Write down the three dissociation products of phosphoric acid in order of decreasing tendency to form ion-pairs.
PO4 > HPO4 > H2PO4
Name three biogenic substances which contain phosphorus.
ATP
DNA
Phospholipds
Phosphoesters
Identify two ocean regions where the observed nitrate concentration falls significantly below the expected values relative to phosphate =16*phosphate. Why is that ans what are the biogeochemical processes?
Generally, in low oxygen environments denitrification and anammox play an important role in organic matter recycling processes (see above). Both contribute to N2-loss and a shift from the Redfield-ratio of 16:1 to possibly significant lower relations. This is popular in the Benguela Upwelling System, North-West Indian Ocean upwelling system.
Phosporus does not have a redox chemistry in seawater. What is the reason that we nevertheless speak about indirect redox chemistry of phosphate in. seawater?
Its redox chemistry is determined by the redox chemistry of Fe. Generally, PO43- shows strong adsorption to particles forming insoluble complexes. This happens especially with iron where soluble Fe(II) precipitates to non-soluble Fe(III)-PO4 species. Thus, it has an indirect redox chemistry with iron.
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