With diet options as a proxy, I use stable isotopes to ask urban animals if their tissues integrate different land-use managements! I use invertebrate bodies and mammal hair; as a tweeting, taxidermied squirrel, my favorite tissue to analyze is hair. What's your favorite shark tissue/gas to put into the mass spec!? And what's your favorite isotope (mine's d13C, becase of corn)!?
~Nutmeg Something (& Michelle Frack)