Open AccessA model‐data comparison of δ 13 C in the glacial Atlantic Ocean
Author(s) -
Hesse T.,
Butzin M.,
Bickert T.,
Lohmann G.
Publication year - 2011
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1029/2010pa002085
Subject(s) - geology , oceanography , north atlantic deep water , abyssal zone , glacial period , antarctic bottom water , ocean current , deep sea , thermohaline circulation , sediment , water column , last glacial maximum , carbon cycle , bottom water , deep ocean water , circumpolar deep water , holocene , paleontology , ecology , ecosystem , biology
We compare a compilation of 220 sediment core δ 13 C data from the glacial Atlantic Ocean with three‐dimensional ocean circulation simulations including a marine carbon cycle model. The carbon cycle model employs circulation fields which were derived from previous climate simulations. All sediment data have been thoroughly quality controlled, focusing on epibenthic foraminiferal species (such as Cibicidoides wuellerstorfi or Planulina ariminensis ) to improve the comparability of model and sediment core carbon isotopes. The model captures the general δ 13 C pattern indicated by present‐day water column data and Late Holocene sediment cores but underestimates intermediate and deep water values in the South Atlantic. The best agreement with glacial reconstructions is obtained for a model scenario with an altered freshwater balance in the Southern Ocean that mimics enhanced northward sea ice export and melting away from the zone of sea ice production. This results in a shoaled and weakened North Atlantic Deep Water flow and intensified Antarctic Bottom Water export, hence confirming previous reconstructions from paleoproxy records. Moreover, the modeled abyssal ocean is very cold and very saline, which is in line with other proxy data evidence.