Figure S3. Shallow water (Csw) and deep water
(Cdw) nitrate concentration as a function of percent of
agricultural land (81 sites). The solid gray line is the exponential fit
while dashed lines are upper and lower bounds at the confidence interval
of 95%. Note that filled circles are estimated end-member concentration
from high-frequency stream nitrate (Cstream, see
Methods) while stars are direct field measurements of
Csw and Cdw from intensively studied
sites.