Petroleum-related hydrocarbons in deep and subsurface sediments from South-Western Barents Sea

Stepan Boitsov (1) , Vera Petrova (2) , Henning K.B. Jensen , Anna Kursheva (2) , Ivan Litvinenko (2) , Yifeng Chen , Jarle Klungsøyr (1)

1 IMR - Institute of Marine Research [Bergen]
2 Academician I.S. Gramberg All-Russia Research Institute for Geology and Mineral Resources of the World Ocean (VNIIO)

Subsurface sediments from a pockmark area in South-Western Barents Sea have been earlier found to contain elevated levels of petroleum-related polycyclic aromatic hydrocarbons. This work describes a comprehensive analysis of various biomarkers, including the highly source-specific hopanes, in a 4.5 m long gravity core from the same area, together with subsurface sediment samples from other areas in the region without pockmarks present ("background samples"). A clear difference between the pockmark gravity core and the background sediment cores was found, both with regard to genesis and the level of transformation of organic matter. A number of indicator parameters, such as methylphenanthrene index (MPI-1), point towards a significantly higher maturity of hydrocarbons in the pockmark core throughout its length as compared to the other sampled locations. Higher contents of microbial hopanoids (hopenes) may indicate the former presence of petroleum. These findings confirm the hypothesis of a natural hydrocarbon source in the deeper strata present in the studied location with pockmarks.

Mots clés: Biomarkers; hopanes; sediments; pockmarks; PAH; alkanes; Barents Sea

Domaines: Sciences du Vivant [q-bio]

Stepan Boitsov, Vera Petrova, Henning K.B. Jensen, Anna Kursheva, Ivan Litvinenko, et al.. Petroleum-related hydrocarbons in deep and subsurface sediments from South-Western Barents Sea. Marine Environmental Research, 2011, ⟨10.1016/j.marenvres.2011.04.003⟩. ⟨hal-00703485⟩