text: Redox reactions are highly influential in wetland soil chemistry through transformations including those of carbon, sulfur, nitrogen. The abundance of oxygen changes the abundance of oxidized or reduced states of each compound. Areas of higher oxygen availability (aerobic) tend towards oxidized states and areas of low oxygen availability (anaerobic) tend towards reduced states. The abundance of each type results in a different ecosystem, as the plants and animals of the wetlands require specific conditions for their growth. Common wetland redox reactions include:
  :2NO +10e +12H → N +6HO
  :SO +8e +9H → HS +4HO
  :CO +8e +8H → CH + 2HO
  :MnO +2e +4H → Mn + 2HO
  :Fe(OH) +e +3H → Fe + 3HO
  Dredging allows for an increased flow of water through wetlands, causing anaerobic soil conditions. This change in wetland type results in a change in redox state for each reaction undergone and thus changes the plant species available to grow in those areas. The redox potential (Eh) can help to show the relationship of the redox reactions through the Nernst equation:
  :Eh=E-(RT/nF)ln([Reductants]/[Oxidants][H]) 
  This equation allows for the calculation of the extent of reaction between two redox systems and can be used, for example, to decide whether a particular reaction will go to completion or not.
  An example of a change in these circumstances affecting the wetland system is in the transformation of pyrite (FeS) through the reduction of SO (found in seawater).
  :Fe(OH) + e + H → Fe(OH) + HO
  :SO + 6e + 8H → S + 4HO
  :S + 2e + 2H → HS
  :Fe(OH) + HS → FeS + 2HO
  :FeS + S → FeS (pyrite)
  The drainage of the resulted pyrite then results in oxidation to ferric hydroxide and sulfuric acid, causing extreme acidity (pH < 2).