Editing Nitrogen cycle (section)

===Future acidification===
As illustrated by the diagram on the right, additional [[carbon dioxide]] ({{CO2}}) is absorbed by the [[ocean]] and reacts with water, [[carbonic acid]] ({{chem|H|2|CO|3}}) is formed and broken down into both [[bicarbonate]] ({{Chem2|HCO3-}}) and hydrogen ({{chem|link=Hydronium|H|+}}) ions (gray arrow), which reduces bioavailable [[carbonate]] ({{Chem2|CO3(2-)}}) and decreases ocean [[pH]] (black arrow). This is likely to enhance nitrogen fixation by [[diazotroph]]s (gray arrow), which utilize {{chem|H|+}} ions to convert nitrogen into bioavailable forms such as [[ammonia]] ({{chem|NH|3}}) and [[ammonium]] ions ({{chem2|NH4+}}). However, as pH decreases, and more ammonia is converted to ammonium ions (gray arrow), there is less [[Redox|oxidation]] of ammonia to [[nitrite]] (NO{{su|b=2|p=–}}), resulting in an overall decrease in nitrification and denitrification (black arrows). This in turn would lead to a further build-up of fixed nitrogen in the ocean, with the potential consequence of [[eutrophication]]. Gray arrows represent an increase while black arrows represent a decrease in the associated process.<ref name="O'Brien2016">{{cite journal |title = Implications of Ocean Acidification for Marine Microorganisms from the Free-Living to the Host-Associated |year = 2016|doi = 10.3389/fmars.2016.00047|doi-access = free|last1 = O'Brien|first1 = Paul A.|last2 = Morrow|first2 = Kathleen M.|last3 = Willis|first3 = Bette L.|last4 = Bourne|first4 = David G.|journal = Frontiers in Marine Science|volume = 3| page=47 | bibcode=2016FrMaS...3...47O }} [[File:CC-BY icon.svg|50px]] Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref>

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