A group of researchers recently published the interesting approach of examining a large plug of ear wax (cerumen) taken from a male blue whale (Balaenoptera musculus) that had been hit by ship.
By analyzing the waxy layers built up over the whale’s life, which they compare to growth rings in trees, they came up with a lifetime profile of the chemicals to which the whale had been exposed, as well as a profile of its maturation process and stress levels. This particular earplug was 25.4 cm (10 inch) long, a lot of wax to examine.
The team is encouraging the examination of archived ear wax plugs, some dating back to samples harvested from various whales in the 1950s, to create a multi-generational database that could be used to assess human impact on both the whales themselves, and on the marine environments where they live.
For me, the earplugs less resemble the growth rings on trees, and are more like the core samples taken to research glacial ice, or sediment or rock, for insight into historical composition. Except that with the whale’s waxy earplug, the core sample has been created naturally.
Humans have always liked to gather things, all manner of things. A bit like the proverbial magpie, but our interest isn’t limited to shiny objects.
I suppose what surprises me most about this story isn’t the innovative approach to marine research – it’s the fact that there are entire archives of whale ear wax plugs to which the new method can be applied.
PNAS paper – Blue whale earplug reveals lifetime contaminant exposure and hormone profiles by S.J. Trumble, E.M. Robinson, M. Berman-Kowalewski, C.W. Potter & S. Usenko
GuardianExpress article – Blue Whale Ear Wax Shows Beast’s Hormone Profile by James Fenner