Hydrography, Nutrients, and Carbon Pools in the Pacific Sector of the Southern Ocean: Implications for Carbon Flux
We investigated the hydrography, nutrients, and dissolved and particulate carbon pools in the western Pacific sector of the Antarctic Circumpolar Current (ACC) during austral summer 1996 to assess the region's role in the carbon cycle. Low fCO(2) values along two transects indicated that much o...
Published in: | Journal of Geophysical Research: Oceans |
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Digital Commons @ University of South Florida
2001
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Online Access: | https://digitalcommons.usf.edu/msc_facpub/15 https://doi.org/10.1029/1999JC000090 https://digitalcommons.usf.edu/context/msc_facpub/article/1014/viewcontent/Daly_et_al_2001_Journal_of_Geophysical_Research_3A_Oceans.pdf |
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ftusouthflorida:oai:digitalcommons.usf.edu:msc_facpub-1014 2023-07-30T03:56:56+02:00 Hydrography, Nutrients, and Carbon Pools in the Pacific Sector of the Southern Ocean: Implications for Carbon Flux Daly, Kendra L. Smith, Walker O. Johnson, Gregory C. DiTullio, Giacomo R. Jones, David R. Mordy, Calvin W. Feely, Richard A. Hansell, Dennis A. Zhang, Jia-Zhong 2001-04-15T07:00:00Z application/pdf https://digitalcommons.usf.edu/msc_facpub/15 https://doi.org/10.1029/1999JC000090 https://digitalcommons.usf.edu/context/msc_facpub/article/1014/viewcontent/Daly_et_al_2001_Journal_of_Geophysical_Research_3A_Oceans.pdf unknown Digital Commons @ University of South Florida https://digitalcommons.usf.edu/msc_facpub/15 doi:10.1029/1999JC000090 https://digitalcommons.usf.edu/context/msc_facpub/article/1014/viewcontent/Daly_et_al_2001_Journal_of_Geophysical_Research_3A_Oceans.pdf default Marine Science Faculty Publications Life Sciences Marine Biology article 2001 ftusouthflorida https://doi.org/10.1029/1999JC000090 2023-07-13T20:21:41Z We investigated the hydrography, nutrients, and dissolved and particulate carbon pools in the western Pacific sector of the Antarctic Circumpolar Current (ACC) during austral summer 1996 to assess the region's role in the carbon cycle. Low fCO(2) values along two transects indicated that much of the study area was a sink for atmospheric CO2. The fCO(2) values were lowest near the Polar Front (PF) and the Subtropical Front (STF), concomitant with maxima of chlorophyll a and particulate and dissolved organic carbon. The largest biomass accumulations did not occur at fronts, which had high surface geostrophic velocities (20-51 cm s(-1)), but in relatively low velocity regions near fronts or in an eddy. Thus vertical motion and horizontal advection associated with fronts may have replenished nutrients in surface waters but also dispersed phytoplankton. Although surface waters north of the PF have been characterized as a "high nutrient-low chlorophyll" region, low silicic acid (Si) concentrations (2-4 muM) may limit production of large diatoms and therefore the potential carbon flux. Low concentrations (4-10 muM Si) at depths of winter mixing constrain the level of Si replenishment to surface waters. It has been suggested that an increase in aeolian iron north of the PF may increase primary productivity and carbon export. Our results, however, indicate that while diatom growth and carbon export may be enhanced, the extent ultimately would be limited by the vertical supply of Si. South of the PF, the primary mechanism by which carbon is exported to deep water appears to be through diatom flux. We suggest that north of the PF, particulate and dissolved carbon may be exported primarily to intermediate depths through subduction and diapycnal mixing associated with Subantarctic Mode Water and Antarctic Intermediate Water formation. These physical-biological interactions and Si dynamics should be included in future biogeochemical models to provide a more accurate prediction of carbon flux. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean University of South Florida St. Petersburg: Digital USFSP Antarctic Austral Pacific Southern Ocean The Antarctic Journal of Geophysical Research: Oceans 106 C4 7107 7124 |
institution |
Open Polar |
collection |
University of South Florida St. Petersburg: Digital USFSP |
op_collection_id |
ftusouthflorida |
language |
unknown |
topic |
Life Sciences Marine Biology |
spellingShingle |
