Isotopic signature

And you can use the relative abundance of these heavy isotopes to sort of track nutrient flow in the environment.

And There is a central assumption in isotopic ecology that between trophic levels, so from predator to prey, the isotopic composition of the tissue increases at a static level.

So each trophic level, you basically just add on what they call a delta.

So carbon-13 accumulates slightly more each trophic level.

And not only was it wrong, it was wrong not only in a way that was slightly off, it needed to be tweaked.

It was the whole idea of the whole concept of a static delta was wrong.

What we were trying to understand is how the ratio of stable isotopes changes through biological fractionation from predator to prey and how that changes depending on the isotopic composition of the diet.

Because not every diet has the same isotopic composition, so perhaps there may be a different discrimination between the diet and the tissue, depending on what the diet is.