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changes in the chemistry of carbonates resulting from ocean
acidification. Modeling has also been used to reconstruct the past
changes of the chemistry of carbonates using relatively simple
[ZEE 03] or more sophisticated models (e.g. [AND 05]).
Manipulation experiments in the laboratory have been carried out
to evaluate the response of organisms to the changes in the chemistry
of carbonates of seawater. Several of these studies have used extreme
and unrealistic levels of pCO 2 or pH in the context of anthropogenic
acidification. Other experiments provided little information on the
parameters of the carbonate system other than pH. Nonetheless, these
experiments have produced important results. For example, Swift and
Taylor [SWI 66] have shown that the growth of a coccolithophore
follows a bell curve relative to the pH, a similar response was later
found for describing the effect of the acidification of oceans on the
calcification rate of a coccolithophore [LAN 06].
The first study that aimed to study the response of an organism to
ocean acidification is that of Agegian [AGE 85] who revealed a
negative impact on the growth of calcareous algae. The first article on
a reef-building coral highlighted a decrease of calcification as a
function of decreasing CaCO 3 saturation [GAT 98]. Riebesell et al.
[RIE 00] were the first to show the effects of ocean acidification on
photosynthesis and the calcification of a phytoplankton group
(coccolithophores). The results published in recent years have
sometimes been conflicting. For example, some calcifying organisms do
not seem to be affected by ocean acidification (for example, [IGL 08,
LAN 06, RIE 09, ROD 10]. Several hypotheses have been suggested
for explaining these differences [GAT 11b].
Modeling tools are essential for predicting forthcoming changes
and the biogeochemical impacts of ocean acidification. Caldeira and
Wickett [CAL 03] published a key article explaining the chronology
and magnitude of the past and future changes in oceanic pH. Models
have been used for estimating changes in the carbonate system in the
recent past and in the 21st Century (for example, [ORR 05]),
identifying areas of risk [STE 09], estimating future changes in
calcification [KLE 99] as well as for investigating the feedback on the
carbon cycle (e.g. [HEI 04]).
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