Early Season Depletion of Dissolved Iron in the Ross Sea Polynya: Implications for Iron Dynamics on the Antarctic Continental Shelf
The Ross Sea polynya is among the most productive regions in the Southern Ocean and may constitute a significant oceanic CO2sink. Based on results from several field studies, this region has been considered seasonally iron limited, whereby a "winter reserve" of dissolved iron (dFe) is prog...
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ftolddominionuni:oai:digitalcommons.odu.edu:oeas_fac_pubs-1098 2023-05-15T13:38:02+02:00 Early Season Depletion of Dissolved Iron in the Ross Sea Polynya: Implications for Iron Dynamics on the Antarctic Continental Shelf Sedwick, Peter N. Marsay, C. M. Sohst, B. M. Aguilar-Islas, A. M. Lohan, M. C. Long, M. C. Arrigo, K. R. Dunbar, R. B. Saito, M. A. Smith, W. O. DiTullio, G. R. 2011-01-01T08:00:00Z application/pdf https://digitalcommons.odu.edu/oeas_fac_pubs/96 https://digitalcommons.odu.edu/cgi/viewcontent.cgi?article=1098&context=oeas_fac_pubs unknown ODU Digital Commons https://digitalcommons.odu.edu/oeas_fac_pubs/96 https://digitalcommons.odu.edu/cgi/viewcontent.cgi?article=1098&context=oeas_fac_pubs OEAS Faculty Publications Phytoplankton Community structure Southern Ocean Circumpolar current Growth rates Global ocean World ocean Waters Ice Blooms Model Biogeochemistry Geochemistry Oceanography article 2011 ftolddominionuni 2021-03-02T18:07:46Z The Ross Sea polynya is among the most productive regions in the Southern Ocean and may constitute a significant oceanic CO2sink. Based on results from several field studies, this region has been considered seasonally iron limited, whereby a "winter reserve" of dissolved iron (dFe) is progressively depleted during the growing season to low concentrations (~ 0.1 nM) that limit phytoplankton growth in the austral summer (December-February). Here we report new iron data for the Ross Sea polynya during austral summer 2005-2006 (27 December-22 January) and the following austral spring 2006 (16 November-3 December). The summer 2005-2006 data show generally low dFe concentrations in polynya surface waters (0.10 ± 0.05 nM in upper 40 m, n = 175), consistent with previous observations. Surprisingly, our spring 2006 data reveal similar low surface dFe concentrations in the polynya (0.06 ± 0.04 nM in upper 40 m, n = 69), in association with relatively high rates of primary production (similar to 170-260 mmol C m(-2) d(-1)). These results indicate that the winter reserve dFe may be consumed relatively early in the growing season, such that polynya surface waters can become "iron limited" as early as November; i.e., the seasonal depletion of dFe is not necessarily gradual. Satellite observations reveal significant biomass accumulation in the polynya during summer 2006-2007, implying significant sources of "new" dFe to surface waters during this period. Possible sources of this new dFe include episodic vertical exchange, lateral advection, aerosol input, and reductive dissolution of particulate iron. Article in Journal/Newspaper Antarc* Antarctic Ross Sea Southern Ocean Old Dominion University: ODU Digital Commons Antarctic Austral Ross Sea Southern Ocean The Antarctic |
institution |
Open Polar |
collection |
Old Dominion University: ODU Digital Commons |
op_collection_id |
ftolddominionuni |
language |
unknown |
topic |
Phytoplankton Community structure Southern Ocean Circumpolar current Growth rates Global ocean World ocean Waters Ice Blooms Model Biogeochemistry Geochemistry Oceanography |
spellingShingle |
Phytoplankton Community structure Southern Ocean Circumpolar current Growth rates Global ocean World ocean Waters Ice Blooms Model Biogeochemistry Geochemistry Oceanography Sedwick, Peter N. Marsay, C. M. Sohst, B. M. Aguilar-Islas, A. M. Lohan, M. C. Long, M. C. Arrigo, K. R. Dunbar, R. B. Saito, M. A. Smith, W. O. DiTullio, G. R. Early Season Depletion of Dissolved Iron in the Ross Sea Polynya: Implications for Iron Dynamics on the Antarctic Continental Shelf |
