Fig. 3.

Total mercury (THg) concentrations in the blood of Seaside Sparrows (top) and Marsh Rice Rats (bottom) as a function of δ¹³C (a marker of the provenance of food items; A, C) and δ¹⁵N values (a marker of trophic level; B, D), across site categories, including non-oiled sites (red), sites oiled by the Deepwater Horizon oil spill (green), and sites east of the Mississippi River (blue). Note that the scale for THg (in µg/g wet weight (ww), or parts per million (ppm)) is different in the two species, consistent with higher total concentrations in Seaside Sparrows than Marsh Rice Rats