Geoscience Reference
In-Depth Information
Indirect effects on fishing can also occur through changes of the
food web. For example, several studies suggest that ocean
acidification threatens the existence of pteropods at high latitudes.
Yet, these organisms are important prey, especially for commercial
species, such as pink salmon. Current data do not enable us to make
any conclusions about effects on the resource since, in the
hypothetical situation where pteropods would begin to disappear, it is
unknown which species would occupy the ecological niche left vacant
and whether these species would have the same nutritional value for
pink salmon.
5.4.3.2.
Services associated with coral reefs
Coastal ecosystems (coral reefs, mangroves, salt marshes, seagrass
beds, etc.) are instrumental in the social life and economy of many
regions. Coral reefs, already under threat from intense perturbations
(global warming, pollution, tourism, overfishing, etc.), are among the
ecosystems that are the most sensitive to ocean acidification due to its
impact on calcification of the major reef-building organisms (corals
and calcerous algae). According to Frieler
et al
. [FRI 13], 70% of
coral reefs will be largely degraded between now and 2030 under the
effects of global warming; acidification acting as an additional stress.
Coral reefs have multiple interests for society and the economy. They
protect coasts from erosion and flooding, they form the basis for a
strong tourism industry and are diversity
hotspots
, offering a habitat,
breeding grounds or acting as a source of food for numerous species,
including fish of nutritional, economic and ecological interests
[TUR 11]. The dependence on these services offered by coral reefs is
most pronounced in some of the poorest countries.
There are very few economic studies on coral ecosystems, and the
indirect nature of their services makes evaluation difficult. Coral reefs
provide food, revenue and protection for close to 500 million people
[HOE 11]. Their annual value has been evaluated at 30 billion US
dollars [CES 03]. Brander
et al
. [BRA 12] have estimated that
damages linked to the degradation of coral reefs through ocean
acidification could reach 870 billion US dollars between now and the
end of the century. Recent studies are very pessimistic regarding the
future of these ecosystems [ANT 11, FRI 13], and the threat of their