topic_facet |
Phytoplankton Community structure Southern Ocean Circumpolar current Growth rates Global ocean World ocean Waters Ice Blooms Model Biogeochemistry Geochemistry Oceanography |
description |
The Ross Sea polynya is among the most productive regions in the Southern Ocean and may constitute a significant oceanic CO2sink. Based on results from several field studies, this region has been considered seasonally iron limited, whereby a "winter reserve" of dissolved iron (dFe) is progressively depleted during the growing season to low concentrations (~ 0.1 nM) that limit phytoplankton growth in the austral summer (December-February). Here we report new iron data for the Ross Sea polynya during austral summer 2005-2006 (27 December-22 January) and the following austral spring 2006 (16 November-3 December). The summer 2005-2006 data show generally low dFe concentrations in polynya surface waters (0.10 ± 0.05 nM in upper 40 m, n = 175), consistent with previous observations. Surprisingly, our spring 2006 data reveal similar low surface dFe concentrations in the polynya (0.06 ± 0.04 nM in upper 40 m, n = 69), in association with relatively high rates of primary production (similar to 170-260 mmol C m(-2) d(-1)). These results indicate that the winter reserve dFe may be consumed relatively early in the growing season, such that polynya surface waters can become "iron limited" as early as November; i.e., the seasonal depletion of dFe is not necessarily gradual. Satellite observations reveal significant biomass accumulation in the polynya during summer 2006-2007, implying significant sources of "new" dFe to surface waters during this period. Possible sources of this new dFe include episodic vertical exchange, lateral advection, aerosol input, and reductive dissolution of particulate iron. |
format |
Article in Journal/Newspaper |
author |
Sedwick, Peter N. Marsay, C. M. Sohst, B. M. Aguilar-Islas, A. M. Lohan, M. C. Long, M. C. Arrigo, K. R. Dunbar, R. B. Saito, M. A. Smith, W. O. DiTullio, G. R. |
author_facet |
Sedwick, Peter N. Marsay, C. M. Sohst, B. M. Aguilar-Islas, A. M. Lohan, M. C. Long, M. C. Arrigo, K. R. Dunbar, R. B. Saito, M. A. Smith, W. O. DiTullio, G. R. |
author_sort |
Sedwick, Peter N. |
title |
Early Season Depletion of Dissolved Iron in the Ross Sea Polynya: Implications for Iron Dynamics on the Antarctic Continental Shelf |
title_short |
Early Season Depletion of Dissolved Iron in the Ross Sea Polynya: Implications for Iron Dynamics on the Antarctic Continental Shelf |
title_full |
Early Season Depletion of Dissolved Iron in the Ross Sea Polynya: Implications for Iron Dynamics on the Antarctic Continental Shelf |
title_fullStr |
Early Season Depletion of Dissolved Iron in the Ross Sea Polynya: Implications for Iron Dynamics on the Antarctic Continental Shelf |
title_full_unstemmed |
Early Season Depletion of Dissolved Iron in the Ross Sea Polynya: Implications for Iron Dynamics on the Antarctic Continental Shelf |
title_sort |
early season depletion of dissolved iron in the ross sea polynya: implications for iron dynamics on the antarctic continental shelf |
publisher |
ODU Digital Commons |
publishDate |
2011 |
url |
https://digitalcommons.odu.edu/oeas_fac_pubs/96 https://digitalcommons.odu.edu/cgi/viewcontent.cgi?article=1098&context=oeas_fac_pubs |
geographic |
Antarctic Austral Ross Sea Southern Ocean The Antarctic |
geographic_facet |
Antarctic Austral Ross Sea Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Ross Sea Southern Ocean |
genre_facet |
Antarc* Antarctic Ross Sea Southern Ocean |
op_source |
OEAS Faculty Publications |
op_relation |
https://digitalcommons.odu.edu/oeas_fac_pubs/96 https://digitalcommons.odu.edu/cgi/viewcontent.cgi?article=1098&context=oeas_fac_pubs |
_version_ |
1766100794478690304 |