The silicon cycle impacted by past ice sheets

Jon R. Hawkings*, Jade E. Hatton, Katharine R. Hendry, Gregory F. de Souza, Jemma L. Wadham, Ruza F Ivanovic, Tyler J. Kohler, Marek Stibal, Alexander Beaton, Guillaume Lamarche-Gagnon, Andrew Tedstone, Mathis P. Hain, Elizabeth Bagshaw, Jennifer Pike, Martyn Tranter

*Corresponding author for this work

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

29 Citations (Scopus)
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Globally averaged riverine silicon (Si) concentrations and isotope composition (δ30Si) may be affected by the expansion and retreat of large ice sheets during glacial−interglacial cycles. Here we provide evidence of this based on the δ30Si composition of meltwater runoff from a Greenland Ice Sheet catchment. Glacier runoff has the lightest δ30Si measured in running waters (−0.25 ± 0.12‰), significantly lower than nonglacial rivers (1.25 ± 0.68‰), such that the overall decline in glacial runoff since the Last Glacial Maximum (LGM) may explain 0.06–0.17‰ of the observed ocean δ30Si rise (0.5–1.0‰). A marine sediment core proximal to Iceland provides further evidence for transient, low-δ30Si meltwater pulses during glacial termination. Diatom Si uptake during the LGM was likely similar to present day due to an expanded Si inventory, which raises the possibility of a feedback between ice sheet expansion, enhanced Si export to the ocean and reduced CO2 concentration in the atmosphere, because of the importance of diatoms in the biological carbon pump.

Original languageEnglish
Article number3210
Number of pages10
JournalNature Communications
Publication statusPublished - 10 Aug 2018


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