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Divergent physiological and molecular responses of light- and iron-limited Southern Ocean phytoplankton


Andrew, SM and Strzepek, RF and Whitney, SM and Chow, WS and Ellwood, MJ, Divergent physiological and molecular responses of light- and iron-limited Southern Ocean phytoplankton, Limnology and Oceanography Letters, 7, (2) pp. 150-158. ISSN 2378-2242 (2021) [Refereed Article]

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Copyright Statement

2021 The Authors. Limnology and Oceanography Letters published by Wiley Periodicals LLC. This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, ( which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

DOI: doi:10.1002/lol2.10223


It has recently been shown that Southern Ocean phytoplankton species have evolved to optimize their light-harvesting potential without increasing the high iron-requiring proteins used for photosynthesis. We measured molecular and physiological responses of phytoplankton cultures under a combination of iron and light conditions. While iron-replete cultures mostly increased biovolume, photochemical efficiency (Fv/Fm) and the relative abundance of photosystem II (PSII) and Cytochrome b6f protein compared to iron-limited cultures, light also regulated cellular chlorophyll a content and played a role in controlling PSII protein abundance. Investment of protein resources into the carbon fixing enzyme Ribulose 1,5-bisphosphate carboxylase oxygenase (Rubisco) was species-specific, but increased growth rates correlated with increased investment into Rubisco for all species. Our results suggest that Proboscia inermis uses a divergent molecular strategy to compete for nutrients, light, and CO2 in the Southern Ocean.

Item Details

Item Type:Refereed Article
Keywords:iron, light, physiology, Southern Ocean, phytoplankton, microbial ecology
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological oceanography
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Antarctic and Southern Ocean oceanic processes
UTAS Author:Strzepek, RF (Dr Robert Strzepek)
ID Code:148180
Year Published:2021
Web of Science® Times Cited:2
Deposited By:Australian Antarctic Program Partnership
Deposited On:2021-12-08
Last Modified:2022-10-13
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