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Ocean acidification, a quantifiable process contributing to risk of atmospheric and oceanic oxygen depletion and so possible human extinction? A call for research
  • Robert Brown
Robert Brown
McCarrison Society

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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.