Environmental Engineering Reference
In-Depth Information
19
Spatial and temporal patterns of ocean acidi
cation
during the end-Permian mass extinction
-
an Earth system model evaluation
ying cui, lee r. kump and andy ridgwell
19.1 Introduction
The end-Permian extinction was a geologically abrupt (
~
100 000-year duration)
event that occurred
252 million years ago (Ma) (Burgess
et al
.,
2014
; Joachimski
event was characterized by 8 to 10
C of global warming (Joachimski
et al
.,
2012
),
driven by the massive release of greenhouse gases, as re
~
ected in a contempor-
aneous negative C isotope excursion (CIE) of
(Shen
et al
.,
2011
) in the
ocean. This suggests that either the source or its oxidation product was CO
2
.
Recent analyses of calcium isotopes of marine sediments and the pattern of
extinction selectivity (Clapham and Payne,
2011
; Hinojosa
et al
.,
2012
; Payne
et al
.,
2010
), and volatile studies on melt inclusions from the Siberian Traps (Black
et al
.,
2012
; Black
et al
.,
2014
), suggest that the Siberian Traps volcanism might be
the trigger for the end-Permian extinction.
Besides global warming, one other consequence of CO
2
emission is ocean
acidi
~
6
‰
(Doney
et al
.,
2009
). Rising
atmospheric CO
2
causes a decrease in ocean pH and adjustments in carbonate
chemistry, leading to a reduction in carbonate ion concentration and the saturation
state of calcite and aragonite (Zeebe,
2012
). In addition to impacts on their
physiology, calcifying organisms are also susceptible to dissolution of their
carbonate skeletons (Kleypas
et al
.,
2006
; Turley
et al
.,
2010
).
Although direct proxy data of ocean carbonate chemistry for the end-Permian
are not available, geological evidence suggests that ocean acidi
cation, known as
“
the other CO
2
problem
”
cation, possibly
caused by the large quantity of CO
2
from Siberian Traps volcanism, triggered
the extinction event in the ocean (Payne and Clapham,
2012
). Studies of the
end-Permian extinction selectivity indicate that heavily calci
ed organisms and
