3D soil structure characterization of Biological Soil Crusts from Alpine Tarfala Valley

Cyanobacteria filaments, microfungal hyphae, lichen rhizinae and anchoring rhizoids of bryophytes all togethercontribute to induce formation of structure in the thin soil layer beneath the Biological Soil Crusts (BSCs). Quantitativeassessment of the soil structure beneath the BSCs is primarily hindered by the fragile nature of the crusts.Therefore, the role of BSCs in affecting such soil physical property has been rarely addressed using direct measurements.In this work we applied non-destructive X-ray microtomography imaging on five different samples of BSCs collectedin the Alpine Tarfala Valley (northern Sweden), which have already been characterized in terms of fungalbiodiversity in a previous work.We obtained images of the 3D spatial organization of the soil underneath the BSCs and characterized its structureby applying procedures of image analysis allowing to determine pore size distribution, pore connectivity andaggregate size distribution. Results has then been correlated with the different fungal assemblages of the samples.