Land Use Modulates Viral Impacts on Soil Nitrification and Denitrification

Area of Science:

• Soil microbiology and biogeochemistry
• Environmental science and ecology
• Virology

Background:

• Land use and soil viruses are key drivers of microbial community structure and nitrogen cycling.
• The interplay between land use and viral influence on soil microbial processes, particularly nitrification and denitrification, is not well understood.

Purpose of the Study:

• To investigate how different land uses (forest, greenbelt, agricultural) modulate the effects of active soil viruses on microbial communities and nitrogen cycling.
• To quantify viral impacts on potential nitrification, denitrification rates, and nitrous oxide (N2O) emissions across various land use types.

Main Methods:

• Microcosm experiments using sterilized forest, greenbelt, and agricultural soils inoculated with microbial and active/inactivated viral suspensions.
• Incubation for 14 and 56 days, followed by measurements of bacterial abundance, microbial community composition, potential nitrification and denitrification rates, and N2O emissions.
• Analysis using Partial Least Squares Path Modeling (PLS-PM) and ANOVA to determine relationships between viral effects, land use, soil properties, and microbial communities.

Main Results:

• Active virus addition increased bacterial abundance and altered bacterial and fungal community composition across all land uses.
• Viral addition differentially affected potential nitrification rates, decreasing them in forest and agricultural soils but increasing them in greenbelt soil.
• Nitrogen cycling responses, including denitrification and N2O emissions, varied significantly with land use, viral activity, and incubation time, with viruses altering N2O production pathways in some soils.

Conclusions:

• Active soil viruses play a significant role in shaping soil microbial communities and nitrogen cycling, with their effects being context-dependent on land use and soil type.
• Land-use-driven soil properties, microbial communities, and viral load (VLPs) mediate the impact of viruses on nitrogen cycling indicators.
• This study provides crucial microcosm evidence for the significant influence of active viruses on soil nitrogen cycling processes across diverse land use scenarios.