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A number of laboratories throughout the world measure dissolved methane (CH4) and nitrous oxide (N2O) to quantify their spatial and temporal distributions, determine the rates of production and consumption, and also derive emissions to the overlying atmosphere.  To maximize the scientific value of these studies, dissolved CH4 and N2O measurements made by all laboratories should be intercomparable and of the highest possible accuracy and precision. An important component to achieving community-wide intercomparability for dissolved CH4 and N2O measurements is the production of Standard Operating Protocols (SOPs).  The SOPs need to contain clear and agreed upon guidelines for achieving high quality measurements.  This webpage lists seven draft SOPs for dissolved CH4 and N2O.

These draft SOPs are publicly available for the scientific community to provide further comments from December 2020 to March 31 2021.

Please contact the lead author of the respective SOP and Sam Wilson for more information, and to submit your comments.

After this period of public availability, the SOPs will be published on the Ocean Best Practices Network.  The SOPs will be available individually and collectively as a Best Practice Guide for dissolved CH4 and N2O measurements

The Best Practice Guide for dissolved CH4 and N2O

Chapter 1. Sampling and sample storage for dissolved CH4 and N2O - word document

Chapter 2. Calibration of CH4 and N2O - word document

Chapter 3. Internal control procedures for dissolved CH4 and N2O analysis - word document

Chapter 4. Quantification of dissolved CH4 and N2O via the purge-and-trap method - word document

Chapter 5. Quantification of dissolved CH4 and N2O via headspace equilibrium - PDF document, word document

Chapter 6. Underway measurements of CH4 and N2O in surface seawater - word document

Chapter 7. Data reporting and archiving for dissolved CH4 and N2O - word document, google document for interactive commenting

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Bourbonnais, A., C. Frey, X. Sun, L. A. Bristow, A. Jayakumar, N. E. Ostrom, K. L. Casciotti, B. B. Ward (2021). Protocols for assessing transformation rates of nitrous oxide in the water column. Front. Mar. Sci. | doi: 10.3389/fmars.2021.611937