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Biology

Isotope Fractionation in Stable Isotope Analysis of Food Webs

Quick fact

In food web studies, nitrogen-15 (15N) becomes more concentrated (enriched) by roughly 3–4‰ (parts per thousand) with each step up the food chain, allowing scientists to use this 'isotope clock' to estimate an organism's trophic position.

Why this is interesting

Ever wonder how ecologists know what an animal has been eating without watching it? It turns out the food leaves a subtle chemical signature inside your own body.