The hydrocarbon compounds sources in surface sediments of the Laptev Sea shelf

Abstract

Rapid warming of the Arctic provokes large-scale degradation of permafrost on land terrestrial and in submarines. A vast amount of remobilized organic matter (OM) is involved in the modern biogeochemical cycle. Understanding of the fate of terrestrial OM moving from the land to the Arctic shelf is essential for predicting the potential feedback of Arctic ecosystems. In our research, an attempt was made to characterize the modern OM stored in the surface sediments of the Laptev Sea to estimate its composition variability and to identify the OM sources along with the “coastline - outer shelf” profile. Here we discuss the OM features revealed by Rock-Eval pyrolysis (RE) and the distribution of n-alkanes in combination with sediment grain-size analysis. The GC/MS records are directly comparable with RE data tracing the terrestrial OM along with the entire studied profile. However, we observe both a significant decline of terrestrial input and the rise of hydrobiont in the outer shelf zone. We assume that different OM sources may produce different ranges of RE values.