Increased C amendments diminished A) planktonic photoautotroph biomass (estimated as
Chl \textit{a}) but B) not biofilm photoautotroph biomass. In contrast, both C)
biofilm total biomass and D) number of planktonic bacterial cells increased
with increasing C subsidies. Only the highest C treatment produced biomass that
was significantly greater than (p $<$ 0.05) the other treatments
(significant differences among treatments are denoted by different letters). The bacterial abundance sample for the C:P
$=$ 100 treatment was lost before analysis and is therefore not reported in
panel D.
