Carbon Isotopes in the Ocean: Ensuring High-Quality Results Workshop

Carbon Isotopes in the Ocean: Ensuring High-Quality Results

Isotopic measurements of DIC are contributing to our understanding of biogeochemical and paleoceanographic processes. Until recently, only a few laboratories had the ability to make the precise isotope measurements necessary for studying ocean circulation and the uptake of anthropogenic carbon. At present, there are no recognized standards or reference materials for carbon isotopes in seawater.

This new activity sponsored by OCB aims to define methods of best practice for the measurement of DI¹³C and DI¹⁴C with the goal of guaranteeing data comparability of all measurements across laboratories and over time. We will assemble researchers from laboratories making DI¹³C and/or DI¹⁴C measurements to discuss the different methods in use, recommend best practice protocols, and decide on the best source of reference materials.

November 1-3, 2021 (virtual)

Workshop Planning Committee

Ann McNichol (WHOI)

Roberta Hansman (WHOI/NOSAMS)

Robert Key (Princeton Univ)

Rolf Sonnerup (Univ Washington)

Ann McNichol

Roberta Hansman

Bob Key

Rolf Sonnerup

Agenda

Monday, November 1	Collection and Analysis	All times are in EST
10:00a-10:15a	Introduction: Goals of workshop	Ann McNichol, WHOI
10:15a-12:00p	Analytical Techniques -Collection, preservation, extraction methods, results -Working standardsWatch recording Part 1	Kalina Gospodinova José Quintanilla Brett Walker and Jennifer Walker Sarah Murseli Katy Sparrow Terry Rolfe Maxi Castrillejo Wei-Jun Cai
12:00p-12:30p	Break
12:30p-1:30p	Breakout groups 12:30p - Collection / preservation / storage 12:50p - Extraction Methods 1:10p - Summary/Miscellaneous
1:30p-2:00p	Summary from each group Watch recording Part 2

Tuesday, November 2	Interlaboratory comparisons & Definitions and practices for reporting uncertainties
10:00a-10:45a	Introduction -Historical interlaboratory comparisons	Roberta Hansman, WHOI NOSAMS Ann McNichol Maxi Castillejo
10:45a-11:15a	Database-level data processing and reporting	Bob Key, Princeton Univ
11:15a-11:30a	Overview of afternoon discussion topics - Reporting uncertainties - Future interlaboratory comparisonsWatch recording Part 1
11:30a-12:00p	Break
12:00p-1:30p	Breakout group discussions Reporting uncertainties - Laboratory-level data processing - Best practices / recommendationsFuture interlaboratory comparisons - Format (materials, participants, frequency) - Funding (cost, source)
1:30p-2:00p	Summary from each group Watch recording Part 2

(Homework for Day 3: View Andrew Dickson video: CO2-in-seawater reference materials: yesterday, today, and tomorrow)

Wednesday, November 3	Development of Reference Materials
10:00a-10:30a	Introduction Current practices	Rolf Sonnerup, Univ Washington
10:30a-12:00p	Short and long term strategies Inter-laboratory comparison exercises Panel Discussion: Strategy for going forwardWatch recording Part 1	Andrew Dickson NIST Bob Key Denis Pierrot NOSAMS Liz Canuel Maxi Castrillejo
12:00p-12:30p	Break
12:30p-1:15p	Breakout groups
1:15p-2:00p	Summary and Conclusions Watch recording Part 2

Related Literature

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Casacuberta, N., Castrillejo, M., Wefing, A., Bollhalder, S., & Wacker, L. (2020). High Precision 14C Analysis in Small Seawater Samples. Radiocarbon, 62(1), 13-24. doi:10.1017/RDC.2019.87

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Graven, H., Lamb, E., Blake, D., & Khatiwala, S. (2021). Future Changes in δ¹³C of Dissolved Inorganic Carbon in the Ocean. Earth's Future, 9, e2021EF002173. https://doi.org/10.1029/2021EF002173

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McNichol, A., Jones, G., Hutton, D., Gagnon, A., & Key, R. (1994). The Rapid Preparation of Seawater ΣCO2 for Radiocarbon Analysis at the National Ocean Sciences Ams Facility. Radiocarbon,36(2), 237-246. doi:10.1017/S0033822200040522

Murseli, S., Middlestead, P., St-Jean, G., Zhao, X., Jean, C., Crann, C., . . . Clark, I. (2019). The Preparation of Water (DIC, DOC) and Gas (CO2, CH4) Samples for Radiocarbon Analysis at AEL-AMS, Ottawa, Canada. Radiocarbon,61(5), 1563-1571. doi:10.1017/RDC.2019.14

Su, Jianzhong, Wei-Jun Cai, Najid Hussain, Jean Brodeur, Baoshan Chen, Kuan Huang. 2019. Simultaneous determination of dissolved inorganic carbon (DIC) concentration and stable isotope (δ¹³C-DIC) by Cavity Ring-Down Spectroscopy: Application to study carbonate dynamics in the Chesapeake Bay, Marine Chemistry, Volume 215, 103689, https://doi.org/10.1016/j.marchem.2019.103689.

Torres, Marta E., Mix, Alan C., Rugh, William D., (2005), Precise δ¹³C analysis of dissolved inorganic carbon in natural waters using automated headspace sampling and continuous-flow mass spectrometry. Limnol. Oceanogr. Methods, doi:10.4319/lom.2005.3.349.