Life Sciences Marine Biology Daly, Kendra L. Smith, Walker O. Johnson, Gregory C. DiTullio, Giacomo R. Jones, David R. Mordy, Calvin W. Feely, Richard A. Hansell, Dennis A. Zhang, Jia-Zhong Hydrography, Nutrients, and Carbon Pools in the Pacific Sector of the Southern Ocean: Implications for Carbon Flux |
topic_facet |
Life Sciences Marine Biology |
description |
We investigated the hydrography, nutrients, and dissolved and particulate carbon pools in the western Pacific sector of the Antarctic Circumpolar Current (ACC) during austral summer 1996 to assess the region's role in the carbon cycle. Low fCO(2) values along two transects indicated that much of the study area was a sink for atmospheric CO2. The fCO(2) values were lowest near the Polar Front (PF) and the Subtropical Front (STF), concomitant with maxima of chlorophyll a and particulate and dissolved organic carbon. The largest biomass accumulations did not occur at fronts, which had high surface geostrophic velocities (20-51 cm s(-1)), but in relatively low velocity regions near fronts or in an eddy. Thus vertical motion and horizontal advection associated with fronts may have replenished nutrients in surface waters but also dispersed phytoplankton. Although surface waters north of the PF have been characterized as a "high nutrient-low chlorophyll" region, low silicic acid (Si) concentrations (2-4 muM) may limit production of large diatoms and therefore the potential carbon flux. Low concentrations (4-10 muM Si) at depths of winter mixing constrain the level of Si replenishment to surface waters. It has been suggested that an increase in aeolian iron north of the PF may increase primary productivity and carbon export. Our results, however, indicate that while diatom growth and carbon export may be enhanced, the extent ultimately would be limited by the vertical supply of Si. South of the PF, the primary mechanism by which carbon is exported to deep water appears to be through diatom flux. We suggest that north of the PF, particulate and dissolved carbon may be exported primarily to intermediate depths through subduction and diapycnal mixing associated with Subantarctic Mode Water and Antarctic Intermediate Water formation. These physical-biological interactions and Si dynamics should be included in future biogeochemical models to provide a more accurate prediction of carbon flux. |
format |
Article in Journal/Newspaper |
author |
Daly, Kendra L. Smith, Walker O. Johnson, Gregory C. DiTullio, Giacomo R. Jones, David R. Mordy, Calvin W. Feely, Richard A. Hansell, Dennis A. Zhang, Jia-Zhong |
author_facet |
Daly, Kendra L. Smith, Walker O. Johnson, Gregory C. DiTullio, Giacomo R. Jones, David R. Mordy, Calvin W. Feely, Richard A. Hansell, Dennis A. Zhang, Jia-Zhong |
author_sort |
Daly, Kendra L. |
title |
Hydrography, Nutrients, and Carbon Pools in the Pacific Sector of the Southern Ocean: Implications for Carbon Flux |
title_short |
Hydrography, Nutrients, and Carbon Pools in the Pacific Sector of the Southern Ocean: Implications for Carbon Flux |
title_full |
Hydrography, Nutrients, and Carbon Pools in the Pacific Sector of the Southern Ocean: Implications for Carbon Flux |
title_fullStr |
Hydrography, Nutrients, and Carbon Pools in the Pacific Sector of the Southern Ocean: Implications for Carbon Flux |
title_full_unstemmed |
Hydrography, Nutrients, and Carbon Pools in the Pacific Sector of the Southern Ocean: Implications for Carbon Flux |
title_sort |
hydrography, nutrients, and carbon pools in the pacific sector of the southern ocean: implications for carbon flux |
publisher |
Digital Commons @ University of South Florida |
publishDate |
2001 |
url |
https://digitalcommons.usf.edu/msc_facpub/15 https://doi.org/10.1029/1999JC000090 https://digitalcommons.usf.edu/context/msc_facpub/article/1014/viewcontent/Daly_et_al_2001_Journal_of_Geophysical_Research_3A_Oceans.pdf |
geographic |
Antarctic Austral Pacific Southern Ocean The Antarctic |
geographic_facet |
Antarctic Austral Pacific Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
Marine Science Faculty Publications |
op_relation |
https://digitalcommons.usf.edu/msc_facpub/15 doi:10.1029/1999JC000090 https://digitalcommons.usf.edu/context/msc_facpub/article/1014/viewcontent/Daly_et_al_2001_Journal_of_Geophysical_Research_3A_Oceans.pdf |
op_rights |
default |
op_doi |
https://doi.org/10.1029/1999JC000090 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
106 |
container_issue |
C4 |
container_start_page |
7107 |
op_container_end_page |
7124 |
_version_ |
1772815212703907840 |