학술논문
A Coherent Signature of Anthropogenic Nitrogen Deposition to Remote Watersheds of the Northern Hemisphere.
Document Type
Article
Author
Holtgrieve, Gordon W., ; Schindler, Daniel E.; Hobbs, William O.; Leavitt, Peter R.; Ward, Eric J.; Bunting, Lynda; Chen, Guangjie; Finney, Bruce P.; Gregory-Eaves, Irene; Lisac, Mark J.; Lisi, Peter J.; Nydick, Koren; Regers, Lauren A.; Saros, Jasmine E.; Selbie, Daniel T.; Shapley, Mark D.; Walsh, Patrick B.; Wolfe, Alexander P.; Holmgren, Sofia
Source
Subject
Language
ISSN
00368075
Abstract
Humans have more than doubled the amount of reactive nitrogen (Nr) added to the biosphere, yet most of what is known about its accumulation and ecological effects is derived from studies of heavily populated regions. Nitrogen (N) stable isotope ratios (15 N:14 N) in dated sediments from 25 remote Northern Hemisphere lakes show a coherent signal of an isotopically distract source of N to ecosystems beginning in 1895 ± 10 years (±1 standard deviation). Initial shifts in N isotope composition recorded in lake sediments coincide with anthropogenic CO2 emissions but accelerate with widespread industrial Nr production during the past half century. Although current atmospheric Nr deposition rates in remote regions are relatively low, anthropogenic N has probably influenced watershed N budgets across the Northern Hemisphere for over a century. [ABSTRACT FROM AUTHOR]