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Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: Uptake of organically complexed iron and reduced cellular iron requirements


Strzepek, RF and Maldonado, MT and Hunter, KA and Frew, RD and Boyd, PW, Adaptive strategies by Southern Ocean phytoplankton to lessen iron limitation: Uptake of organically complexed iron and reduced cellular iron requirements, Limnology and Oceanography, 56, (6) pp. 1983-2002. ISSN 0024-3590 (2011) [Refereed Article]


Copyright Statement

Copyright 2011 The Association for the Sciences of Limnology and Oceanography, Inc.

DOI: doi:10.4319/lo.2011.56.6.1983


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.

Item Details

Item Type:Refereed Article
Keywords:adaptation, alga, concentration (composition), diatom, growth rate, iron, laboratory method; ligand, marine ecosystem, nutrient availability, nutrient limitation, nutrient uptake, nutritional requirement, phytoplankton, siderophore
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Adaptation to climate change
Objective Field:Climate change adaptation measures (excl. ecosystem)
UTAS Author:Strzepek, RF (Dr Robert Strzepek)
UTAS Author:Boyd, PW (Professor Philip Boyd)
ID Code:95607
Year Published:2011
Web of Science® Times Cited:113
Deposited By:IMAS Research and Education Centre
Deposited On:2014-10-06
Last Modified:2021-11-17
Downloads:474 View Download Statistics

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