Shortcomings of the isolated abyssal reservoir model for deglacial radiocarbon changes in the mid-depth Indo-Pacific Ocean
Article first published online: 17 FEB 2011
Copyright 2011 by the American Geophysical Union.
Geophysical Research Letters
Volume 38, Issue 4, February 2011
How to Cite
2011), Shortcomings of the isolated abyssal reservoir model for deglacial radiocarbon changes in the mid-depth Indo-Pacific Ocean, Geophys. Res. Lett., 38, L04604, doi:10.1029/2010GL046158., , and (
- Issue published online: 17 FEB 2011
- Article first published online: 17 FEB 2011
- Manuscript Accepted: 3 JAN 2011
- Manuscript Revised: 17 DEC 2010
- Manuscript Received: 11 NOV 2010
- mystery interval;
- carbon cycle;
- ocean ventilation
Severely negative Δ14C anomalies from the mid-depth Pacific and the Arabian Sea have been taken as support for the hypothesized deglacial release of a previously isolated, extremely 14C-deplete deep ocean carbon reservoir. We report box model simulations that cast doubt on both the existence of the hypothesized deep reservoir and its ability to explain the mid-depth Δ14C anomalies. First, the degree of ice age isolation needed to substantially reduce the deep Δ14C of the deep reservoir causes anoxia and the trapping of alkalinity from CaCO3 dissolution, the latter increasing atmospheric CO2. Second, even with a completely 14C-free deep reservoir, achieving the mid-depth Δ14C anomalies of observed duration requires ad hoc stifling of aspects of deep circulation to prevent rapid dissipation of the anomalous 14C-free carbon to the rest of the ocean and the atmosphere. We suggest that the mid-depth anomalies do not record basin-scale Δ14C changes but are instead local phenomena.