Premium
High‐resolution holocene and late glacial atmospheric CO 2 record: variability tied to changes in thermohaline circulation
Author(s) -
Figge Regina A.,
White James W. C.
Publication year - 1995
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/95gb01458
Subject(s) - thermohaline circulation , glacial period , radiocarbon dating , geology , holocene , ice core , peat , oceanography , climatology , atmospheric circulation , carbon cycle , paleontology , ecology , ecosystem , biology
Here we present results from a new method for detecting changes in atmospheric CO 2 based on δ 13 C analyses of selected peat components from a peat core in southern South America. The paleo‐CO 2 ‐record has decadal resolution spanning the last 14,000 radiocarbon years and compares well with Antarctic ice core CO 2 data. Sharp peaks in CO 2 are detected during the late glacial, specifically at 10,200, 11,600, and 12,900 years B.P. When compared to two deep‐sea records interpreted to reflect changes in thermohaline circulation, these CO 2 pulses appear to relate to degassing events of the ocean associated with reinitiation of the thermohaline circulation occurring at this time. Concomitant decreases in atmospheric Δ 14 C during the late glacial are also consistent with a deep oceanic carbon source for the large atmospheric pulses in CO 2 . Results from a simple three‐box model indicate that the magnitude of the CO 2 released during these degassing events is compatible with our observations. The rate of degassing, however, is much slower than that observed in the paleo‐CO 2 ‐record. Two broad Holocene CO 2 excursions are also identified with peaks at 4,200 and 7,700 years B.P. The driving mechanism behind these excursions appears to be different than those in the late glacial.