Summary: Low reservoir ages for the surface ocean from mid-Holocene
Florida corals
Ellen R. M. Druffel,1
Laura F. Robinson,2
Sheila Griffin,1
Robert B. Halley,3
John R. Southon,1
and Jess F. Adkins4
Received 26 July 2007; accepted 1 February 2008; published 13 May 2008.
[1] The 14
C reservoir age of the surface ocean was determined for two Holocene periods (4908­4955 and
3008­3066 calendar (cal) B.P.) using U/Th-dated corals from Biscayne National Park, Florida, United States.
We found that the average reservoir ages for these two time periods (294 ± 33 and 291 ± 27 years, respectively)
were lower than the average value between A.D. 1600 and 1900 (390 ± 60 years) from corals. It appears that the
surface ocean was closer to isotopic equilibrium with CO2 in the atmosphere during these two time periods than
it was during recent times. Seasonal d18
O measurements from the younger coral are similar to modern values,
suggesting that mixing with open ocean waters was indeed occurring during this coral's lifetime. Likely
explanations for the lower reservoir age include increased stratification of the surface ocean or increased D14
C

Source: Adkins, Jess F. - Division of Geological and Planetary Sciences, California Institute of Technology

Collections: Environmental Sciences and Ecology; Geosciences