Regional Patterns in Foliar super(15)N Across a Gradient of Nitrogen Deposition in the Northeastern US

• Published in: Environmental pollution (1987) Vol. 149; no. 3; p. 293
• Main Authors: Pardo, Linda H, McNulty, Steven G, Boggs, Johnny L, Duke, Sara
• Format: Journal Article
• Language: English
• Published: 01.10.2007
• ISSN: 0269-7491

Regional patterns in foliar super(15)N across a gradient of nitrogen (N) deposition in the northeastern US were investigated. Foliar delta super(15)N at 11 high-elevation spruce-fir stands along an N deposition gradient in 1987-1988 and at seven paired northern hardwood and spruce-fir stands in 1999 were investigated. It was difficult to interpret the results because some of the data suggested that the sites were progressing toward N saturation. Other patterns did not suggest direct movement of the sites along the continuum of N saturation. The results showed that at many sites across the region, stream water nitrate concentration decreased to very low levels, which was consistent with movement away from the condition of N saturation.