作 者：Cao, W.Z., Huang, Z., Zhai, W.D., Li, Y., andHong, H.S. 影响因子：2.215

刊物名称：Estuarine, Coastal and Shelf Science

出版年份：2015

卷：163 页码：37-43

Riverine export accounts for a large portion of estuarine and coastal nutrients and could lead to severe eutrophication. However, nitrogen (N) sources at the catchment scale remain unclear because of spatial and temporal variations. The stable isotope of¹⁵N, which has been proven to be effective in deducing sources and testing biogeochemical behaviours, is applied in this study to explore multiple sources of riverine N and their nutrient concentrations in the northern section of Jiulong River catchment seasonally. Results show that drastic seasonal variation in external nitrate sources occurs in the river; manure and sewage dominate during baseflows, whereas organic N in soil and atmospheric deposition dominate during stormflows. The external sources change throughout the year depending on the environmental conditions. Furthermore, riverine nitrate import in the northern Jiulong River is dominated by an external process because of the increasing NO₃^--δ¹⁵N value accompanied by an increasing NO₃^--N concentration (p < 0.05). manure and sewage show an increasing proportion of contribution to the downstream section and proximity to the estuary with high no₃^--δ¹⁵N values. Thefindings in this study highlight the fact that the isotopic composition of riverine NO₃^-- N provides effective evidence for identifying nitrate sources in catchments. The study could serve as a critical reference for nutrient management and eutrophication reversal.

Fig.6.Relationship between NO₃^--δ¹⁵N and NO₃^-- N (p =0.02).