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| Titel |
A high-resolution record of carbon accumulation rates during boreal peatland initiation |
| VerfasserIn |
I. F. Pendea, G. L. Chmura |
| 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 ; 9, no. 7 ; Nr. 9, no. 7 (2012-07-25), S.2711-2717 |
| Datensatznummer |
250007195
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| Publikation (Nr.) |
 copernicus.org/bg-9-2711-2012.pdf |
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| Zusammenfassung |
| Boreal peatlands are a major global C sink, thus having important feedbacks
to climate. A decreased concentration in atmospheric CO2
7000–10 000 yr ago has been linked to variations in peatland C accumulation rates
attributed to a warm climate and increased productivity. Yet, this period
also corresponds to early stages of peatland development (as peatland was
expanding) following retreat of ice sheets and increases in C storage could
be associated with wetland evolution via lake filling or following marine
shoreline emergence. Unravelling past links amongst peatland dynamics, C
storage, and climate will help us assess potential feedbacks from future
changes in these systems, but most studies are hampered by low temporal
resolution. Here we provide a decadal scale C accumulation record for a fen
that has begun transformation from salt marsh within the last 70 yr on the
isostatically rebounding coast of James Bay, Québec. We determined time
frames for wetland stages using palynological analyses to reconstruct
ecological change and 210Pb and 137Cs to date the deposit. The average
short-term C accumulation rates during the low and high tidal marsh and incipient fen
stage (42, 87 and 182 g C m−2 yr−1, respectively) were as much as six
times higher than the global long-term (millennial) average for northern
peatlands. We suggest that the atmospheric CO2 flux during the early
Holocene could be attributed, in part, to wetland evolution associated with
isostatic rebound, which makes land for new wetland formation. Future climate
warming will increase eustatic sea level, decrease rates of land emergence
and formation of new coastal wetlands, ultimately decreasing rates of C
storage of wetlands on rebounding coastlines. |
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