Unravelling the Role of Proglacial Lake Changes on Coastal Dynamics in Greenland

Climate changes are pronounced in Arctic regions and increase the vulnerability of the landscape and coastal zone. The rivers originating from the GrIS, local icecaps and glaciers transport sediment and nutrients towards the ocean, but these sediment fluxes are poorly constrained, and are controlled by sources and sinks en route. Recent work[1] shows that the magnitude of glacially-derived sediment transport to the oceans is sufficient to affect proglacial morphology and deposition in marine environments. Changes in geomorphological features and climatic events have the potential to affect Arctic river and delta dynamics.

This work focus on how proglacial lakes can act as both sources and sinks of sediments. 1) Acting as sinks by storing water, sediment and nutrients in lakes located between the glacier and the coast and thereby recording glacier dynamics and glaciations. Sediment will be trapped in lakes en route from the icesheet to the ocean, where material is sorted and the lakes thereby store the sediment. Or 2) by acting as sediment sources as lakes dammed by glacier tongues or moraines, periodically burst during glacier lake outburst floods (GLOFs) and catastrophically drain and transport sediments and nutrients through the fluvial system to the coast^2, with potentially hazardous consequences to human infrastructure.

Exploiting remote sensing and modelling we use an explorative approach to understand process interactions and estimate the relative importance of proglacial morphological features on delta dynamics in Greenland. Improving our knowledge on landscape changes, advances our understanding of how climatic drivers affect the landscape and the coast ultimately to benefit the indigenous people of the Arctic.

1 Bendixen, M., Iversen L.L., Bjørk A.A., Elberling B., Westergaard-Nielsen A., Overeem I., Barnhart K., Khan S.A., Box J.E., Abermann J., Langley K. and Kroon A. (2017): Delta progradation in Greenland driven by increasing glacial mass loss. Nature 550, p. 101-104. DOI:10.1038/nature23873

2 Ladegaard-Pedersen, P. Sigsgaard, C., Kroon, A., Abermann, J., Skov, K., Elberling B. (2017): Suspended sediment in a high-Arctic river: An appraisal of flux estimation methods. Science of the Total Environment (580), 582-592. https://doi.org/10.1016/j.scitotenv.2016.12.006