Drought Alleviates the Negative Effects of Microplastics on Soil Micro-Food Web Complexity and Stability

Abstract

Soil ecosystems are under considerable pressure due to anthropogenic factors, including microplastics (MPs) pollution and drought. However, little is known about the interactive effects of MPs and drought on soil organisms, especially soil micro-food web. We conducted a microcosm experiment with MPs pollution (including two types and two sizes of MPs) and drought to investigate their interaction effects on soil microbial, protist, and nematode communities in soil micro-food web. We found that MPs significantly decreased the complexity and stability of soil micro-food web, with greater negative effects of biodegradable and smaller-sized MPs than conventional and larger-sized MPs. Drought had negative effects on soil micro-food web in the non-MPs pollution soils while increasing the complexity and stability of soil micro-food web in the MPs pollution soils. Drought increased the proportion of negative correlations between bacteria and fungi in the biodegradable MPs soils while decreasing the proportion of negative correlations between protists and nematodes in the smaller-sized MPs soils. Our study reveals that drought may alleviate the negative effects of MPs on soil micro-food web by reducing competition among lower trophic levels in the biodegradable MPs pollution soils while reducing competition among higher trophic levels in the smaller-sized MPs pollution soils.

Nano-Iron Oxide (Fe3O4) Mitigates the Effects of Microplastics on a Ryegrass Soil–Microbe–Plant System

“…In the present study, the addition of pure MPs induced negative effects on the plant bacterial microbiome. This was reported to be true even in larger soil microfood networks, including soil bacteria, fungi, protists, and nematode communities . In agreement with Liu et al, in the present work MPs decreased the stability of microbial- and microfood networks, with smaller MPs having stronger negative effects than larger MPs.…”

“…This was reported to be true even in larger soil microfood networks, including soil bacteria, fungi, protists, and nematode communities . In agreement with Liu et al, in the present work MPs decreased the stability of microbial- and microfood networks, with smaller MPs having stronger negative effects than larger MPs. For ryegrass in this study, a minor dose effect was observed for both the addition of NPs and MPs, which could singly and jointly increase plant growth.…”

Microplastic fibres affect soil fungal communities depending on drought conditions with consequences for ecosystem functions

“…Therefore, microplastics and drought effects on terrestrial systems are likely strongly modulated by soil biota. On the one hand, microplastics may affect the composition of soil bacterial communities by altering their abundance, diversity and activity with consequences for key processes such as nitrification (Fei et al, 2020; Huang et al, 2019; Seeley et al, 2020; Zhao et al, 2021), or potentially affect soil fungal communities as observed in aquatic systems (Kettner et al, 2017), with consequences on soil micro‐food webs (Liu et al, 2023). Indeed, research has shown that microplastics could accumulate fungal pathogens on their surfaces (Gkoutselis et al, 2021), leading to pathogen transfer into the soil matrix (Yu et al, 2021).…”