The quality control of oceanic carbon dioxide measurements: preparation and distribution of reference materials

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The goal of this project is to provide a mechanism for the quality control of the oceanic carbon dioxide measurements, in particular those that are made as part of international global programs. This will help to ensure that such measurements are comparable and accurate although made in different laboratories at different times; and will be an important factor in the design of a Global Ocean Observing System, as well as playing a significant role in the quality control of ocean acidification measurements. To achieve this, a research team at the Scripps Institute of Oceanography of the University of California at San Diego will prepare and certify reference materials for the parameters of the oceanic carbon dioxide system: total dissolved inorganic carbon, total alkalinity, and hydrogen ion concentration, pH, for a sample of sea water. The reference materials for total dissolved inorganic carbon and for total alkalinity will be based on natural seawater, sterilized, bottled, and analyzed using appropriate reference methods for these parameters. Reference materials for pH will be based on Tris buffers in synthetic seawater and analyzed using classical Harned cells. In addition, they will distribute calibrated acid titrant for alkalinity measurements. These reference materials will be distributed to US and to international investigators to assist in the quality control of oceanic CO2 measurements. During the three years of this project, the team expects to distribute at least 25,000 bottles of reference material. These materials will also be used to provide test samples for use in collaborative studies of the analytical methods used to determine these various parameters. An important part of the project involves planning for the future. The team will work to improve the packaging currently used for the reference materials so as to make it significantly more convenient. The principal investigator will also interact with the US National Institute for Standards and Technology (NIST) to ensure that the current process for preparing and certifying reference materials is appropriately documented. It is essential to assure a long-term supply of reference materials for future ocean science research, and it will be necessary to identify an agency or company that will take on this responsibility. The principal investigator will work with NIST to recommend a plan for the future and will also work to investigate possibilities outside the US, in Europe or Japan. Broader Impacts: The provision of reference materials to the international community helps to improve the overall quality of oceanic carbon data around the world both for field studies of the distribution of oceanic carbon, as well as for studies related to ocean acidification. Thus it is a significant US contribution to research infrastructure in this field. Education: The existence of such a laboratory at a major US oceanographic institution ensures that undergraduate students and graduate students that work in the lab alongside this reference material program benefit from the education in high-quality analytical techniques that is part and parcel of such a program, and also from the ancillary discussions associated with quality control and quality assurance. It also provides a resource for other students in the institution who are interested in making high-quality carbon measurements as part of their research. The principal investigator is also called on to instruct others in CO2 measurements, both by telephone or e-mail conversations, and also in more formal courses. Outreach: The principal investigator will be involved in a number of public outreach efforts related to his research studies on the ocean carbon system. In particular, he expects to continue to make a number of public presentations in the area of ocean acidification, as well as to work with various groups such as the State of California and the California Current Acidification Network to improve the capacity of such groups to make high-quality CO2 measurements.