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Framework of barrier reefs threatened by ocean acidification
Author(s) -
Comeau Steeve,
Lantz Coulson A.,
Edmunds Peter J.,
Carpenter Robert C.
Publication year - 2016
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.13023
Subject(s) - threatened species , ocean acidification , great barrier reef , oceanography , environmental science , reef , coral reef , climate change , ecology , geology , habitat , biology
To date, studies of ocean acidification ( OA ) on coral reefs have focused on organisms rather than communities, and the few community effects that have been addressed have focused on shallow back reef habitats. The effects of OA on outer barrier reefs, which are the most striking of coral reef habitats and are functionally and physically different from back reefs, are unknown. Using 5‐m long outdoor flumes to create treatment conditions, we constructed coral reef communities comprised of calcified algae, corals, and reef pavement that were assembled to match the community structure at 17 m depth on the outer barrier reef of Moorea, French Polynesia. Communities were maintained under ambient and 1200 μatm pCO 2 for 7 weeks, and net calcification rates were measured at different flow speeds. Community net calcification was significantly affected by OA , especially at night when net calcification was depressed ~78% compared to ambient pCO 2 . Flow speed (2–14 cm s −1 ) enhanced net calcification only at night under elevated pCO 2 . Reef pavement also was affected by OA , with dissolution ~86% higher under elevated pCO 2 compared to ambient pCO 2 . These results suggest that net accretion of outer barrier reef communities will decline under OA conditions predicted within the next 100 years, largely because of increased dissolution of reef pavement. Such extensive dissolution poses a threat to the carbonate foundation of barrier reef communities.