Recent and future changes in ocean carbonate chemistry - Ocean Acidification - page 63

shoaling occurs in the North Atlantic where the
ASH is deepest. By 2100, the ASH shoals all the way
to the surface in the Southern Ocean, subarctic
Pacii c, and Arctic Ocean under the IS92a and A2
scenarios. Beyond this century, stabilizing atmos-
pheric CO 2 even at a 450-ppmv target eventually
causes most of the deep ocean to become corrosive
to both aragonite and calcite.
Model projections are improved by correcting for
the present-day model-data bias. With that
approach, differences between model projections
for a given scenario grow with time elapsed from
the reference year, but they generally remain small
throughout this century. The most uncertain aspect
of future projections by far is the future atmospheric
CO 2 trajectory (Fig. 3.7), for which we can only
dei ne a range of scenarios designed to bracket
future human behaviour. Although projecting
future changes in ocean carbonate chemistry is one
of the most certain aspects of ocean acidii cation
research, there remains a need to rei ne our predic-
tive capacity for anthropogenic changes and varia-
bility at high latitudes and in the deep ocean, coastal
areas, and marginal seas. Of particular importance
will be to establish time-series measurements in
these areas, not only to improve our understanding
of present-day variability but also to help improve
future projections.

References

Andersen, N. and Malahoff, A. (1977). The fate of fossil fuel
CO 2 in the oceans , 749 pp. Plenum, New York.
Baes, C.F. (1982). Effects of ocean chemistry and biology
on atmospheric carbon dioxide. In: W.C. Clark (ed.),
1982 Carbon dioxide review , pp. 189-211. Oxford
University Press, Oxford.
Bates, N.R. (2007). Interannual variability of the oceanic
CO 2 sink in the subtropical gyre of the North Atlantic
Ocean over the last 2 decades. Journal of Geophysical
Research , 112 , C09013, doi:10.1029/2006JC003759.
Bates, N.R., Mathis, J.T., and Cooper, L.W. (2009). Ocean
acidii cation and biologically induced seasonality of
carbonate mineral saturation states in the western Arctic
Ocean. Journal of Geophysical Research ,

114 , C11007,

doi:10.1029/2008JC004862.
Blackford, J.C. and Gilbert, F.J. (2007). pH variability and
CO 2 induced acidii cation in the North Sea. Journal of
Marine Systems , 64 , 229-41.
Bolin, B. and Eriksson, E. (1959). Distribution of matter in
the sea and the atmosphere, In: B. Bolin (ed.), The atmos-
phere and the sea in motion , pp. 130-43. Rockefeller
Institute Press, New York.
de Boyer Montégut, C., Madec, G., Fischer, A. S., Lazar, A.,
and Iudicone, D. (2004), Mixed layer depth over the glo-
bal ocean: an examination of proi le data and a proi le-
based climatology. Journal of Geophysical Research , 109 ,
C12003, doi:10.1029/2004JC002378.
Brewer, P.G. (2009). A changing ocean seen with clarity.
Proceedings of the National Academy of Sciences USA , 106 ,
12213-14.
Brewer, P.G. and Peltzer, E.T. (2009). Limits to marine life.
Science , 324 , 347-8.
Broecker, W.S. and Peng, T.H. (1974). Gas exchange rates
between air and sea. Tellus , 26 , 21-35.
Broecker, W.S. and Peng, T.-H. (1982). Tracers in the sea ,
690 pp. Lamont-Doherty Geological Observatory,
New York.
Broecker, W.S. and Takahashi, T. (1966). Calcium carbon-
ate precipitation on the Bahama Banks. Journal of
Geophysical Research , 71 , 1575-602.
Broecker, W.S., Li, Y.-H. and Peng, T.-H. (1971). Carbon
dioxide—man's unseen artifact. In: D.W. Hood (ed.),
Impingement of man on the oceans, pp. 287-324. Wiley,
New York.
Byrne, R.H., Mecking, S., Feely, R.A., and Liu, X. (2010).
Direct observations of basin-wide acidii cation of the
North Pacii c, Geophysical Research Lett ers, 37 , L020601,
doi:10.1029/2009GL04099.
Caldeira, K. and Wickett, M.E. (2005). Ocean model predic-
tions of chemistry changes from carbon dioxide emis-

3.8 Acknowledgements

I thank N. Bates for providing the BATS data,
M. González-Dávila and M. Santana-Casiano for
providing the ESTOC data, as well as J. E. Dore and
co-authors for making their HOT data pub-
licly available. Thanks also to N. Gruber and
M. Steinacher for insightful reviews. C. Sabine pro-
vided key data and code used to validate my calcu-
lations of the buffer factors dei ned by Egleston et al.
(2010). J.-P. Gattuso advised on structuring, docu-
menting, and validating these fundamental calcula-
tions, now available as a function 'buffesm' in the
'seacarb' software package, since version 2.3.5
(Lavigne and Gattuso 2010). This work was sup-
ported by the 'European Project on Ocean
Acidii cation' (EPOCA) funded by the European
Community's Seventh Framework Programme
(FP7/2007-2013) under grant agreement no. 211384.