Maximum enrichment at any point in time in high density fractions
of $^{13}$C-treatments relative to control (expressed as LFC) shown
for $^{13}$C-cellulose versus $^{13}$C-xylose treatments. Each point
represents an OTU. Blue points are cellulose responders, green xylose
responders, red are responders to both xylose and cellulose, and gray points
are OTUs that did not respond to either substrate. Line indicates a slope of
one. 

