IronPeat - Disentangling the interactions of biotic and abiotic processes that govern iron leaching from peat

Iron leaching from peat soil is a concern, as leached iron ends up in downstream waters where it leads to darkening of waters, interference with nutrient availability in the water, loss of recreational value of lakes and rivers or damage to infrastructure such as clogging of pipes with iron precipitates. Iron leaching is impacted by changes in water table brought on by natural (e.g., large precipitation events) or man-made (e.g., drainage ditches) influences and is especially problematic in the Northern Ostrobothnia region, where peatlands have been extensively drained for use in forestry, construction or agriculture. There have been attempts to remove the surplus iron (e.g., settling ponds), but these have at most had a small impact. Stopping iron leaching at its source rather than trying to mitigate the problems caused by surplus iron would thus be a desirable solution. However, the processes governing iron binding and release in peat are complex and involve a large suite of biotic and abiotic components. Little is known about the impact of single factors, and even less about their interactions. But unless this knowledge becomes available, any interventions aimed at preventing or mitigating iron leaching from peat are bound to fail.

To address this knowledge gap, the IronPeat project aims to investigate the abiotic and microbially catalyzed processes controlling release and binding of iron in nutrient-poor, forest-drained peatlands. The project combines expertise and methodology from soil science, microbiology and peatland hydroecology to design field monitoring and laboratory experiments to disentangle the complex processes governing iron mobility in peat soil. The specific objectives of the proposed project are:

(i) In-depth monitoring of peat and porewater parameters in the field and their seasonal variations

(ii) Assessing the process potential for different microbial processes that possibly affect iron leaching

(iii) Testing the impact of changes in environmental conditions (e.g., oxygen availability, temperature) on the aforementioned processes