Distribution in ocean
Hydrogen ion concentrations,
often expressed as pH = -log10 (H+), are controlled
by respiration and photosynthsis, which alter the carbonic acid concentration in
seawater (data).
There is a strong correlation between oxygen and
pH, therefore.
Speciation
The major form of hydrogen, other than in water, is H+ ion and its
complexes with sulfate (HSO4-) and fluoride (HF0).
Trace amounts of hydrogen gas H2 may also be generated.
Analysis
Hydrogen ion is classically determined with a glass pH electrode. Recent
work has shown that hydrogen ion concentrations can be determined with much
greater accuracy in seawater using colorimetry with acid-base indicators.