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Impacts of elevated atmospheric ozone on peatland below-ground DOC chacteristics

Jones, Timothy G.; Freeman, Chris; Lloyd, Andrew; Mills, Gina. 2009 Impacts of elevated atmospheric ozone on peatland below-ground DOC chacteristics. Ecological Engineering, 35. 971-977. 10.1016/j.ecoleng.2008.08.009

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Abstract/Summary

Rising concentrations of tropospheric ozone are having detrimental impacts on the growth of crop and forest species and some studies have reported inhibition of the allocation of carbon below ground. The effects of ozone on peatland ecosystems have received relatively little attention, despite their importance within the global carbon cycle. During this study, cores from a Welsh minerotrophic fen and ombrotrophic bog were exposed to four ambient/ elevated ozone concentration regimes representing current and predicted 2050 profiles. A large and significant reduction in the concentration of porewater dissolved organic carbon (DOC) was recorded in the fen cores exposed to the elevated ozone concentrations (up to −55%), with a concurrent shift to a higher molecularweight of the remaining soil carbon. No effects of ozone on DOC concentrations or characteristics were recorded for the bog cores. The data suggest higher ozone sensitivity of plants growing in the fen-type peatland, that the impacts on the vegetation may affect soil carbon characteristics through a reduction in root exudates and that theremay have been a shift in the source of substrate DOC for microbial consumption from vegetation exudates to native soil carbon. Theremay also have been a direct effect of ozone molecules reacting with soil organic matter after being transported into the soil through the aerenchyma tissue of the overlying vegetation. These qualitative changes in the soil carbon in response to elevated ozone may have important implications for carbon cycling in peatland ecosystems, and therefore climate change.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1016/j.ecoleng.2008.08.009
Programmes: CEH Topics & Objectives 2009 - 2012 > Biogeochemistry > BGC Topic 1 - Monitoring and Interpretation of Biogeochemical and Climate Changes > BGC - 1.3 - Quantify & attribute changes in biogeochemiical cycles ...
CEH Sections: Emmett
ISSN: 0925-8574
Additional Keywords: Ozone, peatlands, fen, bog, DOC, carbon-cycling, phenolics, molecular weight, SUVA
NORA Subject Terms: Ecology and Environment
Date made live: 17 Mar 2011 12:34
URI: http://nora.nerc.ac.uk/id/eprint/4464

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