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International Journal of Aquaculture 2012, Vol.2, No.1, 1
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4
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2
Physical and chemical properties of water in Noruzlo reservoir in 2008
Transparency
(m)
Chlorophyll-a
(µg/L)
Water
Temperature (
℃
)
PH
PO
4
(mg/L)
TN
(mg/L)
BOD
(mg/L)
N-NH
4
(mg/L)
Jan.
1
5.8
7
8.2
0.12
0.51
5.45
0.29
Feb.
0.88
2.8
5.2
7.7
0.17
0.21
3.21
0.18
March
1.1
4.7
7.6
8
0.12
0.37
3.15
0.10
April
0.98
8.7
15
7.9
0.44
0.54
1.12
0.15
May
1.4
3.6
16.8
8.2
0.35
0.18
3.21
0.08
June
1.2
2.1
21
8.5
0.43
0.28
2.18
0.21
July
0.58
0.89
23.8
7.8
0.28
0.85
3.16
0.16
Aug.
1.2
1.2
26.5
7.4
0.15
0.22
1.98
0.18
Sep.
0.56
2.2
26.8
7.9
0.32
0.18
5.58
0.25
Oct.
0.85
0.54
19
8.3
0.21
0.54
5.35
0.12
Nov.
1.1
3.2
15
8
0.18
0.15
6.68
0.35
Dec.
1.2
3.1
12.5
8.1
0.12
0.37
3.12
0.25
Average 1
3.2
16.3
8
0.24
0.37
3.68
0.19
The maximum chlorophyll-a observed at the reservoir
water was 8.7 µg/L and the minimum was 0.54 µg/L
being obtained in April and October respectively. The
maximum transparency value (1.4 m) was observed in
May while the minimum of 0.56 m being obtained in
September. The higher temperatures were recorded
from July to September, with a maximum value of
26.8
℃
, while the minimum value was observed in
February, with 5.2
℃
. pH was fluctuated between 7.4
and 8.5. The chemical variables of water including
PO
4
, TN, BOD and N-NH4 are indicated in Table1.
Concerning the protozoa density, a high-density
period was detected in February with 3.93×10
3
cells/L,
The lowest-density was observed in October with
0.76×10
3
cells/L which was statistically significant
(p<0.05). The mean values density was 1.89×10
3
cells/L.
The composition and density of ciliates in Noruzlo
dam reservoir are presented in Figure 1 and
Figure 1 Monthly distribution of ciliates population in Noruzlo
reservoir in 2008
Three different periods can be observed with respect
to the density of protozoa detected, i.e. January-
February, July-August and October-November.
As shown in Table 2, a total number of 43 Ciliata
species were found in plankton samples. The highest
and the lowest Hymnostomatida (8 species) species
diversity was belonged to Pleurostomatida (1 species)
respectively, which was statistically significant
(P<0.01). The annual average density of ciliata was
1 893 Ind/L, fluctuated between 966 cells/L during the
low-density period and 2 203 cells/L during the
high-density period, which was statistically significant
(p<0.05). The densities of ciliates showed clearly
marked seasonal changes in Noruzlo dam reservoir.
During this period Prostomatida (
Eoleps hirtus
),
Haptorida (
Paradileptus elephantinus
), Hymnostomatida
(
Paramecium bursaria
), Scuticociliatida (
Pleuronema
coronatum
,
Cyclidium citrullus
), Heterotrichida
(
Condylostoma rugosum
,
Metopus.sp
), and Hypotrichida
(
Aspidisca costata
) constituted about 60% of the total
number of the ciliata.
2 Discussion
The highest density of planktonic ciliates in the
Noruzlo dam reservoir was observed from January to
April
.
The densities of ciliates showed clearly marked
seasonal changes in the reservoir. Also the peaks in
the winter and the summer were probably determined
by abiotic water factors. This trend was also observed
in other
mesotrophic
lakes (Takamura et al., 2000;
Ventela et al., 2002).