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Limitation of algal growth by iron deficiency in the Australian Subantarctic region
journal contribution
posted on 2023-05-16, 11:50 authored by Sedwick, PN, DiTullio, GR, Hutchins, DA, Boyd, PW, Griffiths, FB, Crossley, AC, Trull, T, Queguiner, BIn March 1998 we measured iron in the upper water column and conducted iron- and nutrient-enrichment bottle-incubation experiments in the open-ocean Subantarctic region southwest of Tasmania, Australia. In the Subtropical Convergence Zone (∼42°S, 142°E), silicic acid concentrations were low (< 1.5 μM) in the upper water column, whereas pronounced vertical gradients in dissolved iron concentration (0.12-0.84 nM) were observed, presumably reflecting the interleaving of Subtropical and Subantarctic waters, and mineral aerosol input. Results of a bottle-incubation experiment performed at this location indicate that phytoplankton growth rates were limited by iron deficiency within the iron-poor layer of the euphotic zone. In the Subantarctic water mass (∼46.8°S, 142°E), low concentrations of dissolved iron (0.05-0.11 nM) and silicic acid (< 1 μM) were measured throughout the upper water column, and our experimental results indicate that algal growth was limited by iron deficiency. These observations suggest that availability of dissolved iron is a primary factor limiting phytoplankton growth over much of the Subantarctic Southern Ocean in the late summer and autumn. Copyright 1999 by the American Geophysical Union.
History
Publication title
Geophysical Research LettersVolume
26Issue
18Pagination
2865-2868ISSN
0094-8276Department/School
Institute for Marine and Antarctic StudiesPublisher
American Geophysical UnionPlace of publication
WashingtonRepository Status
- Restricted