A 200 year record of carbon‐13 and carbon‐14 variations in a Bermuda coral

A 200 year old brain coral, captured in Bermuda in 1976 was slabbed and x‐rayed. Using the annual growth bands sequential, dated samples were taken over the entire growth period of the coral and analyzed for Δ 14 C, δ 13 C and δ 18 O. During the past 80 years atmospheric variations in Δ 14 C and δ 13 C due to human effects, such as release of bomb C‐14 and dilution of both C‐14 and C‐13 by fossil fuel burning, are closely tracked by the coral. Prior to 1900 divergences between the coral and tree Δ 14 C and δ 13 C can be related to world‐wide changes in plant production and possibly oceanic upwelling rates.