Journal of Geographical Sciences ›› 2008, Vol. 18 ›› Issue (1): 46-58.doi: 10.1007/s11442-008-0046-0

• Climate and Environmental Change • Previous Articles     Next Articles

Spatial distributions of organic carbon and nitro-gen and their isotopic compositions in sediments of the Changjiang Estuary and its adjacent sea area

GAO Jianhua1, WANG Yaping1, PAN Shaoming1, ZHANG Rui1, LI Jun2, BAI Fenglong1   

  1. 1. Key Laboratory of Coast and Island Development of Ministry of Education, Nanjing University, Nanjing 210093, China|
    2. Qingdao Institute of Marine Geology, Qingdao 266071, China
  • Received:2007-08-10 Revised:2007-09-29 Online:2008-02-25 Published:2008-02-25
  • Supported by:

    National Basic Research Program of China, No.2002CB412401; National Natural Science Foundation of China, No.40506022; No.40506013; Natural Science Foundation of Jiangsu Province, No.BK2006131

Abstract:

The spatial distribution patterns of total organic carbon and total nitrogen show significant correlations with currents of the East China Sea Shelf. Corresponding to distribu-tions of these currents, the study area could be divided into four different parts. Total organic carbon, total nitrogen, and organic carbon and nitrogen stable isotopes in sediments show linear correlations with mean grain size, respectively, thus “grain size effect” is an important factor that influences their distributions. C/N ratios can reflect source information of organic matter to a certain degree. In contrast, nitrogen stable isotope shows different spatial distri-bution patterns with C/N and organic carbon stable isotope, according to their relationships and regional distributions. The highest contribution (up to 50%) of terrestrial organic carbon appears near the Changjiang Estuary with isolines projecting towards northeast, indicating the influence of the Changjiang dilution water. Terrestrial particulate organic matter suffers from effects of diagenesis, benthos and incessant inputting of dead organic matter of plankton, after depositing in seabed. Therefore, the contribution of terrestrial organic carbon to par-ticulate organic matter is obviously greater than that to organic matter in sediments in the same place.

Key words: total organic carbon, total nitrogen, stable carbon and nitrogen isotopes, material sources, Changji-ang Estuary and its adjacent sea area