Nuclear bombs determines age of fin whales

A new study finds that bomb radiocarbon determines absolute age of adult fin whales.

Bomb radiocarbon determines age of fin whales

A new study, published recently in the research journal Frontiers in Marine Science, reveals that Bomb radiocarbon determines absolute age of adult fin whales, and validates use of earplug growth bands for age determination.

The atmospheric testing of atomic bombs in the 1950s and 1960s resulted in a rapid and well-documented increase in atmospheric radiocarbon, which was subsequently deposited in the calcified tissues of all surface-dwelling organisms. In the pelagic marine environment, the bomb radiocarbon first became apparent around 1958, peaking around 1968. The period of radiocarbon increase was virtually synchronous around the world, thus making it an ideal dated marker for any organism forming growth bands during the 1960´s.
Baleen whales are one of the few vertebrate taxa for which there are no confirmed estimates of longevity or methods of age determination. Lamina counts in the waxy earplug are assumed to represent age, but ageing accuracy is completely unknown.

Nuclear bombs and earplug growth

In the study, nuclear bomb radiocarbon assays of the earplug growth sequence in three adult fin whales (Balaenoptera physalus) were used to prepare the most complete within-individual bomb radiocarbon chronologies yet reported for any vertebrate.
The whale radiocarbon chronologies matched those of known-age carbonate reference chronologies very well, indicating that the earplug laminae were both metabolically stable and formed throughout the life of the whale. Earplug lamina counts accurately represented absolute ages of 65-85 yr to within 6% of the correct age.
Given the results of the study, recent applications of earplug laminae for reconstructing diet and life history events appear to be firmly based, with the potential for further elemental and isotopic applications analogous to those of the otolith.