Introduction

I remember the first time I discovered the power of stable isotopes. It was by accident. It was thirty years ago, when I was a beginning graduate student along the south Texas coast. That summer I helped a visiting professor collect rodents (mice, rats, and ground squirrels) in a coastal sand dune community. Yes, I worked with the rodent traps, but I also got bored and wandered off during the hot afternoon hours, collecting plants and grasshoppers from the dunes. One evening later in that summer of 1976 we were at the mass spectrometer, watching the chart recorder display the isotope results for our collections. It was fascinating. One sample was very enriched in the heavy carbon stable isotope, ¹³C, and the next sample was depleted in ¹³C. A great divide was evident in the isotopes of the sand dune community.We watched the chart recorder for hours as sample after sample showed the basic ¹³C distinction, or variations on this ¹³C isotope theme.