OC3 was active from 2014 to 2019 and focussed on reconstructing ocean circulation and carbon cycling over the last 20,000 years by synthesizing carbon isotopes (d13C) measured on shells of benthic foraminifera from sediments of all ocean basins. More than 90 international scientists were involved.
- To synthesize core-top data and compare to water-column measurements for a new global calibration (completed).
- To synthesize down-core data and create an easily updatable database with consistent age models and uncertainty estimates.
- To analyze the down-core database and compare it with model results in order to better understand and quantify changes in ocean circulation and carbon cycling during the past 20,000 years.
The OC3 working group was active from 2014 to 2019.
It focused on changes in the amount of carbon stored in the oceans which are thought to have played an important role in past variations of atmospheric CO2 and climate. Deep circulation controls the ocean's storage and redistribution of heat and carbon. Climate changes in turn affect physical (e.g. dust and iron supply, mixing, upwelling) and biological (e.g. plankton productivity) processes in the oceans.
Recent model simulations imply that a combination of these processes could explain glacial-interglacial CO2 variations. New paleodata reveal the transition of circulation, atmospheric CO2, and climate from the Last Glacial Maximum (~21,000 years ago) to the present in unprecedented detail including several rapid changes; however, the evidence from the deep ocean is still extremely limited.
Due to extensive labor needed to generate consistent age models as well as to ensure data quality, the group was granted an extension, which ended in December 2019, to complete the work. During the first years of OC3, strategies for the data synthesis, data storage and age-model generation were developed. Additional to the workshop reports, regional syntheses for the Southern Ocean sector of the Atlantic and Pacific, and a global coretop δ13C compilation, were published (see Publications).
The data collection was set up in close collaboration with NOAA (Carrie Morrill) and PANGAEA (in house MARUM) and will be made available through NOAA and PANGAEA.
Planned timeline for the extension
October 2018: Release of the final database structure
January 2019: Accomplishment of version 0 of database
February 2019: Submission of manuscript with the regional North Atlantic dataset
February 2019: Submission of manuscript describing OC3 database, release of database version 0 together with database paper
February to June 2019: Collection of unpublished datasets, compilation of global dataset
EGU 2019: Splinter meeting of joint IPODS and OC3 group
December 2019: AGU session with OC3 associated topic