In the tropics, termites are major players in the mineralization of organic matter leading to the production of greenhouse gases including nitrous oxide (N2O). Termites have a wide trophic diversity and their N-metabolism depends on the feeding guild. This study assessed the extent to which N2O emission levels were determined by termite feeding guild and tested the hypothesis that termite speci...

The nitrous oxide emissions were measured at three tundra sites and one snowpack on the Fildes Peninsula in the maritime Antarctic in the summertime of 2002. The average fluxes at two normal tundra sites were 1.1+/-2.2 and 0.6+/-1.7 microg N2O m(-2)h(-1), respectively. The average flux from tundra soil site with penguin dropping addition was 3.7+/-2.0 microg N2O m(-2)h(-1), 3-6 times those from...

Nitrous oxide (N2O) is a trace gas that contributes to the greenhouse effect and stratospheric ozone depletion. The N2O yield from nitrification (moles N2O-N produced per mole ammonium-N consumed) has been used to estimate marine N2O production rates from measured nitrification rates and global estimates of oceanic export production. However, the N2O yield from nitrification is not constant. Pr...

Our purpose was to measure simultaneous fluxes from soil of both N2O and N2 from the same plot in the field using the 15N-gas "nonequilibrium" technique (i.e., the "Hauck" technique) as used previously for N2. We accommodated analysis of N2O by modifying the head amplifier of our mass spectrometer. Our system accurately measured the 15N enrichments of labeled soil slurries for both N2 and N2O. ...

Denitrification is mediated by microbial, and physicochemical, processes leading to nitrogen loss via N2O and N2 emissions. Soil pH regulates the reduction of N2O to N2, however, it can also affect microbial community composition and functional potential. Here we simultaneously test the link between pH, community composition, and the N2O emission ratio (N2O/(NO + N2O + N2)) in 13 temperate past...

Both plant invasion and nitrogen (N) enrichment should have significant impact on mangrove ecosystems in coastal regions around the world. However, how N2O efflux in mangrove wetlands responds to these environmental changes has not been well studied. Here, we conducted a mesocosm experiment with native mangrove species Kandelia obovata, invasive salt marsh species Spartina alterniflora, and the...

Nitrous oxide (N2O; laughing gas) has been a widely used anesthetic/analgesic since the 19th century, although its cellular mechanism of action is not understood. Here we characterize the effects of N2O on excitatory and inhibitory synaptic transmission in microcultures of rat hippocampal neurons, a preparation in which anesthetic effects on monosynaptic communication can be examined in a setti...

Emissions of N2O from soils of the Southwestern US are thought to result from the activity of anaerobic denitrifying bacteria, but the seasonal dryness and sandy texture of these soils are more conducive to the activities of aerobic microbes. Here, we present incubations of semiarid soils with added compounds known to stimulate the N-cycling processes ammonification (proteins, oligopeptides, an...

Agricultural soils are the most important anthropogenic source of nitrous oxide to the atmosphere. We observed large shifts with time in the emission rate (from 170 to 16 ng N cm−2 h−1) and in δ15N of N2O emitted (from −46‰ to +5‰ relative to atmospheric N2) from a urea-fertilized and irrigated agricultural field in Mexico. We calculated overall instantaneous enrichment factors for the sampling...

Nitrous oxide (N2O)-reducing bacteria, which reduce N2O to nitrogen in the absence of oxygen, are phylogenetically spread throughout various taxa and have a potential role as N2O sinks in the environment. However, research on their physiological traits has been limited. In particular, their activities under microaerophilic and aerobic conditions, which severely inhibit N2O reduction, remain poo...