Production of consensus material for dissolved methane and nitrous oxide

The goal of this project is to increase the quality of measurements of two important greenhouse gases, methane and nitrous oxide, dissolved in seawater. These gases are repeatedly measured every year throughout the global ocean by many laboratories and it is important that the measurements are consistent and directly comparable to one another. A valuable component to establishing commonality and communication between independent laboratories is the use of consensus material, which is the focus of this project.

The production and distribution of consensus material represents part of a broader and ongoing program of activity – including workshops, intercomparison exercises, and the production of standards – which is all designed to assess performance and improve the accuracy of dissolved methane and nitrous oxide measurements. This research project will benefit the international research community that is actively involved in measurements of dissolved methane and nitrous oxide.

Dissemination of the results from independent analysis of the consensus material will be via publication in the scientific literature. The production of the consensus material will be filmed and made into a concise movie clip that will accompany a previous video produced by the lead investigator on the importance of non-CO2 greenhouse gases in the ocean.

Together, methane and nitrous oxide comprise almost a quarter of the total radiative forcing budget attributed to greenhouse gases and their current tropospheric mole fractions and rates of increase are unprecedented in recent Earth history. Furthermore, both methane and nitrous oxide have a higher warming potential than carbon dioxide. Despite their critical importance, measurements of methane and nitrous oxide in the global oceans are much less coordinated than carbon dioxide.

The scientific community is taking steps to improve this situation and has an overall goal to collectively achieve an accuracy and precision of less than 1% for methane and nitrous oxide measurements. The production and distribution of consensus material through this project is a critical step towards achieving this goal as it will facilitate the evaluation of existing measurements conducted by independent laboratories.

In particular, the consensus material will be used to evaluate progress that is anticipated to have resulted from a set of intercomparison exercises that were conducted during 2014-2017 and ongoing contributions to a Best Practice Guide for dissolved methane and nitrous oxide measurements. Using a two hundred liter reservoir, consensus material will be prepared using seawater collected near the University of Hawaii for a range of dissolved methane and nitrous oxide concentrations.

Consensus material will be shipped to requesting members of the scientific community who will provide their measured values for intercomparison. The work will be promoted via the US Ocean Carbon & Biogeochemistry program which maintains a specific website about this effort and related activities.

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.