25
2 Eutrophication: Global Scenario and Local Threat to Dynamics of Aquatic Ecosystems
Table 2.2
Relative proportion of the occurrence of selected duckweeds, physico-chemical characteristics of water, atmospheric temperature, monthly precipitation and wind velocity in Lal
Diggi pond
Month
L:S ratio**
(Number)
Wolffia
occurrence
(Number)
pH
Turbidity Dissolved oxygen (mg L −1
)
Total dissolved
salts (mg L
−1
)
Nitrate
(mg L
−1
)
Phosphate
(mg L
−1
)
Potassium
(mg L
−1
)
Rainfall*
(mm)
Average atmospheric* temperature (°C)
Average wind
velocity* (km h −1
)
Min. Max.
April 2003
–
–
7.7 ± 0.3
25 ± 2.6
3.60 ± 0.21
2,290 ± 512
0.8 ± 0.3
3.9 ± 0.16
23.7 ± 1.9
3.2
20.6
36.6
7.920
May
–
–
8.1 ± 0.4
24 ± 3.3
3.30 ± 0.18
2,361 ± 407
11.2 ± 0.6 3.8 ± 0.17
24.6 ± 2.8
2.0
25.3
40.0
8.237
June
–
–
8.1 ± 0.4
25 ± 4.4
3.60 ± 0.17
2,416 ± 506
11.3 ± 0.7 3.6 ± 0.16
24.3 ± 3.1
10.0
25.8
38.1
8.870
July
105:36
0
7.6 ± 0.34 20 ± 2.7
4.60 ± 0.18
1,933 ± 461
11.3 ± 0.3 3.5 ± 0.21
20.3 ± 1.3
11.4
2.64
36.9
7.286
August
138:52
–
7.1 ± 0.39 18 ± 2.1
5.60 ± 0.27
1,763 ± 498
9.8 ± 0.6
2.8 ± 0.13
19.6 ± 1.8
277.2
25.0
32.2
6.494
September
37:39
20
7.3
± 0.3
17 ± 2.2
5.58 ± 0.31
1,952 ± 524
9.3 ± 0.3
2.4 ± 0.12
23.1 ± 1.8
117.9
23.7
34.1
6.178
October
153:64
43
7.3 ± 0.2
19 ± 2.5
5.11 ± 0.22
2,061 ± 318
9.8 ± 0.2
3.6 ± 0.11
24.6 ± 2.6
95.0
18.6
30.3
4.910
November
184:45
47
6.8 ± 0.3
20 ± 3.8
4.80 ± 0.18
1,822 ± 276
9.8 ± 0.3
3.1 ± 0.14
23.3 ± 2.1
–
11.5
27.9
4.594
December
–
–
6.9 ± 0.6
21 ± 4.0
3.30 ± 0.21
1,890 ± 386
9.8 ± 0.6
3.2 ± 0.13
20.6 ± 3.2
–
8.0
17.2
4.752
January 2004 19:39
–
6.9 ± 0.3
21 ± 3.8
3.60 ± 0.23
2,013 ± 427
10.1 ± 0.4 3.1 ± 0.16
20.3 ± 3.1
11.7
7.1
15.6
5.227
February
219:65
–
7.3 ± 0.2
22 ± 3.7
3.70 ± 0.18
1,682 ± 366
10.3 ± 0.5 3.6 ± 0.14
19.6 ± 2.8
–
9.8
23.3
5.544
March
195:55
–
7.3 ± 0.2
23 ± 3.9
4.20 ± 0.13
1,631 ± 402
10.5 ± 0.3 3.8 ± 0.11
22.5 ± 2.2
–
15.7
32.4
6.811
April
–
–
7.6 ± 0.4
26 ± 2.8
–
–
–
–
–
–
21.9
38.0
6.860
*Courtesy: Meteorological Survey of India, Govt. of India
** Median of the number of each species in 3 quadrats of 25 × 10 cm 2
approximatelyWithin parenthesis numerical ratio of L:S each quadrat against a fixed number (6) of Spirodela polyrrhiza
individuals
2 Eutrophication: Global Scenario and Local Threat to Dynamics of Aquatic Ecosystems
Table 2.2
Relative proportion of the occurrence of selected duckweeds, physico-chemical characteristics of water, atmospheric temperature, monthly precipitation and wind velocity in Lal
Diggi pond
Month
L:S ratio**
(Number)
Wolffia
occurrence
(Number)
pH
Turbidity Dissolved oxygen (mg L −1
)
Total dissolved
salts (mg L
−1
)
Nitrate
(mg L
−1
)
Phosphate
(mg L
−1
)
Potassium
(mg L
−1
)
Rainfall*
(mm)
Average atmospheric* temperature (°C)
Average wind
velocity* (km h −1
)
Min. Max.
