Atlantic deep water provenance decoupled from atmospheric CO<sub>2</sub> concentration during the lukewarm interglacials.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29222483.
- Also identified by DOI 10.1038/s41467-017-01939-w and PMC identifier 5722826.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Ice core records show that atmospheric CO<sub>2</sub> concentrations and Antarctic temperature were lower during the 'lukewarm interglacials' from 800 to 430 ka than the subsequent five interglacials. These different interglacial 'strengths' have been hypothesised to be controlled by Antarctic overturning circulation. How these variations in Antarctic overturning relate to Northern Atlantic overturning circulation, a major driver of Northern Hemisphere climate, is uncertain. Here we present a high-resolution record of authigenic neodymium isotopes-a water mass tracer that is independent of biological processes-and use it to reconstruct Atlantic overturning circulation during the last 800 kyr. This record reveals a similar proportion of North Atlantic Deep Water during the 'lukewarm interglacials' and the more recent interglacials. This observation suggests that the provenance of deep water in the Atlantic Ocean can be decoupled from ventilation state of the Southern Ocean and consequently the atmospheric concentration of carbon dioxide.