Geoscience Reference
In-Depth Information
based on our current understanding of experimental,
i eld, and modelling research, some changes that will
probably occur as seawater CO
2
increases and pH
decreases are:
gratefully acknowledges support from NSF Grant
OCE 07-49401 for his part in the preparation of this
chapter. The authors are grateful to Ms. Lica Krug
for assistance compiling Table 1.
(1) Benthic ecosystems are likely to undergo a tran-
sition where benthic non-calcifying organisms
are favoured over benthic calcii ers because
several important life stages of calcii ers and
processes such as recruitment and growth are
negatively affected by ocean acidii cation.
(2) Net calcii cation and CaCO
3
accretion of coral
reefs will decrease and, at some point in time,
a transition to net dissolution and net loss of
CaCO
3
will occur. Over time, this will result
in decreased structural complexity and
decreased biodiversity, but it is important to
recognize that the transition itself is not the
same as the 'end' to corals and other calcii -
ers, which will continue to build their shells
and skeletons even once this threshold has
been crossed.
(3) As the saturation state with respect to carbon-
ate minerals is shoaling throughout the global
ocean, the carbonate compensation depth and
the maximum depths where deep-sea corals,
bioherms, and other calcii ers could develop
are likely to move to shallower depths in all
ocean basins.
(4) It is important to keep in mind that although
tropical and subtropical coral reefs may be the
most visible and important benthic calcifying
ecosystems to be affected by ocean acidii ca-
tion, other carbonate systems are vulnerable
to the same process and represent approxi-
mately 60% of benthic carbonate production
and 50% of carbonate accumulation in the
shallow ocean.
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7.5 Acknowledgements
This work is a contribution to the 'European Project
on Ocean Acidii cation' (EPOCA) which received
funding from the European Community's Seventh
Framework Programme (FP7/2007-2013) under
grant agreement no. 211384. A.J.A. gratefully
acknowledges support from NSF Grant OCE
09-28406 and NOAA NA10AR4310094. F.T.M.
