Page 225 - Freshwater-Biology-and-Ecology-Handbook

Microbial taxa Trophic group
M = mixotrophic phytoflagellates producers
P = producers consumers
C = ciliates decomposers
F = colourless flagellates
Z = zooplankton
B = bacteria

Saprobic degree
h = hypersaprobity
m = metasaprobity
i = isosaprobity
p = polysaprobity
α = α-mesosaprobity
β = β-mesosaprobity
o = oligosaprobity
x = xenosaprobity
After Sládeček (1973)

Figure 5.3
Saprobic scale indicating biological communities associated with different degrees of saprobity (after Sládeček 1973). (76)

Saprobic indices are average scores per individual organism (in contrast to ASPTs,
which are average scores per taxon). However, most include an indicator weighting
according to the narrowness of the range of saprobity in which an organism is found.
The highest weighting is given to organisms that are found in a narrow range of
conditions and which are therefore good indicators of that particular quality.

A general formula is given below:

Σ (weighting × value × abundance)
Saprobic index =
total abundance

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