Radiocarbon constraints on the extent and evolution of the South Pacific glacial carbon pool.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27157845.
- Also identified by DOI 10.1038/ncomms11487 and PMC identifier 4865812.
- 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
During the last deglaciation, the opposing patterns of atmospheric CO2 and radiocarbon activities (Δ(14)C) suggest the release of (14)C-depleted CO2 from old carbon reservoirs. Although evidences point to the deep Pacific as a major reservoir of this (14)C-depleted carbon, its extent and evolution still need to be constrained. Here we use sediment cores retrieved along a South Pacific transect to reconstruct the spatio-temporal evolution of Δ(14)C over the last 30,000 years. In ∼2,500-3,600 m water depth, we find (14)C-depleted deep waters with a maximum glacial offset to atmospheric (14)C (ΔΔ(14)C=-1,000‰). Using a box model, we test the hypothesis that these low values might have been caused by an interaction of aging and hydrothermal CO2 influx. We observe a rejuvenation of circumpolar deep waters synchronous and potentially contributing to the initial deglacial rise in atmospheric CO2. These findings constrain parts of the glacial carbon pool to the deep South Pacific.