Concentration of organic compounds in the snow-ice cover of the Eastern Antarctic

This paper presents data on concentrations and composition of organic substances, lipids, and hydrocarbons, in the snow-ice cover of fast ices and continental lakes of Antarctic. It was shown that organic compounds were accumulated in layers with the most intense autochthonous processes (mainly at the snow-ice and ice-water boundaries). These zones remain active at a biogeochemical medium even at low temperatures. The maximum content of organic compounds (10-20 times that of the snow-ice cover of other regions) and a sharp change in the proportions of their migration forms in the ice volume were detected in the regions of penguin colonies (fast ice in the Buromsky Island and a lake in the Haswell Island). Contents and composition of hydrocarbons in Antarctic ices were compared with those of Arctic ices.

(Table 1) C1 - C8 volatile compounds in sediments from DSDP Leg 63 Holes

Low-temperature diagenetic reactions (less than 50°C) are held responsible for the generation of small amounts of C1-C8 hydrocarbons (less than 100 ng hydrocarbon/g dry weight of sediment) at outer continental shelf Deep Sea Drilling Project Sites 468 and 469 (sub-bottom depths 415 m and 454 m, respectively). In contrast, Site 471 shows an exponential rise in hydrocarbon yields at depths greater than 500 meters. The high yields of C4-C8 hydrocarbons (up to 30 ng hydrocarbon/g dry weight of sediment) in this area of high geothermal and volcanic activity suggest the penetration of an active petroleum-generating zone. Similar arguments apply to Site 467, where relatively high levels (up to 3 µg hydrocarbon/g dry weight sediment) occurred in very shallow (250-600 m) sediments.