Nitrification, mediated by ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), is important in global nitrogen cycling. In estuaries where gradients of salinity and ammonia concentrations occur, there may be differential selections for ammonia-oxidizer populations. The aim of this study was to examine the activity, abundance, and diversity of AOA and AOB in surface oxic sedime...

Nitrous oxide (N(2)O) is a greenhouse gas with a global warming potential far exceeding that of CO(2). Soil N(2)O emissions are a product of two microbially mediated processes: nitrification and denitrification. Understanding the effects of landscape on microbial communities, and the subsequent influences of microbial abundance and composition on the processes of nitrification and denitrificati...

In unsaline loam soil, a laboratory experiment was undertaken studying the effect of using diluted saline water from Karoon lake at Fayoum Governorate, on transformations and subsequent nitrification of two ammoniacal fertilizers, namely (NH4)2SO4 and urea, in the presence or absence of natural organic amendments, namely clover and wheat straw. Ammonification and nitrification of both fertilize...

Nitrification, the chemoautotrophic process by which NH4-N is converted to NO,-N, is an integral biogeochemical transformation in stream ecosystems. Previous research has shown that experimental addition of dissolved organic C inhibits rates of nitrification, and that NH4-N addition stimulates rates of nitrification. In many streams, large amounts of C and N may be present in particulate and so...

The aim of this work was to study the effect of the herbicides glyphosate, nonanoic acid, and dichlorprop-P and the insecticides potassium oil, malation and Pyretrin and their combinations on nitrification. Nitrification was measured in slurries from the eutrophic and shallow Brabrand Lake (Aarhus, Denmark), by inhibiting oxidation of nitrite to nitrate with chloride. All herbicides and insecti...

The source of N(2)O produced in soil is often uncertain because denitrification and nitrification can occur simultaneously in the same soil aggregate. A technique which exploits the differential sensitivity of these processes to C(2)H(2) inhibition is proposed for distinguishing among gaseous N losses from soils. Denitrification N(2)O was estimated from 24-h laboratory incubations in which nitr...

Acclimation of nitrifying bacteria using inorganic carbon source (bicarbonate) and organic carbon source (bicarbonate + glucose) was performed in this study. Sequential batch reactors were inoculated by activated sludge (mixed culture of heterotrophic and nitrifying bacteria), and fed by synthetic wastewater contain high concentration of ammonium (1000 mg·L). Adapted nitrifying bacteria, only u...