Read on Twitter
My #SpookyScience This is an eye lens. By measuring #Isotopes in lenses we can work out where an animal has been, what it has been eating and maybe other things. In other words WE SEE THROUGH THE EYES OF THE DEAD!!!
If you want to know how this works: Eye lenses are made of a crystalline protein and increase in size as the anial grows. There are no cells in a lens, so the protein stays intact from birth (or hatching) to death ...
.. New protein is added at the edges of the lens. The lens ends up something like an onion. And, like an onion, you can 'peel' layers of a lens reflecting time from death back to birth/hatching..
The protein in the lens can be analysed to measure the relative amounts of light and heavy isotopes of carbon, nitrogen and other elements. The carbon and nitrogen used to build lens protein comes from the animal's diet - so we can track what the animal ate through liife..
And the isotope values of the diet vary across regions - so we can also track where the animal was feeding.
https://peerj.com/articles/4883/
https://www.int-res.com/abstracts/meps/v624/p103-116/
https://www.int-res.com/prepress/m13525.html https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0108935
https://peerj.com/articles/4883/
https://www.int-res.com/abstracts/meps/v624/p103-116/
https://www.int-res.com/prepress/m13525.html https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0108935
The middle of the eye lens is the earliest part of life. Radiocarbon or bomb radiocarbon dating of eye lens cores can be used to estimate the age of long lived animals (and people) https://science.sciencemag.org/content/353/6300/702
Finally - lenses of aquatic animals are spherical not 'lens-shaped' (fish-eye lenses) because there is less difference in refractive index between water and the eye than there is between air and the eye: so for animals living in water lens needs to have greater refractive power.
