Abstract: The sources of atmospheric N, atmospheric N deposition and N transport were studied in Guiyang area using tissue N contents and N isotope in epilithic mosses. The result s indicated that tissue N contents in epilithic mosses can be used to show the spatial variat ion of atmospheric N deposition. The significant difference in nitrogen isotopic ratios between urban and suburban ( or rural) epilithic mosses was suggestive of two atmospheric N sources. More positive δ
15N values in epilithic mosses from urban to rural sites reflected the decrease of urban-derived N and the increase of agricultural-derived N. In Guiyang area, N contents in epilithic mosses exponentially decreased with the distance from the city center ( y = 1. 5e
- 0. 13x + 1. 26) while the δ
15 N values logarithmically increased with the distance [ y= 2. 54ln ( x ) - 12.227] , suggesting that urban-derived NH x decreased with the distance during its transport . The above equation was resolved using a limit at ion method. The results showed that the distance influenced by urban-derived NHx w as < 41 km and agricultural-derived NH x turned to be more important than urban-derived NHx beyond the distance of 17. 2 km.
Key words: N sources; Atmospheric N deposition; N transport ; N isotope; epilithic moss; Guiyang area
*Corresponding Author, E-Mail: xiaohuayun@vip.skleg.cn
Bulletin of Mineralogy, Petrology and Geochemistry Vol. 30, No.1, 2011, page 18-25
(Source from http://www.cnki.com.cn/)
