부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ecss.2006.08.016 Byline: Y. Wu (a), J. Zhang (a)(b), S.M. Liu (b), Z.F. Zhang (c), Q.Z. Yao (a), G.H. Hong (d), L. Cooper (e) Abstract: Dissolved, particulate, soil and plant samples were collected from the Yangtze River (Changjiang) system in May 1997 and May 2003 to determine the sources and distribution of organic and inorganic matter within the river system. Average dissolved organic carbon (DOC) concentrations within the main stream were 105[mu]M C in 1997 and 108[mu]M C in 2003. Particulate organic carbon (POC) ranged from 0.5% to 2.5% of total suspended matter (TSM). Both dissolved inorganic carbon (DIC) and particulate inorganic carbon (PIC) concentrations decreased from upper to lower reaches of the river, within the ranges 1.2-2.7mM and 0.08-4.3% of TSM, respectively. [delta].sup.13C and [delta].sup.15N values for tributaries and the main stream varied from -26.8a[degrees] to -25.1a[degrees] and 2.8a[degrees] to 6.0a[degrees], respectively. A large spatial variation in particulate organic matter (POM) is recorded along the main stream, probably due to the contributions of TSM from major tributaries and POM input from local vegetation sources. The dominance of C-3 plants throughout the entire basin is indicated by [delta].sup.13C and [delta].sup.15N values, which range from -28.8a[degrees] to -24.3a[degrees] and from -0.9a[degrees] to 5.5a[degrees], respectively. The [delta].sup.13C and [delta].sup.15N values of organic matter within surface soil from alongside tributaries and the main stream vary from -28.9a[degrees] to -24.3a[degrees] and 2.7a[degrees] to 4.5a[degrees], respectively. Although these differences are subtle, there is a slight enrichment of.sup.15N in soils along the main stream. Various approaches, such as C/N and stable isotopes, were used to trace the sources of organic matter within the river. Riverine POM is mostly derived from soil; the contribution from phytoplankton is minor and difficult to trace via the composition of particles. POC flux has decreased from >5x10.sup.6 tyr.sup.-1 during the period 1960-1980 to about 2x10.sup.6 tyr.sup.-1 in 1997. This trend can be explained by decreasing sediment load within the Yangtze River. The export of TOC from the Yangtze River at the end of the 20th Century is approximately equivalent to that of the Zaire River, less than that of the Amazon River, and higher than that of other large rivers such as the Mississippi. Large amounts of DOC and POC were transported to coastal areas of the East China Sea over a short period during 1998 flood events, containing large amounts of nutrients and pollutants. Such an event could be an important trigger for coastal environmental problems and changes to the health of ecosystems. Author Affiliation: (a) State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 3663 North Zhongshan Road, 200062 Shanghai, P.R. China (b) Department of Marine Chemistry and Chemical Engineering, Ocean University of China, 5 Yushan Road, 266003 Qingdao, P.R. China (c) Nantong Institute of Environmental Sciences, 11 Qianjin Road, 314151 Nantong, P.R. China (d) Korea Ocean Research and Development Institute, Ansan P.O. Box 29, Seoul 425-600, South Korea (e) Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN 37996-1610, USA Article History: Received 9 August 2005; Accepted 10 August 2006