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Nitrogen limitation constrains sustainability of ecosystem response to CO2.

Authors :
Reich, Peter B.
Hobbie, Sarah E.
Lee, Tali
Ellsworth, David S.
West, Jason B.
Tilman, David
Knops, Johannes M. H.
Naeem, Shahid
Trost, Jared
Source :
Nature; 4/13/2006, Vol. 440 Issue 7086, p922-925, 4p, 1 Chart, 1 Graph
Publication Year :
2006

Abstract

Enhanced plant biomass accumulation in response to elevated atmospheric CO<subscript>2</subscript> concentration could dampen the future rate of increase in CO<subscript>2</subscript> levels and associated climate warming. However, it is unknown whether CO<subscript>2</subscript>-induced stimulation of plant growth and biomass accumulation will be sustained or whether limited nitrogen (N) availability constrains greater plant growth in a CO<subscript>2</subscript>-enriched world. Here we show, after a six-year field study of perennial grassland species grown under ambient and elevated levels of CO<subscript>2</subscript> and N, that low availability of N progressively suppresses the positive response of plant biomass to elevated CO<subscript>2</subscript>. Initially, the stimulation of total plant biomass by elevated CO<subscript>2</subscript> was no greater at enriched than at ambient N supply. After four to six years, however, elevated CO<subscript>2</subscript> stimulated plant biomass much less under ambient than enriched N supply. This response was consistent with the temporally divergent effects of elevated CO<subscript>2</subscript> on soil and plant N dynamics at differing levels of N supply. Our results indicate that variability in availability of soil N and deposition of atmospheric N are both likely to influence the response of plant biomass accumulation to elevated atmospheric CO<subscript>2</subscript>. Given that limitations to productivity resulting from the insufficient availability of N are widespread in both unmanaged and managed vegetation, soil N supply is probably an important constraint on global terrestrial responses to elevated CO<subscript>2</subscript>. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00280836
Volume :
440
Issue :
7086
Database :
Complementary Index
Journal :
Nature
Publication Type :
Academic Journal
Accession number :
20468530
Full Text :
https://doi.org/10.1038/nature04486