Every breath we take reminds us we require oxygen. Crucially, whilst there is wider research into the oceanic impact of climate change, including warming and acidification, and on oxygen content of oceans, there is very little research into the specific impact of acidification and related carbon dioxide changes on marine photosynthetic oxygen production. Oceans are underappreciated. Marine sources provide 40-70% of our oxygen. Many post-Cambrian explosion historic extinction events appear to be related to oxygen levels or anoxic ocean die-off. Were research to be commissioned, that provides clear evidence of risk to oceanic oxygen production and therefore atmospheric oxygen levels, the conclusions could be far-reaching, including identifying potential tipping points that may result in human extinction. The probability of an inadequate human response to risks is increased by; time lags of “many hundreds, if not thousands, of years” in ocean warming and in acidification; underestimation of the greater interdependence of marine ecosystems; the non-visibility of change, combined with lack of public comprehension that once major change ‘hysteresis’ has taken place, it may be impossible to reverse the ecological ‘regime change’. Importantly, in the current ‘Anthropocene’, net oxygen production from land sources is now limited due to fossil fuel use, as well as farming and logging practices, which recycle and or exploit reserves rather than sequestering net carbon. The health of net oceanic global oxygen production cannot be assumed from the presumed dominance of photosynthetic marine bacteria in ocean blooms as the impact of mixotrophs and anoxygenic bacteriochlorophyll photosynthetic bacteria is often not represented in related system modelling. Currently, most public focus is on global warming as reflected in weather and related consequences, which are not viewed as immediate threats to day-to-day life, living standards or indeed survival. In contrast, were research to bear out the possibilities of oxygen depletion or potential for an oxygen-related extinction risk, and particularly in relation to ocean acidification, the danger may be better understood leading to more cohesive public demand for action in finding alternative fuel sources.

Greater public, and research, focus on oceanic and atmospheric oxygen budgets is needed. Oceans are “losing their breath”; there has been a 1-2% loss, 77-154 gigatons (GT) of total oceanic oxygen (O2) 7,700GT (est.), over the last 50 years. Low O2 ocean areas occur more frequently and more widely; O2 minimum zone (OMZ) depths are rising; and sulphidic events are more common. Where is lost ocean oxygen ‘gO2ing’? Oxygen (O2) is recharged by phototropic O2 producing organisms in both the oceans and on land. Pre-human activity, O2, and CO2 (190-260ppm.) levels likely oscillated within a relatively stable band, for 800,000 years or more. Thus, O2 usage by volcanism, fires, and soil and sea biomes, must have balanced ocean and land based photosynthetic O2 production, as cyclically regulated by ‘Gaian’ feedback. Therefore, additive anthropogenic related increases in CO2 production, must result in net atmospheric O2 loss, including ocean outgassing. Importantly, exchange of oxygen between the oceans and atmosphere is determined by ‘Henry’s Law’, as influenced by oceanic temperature change (warmer waters dissolve less oxygen), and also salinity. Undissolved oxygen concentrations within upper ocean layers, will be higher due to the water pressure gradient, so less oxygen being dissolved at lower pressures. Thus, subject to usage by sea life forms; and thermoclines and haloclines; will likely be replenished from below, tending to surface saturation, even if the OMZs are rising so decreasing in depth? Henry’s law dictates, as anthropogenic reduction of atmospheric O2 reduces partial pressure, dissolved ocean oxygen will equilibrate, releasing stored oxygen to the atmosphere. Thus, over time, if atmospheric O2 continues to fall due to anthropogenic usages, irrespective of other factors, oceanic O2 will arguably be diminished year on year; ultimately will oceans become sufficiently anoxic to be unstable? Research suggests risk of species extinction type events of varying severity strongly correlate to anoxic ocean events. Due to Henry’s Law; will continued anthropogenic oxygen including fossil fuel use, inevitably lead to oceanic oxygen outgassing depletion, and absent change, ultimately an extinction event risk? Is a global Manhattan type project needed to find viable non-carbon-based, non-oxygen using, energy sources?