PROJECT SUMMARY
Climate change has resulted in permafrost thaw in northwestern Canada which risks releasing stored carbon into the atmosphere as carbon dioxide (CO2) or methane (CH4). Northern Canada is full of carbon-rich peatlands which may be affected by this. Modelling greenhouse gas (GHG) emissions gives insights into the complex interactions between human activities, the environment, and the climate system and helps inform policy – However most climate models don’t include permafrost carbon. Due to the presence of permafrost, northern peatlands consist of unique landscape forms−largely peat plateaus, bogs, and channel fens. To properly understand the current and projected global carbon balance, it is imperative to understand the unique GHG emissions of different peatland types.
Channel fens (Figure 1) transport water throughout northern landscapes, and account for ~20-40 % of peatlands in the region, but they exhibit variable conditions which has resulted in a knowledge gap and inaccuracies in GHG projections. Unlike other wetland types, fens exist in many nutrient (trophic) states from poor to extreme rich which makes modelling methane emissions accurately a challenge. Climate change is resulting in permafrost thaw which leads to channel fen expansion which may alter hydrology and vegetation which can influence methane emissions in peatlands.
The overall objective of the proposed research is to understand and quantify methane emissions of northern peatlands along their trophic gradients in the discontinuous permafrost region. Three channel fens, and one bog in Lutose, AB that exist along a nutrient gradient were studied during monthly trips in order to collect seasonal data and information regarding the vegetation, water chemistry, hydrology, climatic conditions, and GHG emissions using soil chamber techniques (Figure 2).
The overall objective of the proposed research is to understand and quantify methane emissions of northern peatlands along their trophic gradients in the discontinuous permafrost region. Three channel fens, and one bog in Lutose, AB that exist along a nutrient gradient were studied during monthly trips in order to collect seasonal data and information regarding the vegetation, water chemistry, hydrology, climatic conditions, and GHG emissions using soil chamber techniques (Figure 2).
This study found that northern peatlands follow southern peatland differentiation criteria,. Therefore, classifying them based on already-existing criteria like pH, EC, Ca, and Mg (Vitt and Chee 1990) is possible. Using iron concentrations may also be a good indicator. There are distinct differences in site environmental conditions such as vegetation, water chemistry, moisture, and methane emissions between and within some trophic environments. However, this study found that the bog and extreme-rich fen, as well as the poor and extreme-rich fen, did not exhibit significantly different methane emissions.
Different environmental variables predict more of the fluctuating methane emissions at different trophic levels in Lutose peatlands. However, within these areas, elevated soil temperatures contribute to increased methane emissions. We also saw the effect of soil moisture varied by trophic level. |
Even on a small spatial scale (<1 km), there can be several trophic levels that exist and produce differing methane emissions. Techniques to determine soil pH, moisture, and ground vegetation cover are being developed and refined, so if we have dependable ways to differentiate between fen types, and know that they cannot be modelled together, these improvements in technology will go a long way towards helping us model emissions. When making models for GHG emissions of northern peatlands, differing trophic levels must be accounted for.
ACKNOWLEDGEMENTS
Thank you to Jazmin Greyeyes-Howell, Michael Goshko, Brooklyn Bolstad, Finn Kurylowicz, and Fares Mandour for their help in the field and beyond, as well as my supervisor David Olefeldt and the rest of the CAWS lab for their support, especially Jessica Lagroix.
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