We conducted a series of stepwise NO3 2 additions to investigate the response of NO3 2 uptake to short-term (acute) changes in N concentration in 3 prairie streams. Observed NO3 2 uptake rates increased with short-term elevations in NO3 2 concentration and were consistent with linear and Michaelis–Menten kinetics models. We compiled these data with uptake rates from additional published studies...

Attributing nitrogen export to specific land use within heterogeneous catchments remains a challenge due the spatio-temporal variability in conditions influencing mobilization and fate of species. This study demonstrates that measurement dual stable isotopes nitrate, taken along with routine tributary nitrate (NO3−-N) ammonium (NH4+-N), aids apportioning sources overall load during wet periods....

In the present research the growth and metabolism of cyanobacterium Fischerella sp. FS18, isolated from rice fields of Gillan Province (Iran), were evaluated in different nitrogen sources. This strain is a good candidate as biological fertilizer due to high efficiency to N2 fixation. In this way, cells in logarithmic phase of stock were treated with different nitrogen sources (N-free, 1 & 2 mM ...

The transport of organic N compounds to the shoot in the xylem sap of nodulated soybean plants was investigated in an attempt to better understand the changes in N metabolism under root hypoxia (first 5 days of flooding), with different sources of N in the medium. NO3 is beneficial for tolerance of plants to waterlogging, whereas other N sources such as NH4 + and NH4NO3, are not. Nevertheless, ...

The purpose of this field study was to determine the relationship between environmental conditions, particularly high nitrate (NO3 ), low salinity events, and both nitrogen (N) storage (NO3 , ammonium [NH4 ], free amino acids [FAA], protein, and total N) and nitrate reductase (NR) activity in the macroalgae Enteromorpha lingulata and Gelidium pusillum in the lower Mobile Bay estuary (Alabama, U...

Myriophyllum elatinoides was reported to effectively treat wastewater by removing nitrogen (N) and phosphorus (P). However, little is known about the abundance and community structure of ammonia-oxidizing microorganisms associated with M. elatinoides purification systems. The objective of this research was to characterize the abundance and community structure of ammonia-oxidizing microorganisms...

Urban regions of southern California receive up to 45 kg Nha y from nitrogen (N) deposition. A field decomposition study was done using N-labelled litter of the widespread exotic annual grass Bromus diandrus to determine whether elevated soil N is strictly from N deposition or whether N mineralization rates from litter are also increased under N deposition. Tissue N and lignin concentrations, w...

In the seasonally stratified Gulf of Aqaba Red Sea, both NO 2 release by phytoplankton and NH þ 4 oxidation by nitrifying microbes contributed to the formation of a primary nitrite maximum (PNM) over different seasons and depths in the water column. In the winter and during the days immediately following spring stratification, NO 2 formation was strongly correlated (R 2 = 0.99) with decreasing ...

This study was completed to understand the resilience of an ion exchange (IEX) process for its ability remove variable ammonium (NH4+-N) loads) and prove environmental benefits through a life cycle assessment (LCA). The tertiary 10 m3/day demonstration scale IEX fed with NH4+-N concentrations (<0.006–26 mg /L) naturally found in municipal wastewater. Zeolite-N used as media regeneration 10% pot...