Understanding the current use and future needs of CO2 in seawater certified reference materials

Certified reference materials (CRMs) are fundamental for accurate and precise measurements of seawater CO2 system parameters and research related to ocean acidification and oceanic carbon cycles. Currently, there is a single global source of reference materials for total alkalinity, dissolved inorganic carbon, and pH in seawater and a calibrated HCl titrant for seawater alkalinity analysis (Andrew Dickson Laboratory, Scripps Institution of Oceanography, University of California San Diego). When production of these materials was halted during lab closures due to the Covid-19 pandemic, a shortage of CRMs ensued and highlighted the risks associated with having a single producer of CRMs. Distribution of CRMs was halted from for a year starting in March 2020.