Fatty acids and their carbon isotopes in surface sediments from the Pearl River Estuary and northwestern South China Sea

Here, we examined source-specific biomarker (normal fatty acids (n-FAs)) contents and isotope compositions in surface sediments in an alongshore transect southwestward from the Pearl River mouth.

The C~28+30~ rather than other long-chain n-FAs were found to be the most representative for OC~terr~, and a plant wax mean residence time (MRT) of 3060 ± 90 yr was estimated in the Pearl River watershed from the ¹⁴C age of C~28+30~ n-FA in the river mouth sample. A four-source mixing model demonstrated that the mean burial efficiency of fossil and soil OC is 85% and 49%, respectively, indicating the refractory nature of fossil OC but a significant loss of soil OC due to remineralization during transport in the marine environment before final burial.