Knowledge and implications of global change in the oceans for biology, ecology, and ecosystem services - Ocean Sustainability in the 21st Century - page 150

human well-being (Costanza et al., 1997 ; Grehan et al. , 2009 ) . Marine ecosystems such
as kelp beds, coral reefs, and seagrass meadows are socially and economically important,
and their ecosystem services are estimated to be worth trillions of dollars to the global
economy each year (Costanza et al., 1997 ). The loss of these habitats represents a leading
cause of the loss of biodiversity and ecosystem services (Lotze et al., 2006 ; Airoldi and
Beck, 2007 ) which may also have major socio-economic consequences. Similarly to the
terrestrial biomes (Sala et al., 2000 ) , marine biodiversity is simultaneously impacted by a
range of human activities such as overfishing, habitat destruction, and pollution (Dulvy et
al., 2003 ; Lotze et al., 2006 ; Worm et al., 2006 ) . Climate change may add to and amplify
theseimpactsonmarinebiodiversity(Walther et al., 2002 ; Cheung et al., 2009 ) .Thenegat-
ive effects of climate change on specific habitats can have unpredictable consequences for
other species/habitats and human activities (both in term of social and economic interest).
Change in distributions and community structure of marine species may indeed affect fish-
ing activities (both commercial and recreational fisheries) and have socio-economic im-
pacts on vulnerable coastal communities (Allison et al., 2009 ) . Many fisheries are already
extensively overfished and the changing environmental conditions may contribute to de-
cliningstocksoffishspecies.Shiftsinthediversityandabundanceofthebio-erodingfauna
may cause a weakening of reef infrastructure, exacerbating the impacts of storms and high-
ersealevelsonreeffragmentation(Przeslawski et al., 2008 ) .Thismayleadtoadecreasein
the protective wave-reducing role of fringing reefs, leading to increased erosion of beaches
and coastal structures (Hutchings and Salvat, 2000 ; Sheppard et al., 2005 ) . Benthic inver-
tebrates are also a rich source of bioactive compounds with various medicinal, industrial,
and commercial applications. Pharmaceuticals based on the neurotoxins from tropical cone
shells are now in clinical use as the most powerful relievers of severe pain (Hogg, 2006 ) .
Notably, bioactive compounds of certain invertebrates may vary with region and reef (Fa-
hey and Garson, 2002 ; Page et al., 2005 ) . All compounds with potential economic interest
are likely to be influenced by food sources, changes in microbial faunas across small en-
vironmental gradients, or seasonally changing habitat conditions (Fahey and Garson, 2002 ;
Page et al., 2005 ). Loss of a species will mean loss of these important compounds for hu-