good indicators for many reasons.
These species can "predict" the
overall water quality in a given area. Concentrations of pollutants, temperature
and oxygen level can all be determined based on the presence or absence
of certain species. Benthic macro-invertebrates include aquatic insects,
mollusks, crustaceans, and worms. They can be classified into three main
groups based on their tolerance to pollution and oxygen levels
Students collecting indicator species
East Branch Perkiomen Creek - June 2001
|Certain species of benthic
macroinvertebrates indicate different types of water quality. Benthic
means bottom-dwelling. Macro means large enough to be seen, and
invertebrates are animals without backbones. They are considered
-They are sensitive to both physical
and chemical changes in their environment.
-It is easy to collect and classify
-There is a diversity of species
included in this group.
-They can't easily leave polluted