Publication Date:
2014-12-15
Description:
Anthropogenic CO 2 is causing warming and ocean acidification. Coral reefs are being severely impacted, yet confusion lingers regarding how reefs will respond to these stressors over this century. Since the 1982-83 El Niño-Southern Oscillation warming event, the persistence of reefs around the Galápagos Islands has differed across an acidification gradient. Reefs disappeared where pH 〈 8.0 and aragonite saturation state (Ω arag ) ≤ 3 and have not recovered, whereas one reef has persisted where pH 〉 8.0 and Ω arag 〉 3. Where upwelling is greatest, calcification by massive Porites is higher than predicted by a published relationship with temperature despite high CO 2 , possibly due to elevated nutrients. However, skeletal P/Ca, a proxy for phosphate exposure, negatively correlates with density ( R = -0.822, p 〈 0.0001). We propose that elevated nutrients have the potential to exacerbate acidification by depressing coral skeletal densities and further increasing bioerosion already accelerated by low pH.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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