Nitrification, denitrification and nitrate reduction rates in the sediments at two stations in Hiroshima Bay were studied seasonally from August 1994 to May 1995. The acetylene (C2H2) inhibition technique was used to evaluate the rate of these processes. The seasonal average of nitrification and denitrification rates ranged from 0.00 to 299 μg atN m–2h–1 and 0.00 to 69.0 μg atN m–2h–1, respecti...

The extraction behavior of neodymium and other rare earths from nitric acid media by the functionalized ionic liquid trioctylmethylammonium dioctyl diglycolamate, [A336][DGA], was investigated. The nonfluorinated ionic liquid trioctylmethylammonium nitrate, [A336][NO3], was used as diluent. The extraction behavior of neodymium(III) in this ionic liquid solution was carried out as a function of ...

Nitrate contamination in rivers has raised widespread concern in the world, particularly in arid/semi-arid river basins lacking qualified water. Understanding the nitrate pollution levels and sources is critical to control the nitrogen input and promote a more sustainable water management in those basins. Water samples were collected from a typical semi-arid river basin, the Weihe River watersh...

Plant nitrogen (N) use is a key component of the N cycle in terrestrial ecosystems. The supply of N to plants affects community species composition and ecosystem processes such as photosynthesis and carbon (C) accumulation. However, the availabilities and relative importance of different N forms to plants are not well understood. While nitrate (NO3-) is a major N form used by plants worldwide, ...

Sustainable agricultural practices are needed to minimize nitrate leaching. The crop-soil simulation model STICS coupled with a geographic information system was used to estimate the amount of NO3 leaching and to assess the ability of alternative management practices to reduce NO3 leaching in a nitrate vulnerable zone (NVZ) in La Rioja, Spain. Model performance was examined by comparing the sim...

In sugar beet seedling period and sugar accumulation period, the quantity of NR-mRNA raised with the rate of nitrate nitrogen and ammonium nitrogen raised, and the activity of NR raised also, that was the quantity of NR-mRNA of NO3/NH4 —4:0 was the highest. In phyllome formation period and root growth period, the quantity of NR-mRNA of NO3/NH4—3:1 was the highest, and its activity was the highe...

To measure the concentration of nitrites and nitrates by chemiluminescence, we examined the efficiency of five reducing agents [V(III), Mo(VI) + Fe(II), NaI, Ti(III), and Cr(III)] to reduce nitrite (NO2-) and (or) nitrate (NO3-) to nitric oxide (NO). The effect of each reducing agent on the conversion of different amounts of NO2- and (or) NO3- (100-500 pmol, representing concentrations of 0.4 t...

Nitrate addition stimulated sulfide oxidation by increasing the activity of nitrate-reducing sulfide-oxidizing bacteria (NR-SOB), decreasing the concentration of dissolved H2S in the water phase and, consequently, its release to the atmosphere of a pilot-scale anaerobic bioreactor. The effect of four different concentrations of nitrate (0.12, 0.24, 0.50, and 1.00 mM) was investigated for a peri...

The Catskill Mountains of southeastern New York State have among the highest rates of atmospheric nitrogen deposition in the United States. Some streams draining Catskill catchments have shown dramatic increases in nitrate concentrations while others have maintained low nitrate concentrations. Streams in which exchange occurs between surface and subsurface (i.e. hyporheic) waters are thought to...