Effects of Microplastics on Soil Ecosystems

Microplastics are tiny plastic particles that are less than 5 millimeters in size and are increasingly recognized as a global environmental contaminant. They can originate from various sources, such as the breakdown of larger plastic debris, microbeads in personal care products, and synthetic fibers from clothing. When these particles enter the soil, they have the potential to significantly affect soil microbial communities and their functions. Understanding the effects of microplastics on soil microbial communities is crucial because these communities play a vital role in maintaining soil fertility, supporting plant growth, and regulating greenhouse gas emissions. The accumulation of microplastics may physically alter soil structure, potentially affecting water retention, aeration, and the overall habitat for soil microbes. Microplastics could change the composition of soil microbial communities by preferentially adsorbing certain microbes over others, leading to shifts in the balance of bacteria, fungi, and other microorganisms. The presence of microplastics might inhibit or stimulate the activity of certain microbes, affecting processes such as decomposition of organic matter, nitrogen fixation, and nutrient cycling. Microplastics have the potential to adsorb various environmental pollutants, such as heavy metals and organic chemicals, which can then be transferred to soil microbes, potentially leading to toxic effects. Microplastics may affect the availability of nutrients to microbes by altering soil chemistry or by acting as a physical barrier to microbial access to nutrients.

There is a concern that microplastics could be degraded by microbes and then accumulate in the soil food web, with unknown consequences for soil ecosystem function. Microplastics can potentially disrupt the symbiotic relationships between microbes and plants, such as mycorrhizal associations, which are important for nutrient uptake and plant health. Microplastics may provide a surface for microbes to aggregate and potentially facilitate the transfer of genetic material, including antibiotic resistance genes. The overall implications of microplastic contamination for soil health and function are complex and not fully understood, necessitating further research to determine the long-term impacts on soil ecosystems.

This Research Topic is to present original research and review articles focusing on the composition and function of soil microbial communities affected by microplastics. Research areas may include (but are not limited to) the following:

- Investigate how microplastics affect the diversity and function of soil microbes, including bacteria, archaea, fungi, and protists, as well as their roles in the soil food web.
- Determine how microplastics affect symbiotic relationships between soil organisms, including plant-microbe interactions and interactions among microbes.
- Investigate how microplastics alter the physical properties of soil, such as soil structure, water retention capacity, and aeration, thereby affecting the habitats of soil organisms.
- Study the resilience of the soil microbial food web to microplastic pollution and how management practices can enhance this resilience.
- Study the long-term presence of microplastics in soil and their impact on soil organism communities and ecosystem functions.
- Researching the effects of additives commonly found in plastics, which may leach out and affect soil microbial communities.
- Investigating the biodegradation of microplastics by soil microbes, identifying the types of microbes involved, and understanding the metabolic pathways they use to break down plastics.
- Examining how microplastics might affect the symbiotic relationships between soil microbes and plants, including impacts on nutrient cycling and plant health.
- Exploring the formation of biofilms on microplastic surfaces and the role these microbial communities play in the soil ecosystem.