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Updated: Jul 12, 2026
08:16
Ice Generation and the Heat and Mass Transfer Phenomena of Introducing Water to a Cold Bath of Brine
Published on: March 13, 2017
Ventilation of the glacial deep Pacific Ocean
Wallace Broecker1, Stephen Barker, Elizabeth Clark
1Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W/Post Office Box 1000, Palisades, NY 10964, USA. broecker@ldeo.columbia.edu
Science (New York, N.Y.)
|November 13, 2004
Summary
Radiocarbon dating of deep-sea cores reveals that glacial ocean ventilation rates were similar to today. This challenges theories linking slower deep-ocean circulation to increased atmospheric carbon-14 levels during ice ages.
Area of Science:
- Paleoceanography
- Marine Geochemistry
Background:
- Understanding past ocean circulation is crucial for climate modeling.
- The role of deep-ocean ventilation in regulating atmospheric carbon dioxide during glacial periods remains debated.
- Radiocarbon (14C) is a key tracer for ocean circulation and carbon cycling.
Purpose of the Study:
- To investigate deep-ocean ventilation rates during peak glacial time using radiocarbon dating.
- To evaluate the contribution of ocean circulation changes to atmospheric 14C/C ratios during glacial periods.
Main Methods:
- Radiometric dating of coexisting benthic and planktic foraminifera from deep-sea cores.
- Radiometric dating of coexisting wood and planktic foraminifera from the same site.
- Comparison of radiocarbon ages to reconstruct water mass ages and surface-ocean-atmosphere 14C/C differences.
Main Results:
- The radiocarbon age of deep Pacific water (2 km depth) during peak glacial time was not older than present-day.
- The difference in 14C/C ratios between the atmosphere and surface ocean was similar during glacial and modern times.
- These findings suggest that deep-ocean ventilation did not significantly slow down during glacial periods.
Conclusions:
- Deep-ocean circulation and ventilation rates were comparable between glacial and interglacial periods.
- Slowdowns in deep-ocean ventilation are unlikely to be the primary driver of increased atmospheric 14C/C ratios during glacial times.
- Past oceanographic conditions can be effectively reconstructed using radiocarbon dating of marine and terrestrial materials.
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