The Quality Control of Oceanic CO2 Measurements: Preparation and Distribution of Reference Materials

The goal of this project is to continue to provide a mechanism for the quality control of 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. Such measurements are important components of global scale survey cruises such as those of the Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP), as well as playing a significant role in the quality control of ocean acidification measurements.

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. It is a significant US contribution to global research infrastructure in this field. Numerous students are involved in, and receive training through, this program.

To achieve the goal outlined above, the Scripps laboratory will prepare and certify reference materials for the following parameters of the oceanic carbon dioxide system in seawater: total dissolved inorganic carbon, total alkalinity, and pH. 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 are based on Tris buffers in synthetic seawater and calibrated using spectrophotometric pH measurements. In addition, the laboratory will distribute calibrated acid titrant for alkalinity measurements. 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 laboratory expects to distribute about 30,000 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.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.