ORGANIC GEOCHEMICAL STUDIES OF SINKING PARTICULATE MATERIAL IN CHINA SEA AREA(I) - ORGANIC-MATTER FLUXES AND DISTRIBUTIONAL FEATURES OF HYDROCARBON COMPOUNDS AND FATTY-ACIDS

Sinking particulate material collected from Nansha Yongshu reef lagoon and the continental shelf of the East China Sea by sediment traps has been analyzed and studied for the first time using organic geochemica l method. The results show that about half of the sinking particulate organic matter in the two study areas are consumed before reaching the depth of 5 m to the sea floor and the degree of this consumption in Y ongshu reef lagoon is larger than that in the continental shelf of the East China Sea. The distributions of hydrocarbons and fatty acids ind icate that the minor difference of biological sources of sinking parti culate organic matter exists between Yongshu reel lagoon and the conti nental shelf of the East China Sea, but they mainly come from marine p lankton. Stronger biological and biochemical transformations of sinkin g particulate organic matter are also observed and the intensity oi th is transformation in Yongshu reef lagoon is greater than that in the c ontinental shelf of the East China Sea. It is found that the occurrenc e of C-25 highly branched isoprenoid (HBI) diene may be related to the composition of diatom species.