We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Polyethylene microplastic and soil nitrogen dynamics: Unraveling the links between functional genes, microbial communities, and transformation processes
Summary
Researchers conducted a six-month experiment to understand how polyethylene microplastics in soil affect nitrogen cycling, a process critical for soil fertility and plant nutrition. They found that while total nitrogen levels stayed stable, microplastics significantly altered the forms of nitrogen present by increasing ammonium and nitrate while decreasing dissolved organic nitrogen. The study suggests that microplastics reshape soil microbial communities and their nitrogen-processing activities, potentially disrupting the natural nutrient balance in agricultural soils.
Microplastics (MPs) have emerged as pollutants of growing concern due to their potential threat to soil ecosystems. While some studies have investigated the effects of MPs on soil nitrogen content, the underlying physicochemical and microbial driving mechanisms still need to be explored. In this study, a six-month incubation experiment was conducted with varying polyethylene MP addition rates: CK (0%, mass ratio), MP0.5 (0.5%), MP1 (1%), MP2 (2%), MP4 (4%), and MP8 (8%). The experiment aimed to examine the effects of MPs on soil nitrogen content, physicochemical properties, nitrogen cycling-related genes, microorganisms, and gross nitrogen transformation rates. The results revealed no significant changes in soil total nitrogen and dissolved total nitrogen. However, dissolved organic nitrogen significantly decreased by 16.00-54.60% following MP addition, while ammonium (NH-N, 45.71-271.43%) and nitrate (NO-N, 43.15-209.54%) nitrogen and microbial biomass nitrogen (46.02-123.70%) significantly increased. Soil pH, bulk density, and soil porosity decreased after MP addition, while soil carbon contents, water-stable macroaggregates, and redox potential increased. The soil microbial community structure changed significantly, and microbial diversity increased under MP treatment. MP addition significantly altered the abundance of soil nitrogen cycling functional genes. The relative abundance of nitrogen fixation and denitrification genes decreased with increasing MP addition rates, while organic degradation and synthesis genes increased. The soil nitrogen cycling functional microbial composition shifted dramatically with increased MP addition. Networks with high addition rates (MP2 +MP4 +MP8) exhibited more total nodes, total links, negative links, node degrees, and modules but shorter average path distances and lower modularity than those with low addition rates (CK +MP0.5 +MP1), reflecting increased network complexity induced by MPs. The gross ammonification rate, NH-N consumption and immobilization rates, and NO-N immobilization rate increased, while the gross nitrification rate and net nitrification rate exhibited an initial increase followed by a decrease with increasing MP addition rates, peaking at MP2. Furthermore, redundancy analysis and structural equation modeling demonstrated that soil physicochemical properties significantly affected soil nitrogen cycling genes and microorganisms, ultimately altering nitrogen content. In conclusion, polyethylene MPs promoted soil nitrogen mineralization and transformation and changed the related functional microorganism community structure, exhibiting a noticeable dose-effect relationship. This study provides deeper insight into the effects of MPs on soil nitrogen cycling.
Sign in to start a discussion.
More Papers Like This
Polyethylene and polyvinyl chloride microplastics promote soil nitrification and alter the composition of key nitrogen functional bacterial groups
Researchers found that polyethylene and PVC microplastics in soil increased nitrification (a key step in the nitrogen cycle) and changed the composition of nitrogen-processing bacteria. These changes could affect soil fertility and the availability of nutrients for crops. The study highlights how microplastic contamination in agricultural soil may have hidden effects on food production by altering fundamental soil processes.
LDPE microplastics affect soil microbial communities and nitrogen cycling
Researchers found that adding polyethylene microplastics to soil changed the bacterial communities and disrupted the nitrogen cycle, which is essential for soil fertility and plant growth. Microplastics increased the activity of certain nitrogen-processing genes while decreasing others, shifting the balance of nutrient cycling. These changes in soil function could ultimately affect crop health and the quality of food grown in microplastic-contaminated agricultural land.
Differential impacts of polyethylene microplastic and additives on soil nitrogen cycling: A deeper dive into microbial interactions and transformation mechanisms
This study tested how polyethylene microplastics, their base resin, and plastic additives each affect nitrogen cycling in soil -- a process essential for plant growth. All three altered the soil's nitrogen balance and microbial communities in different ways, with microplastics increasing certain nitrogen transformation rates the most. These findings matter because disrupted nitrogen cycling in farmland could affect crop nutrition and ultimately the quality of food humans eat.
Microplastic induces microbial nitrogen limitation further alters microbial nitrogentransformation: Insights from metagenomic analysis
Researchers studied how both conventional and biodegradable microplastics affect nitrogen cycling in soil over 120 days. They found that biodegradable microplastics significantly disrupted microbial nitrogen processes by acting as a carbon source that shifted bacterial communities toward nitrogen-fixing species. The findings suggest that even biodegradable plastics in soil can alter nutrient availability in ways that may affect soil fertility and plant growth.
Mechanisms of polyethylene microplastics on microbial community assembly and carbon-nitrogen transformation potentials in soils with different textures
Researchers used DNA sequencing to examine how polyethylene microplastics affect soil microbial communities and carbon-nitrogen cycling across soils with different textures. They found that microplastics significantly shifted microbial community composition and altered the abundance of genes involved in carbon and nitrogen transformation, with effects varying by soil type. The study suggests that microplastic contamination may disrupt fundamental nutrient cycling processes differently depending on soil characteristics.