Geochemistry of corals: Proxies of past ocean chemistry, ocean circulation, and climate

This paper presents a discussion of the status of the field of coral geochemistry as it relates to the recovery of past records of ocean chemistry, ocean circulation, and climate, The first part is a brief review of coral biology, density banding, and other important factors involved in understanding corals as proxies of environmental variables, The second part is a synthesis of the information available to date on extracting records of the carbon cycle and climate change, II is clear from these proxy records that decade time-scale variability of mixing processes in the oceans is a dominant signal, That Western and Eastern tropical Pacific El Nino-Southern Oscillation (ENSO) records differ is an important piece of the puzzle for understanding regional and global climate change, Input of anthropogenic CO2 to the oceans as observed by C-13 and C-14 isotopes in corals is partially obscured by natural variability, Nonetheless, the general trend over time toward lower delta(18)O values at numerous sites in the world's tropical oceans suggests a gradual warming and/or freshening of the surface ocean over the past century.