Fe and Zn Effects on the Si Cycle and Diatom Community Structure in Two Contrasting High and Low-silicate HNLC Areas

Karine Leblanc, Clinton Hare, P. W. Boyd, Kenneth Bruland, Bettina Sohst, Stuart Pickmere, Maeve Lohan, Kristen N. Buck, Michael Ellwood, David Hutchins

Research output: Contribution to journalArticlepeer-review

Abstract

We compared the importance of Fe, Zn and Si availability for diatom growth and silicification through microcosm enrichment experiments in two contrasting HNLC systems of the Sub-Arctic and Sub-Antarctic Pacific. The Bering Sea was characterized by low Fe and Zn concentrations (Pseudo-nitzschiasp. and Cylindrotheca closterium ), an increase in Chl a , biogenic silica, and particulate organic carbon and nitrogen, and a 2–3-fold decrease in the average cellular Si content. Zn had no impact on biomass parameters or diatom community structure in this region.

The Sub-Antarctic Zone (SAZ) was a low Si-HNLC system, with initial silicic acid levels of 0.45 μM and Fe and Zn concentrations Pseudo-nitzschiasp.) towards a smaller and less silicified solitary pennate ( Cylindrotheca closterium ), potentially prone to more rapid silica dissolution in the surface layer.

Despite the dominance by the same two diatom genera, these two high-latitude regimes exhibited different nutrient limitation scenarios. Diatom growth in the Bering Sea was strongly Fe-limited, while the SAZ was mainly limited by Si and only secondarily by Fe.

Original languageAmerican English
JournalDeep Sea Research Part I: Oceanographic Research Papers
Volume52
DOIs
StatePublished - Oct 1 2005

Keywords

  • Iron
  • Zinc
  • Silicate
  • Diatoms
  • HNLC
  • HNLSiLC
  • Trace metal limitation

Disciplines

  • Life Sciences

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