Biodegradable microplastic particles in soils can lead to an increased rise in CO2 emissions to the Earth's atmosphere. This is shown by an interdisciplinary study published in Applied Soil Ecology by the Collaborative Research Centre 1357 "Microplastics" at the University of Bayreuth. In this study, experts in soil ecology and ecological microbiology compare the effects of a conventional and a biodegradable plastic in different soils in a systematic way for the first time. The consequences for the microbial biomass in the soils, especially on bacteria and fungi, are also analyzed.