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of core MD95-2042 (Figure 8h) [Shackleton et al., 2000]
clearly reflects the oscillations depicted in the EPICA Dron-
ning Maud Land ice core record (Figure 8i) [EPICA Com-
munity Members, 2006]. The GNAIW/AABW boundary
was therefore located deeper in the water column off south-
ern Iberia than in the western Atlantic Basin [Curry and
Oppo, 2005] and the northeastern Atlantic [Sarnthein et al.,
2001], most probably due to the presence of the deeper
and paleoceanographic studies have shown that AAIW pen-
etrated farther northward during glacial times [Pahnke et al.,
2008].
Millennial-scale oscillations in the ventilation of the water
column were finally recorded in the intermediate to bottom
waters, i.e., those water masses directly re
ecting the status
of the overturning circulation either in the Mediterranean Sea
or in the Atlantic Ocean (Figures 9e
-
9h). The record of core
MD99-2339 bathed by the lower MOW core (Figures 2, 9e)
shows clear cyclicity with relatively poorer ventilation dur-
ing the Greenland interstadials and better during the Green-
land stadials [Voelker et al., 2006], similar to the pattern
observed for the Western Mediterranean Deep Water [Cacho
et al., 2000; Sierro et al., 2005]. Records from the Mediter-
ranean Sea
flowing MOW.
7.2. Water Column Ventilation
In the upper 400 m of the water column, nutrient levels and
thus ventilation of the respective water mass (Figures 9b
-
9d)
were not driven by the millennial-scale variability seen in the
δ
s eastern and western basins indicate that inter-
mediate and deep waters were well oxygenated during
Greenland stadials and during the greater parts of the Hein-
rich stadials [Bassetti et al., 2010; Cacho et al., 2000;
Schmiedl et al., 2010; Sierro et al., 2005]. Thus, the poor
ventilation of the MOW during the Heinrich stadials must
result from the admixing of poorly ventilated Atlantic waters
such as the ENACW
st
re
'
18
O records. For G. ruber white, glacial values tend to be
lower than the Holocene ones reflecting the oligotrophic
waters in the central Gulf of Cadiz. During the glacial and
deglacial section, the lower values probably mirror local
conditions with periods of stronger winter mixing, the time
for refurbishing nutrients in the Gulf of Cadiz [Navarro and
Ruiz,2006].ForG. bulloides, the trend is opposite with
higher values during the glacial. Since the G. bulloides
record is from core MD95-2042 off Sines and thus from a
region potentially experiencing upwelling, the G. bulloides
δ
ected in the G. truncatulinoides
data (Figure 9d) and potentially also AAIW. In the upper
NADW/GNAIW level at 2465 m (Figure 9e) and deeper
down, the ventilation status was primarily driven by the
well-known up and down movement of the NADW/AABW
interface with better ventilation (equal to NADW) during the
interstadials, when AMOC was strong, and poorer ventila-
tion during the stadials (equal to AABW). When NADWwas
present, benthic
13
C record was most likely modified by the productivity
conditions in this region. Glacial productivity, and thus nu-
trient consumption, was higher in this region than during the
Holocene [Salgueiro et al., 2010]. The glacial subthermo-
cline waters (100
13
C values were similar from 2465 to 3146
m water depth and during glacial times also not much dif-
ferent at 4602 m (Figures 9f
-
9f-9h), indicating a homogeny in
the deeper-water column during the interstadials that is also
seen today [Alvarez et al., 2004]. During the LGM and most
Heinrich stadials, the 2465 m data show, however, excur-
sions to higher
400 m) were mostly well ventilated and
contained few nutrients hinting to ENACW
st
as prevailing
water mass. Only during Heinrich stadials 1 and 4 were
lower
-
δ
13
C values recorded that could indicate that either
less ventilated ENACW
sp
penetrated into the Gulf of Cadiz
along with the melting icebergs [Voelker et al., 2006] or that
Antarctic Intermediate Water (AAIW) was mixed into the
subtropical ENACW. Small amounts of AAIW can be found
in the Gulf of Cadiz waters today [Cabeçadas et al., 2003],
δ
13
C values that were in the range of those
recorded in the lower MOW core at site MD99-2339 (Fig-
ures 9e, 9f ). Thus, the benthic
δ
δ
13
C data conrm what the
Figure 8.
(opposite) Vertical gradients in the hydrography at the southwestern Iberian margin over the last 65 kyr in comparison to the
(a) Greenland (Greenland Ice Sheet Project 2 (GISP2)) [Grootes and Stuiver, 1997] and (i) Antarctic (EPICA Dronning Maud Land)
[EPICA Community Members, 2006] ice core records. (b and c) Uppermost water column conditions as re
18
O
values of cores MD99-2339 (black) [Voelker et al., 2009; this study] and MD99-2336 (gray) [Voelker et al., 2009; this study] and in the G.
bulloides
ected in the G. ruber white
δ
18
O data of core MD95-2042 [Cayre et al., 1999; Shackleton et al., 2000]. (d) ENACW-level subsurface water conditions based
δ
18
OofG. truncatulinoides from cores MD99-2339 (black) [Voelker et al., 2009; this study] and MD99-2336 (gray) [Voelker et al.,
2009; this study]. (e) Response in the lower MOW
on the
δ
flow strength (core MD99-2339 [Voelker et al., 2006]) to the millennial-scale
variability. Deep water temperature changes at (f) 2465 m (MD01-2444 [Skinner and Elder
'
s
eld, 2007]) and (g) 3146 m (MD99-2334K
[Skinner et al., 2003]). For core MD01-2444, the original data are shown in gray, and a three-point moving average record is shown in
black. (h) Benthic
18
O record of core MD95-2042 [Shackleton et al., 2000]. GI, H, and AIM refer to Greenland interstadials, Heinrich
stadials, and Antarctic isotope maxima, respectively. Depth ranges on the right refer to the living depths of the respective planktic
foraminifer (Figures 8a
δ
-
8c) [Voelker et al., 2009] or to the depth of the respective core site(s).
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