Indicators Based on Ratios between Different Classes of Organisms or Elements

Increase or decrease of one species in relation to another can give useful information about changes in systems. Depending on the problem and the system that has to be investigated, different indices are applicable.

Nygard's algal index

This index is used to evaluate the nutritional status of lake ecosystems and their fertility. The index can be calculated as a compound quotient out of:

Myxophycean + chlorococcales + centric + Euglenophyceae/desmids

Oligotrophic systems have a quotient between 0.01 and 1.0, eutrophic systems between 1.2 and 2.5. Further Nygard's indices are based on ratios between Myxophyceae and desmids, chlorococcales and desmids, centric and pinnate diatoms or Euglenophyta and Myxophyceae + chlorococcales.

Diatoms/nondiatoms ratio

In the context of altering nutrient charges in aquatic systems, the ratio of the major phytoplankton groups diatoms versus flagellates (diatoms-nondiatoms ratio) can be used as indicator. Regarding for example eutro-phication, nutrient reductions can be seen in a decrease in flagellate abundance.

Oplan Termites

Oplan Termites

You Might Start Missing Your Termites After Kickin'em Out. After All, They Have Been Your Roommates For Quite A While. Enraged With How The Termites Have Eaten Up Your Antique Furniture? Can't Wait To Have Them Exterminated Completely From The Face Of The Earth? Fret Not. We Will Tell You How To Get Rid Of Them From Your House At Least. If Not From The Face The Earth.

Get My Free Ebook


Post a comment