15 April 2019. Today, the Canadian Journal of Zoology published a perspective on the progress and challenges of experimental ocean acidification research, written by Hannes last year as an extension of keynote lectures on this topic given at the Annual meeting of the Canadian Zoological Society (St. John’s, NL, Canada) and the Gordon Research Symposium (Waterville Valley, NH). The perspective takes stock of the progress achieved in the field over past two decades in four key areas, hoping to inspire particularly new researchers to the field to build on this foundation.

Abstract: Experimental studies assessing the potential impacts of ocean acidification on marine organisms have rapidly expanded and produced a wealth of empirical data over the past decade. This perspective examines four key areas of transfor- mative developments in experimental approaches: (1) methodological advances; (2) advances in elucidating physiological and molecular mechanisms behind observed CO₂ effects; (3) recognition of short-term CO₂ variability as a likely modifier of species sensitivities (Ocean Variability Hypothesis); and (4) consensus on the multistressor nature of marine climate change where effect interactions are still challenging to anticipate. No single experiment allows predicting the fate of future populations. But sustaining the accumulation of empirical evidence is critical for more robust estimates of species reaction norms and thus for enabling better modeling approaches. Moreover, advanced experimental approaches are needed to address knowledge gaps including changes in species interactions and intraspecific variability in sensitivity and its importance for the adaptation potential of marine organisms to a high CO₂ world.