Hypothesized Link Between Glacial/Interglacial Atmospheric CO2 Cycles and Storage/Release of CO2-Rich Fluids From Deep-Sea Sediments - Abrupt Climate Change: Mechanisms, Patterns, and Impacts - page 128

Figure 2. The 14 C ages of fossil planktonic and benthic foraminifera from core VM21-30 as depicted by Stott et al. [2009].

et al. However, in a study by Magana et al. [2010], the
benthic foraminiferal 14 C ages from a core collected in the
Santa Barbara Basin are not anomalously old during the last
glacial termination. Yet in a study of a core collected at
intermediate depth in the Arabian Sea, Bryan et al. [2010]
report a deglacial Δ

northeastern and tropical eastern Pacific have documented
CO 2 -rich fluids venting [Chivas et al., 1987; Embley et al.,
2006; Lupton et al., 2008; Lupton et al., 2006; Resing et al.,
2009] at intermediate water depths (~1000 m). Estimates of
the CO 2 flux at these sites are sparse, and the areal extent of
active vents that are emitting a separate CO 2 gas or liquid
phase is not known. Therefore, our knowledge of how these
vent systems contribute to an overall global carbon budget is
changing as new information becomes available. Nonethe-
less, the initial results from the surveys that have documented
liquid CO 2 or CO 2 -rich fluids venting in the Pacific appear to
greatly exceed estimates of CO 2 flux based on observations
at Mid Ocean Ridge (MOR) systems. Hence, submarine
vents in the Pacific may represent a greater source of carbon
to the global carbon budget than previously estimated [Lup-
ton et al., 2008; Resing et al., 2009]. For example, at just one
vent site on the Mariana Trench, Lupton et al. [2006] esti-
mated the carbon ux to be 8 10 8 mol CO 2 yr 1 , which is
about 0.1% of the global MOR carbon flux. Remarkably, at
Eifuku on the Mariana system, approximately 98% of the
CO 2 flux is liquid CO 2 droplets. Most importantly, liquid
CO 2 is not only venting from these sites, it also accumulates
within the sediments on the margins of the active volcanoes
and is being stored beneath hydrate caps that regulate the flux
of CO 2 from the sediments.

14 C anomaly that appears to match the
Baja margin record, arguing that it is evidence of a formally
isolated deepwater mass that ventilated through the Southern
Ocean during the deglaciation. On the other hand, Rose et al.
[2010] reconstructed 14 C ages of planktonic and benthic
foraminifera from two cores collected at intermediate water
depths in the southwestern Pacific and Southern Ocean and
found no Δ

14 C excursion and hence no evidence that SAMW
core RR0503-JPC64) or AAIW (core MD97-2120) were
anomalously old during the last deglaciation. Rose et al.
suggest that perhaps the Δ

14 C excursion found on the Baja
margin (they do not mention the Galapagos record) is indic-
ative of a North Pacific source. But this would not be consis-
tent with the Santa Barbara Basin or the Arabian Sea record.

14 C-DEPLETED
CARBON IN THE OCEAN?

4. ARE THERE OTHER SOURCES OF Δ

During the past decade, surveys of active submarine vol-
canic arcs in the Pacific and hydrothermal vents in the