DOI: 10.5061/dryad.mpg4f4r72
title: Data from: Nitrogen availability and changes in precipitation alter microbially-mediated N emissions from a Pinyon Juniper dryland

description: 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.
description: Please see the detailed methods in the manuscript.
description: # Data from: Nitrogen availability and changes in precipitation alter
 microbially-mediated N emissions from a Pinyon Juniper dryland
 [https://doi.org/10.5061/dryad.mpg4f4r72](https://doi.org/10.5061/dryad.mpg4f4r72) This dataset includes the data presented in the manuscript "Nitrogen availability and changes in precipitation alter microbially-mediated N emissions from a Pinyon Juniper dryland". Briefly, we collected soils from a Pinyon-Juniper dryland ecosystem in southern California after we manipulated the summer and winter precipitation. In the lab, we treated the soils with nitrification inhibitors to compare the relative contribution of ammonia oxidizing bacteria (AOB) versus ammonia oxidizing archaea (AOA) to N gas emissions. We measured the NO and N2O emissions from nitrification and denitrifcation. We also measured soil moisture and inorganic N pools to assess the net rates of nitrification and mineralization. All soils were wet up to 100% water holding capacity and allowed to dry during their 48 hour incubation period. Lastly, we did quantitative polymerase chain reaction (qPCR) to the abundance of AOA and AOB nitrifiers for each dry soil group.  # Description of the data and file structure Combined_Fluxes.csv: This file contains the soil nitric oxide (NO) and nitrous oxide (N2O) flux data from soils wetted to 100% water holding capacity (WHC), 50% WHC, 50% WHC with AOB inhibition, and 50% WHC with total inhibition in a lab incubation. Methods for flux measurements and flux calculations are described in the manuscript text. Moisture_GWC.csv: This file contains initial soil moisture data that are presented in the manuscript and supplementary information.   Net_N_rates.csv: This file contains initial soil nitrate and initial ammonia concentrations. These were used to calculate the net rates of nitrification, NH4+ production, and net nitrogen mineralization from the soil examined in this study. The field treatments refer to which plot/field treatment and lab treatments refer to which were selectively inhibited ammonia oxidizing bacteria or all heterotrophic nitrifiers. qPCR.csv: This file contains data on the abundance of ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) in dry soils. The abundance of AOA and AOB was assessed using quantitative polymerase chain reaction (qPCR). Empty cells indicate missing or not available data.