Ocean Acidification and its Consequences - Ocean in the Earth System - page 209

latitudes species (e.g. [COM 10b]) (Figure 5.8). All results indicate a
significant reduction in their calcification at high pCO 2 levels, and
Bednaršek et al . [BED 12] have shown that the shells of pteropods
collected in the Southern Ocean at a depth of 200 m, where seawater
is under-saturated in aragonite, show undeniable signs of dissolution.
Only two studies have focused on temperate pteropods [COM 10a,
COM 12]).
Figure 5.8. Arctic pteropod (Limacina helicina): a) marked with the a fluorescent dye
(calcein) and b) maintained at a controlled pH (pH T ~8,09); c) at a pH projected for
the end of the century (pH T ~7,8). The arrows indicate the growth over five days after
the marking of the operculum (white rectangle)
Foraminifera and pteropods are the zooplanktonic organisms which
have been most studied. There is very little information on non-
calcifying zooplankton such as copepods. Some of the experiments
were performed in the laboratory, but at acidity levels much higher
than those projected for the next 100-300 years (e.g. [KUR 04]).
Results obtained in mesocosms at pH values, which are representative
of the values expected during the course of this century, suggest that
the acidification of seawater does not have any effect on the structure
of the mesozooplanktonic community [NIE 13], the grazing ability of
microzooplankton [SUF 08] and the filtering and production of