ABSTRACT
Natural variations in seawater pH and atmospheric carbon dioxide levels are documented that preclude anthropogenic input. Moreover, some methods for measuring oceanic carbon are suspect. Overall, there is a huge uncertainty as to what extent organism adaptation or acclimatization will mitigate the long term effects of ocean acidifi cation (Widdicombe and Spicer 2008). Interactions with other elements, latitudes, temperature, and depth are also documented (Andersson et al. 2008). For example, factors which determine the mineralogy, composition, and texture and rate of crystallization of carbonate precipitates from seawater or marine pore waters are signifi cantly modifi ed by the Mg 2+/Ca2+ ratio of the solution, presence of orthophosphate ions, sulfate concentration of the fl uids, water temperature, and salinity (Zhong and Mucci 1989). These modifi ers-and others-must be considered in any review of human-caused oceanic acidifi cation from combustion of fossil fuels.
