106
Table 1. Limnological characteristics for the study ponds In Tobeltal, South Germany. Temperature measurements are given for water
surface (0--5 cm). Driving activity T = tanks; driving activity C = cars and motor cycles. The chemical data are based on 8 to 18
measurements from April to November; temperature was measured every 2 to 3 days.
ponds
5
12
13
15
16
20
27
35
no. of draught periods
3
0
0
0
8
2
6
2
max. volume (m 3 )
3.0
6.7
511.1
20.6
0.7
4.7
0.6
4.5
thickness of sediment (cm)
3
13
17
18
3
20
2
11
max. water temperature (0 C)
34.9
31.3
33.8
35.4
33.1
35.3
30.5
26.6
(and date)
(11.7.)
(30.7.)
(11.7.)
(30.7.)
(20.6.)
(11.7.)
(11.7.)
(11.7.)
max. temperature difference (0C)
22.3
19.2
15.1
22.5
23.4
18.5
17.8
15.0
between 6.00 and 15.30
(20.6.)
(30.7.)
(30.7.)
(30.7.)
(20.6.)
(9.7.)
(20.6.)
(20.6.)
Conductivity 20°C (Jl.S cm-')
484-797
177-353
187-366
205-355
209-273
200--391
225-324
216-370
pH
7.9-9.0
7.8-8.8
7.6-8.6
7.8-8.6
7.7-8.6
7.8-8.7
7.9-8.7
7.2-8.8
Alkalinity (mvall-')
1.5-3.7
2.0--3.0
1.4-2.1
1.6-3.3
1.6-2.7
1.3-2.8
1.4-2.1
1.5-2.5
Ca 2 + (mvall-')
1.2-7.0
2.2-3.1
1.6-2.6
2.2-3.4
2.1-3.0
2.0--2.9
1.7-2.2
1.9-2.9
Mg2+ (mvall-')
0.2-0.8
0.1-0.2
0.1-0.2
0.1-0.2
0.1-0.2
0.1-0.3
0.1-0.2
0.1-0.2
P04 -P (Jl.g 1-')
9-39
4-11
6-19
5-16
5-11
6-13
5-15
7-21
N03-N (mgl-')
0.1-0.3
0.1-0.3
0.1
0.1-0.2
0.1
0.1
0.1
0.1
02 (S)
69-93
61-95
51-88
76-91
83-94
73-92
65-89
69-87
Presence of Branchipus
+
+
+
+
+
+
Presence of macrophytes
+
Presence of Spirogyra
+
+
Driving activities
C
(C)
no
T(C)
T(C)
T(C)
T(C)
(T(C)
Table 2. Period of occurrence of Branchipus schaefferi in the study ponds with temperature at water surface of the ponds
at 6.00 and 15.30, respectively and with number and duration of the generations.
Pond
5
15
Occurrence
9.5.-16.11.
20.4.-21.11.
Water temperature (OC)
3.6/15.0
4.6/17.5
at the first occurrence
at 6.00/15.30
Water temperature (0C)
2.8/3.0
3.1/4.4
at the disappearance
at 6.00115.30
No. of generations
4
6
which reproduce
Max. duration of a
66
64
reproducing generation (d)
Min. duration of a
reproducing generation (d)
20
20
The water temperature at the surface of the ponds
may rise to 35°C in summer, the maximum differences between day and night can be 22.5 °C (Table 1).
The ponds are relatively nutrient poor and contain soft
water. Oxygen saturation is about 80%.
16
20
27
35
9.5.-17.10.
20.4.-26.11.
16.5.-2.11.
6.6.-5.9.
