Department of Earth System Science

High-precision A14C and stable isotope (8180 and 613C) records are reported for post-bomb corals from three sites off the eastern Australian coast. We observe that A14C values increased from ca. -50%o in the early 1950s to +130% by 1974, then decreased to 110% by 1991. There is general agreement between the coral results and &4C of dissolved inorganic carbon (DIC) in seawater measured previously for locations in the South Pacific. A14C values at our southern hemisphere sites increased at a slower rate than those observed previously in the northern hemisphere. Small variations in the A14C records among our three sites are likely due to differences in circulation between the shallow coastal waters and the open ocean influ- enced by seasonal upwelling. Low A14C is associated with most El Nino/Southern Oscillation (ENSO) events after 1970, indi- cating 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 A14C values in the corals during this time.