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Iron stable isotopes track pelagic iron cycling during a subtropical phytoplankton bloom
Citation
Ellwood, MJ and Hutchins, DA and Lohan, MC and Milne, A and Nasemann, P and Nodder, SD and Sander, SG and Strzepek, R and Wilhelm, SW and Boyd, PW, Iron stable isotopes track pelagic iron cycling during a subtropical phytoplankton bloom, Proceedings of the National Academy of Sciences of the United States of America, 112, (1) pp. E15-E20. ISSN 0027-8424 (2015) [Refereed Article]
Copyright Statement
Copyright 2014 The Authors
DOI: doi:10.1073/pnas.1421576112
Abstract
The supply and bioavailability of dissolved iron sets the magnitude of surface productivity for ∼40% of the global ocean.
The redox state, organic complexation, and phase (dissolved versus particulate) of iron are key determinants of iron bioavailability
in the marine realm, although the mechanisms facilitating exchange between iron species (inorganic and organic) and phases
are poorly constrained. Here we use the isotope fingerprint of dissolved and particulate iron to reveal distinct isotopic
signatures for biological uptake of iron during a GEOTRACES process study focused on a temperate spring phytoplankton bloom
in subtropical waters. At the onset of the bloom, dissolved iron within the mixed layer was isotopically light relative to
particulate iron. The isotopically light dissolved iron pool likely results from the reduction of particulate iron via photochemical
and (to a lesser extent) biologically mediated reduction processes. As the bloom develops, dissolved iron within the surface
mixed layer becomes isotopically heavy, reflecting the dominance of biological processing of iron as it is removed from solution,
while scavenging appears to play a minor role. As stable isotopes have shown for major elements like nitrogen, iron isotopes
offer a new window into our understanding of the biogeochemical cycling of iron, thereby allowing us to disentangle a suite
of concurrent biotic and abiotic transformations of this key biolimiting element.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | iron isotopes, marine biogeochemical cycles, trace metals, phytoplankton blooms, GEOTRACES |
| Research Division: | Earth Sciences |
| Research Group: | Oceanography |
| Research Field: | Chemical Oceanography |
| Objective Division: | Environment |
| Objective Group: | Physical and Chemical Conditions of Water |
| Objective Field: | Physical and Chemical Conditions of Water in Marine Environments |
| UTAS Author: | Boyd, PW (Professor Philip Boyd) |
| ID Code: | 107024 |
| Year Published: | 2015 |
| Web of Science® Times Cited: | 23 |
| Deposited By: | IMAS Research and Education Centre |
| Deposited On: | 2016-03-02 |
| Last Modified: | 2017-10-31 |
| Downloads: | 0 |
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