Decomposability of Soil Samples along a Moisture Gradient in a Peat Bog in Siikaneva, Finland

Climate change is already affecting moisture dynamics in wetlands and previously moist soils. Elongated and localized dry spells lead to more aerobic conditions in previously oxygen depleted soils, favourable for organic matter decomposition. The substrate quality of older organic matter might, on the other hand, limit decomposition rates. The persistence of organic material towards microbial degradation and its relation to physico-chemical characteristics as well as biomarkers is however still unclear.

We are investigating soil organic matter characteristics and comparing them to soil respiration rates to quantify the soil’s persistence towards aerobic decomposition. Lipid biomarkers together with physico-chemical characteristics will assess the source and quality of soil organic matter and be compared to 60 days of aerobic respiration rates. Soil samples were taken up to 1m along a moisture gradient from a peat bog, an intermediate bushy site, and the adjacent forest in Siikaneva, Finland.

We hypothesize that soil respiration in aerobic incubations can be predicted by soil characteristics. Thus, from this data set, estimates of soil carbon vulnerability could be inferred and help predict decomposition rates with progressing climate change.