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Nitrification is the biological oxidation of ammonia to nitrate via the intermediary nitrite. Nitrification is an important step in the nitrogen cycle in soil. The process of complete nitrification may occur through separate organisms [1] or entirely within one organism, as in comammox bacteria. The transformation of ammonia to nitrite is ...
The ANaerobic AMMonia OXidation process is also known as the ANAMMOX process, an abbreviation coined by joining the first syllables of each of these three words. This biological process is a redox comproportionation reaction, in which ammonia (the reducing agent giving electrons) and nitrite (the oxidizing agent accepting electrons) transfer ...
Nitrogen-15 (15 N) tracing is a technique to study the nitrogen cycle using the heavier, stable nitrogen isotope 15 N.Despite the different weights, 15 N is involved in the same chemical reactions as the more abundant 14 N and is therefore used to trace and quantify conversions of one nitrogen compound to another.
Utilizing a large amount of metabolic energy and the enzyme nitrogenase, some bacteria and cyanobacteria convert atmospheric N 2 to NH 3, a process known as biological nitrogen fixation (BNF). [4] The anthropogenic analogue to BNF is the Haber-Bosch process, in which H 2 is reacted with atmospheric N 2 at high temperatures and pressures to ...
Nitrite oxidoreductase (NOR or NXR) is an enzyme involved in nitrification.It is the last step in the process of aerobic ammonia oxidation, which is carried out by two groups of nitrifying bacteria: ammonia oxidizers such as Nitrosospira, Nitrosomonas, and Nitrosococcus convert ammonia to nitrite, while nitrite oxidizers such as Nitrobacter and Nitrospira oxidize nitrite to nitrate.
A process flow diagram (PFD) is a diagram commonly used in chemical and process engineering to indicate the general flow of plant processes and equipment. The PFD displays the relationship between major equipment of a plant facility and does not show minor details such as piping details and designations.
In this biological process, which is a redox comproportionation reaction, nitrite and ammonium ions are converted directly into a diatomic molecule of nitrogen and water. [8] NH + 4 + NO − 2 → N 2 + 2 H 2 O (ΔG° = −357 kJ⋅mol −1). [9] Globally, this process may be responsible for 30–50% of the N 2 gas produced in the oceans. [10]
Diagram of new and regenerated production with nitrification confined to the aphotic zone. This was used to frame the f-ratio and its link to export production. Bio-available nitrogen occurs in the ocean in several forms, including simple ionic forms such as nitrate (NO 3 −), nitrite (NO 2 −) and ammonium (NH 4 +), and more complex organic forms such as urea ((NH 2) 2 CO).