OBJECTIVE To develop a coated electrode of immobilized denitrificants and to evaluate the performance of a bioelectrochemical reactor to enhance and control denitrification. METHODS Denitrifying bacteria were developed by batch incubation and immobilized with polyvinyl alcohol (PVA) on the surface of activated carbon fiber (ACF) to make a coated electrode. Then the coated electrode (cathode) ...

[1] Recent analysis of sedimentary dN records over the last 200,000 years has shown an expansion of water column denitrification zones during warmer periods and a shrinkage of these oxygen-poor regions during glacial periods. Two different mechanisms could be responsible for driving the changes in the denitrification records: variations in local productivity leading to a change in remineralizat...

In coastal marine sediments, denitrification and fermentation are important processes in the anaerobic decomposition of organic matter. Microbial communities performing these two processes were enriched from tidal marine sediments in replicated, long term chemostat incubations at 10 and 25°C. Whereas denitrification rates at 25°C were more or less stable over time, at 10°C denitrification activ...

It is generally assumed that during denitrification bacteria oxidize organic substances completely to carbon dioxide concomitant with the reduction of nitrate or nitrite to nitrogen and nitrous oxide. This assumption is based upon the early experiments of Gayon and Dupetit (1886) which demonstrated that the ratio of carbon dioxide to nitrogen in denitrifying cultures corresponded to the theoret...

A combined bioelectrochemical and sulfur autotrophic denitrification process for drinking water treatment was put forward and investigated extensively in this paper. In this new process, the bioelectrochemical denitrification was carried out in the upper part of the reactor while sulfur denitrification in the lower part. The H+ produced in Sulfur Part could be consumed by hydrogen denitrificati...

[1] We present a new nitrogen isotope model incorporated into the three‐dimensional ocean component of a global Earth system climate model designed for millennial timescale simulations. The model includes prognostic tracers for the two stable nitrogen isotopes, N and N, in the nitrate (NO3 ), phytoplankton, zooplankton, and detritus variables of the marine ecosystem model. The isotope effects o...

Quantitative estimates of denitrification are needed in designing artificial wetlands to optimize nitrate (NOj-) removal. Acetylene blockage and ~SN-tracer methods were employed to quantify denitriflcation in constructed wetlands receiving agricultural tile drainage, using plastic tubes to enclose in situ mesocosms. Estimates were also made through NO;disappearance from mesocosm water columns. ...

A method for estimating denitrification and nitrogen fixation simultaneously in coastal sediments was developed. An isotope-pairing technique was applied to dissolved gas measurements with a membrane inlet mass spectrometer (MIMS). The relative fluxes of three N(2) gas species ((28)N(2), (29)N(2), and (30)N(2)) were monitored during incubation experiments after the addition of (15)NO(3)(-). For...

Urine excreted by cattle can produce very high concentrations of available N in relatively small volumes of soil and lead to high nitrous oxide (N2O) emissions. Application of the nitrification inhibitor dicyandiamide (DCD) can inhibit nitrification. DCD application results in lower nitrate (NO3 ) concentrations and N2O emissions from denitrification in urine affected soils. However, the effect...

The eastern oyster (Crassostrea virginica) is a foundation species providing significant ecosystem services. However, the roles of oyster microbiomes have not been integrated into any of the services, particularly nitrogen removal through denitrification. We investigated the composition and denitrification potential of oyster microbiomes with an approach that combined 16S rRNA gene analysis, me...