Isotopic signature of nitrate in two contrasting watersheds of Brush Brook,Vermont, USA |
| |
| Authors: | Heidi C Hales Donald S Ross Andrea Lini |
| |
| Institution: | (1) Department of Environmental Conservation, 103 S. Main St., Waterbury, VT 05671, USA;(2) Department of Plant and Soil Science, University of Vermont, Burlington, VT 05405, USA;(3) Department of Geology, University of Vermont, Burlington, VT 05405, USA |
| |
| Abstract: | We used the dual isotope method to study differences in nitrate export in two subwatersheds in Vermont, USA. Precipitation,
soil water and streamwater samples were collected from two watersheds in Camels Hump State Forest, located within the Green
Mountains of Vermont. These samples were analyzed for the δ15N and δ18O of NO3−. The range of δ15N–NO3− values overlapped, with precipitation −4.5‰ to +2.0‰ (n = 14), soil solution −10.3‰ to +6.2‰ (n = 12) and streamwater +0.3‰ to +3.1‰ (n = 69). The δ18O of precipitation NO3− (mean 46.8 ± 11.5‰) was significantly different (P < 0.001) from that of the stream (mean 13.2 ± 4.3‰) and soil waters (mean 14.5 ± 4.2‰) even during snowmelt periods. Extracted
soil solution and streamwater δ18O of NO3− were similar and within the established range of microbially produced NO3−, demonstrating that NO3− was formed by microbial processes. The δ15N and δ18O of NO3− suggests that although the two tributaries have different seasonal NO3− concentrations, they have a similar NO3− source. |
| |
| Keywords: | δ 15N δ 18O Nitrate Nitrogen isotopes Oxygen isotopes Vermont |
| 本文献已被 SpringerLink 等数据库收录！ |
|
