328
Exercise 25
Table 25.2. Data obtained during a 24-h period in August in a clear-water lake in the North
Temperate Zone.
Depth (ro)
o
2
4
6
8
10
o
2
4
6
8
10
o
2
4
6
8
10
Depth (m)
o
2
4
6
8
10
Depth (m)
o
2
4
6
8
10
Depth (m)
o
2
4
6
8
10
1600h
o
101
572
1212
236
101
2862
2391
9326
9124
3704
303
3491
2222
2930
4377
909
67
Zooplankton
1950h
0100h
0600h
Kellicottia longispina (number/m 3 )
34
269
404
34
269
943
1246
1414
67
67
943
1178
707
168
471
1010
168
34
Polyarthra vulgaris (number/m 3 )
5523
7037
10,034
3872
8239
13,333
6767
9124
14,345
13,604
9764
11,313
6228
11,717
7071
1011
2458
1010
Ceratium sp. (number/m 3 )
3097
3673
2761
2727
3333
2427
3572
2390
67
1616
201
505
2694
2997
3602
2559
1380
100
1215h
269
269
1313
1010
o
o
7273
11,852
15,992
9225
1650
202
3030
3232
3299
4444
370
101
Relative total solar irradiance (cal x 1O- 3 /cm 2 -min)
1550h
168
202
741
370
34
202
8519
14,242
10,676
10,572
9428
5758
3636
3300
2727
4309
640
572
1600h 1850h 1950h 2050h 0100h 0455h 0600h 0740h 1215h 1600h
301
20
0.58 <0.01 <0.01
<0.01
3.1
111
440
245
107
7.3
0.50 <0.01 <0.01
<0.01
3.1
43
160
85
40
3.5
0.15 <0.01 <0.01
<0.01
0.62
9.3
49
31
13
0.93
0.03 <0.01 <0.01
<0.01
0.44
3.8
7.3
3.8
1.4
0.13 <0.01
<0.01 <0.01
<0.01
0.Q4
0.57
2.0
1.5
0.13 <0.01
<0.01 <0.01 <0.01
<0.01 <0.01
<0.01 <0.01
0.05
1430h
21.9
21.8
15.5
9.1
6.9
6.4
1430h
8.1
8.2
9.7
9.3
4.4
1.6
1830h
22.0
21.3
15.1
9.6
7.1
6.5
1830h
7.8
8.2
9.2
10.4
5.2
1.6
2200h
21.6
21.6
15.8
9.1
7.2
6.4
Temperature Cc)
0200h
0600h
21.2
20.8
21.2
15.5
9.3
7.1
6.5
20.8
15.3
9.2
7.2
6.4
Dissolved oxygen (rog/I)
2200 h
0200 h
0600 h
7.8
7.8
8.2
8.1
8.3
7.9
9.4
8.7
8.4
9.1
9.4
9.4
6.6
6.6
6.6
1.5
1.6
Ui
1000h
20.9
20.7
15.5
9.2
7.1
6.4
1000h
8.2
8.3
8.4
9.2
6.5
1.6
1215h
21.3
21.1
15.4
9.3
7.2
6.4
1215h
8.2
8.4
9.1
9.7
6.6
1.5
1600h
22.2
22.0
15.5
9.3
7.2
6.4
1600h
8.1
8.2
9.8
10.1
6.6
1.6
- - - - - - - - - - - - _ . _ - - - - - - - - - - _ . _ - - - - -