“MEASURED ONCE, ACCEPTED EVERYWHERE”: a concept necessary to reliably assess and quantify seawater acidification in relation to climate change

The on-going uptake by the ocean of anthropogenic atmospheric CO2 is resulting in a decrease in pH, a process termed ocean acidification. This phenomenon is taking place in parallel to climate change, which causes enhanced ocean temperatures and water column stratification, and is also a consequence of increased anthropogenic greenhouse gas emissions.

Ocean acidification can provoke substantial changes in ocean chemistry i.e. carbonate chemistry and ecosystems. Ocean acidification has also negative effects on many societal and economical issues. As an example, according to recent publications, higher levels of ocean acidity will lead to disruptions to the oceanic carbon cycle, which is estimated to cost €1 trillion by 2100 and will have lasting impact upon future generations.

However, evidence of how seawater acidity is changing from local to global scales will be critical to determining ecosystem impacts and for informing policy makers on mitigation or adaptation options. With this respect there is a need for consistent standard procedures to be used across the international community.
SapHTies project addresses metrological challenges for the measurement of seawater acidity necessary to improve the ISO 18191:2015 standard “Determination of pHT in seawater – Method using the indicator dye m-cresol purple”.

The outcomes of the project will have a major impact in the capacity to deliver accurate and traceable measurements results compared to current procedures use to assess and quantify seawater acidity. This will be significant for the science and also for delivering tools needed to provide communities and policy makers in Europe and internationally with evidence to act to ensure a sustainable future ocean.