Rewetting of extracted peatlands can reduce greenhouse gas emissions

Peatlands are the most widespread of all wetland types globally. They account for approximately 3 % of the earth’s land and freshwater surface but contain up to 30 % of the global soil carbon due to sedentary peat accumulation. In Northern Europe, peat extraction for horticultural purposes and energy production has a long tradition.

In order to restore the hydrology of a terminated extracted peatland one of several post-use alternatives of the area is rewetting, i.e. raising the water level. This can also reduce water pollution and loss of biodiversity. In addition, rewetting creates suitable conditions for peat-forming plants that increase carbon storage in form of peat.

However, very little is known about greenhouse gas emissions from extracted peatlands after rewetting. Therefore, Sabine Jordan has in her doctoral thesis investigated how rewetting of extracted peatlands affected the emission of the greenhouse gases carbon dioxide, methane and nitrous oxide.

Specifically, she aimed to determine the relationships between greenhouse gas emission fluxes and water conditions, soil/water temperature and vegetation cover. She measured greenhouse gas emission fluxes in two rewetted extracted peatlands in Sweden.

The overall climate impact of methane emissions from the study areas did not exceed the impact of soil and plant respiration. The net carbon dioxide flux was also higher than the impact of methane emissions during summer. However, greenhouse gas emissions could vary between years and sites can shift from sinks to sources.

– To construct shallow lakes showed a great potential for lowering greenhouse gas fluxes to the atmosphere, says Sabine.

Sabine Jordan will defend her thesis on the 27^th of October 9.15 in Room L at Unvervisningshuset, Ultuna. The opponent will be Associate Professor Maria Strack from the Department of Geography and Environmental Management, University of Waterloo, Waterloo, Canada.