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| Titel |
Old carbon efflux from tropical peat swamp drainage waters |
| VerfasserIn |
Leena Vihermaa, Susan Waldron, Stephanie Evers, Mark Garnett, Jason Newton |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093277
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| Publikation (Nr.) |
 EGU/EGU2014-7864.pdf |
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| Zusammenfassung |
| Tropical peatlands constitute ~12% of the global peatland carbon pool, and of this 10% is in
Malaysia1. Due to rising demand for food and biofuels, large areas of peat swamp forest
ecosystems have been converted to plantation in Southeast Asia and are being subjected to
degradation, drainage and fire, changing their carbon fluxes eg.2,3. Dissolved organic carbon
(DOC) lost from disturbed tropical peat can be derived from deep within the peat column and
be aged from centuries to millennia4 contributing to aquatic release and cycling of old
carbon.
Here we present the results of a field campaign to the Raja Musa Peat Swamp Forest
Reserve in N. Selangor Malaysia, which has been selectively logged for 80 years before being
granted timber reserve status. We measured CO2 and CH4efflux rates from drainage
systems with different treatment history, and radiocarbon dated the evasion CO2 and
associated [DOC]. We also collected water chemistry and stable isotope data from the
sites.
During our sampling in the dry season CO2 efflux rates ranged from 0.8 - 13.6 μmol m-2
s-1. Sediments in the channel bottom contained CH4 that appeared to be primarily lost by
ebullition, leading to sporadic CH4 efflux. However, dissolved CH4 was also observed in
water samples collected from these systems. The CO2 efflux was aged up to 582±37 years
BP (0 BP = AD 1950) with the associated DOC aged 495±35 years BP. Both DOC and
evasion CO2 were most 14C-enriched (i.e. younger) at the least disturbed site, and implied a
substantial component of recently fixed carbon. In contrast, CO2 and DOC from the other
sites had older 14C ages, indicating disturbance as the trigger for the loss of old
carbon.
1Page et al., 2010
2Hooijer et al., 2010
3Kimberly et al., 2012
4Moore et al., 2013 |
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