High-precision D14C and stable isotope (d18O and d13C) records are reported for post-bomb corals from three sites off the eastern Australian coast. We observe that D14C values increased from ca. -50 per mil in the early 1950s to +130 per mil by 1974, then decreased to 110 per mil by 1991. There is general agreement between the coral results and D14C of dissolved inorganic carbon (DIC) in seawater measured previously for locations in the South Pacific. D14C values at our southern hemisphere sites increased at a slower rate than those observed previously in the northern hemisphere. Small variations in the D14C records among our three sites are likely due to differences in circulation between the shallow coastal waters and the open ocean influenced by seasonal upwelling. Low D14C is associated with most El Niño/Southern Oscillation (ENSO) events after 1970, indicating input of low 14C waters from the southern-shifted South Equatorial Current. The exception is the severe ENSO event of 1982-1983 when upwelling in the South Equatorial Current could have ceased, causing normal D14C values in the corals during this time.
[Radiocarbon Volume 37, Number 2, 1995]