Earth and Planetary Sciences (all); General Earth and Planetary Sciences
Abstract :
[en] 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.
Disciplines :
Earth sciences & physical geography
Author, co-author :
Overeem, I. ; Community Surface Dynamics Modeling System, INSTAAR, University of Colorado, Boulder, United States
Hudson, B.D.; Community Surface Dynamics Modeling System, INSTAAR, University of Colorado, Boulder, United States ; Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, United States
Syvitski, J.P.M.; Community Surface Dynamics Modeling System, INSTAAR, University of Colorado, Boulder, United States
Mikkelsen, A.B.; Department of Geoscience and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
Hasholt, B.; Department of Geoscience and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
Van Den Broeke, M.R.; IMAU, Utrecht University, Utrecht, Netherlands
Noël, Brice ; Université de Liège - ULiège > Département de géographie > Climatologie et Topoclimatologie ; IMAU, Utrecht University, Utrecht, Netherlands
Morlighem, M. ; Department of Earth System Science, University of California, Irvine, United States
Language :
English
Title :
Substantial export of suspended sediment to the global oceans from glacial erosion in Greenland
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