期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2008
卷号：105
期号：30
页码：10450-10455
DOI：10.1073/pnas.0712167105
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Ocean acidification describes the progressive, global reduction in seawater pH that is currently underway because of the accelerating oceanic uptake of atmospheric CO2. Acidification is expected to reduce coral reef calcification and increase reef dissolution. Inorganic cementation in reefs describes the precipitation of CaCO3 that acts to bind framework components and occlude porosity. Little is known about the effects of ocean acidification on reef cementation and whether changes in cementation rates will affect reef resistance to erosion. Coral reefs of the eastern tropical Pacific (ETP) are poorly developed and subject to rapid bioerosion. Upwelling processes mix cool, subthermocline waters with elevated pCO2 (the partial pressure of CO2) and nutrients into the surface layers throughout the ETP. Concerns about ocean acidification have led to the suggestion that this region of naturally low pH waters may serve as a model of coral reef development in a high-CO2 world. We analyzed seawater chemistry and reef framework samples from multiple reef sites in the ETP and found that a low carbonate saturation state ({Omega}) and trace abundances of cement are characteristic of these reefs. These low cement abundances may be a factor in the high bioerosion rates previously reported for ETP reefs, although elevated nutrients in upwelled waters may also be limiting cementation and/or stimulating bioerosion. ETP reefs represent a real-world example of coral reef growth in low-{Omega} waters that provide insights into how the biological-geological interface of coral reef ecosystems will change in a high-CO2 world.
