The silicon cycle impacted by past ice sheets

• DOI: 10.1038/s41467-018-05689-1
• Publication Date: 2018-08-06T15:37:09Z
• Authors: Jon R. Hawkings; Jade E. Hatton; Katharine R. Hendry; Gregory F. de Souza; Jemma L. Wadham; Ruza Ivanovic; Tyler J. Kohler; Marek Stibal; Alexander Beaton; Guillaume Lamarch...; Andrew Tedstone; Mathis P. Hain; Elizabeth Bagshaw; Jennifer Pike; Martyn Tranter
• Keywords: Meltwater; Last Glacial Maximum; Greenland ice sheet

Abstract Globally averaged riverine silicon (Si) concentrations and isotope composition (δ 30 Si) may be affected by the expansion retreat of large ice sheets during glacial−interglacial cycles. Here we provide evidence this based on δ Si meltwater runoff from a Greenland Ice Sheet catchment. Glacier has lightest measured in running waters (−0.25 ± 0.12‰), significantly lower than nonglacial rivers (1.25 0.68‰), such that overall decline glacial since Last Glacial Maximum (LGM) explain 0.06–0.17‰ observed ocean rise (0.5–1.0‰). A marine sediment core proximal to Iceland provides further for transient, low-δ pulses termination. Diatom uptake LGM was likely similar present day due an expanded inventory, which raises possibility feedback between sheet expansion, enhanced export reduced CO 2 concentration atmosphere, because importance diatoms biological carbon pump.