Soil under stress: The importance of soil life and how it is influenced by (micro)plastic pollution

Soil organisms and specifically microorganisms are indispensable to life on Earth. They regulate essential
ecosystem functions from carbon sequestration to primary production. These organisms often experience
stress when the balance of the soil system is disrupted by agricultural practices and environmental disturbances. A new stressor is plastic, which can be found in soils, in and around soil-dwelling organisms, and
close to plants. The presence of plastic can affect soil chemistry, plant growth and the survival of higherorder organisms. Microbial organisms respond sensitively to these changes in their surroundings and will
thus be (in)directly affected by plastic. Eventually, this results in a different microbial activity, composition
and reduced diversity. Plastic might even serve as a specific habitat for microorganisms, generally referred
to as the plastisphere. In this review, we make predictions based on the observed effects of (micro)plastics
and the potential impact on the plant-soil-microbiome system. We use prior knowledge of other disturbances (e.g. tillage and pesticides) which have been studied for many years in relation to the soil microbial
community. Further research is needed to develop standardized methods to study smaller plastic particles
(micro- and nanoplastics) as these play the most dominant role in terrestrial ecosystems.