 In all these environments, the highest concentrations were in the first metres, decreasing to the thermocline and reaching the lowest concentrations in the deep oceans.Globally, tropical and subtropical oceans appear to have the most abundant quantity of H2, while the least amount is present in higher latitudes  However, it was observed that the release of hydrogen in the oceans is dependent on the solar radiation, showing a daily change with the maximum peak at noon.Nitrogen fixation, performed by cyanobacteria, leads to the production of one molecule of H2 at least.