Changes in nitrogen cycling during the past century in a northern hardwood forest


Show simple item record McLauchlan, Kendra K. Craine, Joseph M. Oswald, W. Wyatt Leavitt, Peter R. Likens, Gene E. 2009-11-02T21:59:18Z 2009-11-02T21:59:18Z 2009-11-02T21:59:18Z
dc.description.abstract Nitrogen (N) availability, defined here as the supply of N to terrestrial plants and soil microorganisms relative to their N demands, limits the productivity of many temperate zone forests and in part determines ecosystem carbon (C) content. Despite multidecadal monitoring of N in streams, the long-term record of N availability in forests of the northeastern United States is largely unknown. Therefore, although these forests have been receiving anthropogenic N deposition for the past few decades, it is still uncertain whether terrestrial N availability has changed during this time and, subsequently, whether forest ecosystems have responded to increased N deposition. Here, we used stable N isotopes in tree rings and lake sediments to demonstrate that N availability in a northeastern forest has declined over the past 75 years, likely because of ecosystem recovery from Euro-American land use. Forest N availability has only recently returned to levels forecast from presettlement trajectories, rendering the trajectory of future forest N cycling uncertain. Our results suggest that chronic disturbances caused by humans, especially logging and agriculture, are major drivers of terrestrial N cycling in forest ecosystems today, even a century after cessation. en_US
dc.relation.uri en_US
dc.subject 15N en_US
dc.subject Land use history en_US
dc.subject Mirror Lake en_US
dc.subject Nitrogen availability en_US
dc.subject Paleoecology en_US
dc.title Changes in nitrogen cycling during the past century in a northern hardwood forest en_US
dc.type Article (publisher version) en_US 2007 en_US
dc.citation.doi 10.1073/pnas.0701779104 en_US
dc.citation.epage 7470 en_US
dc.citation.issn 0027-8424 en_US
dc.citation.issue 18 en_US
dc.citation.jtitle Proceedings of the National Academy of Sciences USA en_US
dc.citation.spage 7466 en_US
dc.citation.volume 104 en_US
dc.contributor.authoreid mclauch en_US

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