Coastal erosion vs riverine sediment discharge in the Arctic Shelf seas

This article presents a comparison of sediment input by rivers and by coast al erosion into both the Laptev Sea and the Canadian Beaufort Sea (CBS). Ne w data on coastal erosion in the Laptev Sea, which are based on field measu rements and remote sensing information, and existing data on coastal erosio n in the CBS as well as riverine sediment discharge into both the Laptev Se a and the CBS are included. Strong regional differences in the percentages of coastal erosion and riverine sediment supply are observed. The CBS is do minated by the riverine sediment discharge (64.45x10(6) t a(-1)) mainly of the Mackenzie River, which is the largest single source of sediments in the Arctic. Riverine sediment discharge into the Laptev Sea amounts to 24.10x1 0(6) t a(-1), more than 70% of which an related to the Lena River. In compa rison with the CBS, the Laptev Sea coast on average delivers approximately twice as much sediment mass per kilometer, a result of higher erosion rates due to higher cliffs and seasonal ice melting. Ln the Laptev Sea sediment input by coastal erosion (58.4x10(6) t a(-1)) is therefore more important t han in the CBS and the ratio between riverine and coastal sediment input am ounts to 0.4. Coastal erosion supplying 5.6x10(6) t a(-1) is less significa nt for the sediment budget of the CBS where riverine sediment discharge exc eeds coastal sediment input by a factor of ca. 10.