3.6/15.5
4.3117.8
7.2/18.7
9.7115.6
4.9/11.0
4.7/6.3
4.3/6.1
14.4113.7
5
4
5
4
38
69
47
45
15
20
20
20
The phytoplankton of the ponds is dominated by
greens (Pandorina sp., Scenedesmus sp.) and flagellates (Phacus sp., Phacotus sp., Euglena sp., Trachelomonas sp.). The dominant rotifers are Brachionus rubens and Asplanchna girodilbrightwelli, the
Table 1. Limnological characteristics for the study ponds In Tobeltal, South Germany. Temperature measurements are given for water
surface (0--5 cm). Driving activity T = tanks; driving activity C = cars and motor cycles. The chemical data are based on 8 to 18
measurements from April to November; temperature was measured every 2 to 3 days.
ponds
5
12
13
15
16
20
27
35
no. of draught periods
3
0
0
0
8
2
6
2
max. volume (m 3 )
3.0
6.7
511.1
20.6
0.7
4.7
0.6
4.5
thickness of sediment (cm)
3
13
17
18
3
20
2
11
max. water temperature (0 C)
34.9
31.3
33.8
35.4
33.1
35.3
30.5
26.6
(and date)
(11.7.)
(30.7.)
(11.7.)
(30.7.)
(20.6.)
(11.7.)
(11.7.)
(11.7.)
max. temperature difference (0C)
22.3
19.2
15.1
22.5
23.4
18.5
17.8
15.0
between 6.00 and 15.30
(20.6.)
(30.7.)
(30.7.)
(30.7.)
(20.6.)
(9.7.)
(20.6.)
(20.6.)
Conductivity 20°C (Jl.S cm-')
484-797
177-353
187-366
205-355
209-273
200--391
225-324
216-370
pH
7.9-9.0
7.8-8.8
7.6-8.6
7.8-8.6
7.7-8.6
7.8-8.7
7.9-8.7
7.2-8.8
Alkalinity (mvall-')
1.5-3.7
2.0--3.0
1.4-2.1
1.6-3.3
1.6-2.7
1.3-2.8
1.4-2.1
1.5-2.5
Ca 2 + (mvall-')
1.2-7.0
2.2-3.1
1.6-2.6
2.2-3.4
2.1-3.0
2.0--2.9
1.7-2.2
1.9-2.9
Mg2+ (mvall-')
0.2-0.8
0.1-0.2
0.1-0.2
0.1-0.2
0.1-0.2
0.1-0.3
0.1-0.2
0.1-0.2
P04 -P (Jl.g 1-')
9-39
4-11
6-19
5-16
5-11
6-13
5-15
7-21
N03-N (mgl-')
0.1-0.3
0.1-0.3
0.1
0.1-0.2
0.1
0.1
0.1
0.1
02 (S)
69-93
61-95
51-88
76-91
83-94
73-92
65-89
69-87
Presence of Branchipus
+
+
+
+
+
+
Presence of macrophytes
+
Presence of Spirogyra
+
+
Driving activities
C
(C)
no
T(C)
T(C)
T(C)
T(C)
(T(C)
Table 2. Period of occurrence of Branchipus schaefferi in the study ponds with temperature at water surface of the ponds
at 6.00 and 15.30, respectively and with number and duration of the generations.
Pond
5
15
Occurrence
9.5.-16.11.
20.4.-21.11.
Water temperature (OC)
3.6/15.0
4.6/17.5
at the first occurrence
at 6.00/15.30
Water temperature (0C)
2.8/3.0
3.1/4.4
at the disappearance
at 6.00115.30
No. of generations
4
6
which reproduce
Max. duration of a
66
64
reproducing generation (d)
Min. duration of a
reproducing generation (d)
20
20
The water temperature at the surface of the ponds
may rise to 35°C in summer, the maximum differences between day and night can be 22.5 °C (Table 1).
The ponds are relatively nutrient poor and contain soft
water. Oxygen saturation is about 80%.
16
20
27
35
9.5.-17.10.
20.4.-26.11.
16.5.-2.11.
6.6.-5.9.
3.6/15.5
4.3117.8
7.2/18.7
9.7115.6
4.9/11.0
4.7/6.3
4.3/6.1
14.4113.7
5
4
5
4
38
69
47
45
15
20
20
20
The phytoplankton of the ponds is dominated by
greens (Pandorina sp., Scenedesmus sp.) and flagellates (Phacus sp., Phacotus sp., Euglena sp., Trachelomonas sp.). The dominant rotifers are Brachionus rubens and Asplanchna girodilbrightwelli, the