Document Type

Article

Publication Date

1999

DOI

10.1029/1998GL002284

Publication Title

Geophysical Research Letters

Volume

26

Issue

18

Pages

2865-2868

Abstract

In 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 (< 1.5μM) 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 (0.05-0.11nM) and silicic acid (< 1μM) 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.

Original Publication Citation

Sedwick, P.N., DiTullio, G.R., Hutchins, D.A., Boyd, P.W., Griffiths, F.B., Crossley, A.C., . . . Queguiner, B. (1999). Limitation of algal growth by iron deficiency in the Australian Subantarctic region. Geophysical Research Letters, 26(18), 2865-2868. doi: 10.1029/1998GL002284

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