Fungal community influence on the mobility of dissolved organic carbon and iron under different forest management strategies

The scientific goal is to understand how fungal communities influence mobilization of dissolved organic carbon (OC) and iron (Fe) from forest soils, and how that is influenced by forest management. In the background are striking increases in terrestrial export of OC and Fe to surface waters resulting in browning of aquatic systems. This phenomenon has received ample attention, since it constitutes a significant portion of the global carbon cycle, and any changes in this flux may have consequences for the forests capacity to sequester carbon. Coniferous afforestation has been shown to contribute to these trends, e.g. mobilization of OC and Fe is enhanced under mature spruce forests. This is due to the buildup of organic soil layers under coniferous forests, which sustain high DOC and iron export, but it may also be linked to other aspects of forest management such as tree, species, forest fertilization and ditching of peat soils to promote forestry.

An important and poorly known factor is the role of fungal communities which establish as a consequence of different forestry practices. Fungal decomposition plays an important role in mobilization of DOC from soils, and decomposition processes differ between fungal groups. The aim of the proposed project is therefore to determine the influence of forest management on fungal community composition and the subsequent effect on DOC and iron mobilization.

The project addresses novel aspects of browning, and will make a significant contribution by elucidating what activities in the landscape contributes to browning, which is critical for our understanding on how and where local measures can be implemented to for mitigation.