Post-Little Ice Age increase in sediment accumulation and carbon burial rates in subpolar fjords of Svalbard, European Arctic

Abstract:

The Arctic areas, like Svalbard, are particularly sensitive to global climate changes as proved by modern monitoring data and the past records. One of the most spectacular changes is the rapid retreat of tidewater glaciers during the post-Little Ice Age period (after ~1900) observed in many subpolar fjords in Svalbard. The goal of this study is to assess if the observed changes affected sediment accumulation and carbon burial rates. The study reviews the existing data and new results on ²¹⁰Pb and ¹³⁷Cs based accumulation rates, as well as organic carbon content from Hornsund, Tempelfjorden and Kongsfjorden - the major fjords of western Spitsbergen. In the central parts of the fjords the sediment accumulation rates are generally in the order of several mm per year and in most cases significantly increased after the Little Ice Age. Consequently, also the carbon burial rates have increased. Moreover, due to the retreat, new bays often with area of several km² each and characterised by very high sediment accumulation rates (several cm/year) have been formed in the inner parts of the fjords. They may potentially store large amounts of sediment and carbon. The available data suggest that this kind of fjords may serve as significant sediment and carbon sinks. The study was funded by Polish National Science Centre grant No. 2013/10/E/ST10/00166.