Source of hydrocarbons in marine sediments in Lützow-Holm Bay, Antarctica

We have made an attempt to reconstruct the paleoenvironment of the coastal region around Syowa Station in Lützow-Holm Bay, Antarctica, using organic compounds in marine sediments. A 129 cm long core sample of the oceanic sediment was collected at 69°14′48″S, 39°11′33″E in Lützow-Holm Bay. 14C age showed a smooth pattern of change from about 3000 yBP at the surface to 14,000 yBP at the bottom, except for a change of age in the range of 80–120 cm depth. n-C21 was dominant in the low hydrocarbon content sections at the depths of 0–5, 60–65 and 120–125 cm of the core, whereas long-chain alkanes (C22, C23, C24) were dominant in the high hydrocarbon content sections at the depths of 45–50 and 90–95 cm. These characteristic distribution patterns of n-alkanes suggested that their major source probably is mixed altered and/or recycled material and recent organic material possibly derived from marine organisms. The differences in the δ13C values of individual alkanes from the high and low hydrocarbon content sections of the core were not appreciable, suggesting a common source for these compounds. δ13C values for organic matter in different sections of the core range from −26.0 to −28.5‰, indicating that its major source is marine organisms.