Ocean acidification: a view from reconstructions of past seawater pH

• Main Authors: Calvo, Eva María, Pelejero, Carles
• Format: Conference Object
• Language: unknown
• Published: 2007
• Subjects: Ocean acidification
• Online Access: http://hdl.handle.net/10261/200700

Symposium GLOBEC-IMBER España celebrado del 28-30 marzo de 2007 en Valencia.-- 2 pages It is now well recognised that levels of carbon dioxide (CO2) in the atmosphere have been increasing since the Industrial Revolution due to burning of fossil fuels, leading to global warming. It is not that well known, however, that ~50% of this CO2 is actually being absorbed by the oceans, and that seawater is becoming more acidic because of this. Such pH reduction could have major effects on marine biota, especially on calcareous plankton and coral reef communities, which will be unable to calcify effectively under these new conditions. However, the fate of individual species will depend on their past acclimatisation and ability to adapt, and will remain unknown until the preindustrial range of surface ocean pH is quantified. Using the boron isotope composition of a Porites coral from a reef offshore north-eastern Australia, we have obtained the first record of seawater pH variability, which shows large amplitude pH changes over the last 300 years (Pelejero et al, 2005). The ranges and patterns of temporal and spatial pH variation, however, are still largely unknown and other reefs and oceanic areas need to be studied in order to obtain a more global picture. We now intend to perform further pH reconstructions in corals from the northern Red Sea, one of the northernmost latitudes where Porites corals develop. The feasibility of boron isotopes is also being assessed in other coral species from the Mediterranean Sea, where Porites corals cannot be found. References: Pelejero, C., E. Calvo, M.T. McCulloch, J. Marshall, M.K. Gagan, J.M. Lough, B.N. Opdyke, 2005. Preindustrial to modern interdecadal variability in coral reef pH. Science 309, 2204-2207