We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
The addition of polypropylene microplastics promoted the formation of particulate organic carbon in urban green spaces
Summary
A mesocosm experiment found that adding polypropylene microplastics to urban soils increased soil organic carbon by 18.6–48.2% and particulate organic carbon by 44.2–101.7%, primarily by altering bacterial communities and disrupting the normal relationship between bacterial necromass and organic carbon dynamics. The results reveal that microplastic accumulation in urban green spaces causes complex and lasting disruptions to soil carbon cycling, with uncertain long-term consequences for urban ecosystem function.
The pollution of microplastics (MPs) in terrestrial ecosystems has drawn growing concern. Nevertheless, the influence of MPs on the fractions of soil organic carbon (SOC), particularly in urban soils, is still not well understood. Particulate organic carbon (POC) as a key component of urban soil organic carbon, is a core element for maintaining the functions of urban soil ecosystems. The effect of MPs on soil carbon dynamics was investigated by exposing soils planted with three common green plants to polypropylene microplastics (MPs) at concentrations of 0%, 0.5%, 1%, and 2% (w/w). The addition of MPs resulted in an 18.6% to 48.2% increase in SOC content. MPs notably boosted POC content by 44.2% to 101.7%, while they only increased mineral-associated organic carbon (MAOC) in soil without plants, with a range of 41.8% to 54.7%. There was a significant negative correlation between SOC and bacterial necromass carbon (BNC) in the absence of MPs, but this negative correlation disappeared with the addition of MPs. Compared with the BNC, the fungal necromass carbon (FNC) mainly contributed to the microbial necromass carbon (MNC) (about 74.6%). Bacterial communities were more sensitive to the addition of MPs than fungal communities. Structural equation model confirmed that MPs addition increases SOC content by promoting the accumulation of POC and BNC contribute to MAOC. Overall, the findings highlight the sensitive response of POC to MPs pollution, which could have a potential effect on soil carbon components in urban soil.