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| Titel |
A global model of carbon, nitrogen and phosphorus cycles for the terrestrial biosphere |
| VerfasserIn |
Y. P. Wang, R. M. Law, B. Pak |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 7 ; Nr. 7, no. 7 (2010-07-23), S.2261-2282 |
| Datensatznummer |
250004904
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| Publikation (Nr.) |
 copernicus.org/bg-7-2261-2010.pdf |
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| Zusammenfassung |
Carbon storage by many terrestrial ecosystems can be
limited by nutrients, predominantly nitrogen (N) and phosphorus (P), in
addition to other environmental constraints, water, light and temperature.
However the spatial distribution and the extent of both N and P limitation
at the global scale have not been quantified. Here we have developed a
global model of carbon (C), nitrogen (N) and phosphorus (P) cycles for the
terrestrial biosphere. Model estimates of steady state C and N pool sizes
and major fluxes between plant, litter and soil pools, under present climate
conditions, agree well with various independent estimates. The total amount
of C in the terrestrial biosphere is 2767 Gt C, and the C fractions in
plant, litter and soil organic matter are 19%, 4% and 77%. The
total amount of N is 135 Gt N, with about 94% stored in the soil, 5%
in the plant live biomass, and 1% in litter. We found that the estimates
of total soil P and its partitioning into different pools in soil are quite
sensitive to biochemical P mineralization. The total amount of P (plant
biomass, litter and soil) excluding occluded P in soil is 17 Gt P in the
terrestrial biosphere, 33% of which is stored in the soil organic matter
if biochemical P mineralization is modelled, or 31 Gt P with 67% in soil
organic matter otherwise.
This model was used to derive the global distribution and uncertainty of N
or P limitation on the productivity of terrestrial ecosystems at steady
state under present conditions. Our model estimates that the net primary
productivity of most tropical evergreen broadleaf forests and tropical
savannahs is reduced by about 20% on average by P limitation, and most of
the remaining biomes are N limited; N limitation is strongest in high
latitude deciduous needle leaf forests, and reduces its net primary
productivity by up to 40% under present conditions. |
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