Figure 2
From: Functional microbial diversity explains groundwater chemistry in a pristine aquifer

A comparison of the methane (CH 4 ) and sulfate (SO 4 2-) concentrations of individual wells in the Mahomet aquifer. The amount of sulfate in HS wells is > 0.2 mM, is between 0.03 and 0.2 mM in LS wells, and is less than 0.03 mM in NS wells.