Thesis subject

The relation between peatsoil characteristics, vegetation and hydraulic conductivity of boreal peatlands (fieldwork included)


Boreal peatlands play an important role in the climate of our planet due to the large amounts of carbon stored in these wetland ecosystems. Peatland plants fixed carbon from the atmosphere and transferred it to organic matter. Due to the cold boreal climate and wet, acid conditions in peatlands, decomposition rates are low. This resulted in the accumulation of huge amounts of partly decomposed plant material (mainly peat mosses) throughout the Holocene and the formation of thick peat deposits.

A prerequisite for the accumulation of peat is sufficient wet conditions. Climate change is expected to reduce the wetness of peatlands and may result in a release of CO2 into the atmosphere, which could accelerate climate change worldwide.

Internal feedbacks maintain wet conditions in peatlands, and increase peatland resilience to climate change. One of such feedbacks relates to the spatial organization of different peat soil types and related vegetation. Peatland vegetation is very likely, (though not yet proven!), organized in such a way to optimize peatland water availability. Typically, the vegetation in peatlands is organized in alternating hummocks (dry and elevated) and hollows (wet depressions). Peatland vegetation can remain at the same place for centuries. Moreover, the dead plant material of the current vegetation type added to the peat surface affects properties of peat later formed. This suggests that current hummock-hollow vegetation patterning may provide insight in the spatial distribution of soil properties important for water flow (porosity, hydraulic conductivity, bulk density, degree of decomposition, plant macrofossils). It remains to be explored how strong the relation between vegetation and peat properties is.

 Your research topic

In this thesis you will collect and describe peat cores of hummocks and hollows during a field campaign in a peatland in northern Scandinavia. The peat profile descriptions comprise e.g. plant macrofossils, bulk density, degree of decomposition, porosity, and peat age. Necessary field data also includes hydraulic conductivity. Understanding interrelations between these properties, both their horizontal and vertical distribution, and the persistence of peatland vegetation, is crucial for future peat soil formation and peatland response to climate change. The exact research question will be formulated based on your interest and background, and in discussion with your supervisors.

Students: 1 or 2

Required: SGL22306 or equivalent. Strong muscles, bright brain and liking fieldwork will be advantageous

Duration: 24 ECTS or more

Location: Wageningen and northern Scandinavia

Period: as soon as possible

Supervision: Jelmer Nijp (SGL), Arnaud Temme (SGL)

Theme: 1