Greenland glaciers melt and slide faster when in contact with warm, salty, subsurface ocean water. Additionally, where glaciers slide, they erode their bed, producing large volumes of sediments and transporting them to the ice margin where they accumulate. The large volumes of sediment accumulation can affect the retreat dynamics by forming shoals that buttress the termini and decrease the surface area available for submarine melting. However, how exactly this works is not yet fully understood due to a lack of observation.
To improve this understanding, we will determine the rate of sediment production by glacial erosion from field measurements of bathymetry, water characteristics, and sediment yields at each of the super-sites, over a wide range of climatic settings, with mean annual air temperature ranging from near 0°C in the South to -10 °C in the North.
Quantifying the fluxes of freshwater and sediment is of broader interest because these fluxes deliver substantial amounts of bio-essential nutrients to downstream ecosystems locally and regionally, and they figure in global geochemical cycles. For instance, a recent study suggests that 8 % of modern export of suspended sediments from the continents to the oceans globally may come from the Greenland icesheet alone. This volume is considerable and has diverse, significant implications. There is therefore a need to quantify the current fluxes and to project how they are likely evolving in the future.