Ocean Circulation and Carbon Cycling during the Last Deglaciation: Regional Syntheses of Carbon Isotope Data

27.06 - 29.06.2017  
Corvallis, USA
Contact person:
Andreas Schmittner, This email address is being protected from spambots. You need JavaScript enabled to view it.
Workshop report: 
> Access

PAGES' Ocean Circulation and Carbon Cycling (OC3) working group will hold the "Ocean Circulation and Carbon Cycling during the Last Deglaciation: Regional Syntheses of Carbon Isotope Data" workshop in Corvallis, Oregon, USA, from 27-29 June 2017.


The meeting venue is LaSells Steward Center, Oregon State University, Corvallis, Oregon, USA.

The workshop will be open to approximately 40 participants and will include plenary talks and breakout groups.


Earth’s climatic transition from the Last Glacial Maximum (LGM) to the Holocene is still not fully understood. The associated rise in atmospheric CO2 remains unexplained although it is important for the global warming. Ocean circulation changes during the deglaciation have been linked to the rates of CO2 increase. However, the exact mechanism of that link is unclear and quantifying changes in the ocean’s circulation and carbon storage remain challenging tasks.

This workshop will contribute to making progress through new regional syntheses of carbon isotope data throughout the last deglaciation and comparisons of these syntheses to other paleoclimate proxy reconstructions and isotope enabled model simulations. We plan to address questions such as the following:

- When, at what depths, and by how much did carbon isotopes start to change after the LGM in the Atlantic, Pacific, Indian, and Southern Oceans?
- What do these changes imply about ocean circulation?
- How much did the Atlantic Meridional Overturning Circulation (AMOC) decrease during Heinrich Stadial 1 (HS1)? Was it only weakened or completely shut-down?
- Are carbon isotopes consistent with the idea that an AMOC shutdown weakened the biological pump and triggered the initial CO2 rise during HS1?
- Why did CO2 concentrations during the subsequent Bolling-Allerod stay constant?
- What caused the CO2 rise during the final phases of the deglaciation?
- What role did changes in the Southern Ocean and North Pacific play?

Workshop aims

Objectives of the workshop are to:

- bring together sea-going paleoceanographers, modelers, and database managers
- discuss database issues such as format, links to other databases, LinkedEarth ontology
- discuss methods and uncertainties of age model construction
- discuss how the database can be used to constrain models of ocean circulation change and our ideas about the release of CO2
- create regional syntheses of benthic carbon isotope measurements
- analyze the syntheses, compare them with each other and with other paleoclimate data and models
- draft manuscripts describing the syntheses and analyses suitable for publication in a special issue of a peer-reviewed journal
- discuss what advances need to be made beyond this compilation.


OC3’s overarching goal is to synthesize foraminiferal carbon isotope (δ13C) data and compare them with model simulations in order to better understand past changes in ocean circulation and carbon cycling. OC3 focusses on the last deglaciation but considers all time periods. δ13C is routinely measured on shells of fossil benthic (deep dwelling) and planktonic (near surface) foraminifera and has been used for a long time as a proxy to infer both carbon cycling as well as deep ocean circulation in the past.

During discussions at the inaugural meeting in Bern and subsequent email conversations and teleconferences, a strategy for the data synthesis has been developed. Part of that strategy is a division into regional syntheses in individual ocean basins and sub-basins. Groups of researchers familiar with specific regions will focus on those regions. Attempts will be made to use common techniques for the development of age models. Different methods will be used and uncertainties will be determined. Preliminary syntheses of global published data and regional data (both published and unpublished) have been assembled.

This will be the second OC3 meeting. It will focus on regional syntheses of benthic carbon isotope data in different basins/sub-basins of the ocean. It will be preceded by an open call for unpublished data and preparatory work to develop the regional syntheses.


Deadline extended!

The deadline for abstracts is now Monday 3 April (formerly 27 March). Email your abstract to This email address is being protected from spambots. You need JavaScript enabled to view it.. In the subject line, write "OC3 Workshop 2017".

Financial support

Limited funding for travel support is available. Applicants for travel support will be notified of the decision and the amount of support by 5 April 2017.

Stakeholder engagement

We will work with the Paleoclimate Modeling Intercomparison Project’s (PMIP) working group "Last Deglaciation". The purpose of that working group is to co-ordinate climate model simulations of the last deglaciation including comparison with reconstructions. For the latter purpose our carbon isotope syntheses and data constraints of ocean circulation will be useful. Members of this working group are encouraged to attend the meeting.

LinkedEarth is an NSF funded EarthCube project that aims to facilitate paleoclimate data syntheses. LinkedEarth team members are welcome to attend.

Further information

Access the website:
or contact Andreas Schmittner: This email address is being protected from spambots. You need JavaScript enabled to view it.

Post-meeting material

Minutes - breakdown

- We have agreed to upload the final OC3 downcore database on LinkedEarth ( LinkedEarth will also serve as a long-term platform to crowdsource the curation of the database past the end of the OC3 project.

- The regional syntheses groups will choose a leader who will be first author on the corresponding publication. Each group chooses their own approach of data selection and quality control depending on the scientific questions. However, at least one person, preferably two, will need to quality check each core and add quality flags. Information on data quality including species used, age model and uncertainty, time resolution, and analytical errors will be reported.

- Alan Mix is leading the Pacific synthesis supported by Liz Sikes and Gema Martinez. The Pacific synthesis is already quite well progressed. A paper will be prepared for publication within about 3 months.

- The South Atlantic group (Steve Barker, Stefan Muliza, Dave Lund, and Gema Martinez) will need to 'volunteer' a leader.

- The North Atlantic group (Claire Waelbroeck, Janne Repschlaeger, and Steve Barker) will build on an ongoing effort by Claire. We also need a designated leader for that group.

- The Indian ocean group (Elisabeth Michel, Carlye Peterson) also still needs experts and a designated leader.

- Data from the Southern Ocean sectors will be included in the above groups.

- One paper on the comparison between S. Atlantic and S. Pacific is currently in preparation by Liz Sikes and David Lund.

- Policy for co-authorship: each data contributor will become a co-author on a paper. If the data are not included in one of the above regional syntheses it will be included in the final global data synthesis paper led by Lorraine Lisiecki. Of course, contributors of ideas can also become co-authors depending on the judgement of the lead author.

- We have agreed on the following timeline:
Dec 2017: finalize regional syntheses (each regional group can have an earlier deadline depending on their plans, but we need all regional syntheses completed by the end of this year)
Jun 2018: finalize global synthesis

- Juan Muglia, a postdoc with NSF funding to work on the project, will assist with data management and coordination between groups. He will also lead a paper on model-data comparison focused on the early parts of the last deglaciation that will use the global synthesis. Juan will split the current spreadsheet, which contains all published data, into four spreadsheets that contain only data in the corresponding regions (Pacific, S. Atl., N. Atl, Indian). He will also clean it up by removing time slice data (e.g. only core-top) and then send the resulting regional spreadsheets to the individual groups. The individual groups then need to quality check the data, solicit and include unpublished data, analyze the data and write a paper.

 oc3 wshop jun 17

Workshop participants relax after a long day.