Figure 2.

Mapping ARG database to identify hotspots and examine occurrence, co-occurrence and persistence of ARGs. (A) Total ARG copies versus population density for all 30 surface water samples, size of dot relates to total number of detected ARG copies, red, blue and green dots indicate samples from group 2, 3 and 4, respectively. Green portions of the map indicate no population information was available. (B) Trophic state of environmental surface waters, based on sample grouping via RDA (Fig. S2, Supporting Information).