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Iron availability regulates growth, photosynthesis, and production of ferredoxin and flavodoxin in Antarctic sea ice diatoms
Citation
Pankowski, A and McMinn, A, Iron availability regulates growth, photosynthesis, and production of ferredoxin and flavodoxin in Antarctic sea ice diatoms, Aquatic Biology, 4, (3) pp. 273-288. ISSN 1864-7790 (2009) [Refereed Article]
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© Inter-Research 2009 · www.int-res.com
Official URL: http://www.int-res.com/
DOI: doi:10.3354/ab00116
Abstract
Iron availability affects the growth of not only phytoplankton, but also sea ice diatoms.
Iron availability had a clear effect on the growth rates of Fragilariopsis cylindrus and F. curta. Maximum
growth rates were 0.57 d¨C1 for F. cylindrus and 0.28 d¨C1 for F. curta; Km (half-saturation growth
constant) was 0.51 ¡Á 10¨C12 and 1.3 ¡Á 10¨C12 M for F. cylindrus and F. curta, respectively. For both F.
cylindrus and F. curta, Fv/Fm (quantum yield of fluorescence) was highest and lowest for the cultures
grown with the highest and lowest concentrations of iron, respectively. For both species there was
also a reduction in both rETRmax (maximum relative electron transfer rate) and ¦Á (photosynthetic efficiency)
with decreasing iron concentration. For F. cylindrus grown with the least iron, rETRmax was
half of the iron-replete value, while ¦Á was reduced by 65%. Changes in Ek (light-adaptation parameter)
were not well defined. Immunoassays were developed for the proteins ferredoxin and flavodoxin
in Antarctic pack ice. Iron availability had different effects on the expression of flavodoxin and
ferredoxin in the 2 Fragilariopsis species tested. Cultures of F. cylindrus grown at high iron concentration
produced predominantly ferredoxin, with a small amount of flavodoxin. Ferredoxin was
sequentially replaced by flavodoxin for cultures grown with less iron, although the response was not
a simple switch from one protein to the other. The ability to produce ferredoxin is apparently absent
in F. curta, with relatively constant levels of flavodoxin produced at all iron concentrations. These
results strongly imply that the presence of flavodoxin alone cannot be used as evidence of ironlimited
growth.
Item Details
Item Type: | Refereed Article |
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Keywords: | Antarctic ¡¤ Sea ice ¡¤ Iron ¡¤ Ferredoxin ¡¤ Flavodoxin ¡¤ Microalgae |
Research Division: | Biological Sciences |
Research Group: | Ecology |
Research Field: | Marine and estuarine ecology (incl. marine ichthyology) |
Objective Division: | Environmental Management |
Objective Group: | Terrestrial systems and management |
Objective Field: | Assessment and management of terrestrial ecosystems |
UTAS Author: | Pankowski, A (Mr Andrew Pankowski) |
UTAS Author: | McMinn, A (Professor Andrew McMinn) |
ID Code: | 54382 |
Year Published: | 2009 |
Web of Science® Times Cited: | 28 |
Deposited By: | IASOS |
Deposited On: | 2009-02-19 |
Last Modified: | 2010-05-07 |
Downloads: | 442 View Download Statistics |
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