145
A
(%)14.---------------------.
12
10
8
6
4
2
OL-______ ~~~~ __ L_~~_L_L~~ _ _ L_L_~~~
20 10 g 8 7 6 0 4 3 2 1 .g .8 .7 .6 .0 .4 .3 .2
particle size (}Jm)
100
III
B
r-I
!
r-I
OJ
U
.11 !
.jJ
***
III
.44
10
.22
**
OJ
**
f
>50
=
>
.jJ
[l
E
.88
·OJ
=
~
0
0.0
0.5
1.0
clay (g 1- 1 )
Fig. 3. A. Size frequency distribution (%) of particulates of clay type II, determined by laser sizing. B. Percentage of 'empty' yeast cells in
faecal pellets of Thamnocephaius platyurus (five treatments; five replicates) at different concentration of clay type II, and 0.2 g I-I of baker's
yeast. Bars represent standard deviations. *** & **=significant atp Three hours before the experiments the animals were
fed only algae. Once transfered to the test chambers,
it took them no more than 1 h 30 min to excrete the
algae in the form of faecal pellets. Thus, after 2 h of
experiment, all faecal pellets were removed from the
collectors. At the end of the experiment, the faecal
pellets of each animal were transfered to a container
with 20 ml of clean water and kept at 2 0c. The counting of the yeast cells was done within the next seven
days. The faecal pellets were washed in tap water in