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Nitrogen cycle. 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.
[12] [13] Complete nitrification, the conversion of ammonia to nitrate in a single step known as comammox, has an energy yield (∆G°′) of −349 kJ mol −1 NH 3, while the energy yields for the ammonia-oxidation and nitrite-oxidation steps of the observed two-step reaction are −275 kJ mol −1 NH 3, and −74 kJ mol −1 NO 2 − ...
Elevated nitrate in groundwater is a concern for drinking water use because nitrate can interfere with blood-oxygen levels in infants and cause methemoglobinemia or blue-baby syndrome. [28] Where groundwater recharges stream flow, nitrate-enriched groundwater can contribute to eutrophication , a process that leads to high algal population and ...
In the NO − 3 anion, the oxidation state of the central nitrogen atom is V (+5). This corresponds to the highest possible oxidation number of nitrogen. Nitrate is a potentially powerful oxidizer as evidenced by its explosive behaviour at high temperature when it is detonated in ammonium nitrate (NH 4 NO 3), or black powder, ignited by the shock wave of a primary explosive.
Nitrobacter play an important role in the nitrogen cycle by oxidizing nitrite into nitrate in soil and marine systems. [2] Unlike plants, where electron transfer in photosynthesis provides the energy for carbon fixation, Nitrobacter uses energy from the oxidation of nitrite ions, NO 2 −, into nitrate ions, NO 3 −, to fulfill their energy needs.
Nitrogen assimilation is the formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds present in the environment. Organisms like plants, fungi and certain bacteria that can fix nitrogen gas (N 2) depend on the ability to assimilate nitrate or ammonia for their needs.
Soil pH and texture are both factors that can moderate denitrification, with higher pH levels driving the reaction more to completion. [22] Nutrient composition, particularly the ratio of carbon to nitrogen, is a strong contributor to complete denitrification, [ 23 ] with a 2:1 ratio of C:N being able to facilitate full nitrate reduction ...
Nitrogen leaching occurs when nitrogen compounds, primarily nitrates, move through the soil profile and enter groundwater, potentially contaminating drinking water sources. [2] To mitigate these environmental impacts, various nitrogen management strategies are employed in agriculture.