Raw data from individual responders highlighted in the main text (see
Results). The left column shows OTU relative abundance in density gradient 
fractions for the indicated treatment pair at each sampling point. Time is
indicated by the line color (see legend). Gradient profiles are shaded
to represent the different treatments where orange represents ``control'',
blue ``$^{13}$C-cellulose'', and green ``$^{13}$C-xylose.'' The right column
shows the relative abundance of each OTU in non-fractionated DNA. Enrichment in the
high density fractions of $^{13}$C-treatments indicates an OTU likely
has $^{13}$C-labeled DNA. 

