One primary food resource for many benthic consumers
is organic matter attached to hard substrata.
This resource may include varying amounts of algae,
bacteria, fungi, the exopolymeric substances they
exude, other non-living particulate organic matter,
protozoa, and small metazoa. Hereafter, we will use
the term ‘periphyton‘ to refer to this organic matter on
benthic surfaces. The C : N and C : P ratios of
periphyton vary considerably in lakes