The characteristics and sources of surface sediments in the Pearl River Estuary and its adjacent shelves
珠江口及近海表层沉积有机质的特征和来源

The authors study the characteristics and sources of organic carbon, nitrogen and the hydrolysable amino acids (THAA), total carbohydrates (TCHO), total lipid and acid-insoluble organic compounds (AIOC) in the surface sediments of the Pearl River Estuary (PRE) and its adjacent shelves. The results show that the organic matter in the PRE was mainly derived from mixed sources of terrestrial and aquatic origins, whereas the organic matter in the adjacent shelves was predominantly algal-derived. Terrestrial higher plants were rich in more lignin and cellulose, which were exported to the PRE. As a result, the content of TCHO in the sediment of the estuary was higher than that in the adjacent shelves, while the content of aquatic organic matter in the estuary was close to that in the adjacent shelves. The proportions of THAA and TCHO were 56%, 48% and 19% in plankton, suspended particulate and surface sediment, respectively; suggesting that the organic matter had undergone degradation during the sedimentation to the water-sediment interface.