Sarah Sapper is a PhD student at the University of Copenhagen studying methane and carbon dioxide emissions in meltwater from below the Greenland Ice Sheet.
Department and group: Department of Geosciences and Natural Resource Management
Supervisors: Jesper Riis Christiansen and Christian Juncher Jørgensen
Dissertation title (as for now :D)
Diurnal and seasonal dynamics of greenhouse gas emissions from subglacial meltwater of the Greenland Ice Sheet
Glacier: a body of ice moving down-slope due to gravity
Warm glaciers: are very thick – the pressure of the overlying ice causes melting at the base of the glacier
Cold glacier: thinner ice, the pressure of the ice doesn’t suffice to melt the ice at the bottom of the glacier
Topic – in brief
Measuring methane emissions in meltwater from glaciers
- How much methane is coming out from underneath the ice?
- How does the concentration change (throughout the day and over the entire melt season?
- How important are those emissions in view of climate change?
- Which processes are responsible for it and how does it change?
- Where is the methane coming from?
The hypothesis is that the carbon originates from ‘old’ soil from times when there was no ice.
Microorganisms use that carbon as an energy source (since there is no sunlight or any other apparent sources of energy). Since there is little oxygen below the ice, the carbon pairs with hydrogen instead of oxygen and forms methane. The methane dissolves in the water below a glacier and is transported to the edge of glaciers through meltwater.
In view of climate change? There is no evident connection between a warming climate and an increase in methane emissions at this point. Potentially, increased melting in summer could result in more water flowing trough the bed of a glacier which could flush out more dissolved methane.
Apart from methane emissions from the Greenland Ice Sheet, Sarah and her colleagues also found methane emitted from glaciers in Canada, a new discovery that had not been studied prior to their measurements.
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