Geoscience Reference
In-Depth Information
There are few studies on the direct effects of acidification on
commercial organisms, and the majority have been dedicated to
calcifying organisms due to their presumed sensitivity to acidification.
For example, Gazeau
et al
. [GAZ 07] showed a drop of 25% in
calcification in the blue mussel and 10% in the Pacific oyster. Meta-
analyses [HEN 10, KRO 10, KRO 13] have confirmed this negative
effect on the calcification of bivalve mollusks, while the effects on
crustaceans and cephalopods seem less pronounced. The results
involving mollusks have paved the way for the first economic studies
on the acidification of oceans aiming to estimate potential losses. For
example, Narita
et al.
[NAR 12] calculated that the loss of production
of mollusks caused by the acidification of oceans could cost more than
100 billion US dollars in 2100.
Although there are few studies available on the economic and
societal effects of ocean acidification, there does exist a very tangible
example. The production of oysters on the Northwest coast of the
United States, with a value of 278 million US dollars in 2009, is
already suffering from damage linked to upwellings of deep waters
with a low pH. In 2006, several oyster hatcheries suffered from very
high mortality rates. After several years of research, and due to a
partnership with scientists, the Whiskey Creek Shellfish Hatchery in
Oregon established a link between the mortality and pH of the
seawater that was being pumped into its installations [BAR 12].
The effects of acidification on fish of commercial interest are much
less known despite being the dominant product in the global capture
(69 million tons per year, thus 85% of the total weight). On the whole,
acidification seems to have few direct effects on the reproduction and
physiology of fish, even at very high levels of CO
2
[BRA 13]. In
contrast, studies carried out on tropical fish have highlighted
behavioral effects. Acidification affects sensory systems involving
smell, vision and hearing. This leads to behavioral changes, such as a
sudden preference for an inappropriate habitat or a decline in the ability
to hear predators. The economic consequences of acidification could
reveal themselves to be very significant if these effects also exist in
commercial species [BRA 13].
