Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: Uptake of organically complexed iron and reduced cellular iron requirements
We report results of laboratory studies examining the effect of low levels of iron (Fe) availability on the intracellular Fe concentrations and specific growth rates in Southern Ocean diatoms (Fragilariopsis kerguelensis, Eucampia antarctica, Proboscia inermis, and Thalassiosira antarctica) and Phae...
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American Society of Limnology and Oceanography, Inc.
2015
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ftanucanberra:oai:digitalcollections.anu.edu.au:1885/78856 2023-05-15T13:56:44+02:00 Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: Uptake of organically complexed iron and reduced cellular iron requirements Strzepek, Robert Maldonado, M T Hunter, K Frew, R Boyd, Phillip 2015-12-13T22:42:37Z http://hdl.handle.net/1885/78856 unknown American Society of Limnology and Oceanography, Inc. 0024-3590 http://hdl.handle.net/1885/78856 Limnology and Oceanography Journal article 2015 ftanucanberra 2015-12-21T23:51:44Z We report results of laboratory studies examining the effect of low levels of iron (Fe) availability on the intracellular Fe concentrations and specific growth rates in Southern Ocean diatoms (Fragilariopsis kerguelensis, Eucampia antarctica, Proboscia inermis, and Thalassiosira antarctica) and Phaeocystis antarctica. All species grew on Fe complexed to the siderophore desferrioxamine B (DFB). Concentrations of DFB up to 100-fold in excess of Fe were required to limit growth rates by ≥ 50%. Southern Ocean phytoplankton also grew on Fe complexed by ≥ 10-fold excess concentrations of the siderophores ferrichrome, enterobactin, or aerobactin, whereas the temperate coastal diatoms Thalassiosira weissflogii and Thalassiosira pseudonana did not. Intracellular Fe concentrations and Fe:C ratios of all Southern Ocean species were exceptionally low and decreased with decreasing Fe availability. However, large diatoms had significantly lower cell-volume-normalized Fe content and Fe:C ratios than Phaeocystis. Short-term Fe uptake and extracellular Fe(II) production measurements provided evidence that Phaeocystis possesses a reductive Fe transport pathway. Our findings demonstrate that the largediatom Fe requirements are at least 2-fold lower than currently reported for oceanic algal species and suggest that bioreduction may enable resident phytoplankton to directly use Fe bound to strong organic ligands. Article in Journal/Newspaper Antarc* Antarctica Southern Ocean Australian National University: ANU Digital Collections Southern Ocean |
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Australian National University: ANU Digital Collections |
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description |
We report results of laboratory studies examining the effect of low levels of iron (Fe) availability on the intracellular Fe concentrations and specific growth rates in Southern Ocean diatoms (Fragilariopsis kerguelensis, Eucampia antarctica, Proboscia inermis, and Thalassiosira antarctica) and Phaeocystis antarctica. All species grew on Fe complexed to the siderophore desferrioxamine B (DFB). Concentrations of DFB up to 100-fold in excess of Fe were required to limit growth rates by ≥ 50%. Southern Ocean phytoplankton also grew on Fe complexed by ≥ 10-fold excess concentrations of the siderophores ferrichrome, enterobactin, or aerobactin, whereas the temperate coastal diatoms Thalassiosira weissflogii and Thalassiosira pseudonana did not. Intracellular Fe concentrations and Fe:C ratios of all Southern Ocean species were exceptionally low and decreased with decreasing Fe availability. However, large diatoms had significantly lower cell-volume-normalized Fe content and Fe:C ratios than Phaeocystis. Short-term Fe uptake and extracellular Fe(II) production measurements provided evidence that Phaeocystis possesses a reductive Fe transport pathway. Our findings demonstrate that the largediatom Fe requirements are at least 2-fold lower than currently reported for oceanic algal species and suggest that bioreduction may enable resident phytoplankton to directly use Fe bound to strong organic ligands. |
format |
Article in Journal/Newspaper |
author |
Strzepek, Robert Maldonado, M T Hunter, K Frew, R Boyd, Phillip |
spellingShingle |
Strzepek, Robert Maldonado, M T Hunter, K Frew, R Boyd, Phillip Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: Uptake of organically complexed iron and reduced cellular iron requirements |
author_facet |
Strzepek, Robert Maldonado, M T Hunter, K Frew, R Boyd, Phillip |
author_sort |
Strzepek, Robert |
title |
Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: Uptake of organically complexed iron and reduced cellular iron requirements |
title_short |
Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: Uptake of organically complexed iron and reduced cellular iron requirements |
title_full |
Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: Uptake of organically complexed iron and reduced cellular iron requirements |
title_fullStr |
Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: Uptake of organically complexed iron and reduced cellular iron requirements |
title_full_unstemmed |
Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: Uptake of organically complexed iron and reduced cellular iron requirements |
title_sort |
adaptive strategies by southern ocean phytoplankton to lessen iron limitation: uptake of organically complexed iron and reduced cellular iron requirements |
publisher |
American Society of Limnology and Oceanography, Inc. |
publishDate |
2015 |
url |
http://hdl.handle.net/1885/78856 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Antarc* Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctica Southern Ocean |
op_source |
Limnology and Oceanography |
op_relation |
0024-3590 http://hdl.handle.net/1885/78856 |
_version_ |
1766264317764698112 |