The eastern tropical Indian Ocean is an overall source of atmospheric N2O, in particular toward its northern shelf The Bay of Bengal contributes 0.9%–1.5% of oceanic N2O emissions, which is moder...

Anthropogenic nitrogen (N) deposition and phosphorus (P) enrichment are profoundly altering terrestrial ecosystem stoichiometry, with particularly pro…

Accurate determinations of ammonia (Ra) and nitrite oxidation rates (Rn) are critical for understanding the nitrification process across various ecosystems. However, there is only a limited number of methods available for the quantification of Ra and Rn. Here, we report a new method coupling stable isotope tracing and acidified potassium iodide reduction (SIT-APIR) to measure Ra and Rn simultaneously. 15NH4+ was added to the incubation as a tracer to quantify Ra by calculating produced 15NO2– and 15NO3–, while 15NO2– was employed as a tracer for Rn by determining produced 15NO3–. 15NO2– and 15NO3– were chemically reduced to 15NO with acidified potassium iodide and the produced 15NO was subsequently measured by a membrane inlet mass spectrometer (MIMS). Under the optimized experimental conditions, the detection limit of this method is 0.1 μmol L–1. This method is accurate (relative error: 4.45% for 15NO2–, 0.65% for 15NO3–) and stable (relative standard deviation: 5.56% for 15NO2–, 8.97% for 15NO3–) to quantify the concentrations of 15NO2– (0.1–200 μmol L–1) and 15NO3– (0.1–80 μmol L–1) with excellent calibration curves (R2 ≥ 0.994). Furthermore, the optimal incubation time for nitrification rate measurements was determined by simulating the kinetics of 15NO2– and 15NO3– during incubation with the Gompertz model. In addition to its application to water and sediment samples, this method can also be extended to soil samples. Overall, this newly developed method significantly improved the accuracy and efficiency for determining the nitrification rate in diverse ecosystems with low sample volume and cost.

Read the last Newsletter of the ACTIONr network, and discover among others: -Editorial by the ACTIONr team: “Insights from ACTIONr and Side Projects on Nitrification Inhibitors Mechanisms, Performance...

Nitrification, a key process in the oceanic nitrogen cycle, is an essential source of nitrate for primary production and a potential contributor to ni…

Widespread shallow lakes/ponds receive substantial anthropogenic reactive nitrogen (N) inputs to be vulnerable components of global aquatic ecosystems…

A lab-scale single-chamber microbial fuel cell (SCMFC) with a heterotrophic nitrifying-aerobic denitrifying bacteria (HNADB)-functionalized biocathode…

Urban groundwater frequently exhibits high nitrate loadings, a phenomenon that is especially evident in karst regions. In these regions, dissolution-i…

This study reveals how soil pH regulates microbial N allocation in forest soils across Japan. We show that microbial abundance controls the overall rate of N cycling, while microbial composition and ...

Scientific Reports - Diversity and characterization of the ammonia-oxidizing bacteria responsible for nitrification in tea field soils

The urea to ammonium concentration ratio is a good predictor of the relative importance of urea and ammonium to nitrite and N2O production in the ocean. In addition, the urea to ammonium ratio may be....

The urea to ammonium concentration ratio is a good predictor of the relative importance of urea and ammonium to nitrite and N2O production in the ocean. In addition, the urea to ammonium ratio may be...

At the Faculty of Engineering and Science, Department of Chemistry and Bioscience, a 2.5 year position as Postdoc in “Identification and characterization of ...

Conventional heterotrophic denitrification (HD) struggles with efficient nitrogen removal from low carbon-to-nitrogen (C/N) ratio wastewater due to re…

Nitrification and Urease Inhibitors Market Size and Share Forecast Outlook 2025 to 2035