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Photosynthetic architecture differs in coastal and oceanic diatoms

Citation

Strzepek, RF and Harrison, PJ, Photosynthetic architecture differs in coastal and oceanic diatoms, Nature, 431 pp. 689-692. ISSN 0028-0836 (2004) [Refereed Article]


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DOI: doi:10.1038/nature02954

Abstract

Diatoms are a key taxon of eukaryotic phytoplankton and a major contributor to global carbon fixation. They are ubiquitous in the marine ecosystem despite marked gradients in environmental properties, such as dissolved iron concentrations, between coastal and oceanic waters. Previous studies have shown that offshore species of diatoms and other eukaryotic algae have evolved lower iron requirements to subsist in iron-poor oceanic waters, but the biochemical mechanisms responsible for their decreased iron demand are unknown. Here we show, using laboratory-cultured model species, a fundamental difference between a coastal and an oceanic diatom in their photosynthetic architecture. Specifically, the oceanic diatom had up to fivefold lower photosystem I and up to sevenfold lower cytochrome b6f complex concentrations than a coastal diatom. These changes to the photosynthetic apparatus markedly decrease the cellular iron requirements of the oceanic diatom but not its photosynthetic rates. However, oceanic diatoms might have also sacrificed their ability to acclimate to rapid fluctuations in light intensity—a characteristic of dynamic and turbid coastal waters. We suggest that diatoms, and probably other eukaryotic algal taxa, exploited this difference in the underwater light climate between oceanic and coastal waters, enabling them to decrease their iron requirements without compromising photosynthetic capacity. This adaptation probably facilitated the colonization of the open ocean by diatoms, and contributes to their persistence in this iron-impoverished environment.

Item Details

Item Type:Refereed Article
Keywords:iron, photosynthesis, light, adaptation, diatom, phytoplankton
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological oceanography
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Oceanic processes (excl. in the Antarctic and Southern Ocean)
UTAS Author:Strzepek, RF (Dr Robert Strzepek)
ID Code:147706
Year Published:2004
Web of Science® Times Cited:311
Deposited By:Australian Antarctic Program Partnership
Deposited On:2021-11-11
Last Modified:2021-11-15
Downloads:0

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