Spatial and temporal variations of methane flux measured by autochambers in a temperate ombrotrophic peatland. Issue 5 (23rd May 2014)

• Record Type: Journal Article
• Authors: Lai, Derrick Y. F.; Moore, Tim R.; Roulet, Nigel T.
• Is Part Of: Journal of geophysical research. Volume 119:Issue 5(2014)
• Page Start: 864
• Page End: 880
• Publication Date: 2014-05-23
• Subjects: Geobiology -- Periodicals; Biogeochemistry -- Periodicals; Biotic communities -- Periodicals; Geophysics -- Periodicals; 577.14
• DOI: 10.1002/2013JG002410
• Languages: English
• ISSNs: 2169-8953

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>We measured CH<sub>4</sub> flux at high temporal resolution with triplicate autochambers from three different plant communities at the ombrotrophic Mer Bleue bog in Canada to investigate the spatial and temporal variations, and factors that related to the CH<sub>4</sub> flux. Our results show that seasonal mean CH<sub>4</sub> fluxes from the <italic>Eriophorum</italic>‐dominated community were 1.4–2.2 and 3.7–5.5 times higher than those from <italic>Maianthemum/Ledum</italic> and <italic>Chamaedaphne</italic> communities, respectively. Significant interannual variations in CH<sub>4</sub> flux were observed in <italic>Maianthemum/Ledum</italic> and <italic>Chamaedaphne</italic> communities, attributable to a 55–60% reduction of mean summer (July–September) CH<sub>4</sub> flux in 2010 as a consequence of a 5.5–9.0 cm lower mean summer water table compared to 2009. The <italic>Eriophorum</italic> community showed a much larger rate of increase in CH<sub>4</sub> flux with peat temperature in the early growing season than in midsummer, which might be caused by a concomitant increase in root exudation of labile carbon for methanogenesis. Temporal variability of log‐transformed CH<sub>4</sub> flux was correlated (<italic>r</italic> ≥ 0.4) with peat temperature only when water table was less than 20, 30, and 40 cm below the peat surface for <italic>Maianthemum/Ledum</italic>, <italic>Chamaedaphne</italic>, and <italic>Eriophorum</italic> communities, respectively. This difference in water table threshold among communities might partly be related to differences in rooting depth and hence the ability of plants to sustain CH<sub>4</sub> flux in dry conditions. These results suggest that modeling of CH<sub>4</sub> flux from ombrotrophic peatlands over time should take into account the role of different vegetation types, since the relationships between CH<sub>4</sub> emissions and environmental factors vary among vascular plant communities.</p> </abstract>