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

Zhao, Sharon1

Published Aug 16, 2024 on Dryad. https://doi.org/10.5061/dryad.mpg4f4r72

Data files

Aug 16, 2024 version files 17.95 KB

Abstract

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.