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Iron僕ight interactions differ in Southern Ocean phytoplankton


Strzepek, RF and Hunter, KA and Frew, RD and Harrison, PJ and Boyd, PW, Iron-light interactions differ in Southern Ocean phytoplankton, Limnology and Oceanography, 57, (4) pp. 1182-1200. ISSN 0024-3590 (2012) [Refereed Article]


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Copyright 2012 Association for the Sciences of Limnology and Oceanography, Inc.

DOI: doi:10.4319/lo.2012.57.4.1182


In laboratory experiments we examined the interplay of light and iron availability on the intracellular iron concentrations, specific growth rates, and photosynthetic physiology of Southern (S.) Ocean diatoms (Eucampia antarctica and Proboscia inermis) and the haptophyte Phaeocystis antarctica. Intracellular iron concentrations and iron : carbon (Fe : C) molar ratios increased with decreasing irradiance in temperate coastal (Thalassiosira weissflogii) and oceanic (Thalassiosira oceanica) diatoms, in support of the well-established antagonistic iron-light relationship. In contrast, S. Ocean species required lower cellular iron concentrations and Fe : C ratios than temperate diatoms to grow at comparable rates, and their iron requirements decreased or remained relatively constant with decreasing light. These results suggest that the current paradigm that low light increases algal cellular iron requirements (supplied through "biodilution") is not applicable to S. Ocean phytoplankton. Although iron use efficiencies decreased at sub-saturating light in all species, these reductions were due primarily to lower growth rates, but not higher intracellular Fe : C ratios, in S. Ocean species. We propose that S. Ocean species have overcome the antagonistic iron-light relationship by increasing the size, rather than the number, of photosynthetic units under low irradiances, resulting in an acclimation strategy that does not increase their cellular iron requirements.

Item Details

Item Type:Refereed Article
Keywords:acclimation, concentration (composition), diatom, growth rate, iron, irradiance, light availability, light effect, nutrient availability, photosynthesis, phytoplankton
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:95568
Year Published:2012
Web of Science® Times Cited:108
Deposited By:IMAS Research and Education Centre
Deposited On:2014-10-03
Last Modified:2021-11-17
Downloads:425 View Download Statistics

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