Soil microbial community structure and functionality changes in response to long‐term metal and radionuclide pollution

Abstract

Microbial communities are essential for a healthy soil ecosystem. Metals and radionuclides can exert a persistent pressure on the soil microbial community. However, little is known on the effect of long-term cocontamination of metals and radionuclides on the microbial community structure and functionality. We investigated the impact of historical discharges of the phosphate and nuclear industry on the microbial community in the Grote Nete river basin in Belgium. Eight locations were sampled along a transect to the river edge and one location further in the field. Chemical analysis demonstrated a metal and radionuclide contamination gradient and revealed a distinct clustering of the locations based on all metadata. Moreover, a relation between the chemical parameters and the bacterial community structure was demonstrated. Although no difference in biomass was observed between locations, cultivation-dependent experiments showed that communities from contaminated locations survived better on singular metals than communities from control locations. Furthermore, nitrification, a key soil ecosystem process seemed affected in contaminated locations when combining metadata with microbial profiling. These results indicate that long-term metal and radionuclide pollution impacts the microbial community structure and functionality and provides important fundamental insights into microbial community dynamics in co-metalradionuclide contaminated sites.

Molecular Mechanisms Underlying Bacterial Uranium Resistance

“…Overall, it is clear that the physico-chemical environment imposes restrictions on the applied method, especially for in situ processes. Since uranium-contaminated sites or often co-contaminated with toxic metals ( Sitte et al, 2015 ; Boteva et al, 2016 ; Rogiers et al, 2021a ), in situ bioremediation necessitates the presence of multiple metal resistance mechanisms, which are often present in the indigenous microbial communities thriving in such contaminated sites ( Choudhary and Sar, 2015 ; Agarwal et al, 2020 ; Rogiers et al, 2021a ).…”

Current ionising radiation doses in the Chernobyl Exclusion Zone do not directly impact on soil biological activity

“…This may, in part, be the consequence of soil organisms (invertebrate macrofauna, mesofauna and microorganisms) typically being thought to be relatively insensitive to radiation compared to other biota [ 10 , 11 ]. Some studies have reported effects on soil fauna at sites with high levels of natural radionuclides, including uranium mines [ 12 – 15 ]. However, it is likely that chemical toxicity rather than radiation dose is the cause of effects observed at such sites.…”

Initial responses of influential microbial taxa to metal elements lead to alterations in the forest soil microbial community structure and function

“…These elements must be mobilized from the soil matrix and absorbed by the roots in the form of metal ions (DalCorso et al 2014). Moreover, as one of the main drivers underlying soil microbial community change, metal elements may also exert persistent stress on soil microbial communities, thereby impacting belowground biodiversity that comprises up to a quarter of the Earth's species (Beattie et al 2018;Wagg et al 2019;Rogiers et al 2021). As any soil disturbance may disrupt microbial activity (Bissett et al 2013), understanding the responses of microbial communities to soil metal elements is a fundamental ecological issue for maintaining belowground biodiversity and ecosystem stability.…”

“…As the second genome of plants and facilitators of soil ecosystem change (Coban et al 2022;Zhang et al 2022), soil microbes dominate terrestrial soil habitats (Bardgett & van der Putten 2014;Bahram et al 2018). Furthermore, soil microbes afford primary functions for the formation and maintenance of soil structure and fertility (Bronick & Lal 2005;Rogiers et al 2021); thus, variations in the microbial community may lead to significant changes in soil ecosystems (Rogiers et al 2021).…”