Free or unbound protons may not be there as protons chemical bond or attach electron to make hydrogen gas. So its unlikely to get free, unbound protons in ocean water. deuteron (capture of ambient neutrons by H nucleus) also bonds with Oxygen to make heavy water. Deutron may further catch another neutron to make tritium, which is radioactive .
Ocean water does not contain free hydrogen protons but does contain hydronium ions H3O+. Their concentration determines the pH of sea water where pH = -log10([H3O+]).
Dr. Kumar, your response intimated that there are free neutrons in ocean water, whereas a deuteron might capture a neutron to create tritium; why would there be free neutrons in ocean water?
I do agree with Dr. Kumar's answer. while for Dr. J. Jacopson, free neutrons exist due to spontaneous fission of high atomic mass in NORM radionuclides.