Subject of this lasting study started in 1989 is an inner
mesotrophic lake of Valamo Island (North-Western Russia) - Leshevoe Lake,
with maximal depth 14m, and usual 2-3m.
Overall length of the lake is about 3000m.
During the period of study (1989-2000) a total of 250 repetitive and single
samples were collected and treated in all seasons.
A total of 32 species of Gymnamoebia were found (about 20% of total
known species). 14 of them are new for science.
An original method of amoebae enumeration, elaborated in course
of this work, allowed to estimate
their abundance in the sediments, in respect to their vertical
distribution. Number of amoebae was varied from 9.2 to 69.7 mln
ind/m-2, which is comparable with that of ciliates
in similar habitats.
Three ecological groups of species, according to the typical patterns
of their vertical distribution, were established. This must be taken into account in further
ecological and faunistical studies.
Irregular species distribution and sufficient fluctuations of amoebae
species composition during different seasons and years may be explained
by mean of the hypotesis of "hidden communities".