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Substantial export of suspended sediment to the global oceans from glacial erosion in Greenland

Nature Geoscience volume 10, pages 859863 (2017) | Download Citation

Abstract

Limited measurements along Greenland’s remote coastline hamper quantification of the sediment and associated nutrients draining the Greenland ice sheet, despite the potential influence of river-transported suspended sediment on phytoplankton blooms and carbon sequestration. Here we calibrate satellite imagery to estimate suspended sediment concentration for 160 proglacial rivers across Greenland. Combining these suspended sediment reconstructions with numerical calculations of meltwater runoff, we quantify the amount and spatial pattern of sediment export from the ice sheet. We find that, although runoff from Greenland represents only 1.1% of the Earth’s freshwater flux, the Greenland ice sheet produces approximately 8% of the modern fluvial export of suspended sediment to the global ocean. Sediment loads are highly variable between rivers, consistent with observed differences in ice dynamics and thus with control by glacial erosion. Rivers that originate from deeply incised, fast-moving glacial tongues form distinct sediment-export hotspots: just 15% of Greenland’s rivers transport 80% of the total sediment load of the ice sheet. We conclude that future acceleration of melt and ice sheet flow may increase sediment delivery from Greenland to its fjords and the nearby ocean.

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Acknowledgements

I.O. and B.H. were supported by NSF-OPP award ARC-0909349. M.R.v.d.B. and B.P.Y.N. received funding from NWO/NPP and the Netherlands Earth System Science Centre (NESSC). We thank I. Joughin and E. Enderlin for data sharing. S. Frye, NASA-GSFC, enabled acquisition of ALI imagery.

Author information

Affiliations

  1. Community Surface Dynamics Modeling System, INSTAAR, University of Colorado, Boulder, Colorado 80303, USA

    • I. Overeem
    • , B. D. Hudson
    •  & J. P. M. Syvitski
  2. Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, Washington 98105, USA

    • B. D. Hudson
  3. Department of Geoscience and Natural Resource Management, University of Copenhagen, 1350 Copenhagen, Denmark

    • A. B. Mikkelsen
    •  & B. Hasholt
  4. IMAU, Utrecht University, 3584 CC Utrecht, the Netherlands

    • M. R. van den Broeke
    •  & B. P. Y. Noël
  5. Department of Earth System Science, University of California, Irvine, California 92697, USA

    • M. Morlighem

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Contributions

I.O. and B.H. designed the study and implemented the analysis. J.P.M.S., B.H., A.B.M. M.R.v.d.B., M.M. and B.P.Y.N. contributed to data analysis. I.O. authored the manuscript, all co-authors contributed to the writing.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to I. Overeem.

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DOI

https://doi.org/10.1038/ngeo3046

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