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| Titel |
Transient simulations of the carbon and nitrogen dynamics in northern peatlands: from the Last Glacial Maximum to the 21st century |
| VerfasserIn |
Renato Spahni, Fortunat Joos, Benjamin Stocker, Marco Steinacher, Zicheng Yu |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250074135
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| Zusammenfassung |
| The development of northern high-latitude peatlands played an important role in the carbon
(C) balance of the land biosphere since the Last Glacial Maximum (LGM). At present, carbon
storage in northern peatlands is substantial and estimated to be 500 ± 100 Pg C
(1 Pg C = 1015 g C). Here, we develop and apply a peatland module embedded in a dynamic
global vegetation model (LPX). The peatland module features a dynamic nitrogen cycle, a
dynamic C transfer between peatland acrotelm (upper oxic layer) and catotelm (deep anoxic
layer), hydrology- and temperature-dependent respiration rates, and peatland specific plant
functional types. Nitrogen limitation down-regulates average modern net primary
productivity over peatlands by almost a factor of two. Decadal acrotelm-to-catotelm C
fluxes vary between -20 and +50 g C m-2 yr-1 over the Holocene. Key model
parameters are calibrated with reconstructed peat accumulation rates from peat-core
data. The model reproduces the major features of the peat core data and of the
observation-based modern circumpolar soil carbon distribution. Results from a set of
simulations for possible evolutions of northern peat development and areal extent show
that soil C stocks in modern peatlands increased by 365–550 Pg C since the LGM,
of which 175–272 Pg C accumulated between 11 and 5 kyr BP. Furthermore, our
simulations suggest a persistent C sequestration rate of 35–50 Pg C per 1000 yr
in peatlands under current climate conditions, and that this C sink could either
vanish or turn into a small source by 2100 AD depending on climate trajectories
as projected for different representative greenhouse gas concentration pathways. |
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