The first step of nitrification, the oxidation of ammonia to nitrite, can be performed by ammonia-oxidizing archaea (AOA) or ammonium-oxidizing bacteria (AOB). We investigated the presence of these two groups in three structurally different types of coastal microbial mats that develop along the tidal gradient on the North Sea beach of the Dutch barrier island Schiermonnikoog. The abundance and ...

[1] Nitrification rates, as well as the relationships between rates and ammonia oxidizer abundance (both archaeal and bacterial), were investigated in the Arabian Sea. Ammonia oxidation rates were measured directly using N-NH4 + stable isotope additions in gas-impermeable, trace metal clean trilaminate bags (500 mL) at in situ temperature. Tracer incubations were performed at three stations at ...

For an integrated nitrification-denitrification processes, nitrite formation in the aerobic stage leads to big savings. Recently experimental observations (Garrido et al., 1996) have shown that it is possible to obtain full ammonium conversion with approximately 50 % nitrate and 50 % nitrite in the effluent of a biofilm airlift suspension reactor. With oxygen concentrations between 1 and 2 mg/l...

Over the past few years, new technologies for nitrogen removal have been developed mainly because of the increasing financial costs of the traditional wastewater treatment technologies. Newly discovered pathways, like the anaerobic oxidation of ammonium (ANAMMOX), and uses for nitrogen removal technologies are under discussion. Processes and technologies such as: Partial nitrification; Single r...

A synthetic pharmaceutical manufacturing facility was experiencing recurring upsets of nitrification at its wastewater treatment plant. The main treatment train consisted of trickling filters followed by a conventional activated sludge process with ostensibly adequate treatment capacity (average F/M of 0.1, COD/MLSS-based). An evaluation of the plant’s operating conditions and performance indic...

Aims Land use management affects plant carbon (C) supply and soil environments and hence alters soil nitrogen (N) dynamics, with consequent feedbacks to terrestrial ecosystem productivity. The objective of this study was to better identify mechanisms by which land-use management (clipping and shading) regulates soil N in a tallgrass prairie, OK, USA. Methods We conducted 1-year clipping and sha...

Nitrification is a fundamental component of the global nitrogen cycle and leads to significant fertilizer loss and atmospheric and groundwater pollution. Nitrification rates in acidic soils (pH < 5.5), which comprise 30% of the world's soils, equal or exceed those of neutral soils. Paradoxically, autotrophic ammonia oxidizing bacteria and archaea, which perform the first stage in nitrification,...

Hydroxylamine oxidation by hydroxylamine oxidoreductase (HAO) is a key step for energy-yielding in support of the growth of ammonia-oxidizing bacteria (AOB). Organohydrazines have been shown to inactivate HAO from Nitrosomonas europaea, and may serve as selective inhibitors to differentiate bacterial from archaeal ammonia oxidation due to the absence of bacterial HAO gene homolog in known ammon...

The coupling between nitrification and denitrification and the regulation of these processes by oxygen were studied in freshwater sediment microcosms with O(2) and NO(3) microsensors. Depth profiles of nitrification (indicated as NO(3) production), denitrification (indicated as NO(3) consumption), and O(2) consumption activities within the sediment were calculated from the measured concentratio...

The aim of the study was to determine how soil contamination with diesel oil affected biochemical properties of soil and to determine whether the application of compost, bentonite or lime could recover the biochemical equilibrium of soil. The experiments were carried out in a greenhouse. Typical Eutric Cambisols soil formed from sandy loam was polluted with the following amounts of diesel oil: ...