|Deep ocean carbonate ion increase during mid Miocene CO2 decline|Kender, S.; Yu, J.; Peck, V.L. (2014). Deep ocean carbonate ion increase during mid Miocene CO2 decline. NPG Scientific Reports 4(4187): 6 pp. hdl.handle.net/10.1038/srep04187
In: Scientific Reports (Nature Publishing Group). Nature Publishing Group: London. ISSN 2045-2322, more
|Authors|| || Top |
- Kender, S.
- Yu, J.
- Peck, V.L.
Characterised by long term cooling and abrupt ice sheet expansion on Antarctica ~14 Ma ago, the mid Miocene marked the beginning of the modern ice-house world, yet there is still little consensus on its causes, in part because carbon cycle dynamics are not well constrained. In particular, changes in carbonate ion concentration ([CO32-]) in the ocean, the largest carbon reservoir of the ocean-land-atmosphere system, are poorly resolved. We use benthic foraminiferal B/Ca ratios to reconstruct relative changes in [CO32-] from the South Atlantic, East Pacific, and Southern Oceans. Our results suggest an increase of perhaps ~40 µmol/kg may have occurred between ~15 and 14 Ma in intermediate to deep waters in each basin. This long-term increase suggests elevated alkalinity input, perhaps from the Himalaya, rather than other shorter-term mechanisms such as ocean circulation or ecological changes, and may account for some of the proposed atmospheric CO2 decline before ~14 Ma.