Fig 8.

Illustration of ¹³C_CARBOXYL off-set (versus bulk composition) across a food web represented by herbivorous deer (open circles), omnivorous humans (grey squares) and carnivorous (zooplanktivorous) whales (black diamond), note all datum include error bars ± 1sem. For most amino acids the off-set follows a pattern whales>humans>deer but for Glx this order is reversed (deer>humans>whales) indicating ¹³C depletion across the food web for this amino acid, in agreement with trends previously reported [6].