Large nitrogen oxide emission pulses from desert soils and associated microbiomes

Abstract

Nitrogen (N) trace gas emission pulses produced after wetting dry soils may be important pathways of ecosystem N loss. However, the rates and mechanisms controlling these emissions remain unclear. We tested whether changes in microbial community structure and increased rates of atmospheric N deposition could explain N emissions at two desert sites differing in atmospheric N deposition by * six fold. We measured peak NO x (sum of nitric oxide and nitrogen dioxide) emissions 12 h postwetting. NO x emissions remained elevated over 24 h and increased after adding N. In contrast, we measured the highest nitrous oxide (N 2 O) emissions within only 15 min post-wetting. N 2 O emissions decreased within Keywords Nitrous oxide Á Nitric oxide Á NO x Á N 2 O Á Drying-rewetting Á Nitrogen deposition

Modest Residual Effects of Short-Term Warming, Altered Hydration, and Biocrust Successional State on Dryland Soil Heterotrophic Carbon and Nitrogen Cycling

“…N 2 O emissions in soils to which no glucose and ammonium nitrate were added were negligible, yet the soil microbial community was able to respond rapidly (<24 h) to these inputs. The amount of N emitted as N 2 O (at most 0.5 µg N g dry soil −1 ) from the +CN treatment was trivial compared to the amount of N added (1.5 mg N g dry soil −1 ), but when compared to the much smaller pool of extractable N (∼2-4 µg N g dry soil −1 ) in the initial samples, this flux may represent a substantial potential loss pathway from this ecosystem under the right conditions (Eberwein et al, 2020). This result may partially help to explain the observation that repeated addition of ammonium nitrate over multiple years had minimal impact on the soil microbial community and soil N pools at a nearby site (McHugh et al, 2017).…”

Nitric and nitrous oxide fluxes from intensifying crop agriculture in the seasonally dry tropical Amazon–Cerrado border region

“…To measure NO fluxes we used a flow‐through static chamber where air from the chamber was connected to a field‐portable N 2 O analyzer (2B Tech model 410, detection range: 2–2,000 nl L −1 ; precision: ±1.5 nl L −1 ; measurement rate: 0.1 Hz) as in Eberwein et al. (2020) and Oikawa et al. (2015) and then recirculated to the chamber to measure soil–atmosphere NO fluxes.…”

“…To measure NO fluxes we used a flow-through static chamber where air from the chamber was connected to a fieldportable N 2 O analyzer (2B Tech model 410, detection range: 2-2,000 nl L −1 ; precision: ±1.5 nl L −1 ; measurement rate: 0.1 Hz) as in Eberwein et al (2020) and Oikawa et al (2015) and then recirculated to the chamber to measure soilatmosphere NO fluxes. We modified one of the same steel chambers to create a flow-through chamber attached to the analyzer that measured NO concentrations continuously in the chamber by ozone consumption by NO using ultraviolet absorbance at a flow rate of ∼1 L min -1 and then returned sampled air to the chamber.…”

Examining the Effects of the Covid-19 Lockdowns on Reducing Pollutant Concentrations in Us Urban Areas: Evidence From Los Angeles, Seattle and New York City

“…The Sustainable City XV 567 www.witpress.com, ISSN 1743-3541 (on-line) and post-lockdown periods had no significant changes in mean concentration. The drying of soil in warm, dry climates emits NO 2 [17], which could offset NO 2 reductions due to activity changes and explain how NO 2 concentrations did not change significantly. The reduction in mean NO 2 concentrations from the pre-lockdown period to the lockdown period was significantly larger than the baseline, supporting the hypothesis of the effectiveness of the lockdown.…”