Sediment accumulation and carbon burial rates in subpolar fjords of Svalbard, European Arctic

The Svalbard region is particularly sensitive to global climate changes as proved by modern monitoring data and the past records. One of the most evident results is rapid retreat of 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 impact of these changes on sediment accumulation rates and carbon burial rate. The study reviews the existing data and provide new high resolution results on ²¹⁰Pb and ¹³⁷Cs-based sediment accumulation as well as organic carbon burial rates from a dozen of cores collected in Hornsund fjord, western Spitsbergen. The results prove the sediment accumulation rate to be in order of several mm to several cm/year and large increase in the area of high accumulation rate due to rapid glaciers retreat and formation of new inner fjord bays. In consequence, the total amount of sediment stored in the fjord increases, as well as increase the carbon burial rates. The available data suggest that this kind of fjords may serve as significant sediment and carbon sinks, largely exceeding other polar marine environments. The study was funded by Polish National Science Centre grant No. 2013/10/E/ST10/00166.