Control of Phytoplankton Growth by Iron Supply and Irradiance in the Subantarctic Southern Ocean: Experimental Results From the SAZ Project
The influence of irradiance and Fe supply on phytoplankton processes was studied, north (47°S, 142°E) and south (54°S, 142°E) of the Subantarctic Front in austral autumn (March 1998). At both sites, resident cells exhibited nutrient stress (Fv/Fm 0 at 47°S and 9% I0 at 54°S because of MLDs of 40 (47...
Published in: | Journal of Geophysical Research: Oceans |
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ODU Digital Commons
2001
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Online Access: | https://digitalcommons.odu.edu/oeas_fac_pubs/83 https://doi.org/10.1029/2000JC000348 https://digitalcommons.odu.edu/context/oeas_fac_pubs/article/1113/viewcontent/Boyd_2001_Control_of_phytoplankton_growth_by_i.pdf |
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ftolddominionuni:oai:digitalcommons.odu.edu:oeas_fac_pubs-1113 2023-06-11T04:17:00+02:00 Control of Phytoplankton Growth by Iron Supply and Irradiance in the Subantarctic Southern Ocean: Experimental Results From the SAZ Project Boyd, P. W. Crossley, A. C. DiTullio, G. R. Griffiths, F. B. Hutchins, D. A. Queguiner, B. Sedwick, Peter N. Trull, T. W. 2001-01-01T08:00:00Z application/pdf https://digitalcommons.odu.edu/oeas_fac_pubs/83 https://doi.org/10.1029/2000JC000348 https://digitalcommons.odu.edu/context/oeas_fac_pubs/article/1113/viewcontent/Boyd_2001_Control_of_phytoplankton_growth_by_i.pdf unknown ODU Digital Commons https://digitalcommons.odu.edu/oeas_fac_pubs/83 doi:10.1029/2000JC000348 https://digitalcommons.odu.edu/context/oeas_fac_pubs/article/1113/viewcontent/Boyd_2001_Control_of_phytoplankton_growth_by_i.pdf OES Faculty Publications Phytoplankton Iron Irradiance Subantarctic Southern Ocean Biogeochemistry Marine Biology Oceanography article 2001 ftolddominionuni https://doi.org/10.1029/2000JC000348 2023-05-08T17:59:38Z The influence of irradiance and Fe supply on phytoplankton processes was studied, north (47°S, 142°E) and south (54°S, 142°E) of the Subantarctic Front in austral autumn (March 1998). At both sites, resident cells exhibited nutrient stress (Fv/Fm 0 at 47°S and 9% I0 at 54°S because of MLDs of 40 (47°S) and 90 m (54°S), when these stations were occupied. The greater MLD at 54°S is reflected by tenfold higher cellular chlorophyll a levels in the resident phytoplankton. In the 47°S experiment, chlorophyll a levels increased to >1 μg/L-1 only in the high-Fe treatments, regardless of irradiance levels, suggesting Fe limitation. This trend was also noted for cell abundances, silica production, and carbon fixation rates. In contrast, in the 54°S experiment there were increases in chlorophyll a (to >2 μg/L-1), cell abundances, silica production, and carbon fixation only in the high-light treatments to which Fe had been added, suggesting that Fe and irradiance limit algal growth rates. Irradiance by altering algal Fe quotas is a key determinant of algal growth rate at 54°S (when silicic acid levels are nonlimiting); however, because of the integral nature of Fe/light colimitation and the restricted nature of the current data set, it was not possible to ascertain the relative contributions of Fe and irradiance to the control of phytoplankton growth. On the basis of a climatology of summer mean MLD for subantarctic (SA) waters south of Australia the 47° and 54°S sites appear to represent minimum and maximum MLDs, where Fe and Fe/irradiance, respectively, may limit/colimit algal growth. The implications for changes in the factors limiting algal growth with season in SA waters are discussed. Article in Journal/Newspaper Southern Ocean Old Dominion University: ODU Digital Commons Southern Ocean Austral Journal of Geophysical Research: Oceans 106 C12 31573 31583 |
institution |
Open Polar |
collection |
Old Dominion University: ODU Digital Commons |
op_collection_id |
ftolddominionuni |
language |
unknown |
topic |
Phytoplankton Iron Irradiance Subantarctic Southern Ocean Biogeochemistry Marine Biology Oceanography |
spellingShingle |
