Spatial and temporal patterns of ocean acidification during the end-Permian mass extinction – an Earth system model evaluation - Volcanism and Global Environmental Change - page 302

(a) (b) (c)

Preindustrial (year 1765) Modern (year 2010) Future (year 2100)

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Figure 19.7 Ω calcite reconstruction for

preindustrial time (year 1765); (b) and (e) map view and depth pro

(a) and (d) map view and depth pro le of

Ω calcite
reconstruction for modern times (year 2010); and (c) and (f) map view and depth
pro

le of

Ω calcite reconstruction for the projected future (year 2100) under IPCC
RCP8.5 trajectories of CO 2 . A black and white version of this

le of

figure will appear in
some formats. For the colour version, please refer to the plate section .

Ω first in high-latitude regions, consistent with previous modeling

studies on high-latitude saturation-state change in response to climate change
(e.g. Steinacher et al ., 2009 ) , and then progresses to lower latitudes. On these
short timescales there is little response of the ocean ' is saturation horizon to the
perturbation. If we compare this to our results, the prominent top-down ocean
acidification associated with fossil-fuel burning compares most favorably with our
larger emission scenarios simulated for the end-Permian mass extinction.

calcite occurs

19.4 Discussion
19.4.1 Estimates of C addition based on C isotope balance
Estimates of C addition during the end-Permian mass extinction have been per-
formed elsewhere using simple box models (Grard et al ., 2005 ; Payne et al ., 2010 ;
Rampino and Caldeira, 2005 ; Retallack and Jahren, 2008 ) and an Earth system
model of intermediate complexity (Cui et al ., 2013 ). These estimates are functions
of the magnitude of assumed global CIE based on estimates from particular
geologic sections, generally yielding a higher amount of C release with a higher
magnitude of CIE, ranging from 3 ‰

(Berner, 2002 ). Payne et al .( 2010 ) used a simple mixing model to predict that
the upper estimate of the total amount of C added during the extinction event is
43 200 Gt C, using 3.6

‰ (Rampino and Caldeira, 2005 )to8

13

‰ CIE and assuming the source δ C ¼ ~ - 8 ‰ .

flux and total amount of
C added that we report herein are higher than simple mixing model and box model

It is important to note that the calculated maximum