[Profile distribution and accumulation characteristics of organic carbon and total nitrogen in typical marshes in Sanjiang Plain].

The study on the profile distribution and accumulation characteristics of organic carbon (C) and total nitrogen (N) in two typical marshes in Sanjiang Plain showed that on the sediment profiles of Carex lasiocarpa marsh and Phragmites communis marsh, there existed distinct deposition horizon and illuviation horizon. In deposition horizon (0-60 cm), the average contents of organic C and total N were about 96 and 184 g x kg(-1), and 7.4 and 17.6 g x kg(-1), respectively, while in illuviation horizon, they were at low level. The contents of organic C and total N were exponentially decreased with increasing depth, and had significant correlations with bulk density (P < 0.01). The organic C density was the highest at the depth of 20-40 cm. In the deposition horizon of the two marshes, the stocks of organic C and total N were 1.83 x 10(4) and 1.73 x 10(4) t x km(-2), and 1.45 x 10(3) and 1.67 x 10(3) t x km(-2), respectively, and at the depth of 0-100 cm, they were 2.86 x 10(4) and 2.62 x 10(4) t x km(-2), and 2.18 x 10(3) and 2.49 x 10(3) t x km(-2), respectively. Vegetation type had definite effects on the content and stock of organic C and total N in the marsh profiles.