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| Titel |
On the potential vegetation feedbacks that enhance phosphorus availability – insights from a process-based model linking geological and ecological timescales |
| VerfasserIn |
C. Buendía, S. Arens, T. Hickler, S. I. Higgins, P. Porada, A. Kleidon |
| 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 ; 11, no. 13 ; Nr. 11, no. 13 (2014-07-09), S.3661-3683 |
| Datensatznummer |
250117509
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| Publikation (Nr.) |
 copernicus.org/bg-11-3661-2014.pdf |
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| Zusammenfassung |
| In old and heavily weathered soils, the availability of P might be
so small that the primary production of plants is limited. However,
plants have evolved several mechanisms to actively take up P from
the soil or mine it to overcome this limitation. These mechanisms
involve the active uptake of P mediated by mycorrhiza, biotic
de-occlusion through root clusters, and the biotic enhancement of
weathering through root exudation. The objective of this paper is to
investigate how and where these processes contribute to alleviate P
limitation on primary productivity. To do so, we propose
a process-based model accounting for the major processes of the
carbon, water, and P cycles including chemical weathering at the
global scale. Implementing P limitation on biomass synthesis allows
the assessment of the efficiencies of biomass production across
different ecosystems. We use simulation experiments to assess the relative
importance of the different uptake mechanisms to alleviate P
limitation on biomass production.
We find that active P uptake is an essential mechanism for
sustaining P availability on long timescales, whereas biotic
de-occlusion might serve as a buffer on timescales shorter than
10 000 yr. Although active P uptake is essential for
reducing P losses by leaching, humid lowland soils reach P
limitation after around 100 000 yr of soil evolution. Given
the generalized modelling framework, our model results compare
reasonably with observed or independently estimated patterns and
ranges of P concentrations in soils and vegetation. Furthermore, our
simulations suggest that P limitation might be an important driver
of biomass production efficiency (the fraction of the gross primary
productivity used for biomass growth), and that vegetation on old
soils has a smaller biomass production rate when P becomes limiting.
With this study, we provide a theoretical basis for investigating
the responses of terrestrial ecosystems to P availability linking
geological and ecological timescales under different environmental
settings. |
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