Silicon isotopes indicate enhanced carbon export efficiency in the North Atlantic during deglaciation

Katharine Hendry, Laura F Robinson, Jerry McManus, James Hays

Research output: Contribution to journalArticle (Academic Journal)peer-review

20 Citations (Scopus)
364 Downloads (Pure)

Abstract

Today’s Sargasso Sea is nutrient starved, except for episodic upwelling events caused by wind-driven winter mixing and eddies. Enhanced diatom opal burial in Sargasso Sea sediments indicates that silicic acid, a limiting nutrient today, may have been more available in subsurface waters during Heinrich Stadials, millennial-scale climate perturbations of the last glacial and deglaciation. Here we use the geochemistry of opal-forming organisms from different water depths to demonstrate changes in silicic acid supply and utilization during the most recent Heinrich Stadial. We suggest that during the early phase (17.5–18 ka), wind-driven upwelling replenished silicic acid to the subsurface, resulting in low Si utilization. By 17 ka, stratification reduced the surface silicic acid supply leading to increased Si utilization efficiency. This abrupt shift in Si cycling would have contributed to high regional carbon export efficiency during the recent Heinrich Stadial, despite being a period of increasing atmospheric CO2.
Original languageEnglish
Article number3107
JournalNature Communications
Volume5
Early online date23 Jan 2014
DOIs
Publication statusPublished - 23 Jan 2014

Keywords

  • diatom
  • silicon isotope
  • North Atlantic
  • Heinrich Stadial

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