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| Titel |
A new model of Holocene peatland net primary production, decomposition, water balance, and peat accumulation |
| VerfasserIn |
S. Frolking, N. T. Roulet, E. Tuittila, J. L. Bubier, A. Quillet, J. Talbot, P. J. H. Richard |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2190-4979
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| Digitales Dokument |
URL |
| Erschienen |
In: Earth System Dynamics ; 1, no. 1 ; Nr. 1, no. 1 (2010-10-04), S.1-21 |
| Datensatznummer |
250000124
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| Publikation (Nr.) |
 copernicus.org/esd-1-1-2010.pdf |
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| Zusammenfassung |
| Peatland carbon and water cycling are tightly coupled, so dynamic modeling
of peat accumulation over decades to millennia should account for
carbon-water feedbacks. We present initial results from a new simulation
model of long-term peat accumulation, evaluated at a well-studied temperate
bog in Ontario, Canada. The Holocene Peat Model (HPM) determines vegetation
community composition dynamics and annual net primary productivity based on
peat depth (as a proxy for nutrients and acidity) and water table depth.
Annual peat (carbon) accumulation is the net balance above- and below-ground
productivity and litter/peat decomposition – a function of peat hydrology
(controlling depth to and degree of anoxia). Peat bulk density is simulated
as a function of degree of humification, and affects the water balance
through its influence on both the growth rate of the peat column and on peat
hydraulic conductivity and the capacity to shed water. HPM output includes
both time series of annual carbon and water fluxes, peat height, and water
table depth, as well as a final peat profile that can be "cored" and
compared to field observations of peat age and macrofossil composition. A
stochastic 8500-yr, annual precipitation time series was constrained by a
published Holocene climate reconstruction for southern Québec. HPM
simulated 5.4 m of peat accumulation (310 kg C m-2) over 8500 years,
6.5% of total NPP over the period. Vascular plant functional types
accounted for 65% of total NPP over 8500 years but only 35% of the
final (contemporary) peat mass. Simulated age-depth and carbon accumulation
profiles were compared to a radiocarbon dated 5.8 m, c.9000-yr core. The
simulated core was younger than observations at most depths, but had a
similar overall trajectory; carbon accumulation rates were generally higher
in the simulation and were somewhat more variable than observations. HPM
results were sensitive to century-scale anomalies in precipitation, with
extended drier periods (precipitation reduced ∼10%) causing the
peat profile to lose carbon (and height), despite relatively small changes
in NPP. |
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