A Multi-Year Record of Methane Flux at the Mer Bleue Bog,Southern Canada |
| |
Authors: | Tim R Moore Allison De Young Jill L Bubier Elyn R Humphreys Peter M Lafleur Nigel T Roulet |
| |
Institution: | (1) Department of Geography, and Global Environmental & Climate Change Centre, McGill University, 805 Sherbrooke St. W, Montreal, Quebec, H3A2K6, Canada;(2) Mount Holyoke College, 50 College Street, South Hadley, Massachusetts 01075, USA;(3) Department of Geography and Environmental Studies, Carleton University, Ottawa, Ontario, K1S 5B6, Canada;(4) Department of Geography, Trent University, Peterborough, Ontario, K9J7B8, Canada |
| |
Abstract: | The Mer Bleue peatland is a large ombrotrophic bog with hummock-lawn microtopography, poor fen sections and beaver ponds at
the margin. Average growing-season (May–October) fluxes of methane (CH4) measured in 2002–2003 across the bog ranged from less than 5 mg m−2 d−1 in hummocks, to greater than 100 mg m−2 d−1 in lawns and ponds. The average position of the water table explained about half of the variation in the season average CH4 fluxes, similar to that observed in many other peatlands in Canada and elsewhere. The flux varied most when the water table
position ranged between −15 and −40 cm. To better establish the factors that influence this variability, we measured CH4 flux at approximately weekly intervals from May to November for 5 years (2004–2008) at 12 collars representing the water
table and vegetation variations typical of the peatland. Over the snow-free season, peat temperature is the dominant correlate
and the difference among the collars’ seasonal average CH4 flux is partially dependent on water table position. A third important correlate on CH4 flux is vegetation, particularly the presence of Eriophorum vaginatum, which increases CH4 flux, as well as differences in the potential of the peat profile to produce and consume CH4 under anaerobic and aerobic conditions. The combination of peat temperature and water table position with vegetation cover
was able to explain approximately 44% of the variation in daily CH4 flux, based on 1097 individual measurements. There was considerable inter-annual variation in fluxes, associated with varying
peat thermal and water table regimes in response to variations in weather, but also by variations in the water level in peripheral
ponds, associated with beaver dam activity. Raised water level in the beaver ponds led to higher water tables and increased
CH4 emission in the peatland. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|