Phytoplankton Iron Irradiance Subantarctic Southern Ocean Biogeochemistry Marine Biology Oceanography Boyd, P. W. Crossley, A. C. DiTullio, G. R. Griffiths, F. B. Hutchins, D. A. Queguiner, B. Sedwick, Peter N. Trull, T. W. Control of Phytoplankton Growth by Iron Supply and Irradiance in the Subantarctic Southern Ocean: Experimental Results From the SAZ Project |
topic_facet |
Phytoplankton Iron Irradiance Subantarctic Southern Ocean Biogeochemistry Marine Biology Oceanography |
description |
The influence of irradiance and Fe supply on phytoplankton processes was studied, north (47°S, 142°E) and south (54°S, 142°E) of the Subantarctic Front in austral autumn (March 1998). At both sites, resident cells exhibited nutrient stress (Fv/Fm 0 at 47°S and 9% I0 at 54°S because of MLDs of 40 (47°S) and 90 m (54°S), when these stations were occupied. The greater MLD at 54°S is reflected by tenfold higher cellular chlorophyll a levels in the resident phytoplankton. In the 47°S experiment, chlorophyll a levels increased to >1 μg/L-1 only in the high-Fe treatments, regardless of irradiance levels, suggesting Fe limitation. This trend was also noted for cell abundances, silica production, and carbon fixation rates. In contrast, in the 54°S experiment there were increases in chlorophyll a (to >2 μg/L-1), cell abundances, silica production, and carbon fixation only in the high-light treatments to which Fe had been added, suggesting that Fe and irradiance limit algal growth rates. Irradiance by altering algal Fe quotas is a key determinant of algal growth rate at 54°S (when silicic acid levels are nonlimiting); however, because of the integral nature of Fe/light colimitation and the restricted nature of the current data set, it was not possible to ascertain the relative contributions of Fe and irradiance to the control of phytoplankton growth. On the basis of a climatology of summer mean MLD for subantarctic (SA) waters south of Australia the 47° and 54°S sites appear to represent minimum and maximum MLDs, where Fe and Fe/irradiance, respectively, may limit/colimit algal growth. The implications for changes in the factors limiting algal growth with season in SA waters are discussed. |
format |
Article in Journal/Newspaper |
author |
Boyd, P. W. Crossley, A. C. DiTullio, G. R. Griffiths, F. B. Hutchins, D. A. Queguiner, B. Sedwick, Peter N. Trull, T. W. |
author_facet |
Boyd, P. W. Crossley, A. C. DiTullio, G. R. Griffiths, F. B. Hutchins, D. A. Queguiner, B. Sedwick, Peter N. Trull, T. W. |
author_sort |
Boyd, P. W. |
title |
Control of Phytoplankton Growth by Iron Supply and Irradiance in the Subantarctic Southern Ocean: Experimental Results From the SAZ Project |
title_short |
Control of Phytoplankton Growth by Iron Supply and Irradiance in the Subantarctic Southern Ocean: Experimental Results From the SAZ Project |
title_full |
Control of Phytoplankton Growth by Iron Supply and Irradiance in the Subantarctic Southern Ocean: Experimental Results From the SAZ Project |
title_fullStr |
Control of Phytoplankton Growth by Iron Supply and Irradiance in the Subantarctic Southern Ocean: Experimental Results From the SAZ Project |
title_full_unstemmed |
Control of Phytoplankton Growth by Iron Supply and Irradiance in the Subantarctic Southern Ocean: Experimental Results From the SAZ Project |
title_sort |
control of phytoplankton growth by iron supply and irradiance in the subantarctic southern ocean: experimental results from the saz project |
publisher |
ODU Digital Commons |
publishDate |
2001 |
url |
https://digitalcommons.odu.edu/oeas_fac_pubs/83 https://doi.org/10.1029/2000JC000348 https://digitalcommons.odu.edu/context/oeas_fac_pubs/article/1113/viewcontent/Boyd_2001_Control_of_phytoplankton_growth_by_i.pdf |
geographic |
Southern Ocean Austral |
geographic_facet |
Southern Ocean Austral |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
OES Faculty Publications |
op_relation |
https://digitalcommons.odu.edu/oeas_fac_pubs/83 doi:10.1029/2000JC000348 https://digitalcommons.odu.edu/context/oeas_fac_pubs/article/1113/viewcontent/Boyd_2001_Control_of_phytoplankton_growth_by_i.pdf |
op_doi |
https://doi.org/10.1029/2000JC000348 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
106 |
container_issue |
C12 |
container_start_page |
31573 |
op_container_end_page |
31583 |
_version_ |
1768375751888863232 |