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Saccharides enhance iron bioavailability to Southern Ocean phytoplankton
Citation
Hassler, CS and Schoemann, V and Nichols, CM and Butler, ECV and Boyd, PW, Saccharides enhance iron bioavailability to Southern Ocean phytoplankton, Proceedings of the National Academy of Sciences, 108, (3) pp. 1076-1081. ISSN 0027-8424 (2011) [Refereed Article]
Copyright Statement
Copyright 2011 Proceedings of the National Academy of Sciences
DOI: doi:10.1073/pnas.1010963108
Abstract
Iron limits primary productivity in vast regions of the ocean. Given
that marine phytoplankton contribute up to 40% of global biological
carbon fixation, it is important to understand what parameters
control the availability of iron (iron bioavailability) to these
organisms. Most studies on iron bioavailability have focused on the
role of siderophores; however, eukaryotic phytoplankton do not
produce or release siderophores. Here, we report on the pivotal
role of saccharides—which may act like an organic ligand—in enhancing
iron bioavailability to a Southern Ocean cultured diatom,
a prymnesiophyte, as well as to natural populations of eukaryotic
phytoplankton. Addition of a monosaccharide (>2 nM of glucuronic
acid, GLU) to natural planktonic assemblages from both the polar
front and subantarctic zones resulted in an increase in iron bioavailability
for eukaryotic phytoplankton, relative to bacterioplankton.
The enhanced iron bioavailability observed for several groups
of eukaryotic phytoplankton (i.e., cultured and natural populations)
using three saccharides, suggests it is a common phenomenon. Increased
iron bioavailability resulted from the combination of saccharides
forming highly bioavailable organic associations with iron
and increasing iron solubility, mainly as colloidal iron. As saccharides
are ubiquitous, present at nanomolar to micromolar concentrations,
and produced by biota in surface waters, they also satisfy
the prerequisites to be important constituents of the poorly defined
"ligand soup," known to weakly bind iron. Our findings point
to an additional type of organic ligand, controlling iron bioavailability
to eukaryotic phytoplankton—a key unknown in iron biogeochemistry.
Item Details
Item Type: | Refereed Article |
---|---|
Keywords: | trace metals, carbohydrates, organic matter, exopolymeric substances, plankton |
Research Division: | Earth Sciences |
Research Group: | Oceanography |
Research Field: | Chemical oceanography |
Objective Division: | Environmental Management |
Objective Group: | Marine systems and management |
Objective Field: | Measurement and assessment of marine water quality and condition |
UTAS Author: | Boyd, PW (Professor Philip Boyd) |
ID Code: | 95613 |
Year Published: | 2011 |
Web of Science® Times Cited: | 172 |
Deposited By: | IMAS Research and Education Centre |
Deposited On: | 2014-10-06 |
Last Modified: | 2017-11-01 |
Downloads: | 0 |
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