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Chemically and geographically distinct solid-phase iron pools in the Southern Ocean
B P von der Heyden1, A N Roychoudhury, T N Mtshali
1Department of Earth Sciences, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
Science (New York, N.Y.)
|December 1, 2012
Summary
Marine iron particles in the Southern Ocean vary in composition and oxidation state. These differences, observed between South Africa and Antarctica, impact iron solubility and bioavailability for marine life.
Area of Science:
- Marine chemistry
- Oceanography
- Biogeochemistry
Background:
- Iron is a critical limiting nutrient in vast ocean regions, notably the Southern Ocean.
- Marine iron primarily exists as solid-phase particles, complicating regional-scale characterization of its chemical speciation and mineralogy.
Purpose of the Study:
- To characterize the diversity of iron particles in the Southern Ocean's euphotic zone.
- To investigate regional variations in iron particle oxidation state and composition.
- To understand how these variations influence iron solubility and bioavailability.
Main Methods:
- Analysis of iron particles (20-700 nm) from the Southern Ocean euphotic zone.
- Comparison of iron particle characteristics between South African and Antarctic coastal waters.
- Identification of distinct iron pools within different oceanic frontal zones.
Main Results:
- Observed a diverse range of iron particle sizes (20-700 nm).
- Identified distinct variations in iron particle oxidation state and composition between South African and Antarctic regions.
- Documented different iron pools associated with specific oceanic frontal zones.
Conclusions:
- Regional speciation and mineralogy of marine iron particles significantly vary across the Southern Ocean.
- These variations in iron particle characteristics influence their solubility.
- Changes in solubility can affect the production of bioavailable dissolved iron, impacting marine productivity.
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