Please use this identifier to cite or link to this item: http://hdl.handle.net/2381/12128
Title: Carbon dioxide emissions from an Acacia plantation on peatland in Sumatra, Indonesia
Authors: Jauhiainen, J.
Hooijer, A.
Page, S.E.
First Published: 2012
Publisher: Copernicus GmbH (Copernicus Publications) on behalf of the European Geosciences Union (EGU)
Citation: Biogeosciences, 2012, 9 (2), pp. 617-630
Abstract: Peat surface CO[subscript 2] emission, groundwater table depth and peat temperature were monitored for two years along transects in an Acacia plantation on thick tropical peat (>4 m) in Sumatra, Indonesia. A total of 2300 emission measurements were taken at 144 locations, over a 2 year period. The autotrophic root respiration component of CO[subscript 2] emission was separated from heterotrophic emission caused by peat oxidation in three ways: (i) by comparing CO[subscript 2] emissions within and beyond the tree rooting zone, (ii) by comparing CO[subscript 2] emissions with and without peat trenching (i.e. cutting any roots remaining in the peat beyond the tree rooting zone), and (iii) by comparing CO[subscript 2] emissions before and after Acacia tree harvesting. On average, the contribution of autotrophic respiration to daytime CO[subscript 2] emission was 21% along transects in mature tree stands. At locations 0.5 m from trees this was up to 80% of the total emissions, but it was negligible at locations more than 1.3 m away. This means that CO[subscript 2] emission measurements well away from trees were free of any autotrophic respiration contribution and thus represent only heterotrophic emissions. We found daytime mean annual CO[subscript 2] emission from peat oxidation alone of 94 t ha[superscript −1] y[superscript −1] at a mean water table depth of 0.8 m, and a minimum emission value of 80 t ha[superscript −1] y[superscript −1] after correction for the effect of diurnal temperature fluctuations, which may result in a 14.5% reduction of the daytime emission. There is a positive correlation between mean long-term water table depth and peat oxidation CO[subscript 2] emission. However, no such relation is found for instantaneous emission/water table depth within transects and it is clear that factors other than water table depth also affect peat oxidation and total CO[subscript 2] emissions. The increase in the temperature of the surface peat due to plantation establishment may explain over 50% of peat oxidation emissions. Our study sets a standard for greenhouse gas flux studies from tropical peatlands under different forms of agricultural land management. It is the first to purposefully quantify heterotrophic CO[subscript 2] emissions resulting from tropical peat decomposition by separating these from autotrophic emissions. It also provides the most scientifically- and statistically-rigorous study to date of CO[subscript 2] emissions resulting from anthropogenic modification of this globally significant carbon rich ecosystem. Our findings indicate that past studies have underestimated emissions from peatland plantations, with important implications for the scale of greenhouse gas emissions arising from land use change, particularly in the light of current, rapid agricultural conversion of peatlands in the Southeast Asian region.
DOI Link: 10.5194/bg-9-617-2012
ISSN: 1726-4170
eISSN: 1726-4189
Links: http://hdl.handle.net/2381/12128
http://www.biogeosciences.net/9/617/2012/bg-9-617-2012.html
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: © Author(s) 2012. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Appears in Collections:Published Articles, Dept. of Geography

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