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Paci
c where the hydrate stability horizon would have
shoaled by several hundred meters (Plate 3).
The deglacial warming at intermediate water depths within
the Paci
2006]. Such a release would therefore explain why there is
no evidence for a δ
13 C excursion in benthic foraminifera in
association with the deglacial
14 C excursion [Gon
antini et
al., 1997]. It would, however, explain the small negative
δ
Δ
flux of CO 2
from those parts of the ocean where liquid and hydrate CO 2
accumulated during the glacial. Sea level rise during degla-
ciation would in
c would have increased the steady state
13 C excursion in atmospheric CO 2 [Smith et al., 1999;
Spero and Lea, 2002; Stott et al., 2009]. The
13 C of atmo-
δ
uence the stability horizon in the opposite
direction. However, as much of the MI CO 2 rise occurred
between 18 and 15 kyr B.P., prior to the rapid sea level rise,
we assume that pressure changes due to sea level rise were
not a major influence on the hydrate stability. The release of
this volcanic CO 2 would have injected carbon that was 14 C
dead into intermediate waters but would not have produced a
negative δ
spheric CO 2 decreased from ~
between 18
and 12 kyr B.P. in association with the deglacial Δ
6.5
to
6.8
14 C ex-
cursion. Taking the fractionation between atmospheric CO 2 -
dissolved CO 2 in surface waters to be
8
, the deglacial
13 C excursion documented in the ice core and planktonic
foraminifera in the tropical ocean implies the CO 2 added to
the ocean/atmosphere system had a
δ
13 C composition close
to 1 , the same as the CO 2 venting today from submarine
volcanoes in the Paci
δ
13 C excursion in DIC if the bulk of the CO 2 was
from sites such as those along the Mariana [Lupton et al.,
c[Lupton et al., 2006].
14 C (solid circles) from Cariaco Basin [Hughen et al., 2006] compared to planktonic (open
Figure 3. Surface ocean
Δ
14 C estimates (diamonds) for the western tropical Paci
circles) and benthic
Δ
c core MD98-2181 [Broecker et al., 2004;
14 C values from MD9821081 track the surface ocean record, including the marked decline
during the Mystery Interval. However, benthic
Stott et al., 2007]. Planktonic
Δ
14 C values (open circles) at 2.1 km in the western tropical Paci
Δ
c do not
exhibit the large
excursion between 17.5 and 14 kyr B.P. Linear regressions through the surface and deepwater
values are forced through approximate modern values for surface waters in the tropical Atlantic and Paci
190
c Deep waters at
2.1 km in the western Paci
c[Key et al., 2004]. Calendar ages for MD98-2181 were obtained with the CALIB-4 program
(M. Stuiver et al., CALIB Radiocarbon Calibration, 2005, http://calib.qub.ac.uk/calib). Error bars for MD98-2181
planktonic
14 C are the standard deviation of
14 C estimates based on the 1
Δ
Δ
σ
calendar age ranges.
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