French energy and environment company Lhyfe has published an article in Environmental Research Letters which discusses the results of preliminary modelling of the artificial reoxygenation of the oceans, being one of the goals of the company as it produces green hydrogen.

Climate change-induced ocean warming, and acidification of the ocean as it absorbs more CO₂ from the atmosphere, will reduce available dissolved oxygen, thereby making oceans less habitable for much marine life. The production of 1 kg of green hydrogen however produces around 8 kg of oxygen, creating the opportunity to help reoxygenate the oceans. To this end, Lhyfe has been collaborating with “experts in physical and biogeochemical ocean modelling at Institut de recherche pour le développement (IRD)” in Brest, north-west France, and the results have been promising to date.

Though the modelling is at this stage “coarse”, and it assumes that reoxygenation occurs at “an industrial scale”, there is an increase in 0.07% of the global oxygen inventory, with strong variations at the regional level – some low-oxygen zones would in fact expand (due to increased biochemical activity), while others would contract. The work concluded that “industrial large scale artificial ocean reoxygenation could have an impact on the global [low-oxygen zones] and has to be treated with great care”.

Lhyfe therefore has committed to further studies, particularly on the European continental shelf seas, where the research to date has suggested would benefit from reoxygenation.