Translation Series No.997

Experiments were also carried out on determination
of respiratory intensity of rotifers Brachionus calyciflorus
in tap water and in a medium consisting of algae Scenedesmus
obliguus (0.1-5 million cells/ml). The experiments were carried
out in the dark, in jars with fitted lids (volume of jars
8-11 ml). Before the experiment the rotifers were kept for
one day in appropriate concentrations of algae or in tap water.
In all the experiments the density of rotifers was 18-20 specimens/
ml. Oxygen was determined by the micro-modification Winkler
method. The amount of consumed oxygen was computed from the
difference between the oxygen content in the experimental jar
and in the control jar under the same conditions. In those cases
where the experiment was carried out in an algae medium a
correction was applied which was obtained fromihe amount of
algae consumed by the rotif ers.
According to data provided by Yu. S. Belyatskaya
(1959), who measured the intensity of Brachionus calyciflorus
metabolism by means of a floating microrespirometer, rotifer
absorbs 0.32 x 10 -5 mgm 02 per hour at 20 0 C.
According to
our data, the respiratory intensity for rotifers in tap water
is 0.12 x l0
02 snecimens/hour and when the algae
concentration is increased this value grows to 0.72 x 10
02 specimens/hour at 20 0 C. It can be seen that the common
level of metabolism for rotifers in an algae medium is
approximately 3 times as high as the level of Metabolism in
8 .
tap water.
Having the required empirical data on increase,
metabolism and rations for rotifers at different concentrations
of algae, we computed the amount of food consumed by the
rotifers in populations and when cultivated individually (tables
3 and 4). Food assimilation was l/u = 0.21-0.52. Similar
figures for assimilation are given for some soil Diplopoda /510
(Drift, 1958; l/u = 0.05-0.10), and for long-horned grasshoppers
Orchelimum fidicinum (Smalley, 1960; l/u = 0.275).