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. Read the full proposal.

November 1-3, 2021 (virtual)

Workshop Planning Committee

Ann McNichol (WHOI)

Roberta Hansman (WHOI/NOSAMS)

Robert Key (Princeton Univ)

Rolf Sonnerup (Univ Washington)


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 comparisons
Watch 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
Bob Key
Denis Pierrot

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


First Name Last Name Affiliation Email
Dalida Bedikoğlu Istanbul University
Anna Belcher British Antarctic Survey
Joyeeta Bhattacharya Postdoctoral Researcher
Andreu Blanco University of Vigo
Angelica Bradley Undergrad at UCSD/Scripps
Josh Burton WHOI
Wei-Jun Cai University of Delaware
Elizabeth Canuel VIMS
Nuria Casacuberta ETHZ
Maxi Castrillejo Laboratory of Ion Beam Physics, ETH-Zurich
Jeff Chanton FSU
Yéssica Contreras CICESE
Andrew Dickson Scripps Institution of Oceanography / UC San Diego
Regina Easley National Institute of Standards and Technology
Hedy Edmonds NSF
Kathryn Elder Woods Hole Oceanographic Inst NOSAMS Facility
Anita Flohr National Oceanography Centre, Southampton
Alan Gagnon WHOI
Kalina Gospodinova WHOI
Heather Graven Imperial College London
Linnea Heraty University of Delaware
Juan Carlos Herguera Centro de Investigación Científica y de Ensenñanza Superior (CICESE) herguera@cicese,mx
Maria Carolina Hernandez Ribeiro School of Arts, Science and Humanities of the University of São Paulo (EACH-USP)
Shoko Hirabayashi The University of Tokyo
Zhendong Ji Georgetown
Rebecca Kraft National Institute of Standards and Technology
Karolina Krym A.E. Lalonde AMS Lab
Karolina Krym Andre E. Lalonde AMS Laboratory
Xinyu Li University of Delaware
Kanchan Maiti NSF
Paul Middlestead University of Ottawa
Sarah Murseli Andre E. Lalonde AMS Laboratory
Claire Normandeau Dalhousie University
Chris Osburn NC State University
Zhangxian Ouyang University of Delaware
Denis Pierrot NOAA/AOML
Paul Quay U. Washington
Jose Quintanilla Centro de Investigación Científica y de Ensenñanza Superior (CICESE)
Patrick Rafter UC Irvine
Elliott Roberts University of Delaware
Mark Roberts Woods Hole Oceanographic Institution
Terry Rolfe UW
Nick Rollins University of Southern California
Chinmay Shah PRL
Katy Sparrow Georgia State University
Neil Sturchio University of Delaware
Adam Subhas WHOI
Amanda Timmerman University of Delaware
Pablo Trucco-Pignata University of Southampton-National Oceanography Centre
Bryce Van Dam Helmholtz-Zentrum Hereon
Lukas Wacker LIP, ETH Zürich
Brett Walker University of Ottawa
Jennifer Walker University of Ottawa
Douglas Wallace Dalhousie University
Shing-Lin Wang Department of Geosciences, National Taiwan University
Xuchen Wang Ocean University of China
Jason Waters NIST
Michael Winchester NIST
Xiaomei Xu Dept. of Earth System Sci., University of California, Irvine

Related Literature

Atekwana E.A., Krishnamurthy R.V. Seasonal variations of dissolved inorganic carbon and 13C of surface waters: application of a modified gas evolution technique (1998). Journal of Hydrology 205, 265-278

Barnett BK, Chanton JP, Ahrens R, Thornton L, Patterson WF, III (2020) Life history of northern Gulf of Mexico Warsaw grouper Hyporthodus nigritus inferred from otolith radiocarbon analysis. PLoS ONE 15(1): e0228254.

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

Cheng, L., Normandeau, C., Bowden, R., Doucett, R., Gallagher, B., Gillikin, D.P., Kumamoto, Y., McKay, J.L., Middlestead, P., Ninnemann, U., Nothaft, D., Dubinina, E.O., Quay, P., Reverdin, G., Shirai, K., Mørkved, P.T., Theiling, B.P., van Geldern, R. and Wallace, D.W.R. (2019), An international intercomparison of stable carbon isotope composition measurements of dissolved inorganic carbon in seawater. Limnol Oceanogr Methods, 17: 200-209.

Gao, Pan, Xu, Xiaomei, Zhou, Liping, Pack, Mary A., Griffin, Sheila, Santos, Guaciara M., Southon, John R., Liu, Kexin, (2014), Rapid sample preparation of dissolved inorganic carbon in natural waters using a headspace-extraction approach for radiocarbon analysis by accelerator mass spectrometry, Limnol. Oceanogr. Methods, 12, doi:10.4319/lom.2014.12.174.

Gospodinova, K., McNichol, A.P., Gagnon, A. and Shah Walter, S.R. (2016), Rapid extraction of dissolved inorganic carbon from seawater and groundwater samples for radiocarbon dating. Limnol. Oceanogr. Methods, 14: 24-30.

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.

Kelsey McDuffee, Ellen R.M. Druffel (2007). Daily variability of dissolved inorganic radiocarbon in Sargasso Sea surface water. Marine Chemistry, Volume 106, Issues 3–4, 510-515,

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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,

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An important part of this meeting will be the production of documents summarizing the group recommendations. Recommendations will address proper sampling protocols, storage procedures, appropriate secondary standards, standard reporting procedures, and other issues brought up at the meeting. Our intention is to provide GO-SHIP and the international community with a “Best Practices” protocol detailing the best ways to handle DI13C and DI14C samples from shipboard to reporting/publication as well as to publish articles in AGU Eos and TOS Oceanography. We plan to present the findings at OCB2022 and at Ocean Sciences 2022. We view this meeting as the start of a process to devise  and test standard reference materials and protocols for the ocean sciences isotope community. Follow-up will include calls to prepare and standardize reference materials, as well as conduct round-robin trials to assess the performance of laboratories making isotopic measurements.