Organic geochemistry of marine sediments in Antarctic region; marine lipids in McMurdo Sound
Organic Geochemistry 12(1): 0-27
ISSN/ISBN: 0146-6380 DOI: 10.1016/0146-6380(88)90111-8
The compositions of resolvable lipid components from four sediment cores (0–90 cm) of McMurdo Sound, Ross Sea, have been examined. The various lipid components occur in the following order of abundance: sterols -fatty acids > n-alcohols > n-alkanes > PAH. The data indicate that the organic matter is mainly derived from recycled kerogen mixed with modern marine input. The distribution of lipids and lignin analyses indicate that there is little recognizable higher plant debris in the sediments. The sediments contain unaltered biogenic triterpenoids, and there is no evidence for natural and/or anthropogenic petroleum influx in the region. Aeolian transport of organic carbon from the continents appears to be negligible. The dominance of labile alkenes (C25 compounds) and hopenes and the presence of unsaturated fatty acids down to a depth of 90 cm reflect a very early diagenetic stage. The persistent cold climate has probably helped in the better preservation of these labile lipids in the water column and in the young sediments. Diploptene (17(H),21(H)-hop-22(29)-ene) appeats to originate from autochthonous marine productivity in McMurdo Sound.