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Title
N2O flux from plant-soil systems in polar deserts switch between sources and sinks under different light conditions
Fields of Research (FoR) 2008:
Author(s)
Publication Date
2012-05
Socio-Economic Objective (SEO) 2008
Early Online Version
Abstract
Production and consumption of greenhouse gases such as CO<sub>2</sub>, CH<sub>4</sub> and N<sub>2</sub>O are key factors driving climate change. While CO<sub>2</sub> sinks are commonly reported and the mechanisms relatively well understood, N<sub>2</sub>O sinks have often been overlooked and the driving factors for these sinks are poorly understood. We examined CO<sub>2</sub>, CH<sub>4</sub> and N<sub>2</sub>O flux in three High Arctic polar deserts under both light (measured in transparent chambers) and dark (measured in opaque chambers) conditions. We further examined if differences in soil moisture, evapotranspiration, Photosynthetically Active Radiation (PAR), and/or plant communities were driving gas fluxes measured in transparent and opaque chambers at each of our sites. Nitrous oxide sinks were found at all of our sites suggesting that N<sub>2</sub>O uptake can occur under extreme polar desert conditions, with relatively low soil moisture, soil temperature and limited soil N. Fluxes of CO<sub>2</sub> and N<sub>2</sub>O switched from sources under dark conditions to sinks under light conditions, while CH<sub>4</sub> fluxes at our sites were not affected by light conditions. Neither evapotranspiration nor PAR were significantly correlated with CO<sub>2</sub> or N<sub>2</sub>O flux, however, soil moisture was significantly correlated with both gas fluxes. The relationship between soil moisture and N<sub>2</sub>O flux was different under light and dark conditions, suggesting that there are other factors, in addition to moisture, driving N<sub>2</sub>O sinks. We found significant differences in N<sub>2</sub>O and CO<sub>2</sub> flux between plant communities under both light and dark conditions and observed individual communities that shifted between sources and sinks depending on light conditions. Failure of many studies to include plant-mediated N<sub>2</sub>O flux, as well as, N<sub>2</sub>O soil sinks may account for the currently unbalanced global N<sub>2</sub>O budget.
Publication Type
Journal Article
Source of Publication
Soil Biology & Biochemistry, v.48, p. 69-77
Publisher
Elsevier Ltd
Socio-Economic Objective (SEO) 2020
2012-02-04
Place of Publication
United Kingdom
ISSN
1879-3428
0038-0717
Fields of Research (FoR) 2020
Socio-Economic Objective (SEO) 2020
Peer Reviewed
Yes
HERDC Category Description
Peer Reviewed
Yes
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