Information theoretical indices (K, M, I), introduced in a previous pa
per, are used for characterization and comparison of various types of
lakes studied by IBP in Japan. The index K is a measure of distributio
n of matter among compartments in a system as compared with a referenc
e system, the index M is a measure of concentration of matter in a sys
tem as compared with a reference system, and I = K + M. These indices
are calculated for each lake; and the value M vs. K, the effect of cha
nging reference system, the effect of aggregation of compartments, and
the relation to nitrogen and phosphorus concentrations in lake water
are investigated. The value of M becomes larger as eutrophication prog
resses. The value of K also increases with eutrophication with a large
rate for oligo-mesotrophic lakes and with a small rate for eutrophic
lakes.