Measuring the impact of climate change on an Ottawa Valley Peatland

Mathew Brown is a post-doctoral fellow working under the supervision of DGES faculty member Elyn Humphreys.  He is currently working on an NSERC-funded project examining carbon & methane fluxes from peatlands in the Hudson Bay Lowland and the Ottawa Valley. 

Determining the carbon (C) balance of peatlands is particularly important as they hold about half of the soil organic carbon in Canada. This large storage is due to a slow carbon uptake over the past several thousand years. The Mer Bleue  study in Ottawa’s Greenbelt is monitoring flows of carbon in and out of a domed bog along with manipulative experiments to better understand what factors might lead to changes in the rate of carbon storage at Mer Bleue. This is a collaborative research site run by Elyn Humphreys (Carleton), Nigel Roulet and Tim Moore (McGill), Peter Lafleur (Trent) and Jill Bubier (Mount Holyoke). In operation for nearly 14 years, it represents an extremely valuable dataset and is the second longest running flux station in a peatland worldwide.   These researchers, students, and collaborators from around the world have published over 80 journal articles and 45 honours and graduate theses on Mer Bleue.

Mer Bleue flux tower

Mer Bleue flux tower

The Mer Bleue site uses the eddy-covariance technique to make continuous year-round measurements of fluxes of CO2, CH4 and energy between the peatland and the atmosphere. A wide range of meteorological and soil variables are also measured in order to determine the factors driving these fluxes.  A series of automated chambers measures these fluxes at various points in the bog to determine the spatial variability of these fluxes. We are able to communicate with the flux tower remotely, and have recently installed a phenocam to take pictures of the peatland every 30 min and can be viewed online (http://phenocam.sr.unh.edu/data/latest/merbleue.jpg).

Automated CO2 flux chambers

Automated CO2 flux chambers

Measurements have shown Mer Bleue to be an annual carbon sink; however the magnitude of this sink can be quite variable. As this region is expected to experience substantial temperature increases this century, as well as reductions in water storage, this peatland could switch from a carbon sink to a source, resulting in a positive feedback to climate change.

In order to determine the influence of water storage on the carbon balance of Mer Bleue, a water table draw-down experiment is currently being conducted to identify when and how water table depth influences near surface moisture conditions, as well as CO2, CH4 and energy fluxes. Ultimately, this work will help determine the sensitivity of peatland carbon stocks and carbon  sequestration to current and future climate change.

A number of opportunities exist for graduate students at Mer Bleue and in other areas of the biometeorology group. If interested, please contact Elyn Humphreys (http://http-server.carleton.ca/~erhumphr/Site/Welcome.html).

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