In this citizen science project, we combined a standardised litter bag method (Tea Bag Index) with microbiome analysis of bacteria and fungi colonising the teabags to gain a holistic understanding of the carbon degradation dynamics in temperate European soils. Our method focuses only on the active part of the soil microbiome. The results show that about one-third of the prokaryotes and one-fifth of the fungal species (ASVs) in the soil were enriched in response to the presence of fresh OM.