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

I.A Oberemok,E.V Gershelis,V.S Litvinenko

doi:10.1051/e3sconf/202126608006

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.

Highlights

Increasing global warming in the Arctic leads to a significant rate of terrestrial and submarine permafrost degradation [1,2]
According to the pyrolysis data, total organic carbon (TOC) varies from 0.4 to 2.71 wt%, which is consistent with previous studies in the region [24]
The predominantly higher TOC and S1 values are found in the coastal zone (> 1 wt% and > 0.4 mg HC/g, respectively) (Figure 2)

Summary

Introduction

Increasing global warming in the Arctic leads to a significant rate of terrestrial and submarine permafrost degradation [1,2]. It was shown that an increased supply of remobilized (“old”) OC may lead to severe acidification [5] of the Arctic waters and significantly contribute to the greenhouse effect as a result of the OC to CO2 transformation [6]. About 44 ± 10 Mt [7] of terrestrial OC is exported to the East Siberian Arctic shelf by coastal erosion only. Reliable identification of both OM sources and the mechanisms of its transformation within the “land – shelf” system is an important step towards a comprehensive understanding of the modern Arctic carbon cycle. We can observe that the most vulnerable region is the most severe recipient of climate change, and this situation requires a detailed complex study

Methods

Results

Conclusion