pdf |
| _version_ | 1818256707367731200 |
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| author | R. Death J. L. Wadham F. Monteiro A. M. Le Brocq M. Tranter A. Ridgwell S. Dutkiewicz R. Raiswell |
| author_facet | R. Death J. L. Wadham F. Monteiro A. M. Le Brocq M. Tranter A. Ridgwell S. Dutkiewicz R. Raiswell |
| author_sort | R. Death |
| collection | DOAJ |
| description | Southern Ocean (SO) marine primary productivity (PP) is strongly influenced
by the availability of iron in surface waters, which is thought to exert a
significant control upon atmospheric CO<sub>2</sub> concentrations on
glacial/interglacial timescales. The zone bordering the Antarctic Ice Sheet
exhibits high PP and seasonal plankton blooms in response to light and
variations in iron availability. The sources of iron stimulating elevated SO
PP are in debate. Established contributors include dust, coastal
sediments/upwelling, icebergs and sea ice. Subglacial meltwater exported at
the ice margin is a more recent suggestion, arising from intense iron cycling
beneath the ice sheet. Icebergs and subglacial meltwater may supply a large
amount of bioavailable iron to the SO, estimated in this study at
0.07–0.2 Tg yr<sup>−1</sup>. Here we apply the MIT global ocean model (Follows
et al., 2007) to determine the potential impact of this level of iron export
from the ice sheet upon SO PP. The export of iron from the ice sheet raises
modelled SO PP by up to 40%, and provides one plausible explanation for seasonally
very high in situ measurements of PP in the near-coastal zone. The
impact on SO PP is greatest in coastal regions, which are also areas of high
measured marine PP. These results suggest that the export of Antarctic runoff
and icebergs may have an important impact on SO PP and should be included in
future biogeochemical modelling. |
| first_indexed | 2024-12-12T17:32:02Z |
| format | Article |
| id | doaj.art-c703c1acc4374a2a823e03e7f072ab3f |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-12T17:32:02Z |
| publishDate | 2014-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-c703c1acc4374a2a823e03e7f072ab3f2022-12-22T00:17:21ZengCopernicus PublicationsBiogeosciences1726-41701726-41892014-05-0111102635264310.5194/bg-11-2635-2014Antarctic ice sheet fertilises the Southern OceanR. Death0J. L. Wadham1F. Monteiro2A. M. Le Brocq3M. Tranter4A. Ridgwell5S. Dutkiewicz6R. Raiswell7School of Geographical Sciences, University of Bristol, BS81SS, UKSchool of Geographical Sciences, University of Bristol, BS81SS, UKSchool of Geographical Sciences, University of Bristol, BS81SS, UKGeography, College of Life and Environmental Sciences, University of Exeter, EX4 4RJ, UKSchool of Geographical Sciences, University of Bristol, BS81SS, UKSchool of Geographical Sciences, University of Bristol, BS81SS, UKDepartment of Earth, Atmosphere and Planetary Sciences, Massachusetts Institute of Technology, MA 02139, USASchool of Earth and Environment, University of Leeds, LS2 9JT, UKSouthern Ocean (SO) marine primary productivity (PP) is strongly influenced by the availability of iron in surface waters, which is thought to exert a significant control upon atmospheric CO<sub>2</sub> concentrations on glacial/interglacial timescales. The zone bordering the Antarctic Ice Sheet exhibits high PP and seasonal plankton blooms in response to light and variations in iron availability. The sources of iron stimulating elevated SO PP are in debate. Established contributors include dust, coastal sediments/upwelling, icebergs and sea ice. Subglacial meltwater exported at the ice margin is a more recent suggestion, arising from intense iron cycling beneath the ice sheet. Icebergs and subglacial meltwater may supply a large amount of bioavailable iron to the SO, estimated in this study at 0.07–0.2 Tg yr<sup>−1</sup>. Here we apply the MIT global ocean model (Follows et al., 2007) to determine the potential impact of this level of iron export from the ice sheet upon SO PP. The export of iron from the ice sheet raises modelled SO PP by up to 40%, and provides one plausible explanation for seasonally very high in situ measurements of PP in the near-coastal zone. The impact on SO PP is greatest in coastal regions, which are also areas of high measured marine PP. These results suggest that the export of Antarctic runoff and icebergs may have an important impact on SO PP and should be included in future biogeochemical modelling.http://www.biogeosciences.net/11/2635/2014/bg-11-2635-2014.pdf |
| spellingShingle | R. Death J. L. Wadham F. Monteiro A. M. Le Brocq M. Tranter A. Ridgwell S. Dutkiewicz R. Raiswell Antarctic ice sheet fertilises the Southern Ocean Biogeosciences |
| title | Antarctic ice sheet fertilises the Southern Ocean |
| title_full | Antarctic ice sheet fertilises the Southern Ocean |
| title_fullStr | Antarctic ice sheet fertilises the Southern Ocean |
| title_full_unstemmed | Antarctic ice sheet fertilises the Southern Ocean |
| title_short | Antarctic ice sheet fertilises the Southern Ocean |
| title_sort | antarctic ice sheet fertilises the southern ocean |
| url | http://www.biogeosciences.net/11/2635/2014/bg-11-2635-2014.pdf |
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