Summary: This plain English factsheet outlines the work done by the EPA in monitoring phytobenthos in rivers and lakes.
Phytobenthos is the name given to the tiny organisms commonly found on stones in the bottom of rivers and lakes. Many of the organisms, like bacteria and algae, live in thin layers on the surface of stones, this is called the bio-film and gives the stones their characteristic slippery feel.
Phytobenthos is an important part of the aquatic food chain providing
nourishment for insects which in turn provide food for fish and birds.
When nutrient levels in the water are too high, however, some types of phytobenthos grow too much and can form scums and blooms which can harm other aquatic life and badly affect water quality.
