Data from: Nitrogen availability and changes in precipitation alter microbially-mediated N emissions from a Pinyon Juniper dryland

Climate change is altering precipitation regimes that control nitrogen (N)
cycling in terrestrial ecosystems. In ecosystems exposed to frequent
drought, N can accumulate in soils as they dry, stimulating the emission
of both nitric oxide (NO; an air pollutant at high concentrations) and
nitrous oxide (N2O; a strong greenhouse gas) when dry soils wet up.
Because changes in both N availability and soil moisture can alter the
capacity of nitrifiers (i.e., ammonia oxidizing bacteria (AOB) and archaea
(AOA)) to process N and emit N gases, predicting whether shifts in
precipitation may alter N emissions requires understanding how both AOA
and AOB may respond. Thus, we ask: how does altering summer and winter
precipitation affect nitrifier-derived N trace gas emissions in a dryland
ecosystem? To answer this question, we manipulated summer and winter
precipitation and monitored AOA- and AOB-derived N trace gas emissions,
AOA and AOB biomass, and soil N concentrations. We found that altering
summer precipitation amount increases AOB-derived NO emissions, either by
increasing N concentrations under drier conditions or by promoting AOB
activity under wetter conditions. In contrast to summer, excluding
precipitation in the winter (designed to induce more extreme water
limitation than in summer) did not alter nitrifier-derived NO emissions
despite N accumulating in soils. Instead, the nitrate (NO3-) that
accumulated under extreme dry conditions stimulated N2O emissions after
rewetting dry soils. Increases in seasonal precipitation variability and
intensity that are forecasted under climate change may, therefore,
influence dryland emission of N gases according to the magnitude and
season during which the changes occur.