April 2003
–
–
7.7 ± 0.3
25 ± 2.6
3.60 ± 0.21
2,290 ± 512
0.8 ± 0.3
3.9 ± 0.16
23.7 ± 1.9
3.2
20.6
36.6
7.920
May
–
–
8.1 ± 0.4
24 ± 3.3
3.30 ± 0.18
2,361 ± 407
11.2 ± 0.6 3.8 ± 0.17
24.6 ± 2.8
2.0
25.3
40.0
8.237
June
–
–
8.1 ± 0.4
25 ± 4.4
3.60 ± 0.17
2,416 ± 506
11.3 ± 0.7 3.6 ± 0.16
24.3 ± 3.1
10.0
25.8
38.1
8.870
July
105:36
0
7.6 ± 0.34 20 ± 2.7
4.60 ± 0.18
1,933 ± 461
11.3 ± 0.3 3.5 ± 0.21
20.3 ± 1.3
11.4
2.64
36.9
7.286
August
138:52
–
7.1 ± 0.39 18 ± 2.1
5.60 ± 0.27
1,763 ± 498
9.8 ± 0.6
2.8 ± 0.13
19.6 ± 1.8
277.2
25.0
32.2
6.494
September
37:39
20
7.3
± 0.3
17 ± 2.2
5.58 ± 0.31
1,952 ± 524
9.3 ± 0.3
2.4 ± 0.12
23.1 ± 1.8
117.9
23.7
34.1
6.178
October
153:64
43
7.3 ± 0.2
19 ± 2.5
5.11 ± 0.22
2,061 ± 318
9.8 ± 0.2
3.6 ± 0.11
24.6 ± 2.6
95.0
18.6
30.3
4.910
November
184:45
47
6.8 ± 0.3
20 ± 3.8
4.80 ± 0.18
1,822 ± 276
9.8 ± 0.3
3.1 ± 0.14
23.3 ± 2.1
–
11.5
27.9
4.594
December
–
–
6.9 ± 0.6
21 ± 4.0
3.30 ± 0.21
1,890 ± 386
9.8 ± 0.6
3.2 ± 0.13
20.6 ± 3.2
–
8.0
17.2
4.752
January 2004 19:39
–
6.9 ± 0.3
21 ± 3.8
3.60 ± 0.23
2,013 ± 427
10.1 ± 0.4 3.1 ± 0.16
20.3 ± 3.1
11.7
7.1
15.6
5.227
February
219:65
–
7.3 ± 0.2
22 ± 3.7
3.70 ± 0.18
1,682 ± 366
10.3 ± 0.5 3.6 ± 0.14
19.6 ± 2.8
–
9.8
23.3
5.544
March
195:55
–
7.3 ± 0.2
23 ± 3.9
4.20 ± 0.13
1,631 ± 402
10.5 ± 0.3 3.8 ± 0.11
22.5 ± 2.2
–
15.7
32.4
6.811
April
–
–
7.6 ± 0.4
26 ± 2.8
–
–
–
–
–
–
21.9
38.0
6.860
*Courtesy: Meteorological Survey of India, Govt. of India
** Median of the number of each species in 3 quadrats of 25 × 10 cm 2
approximatelyWithin parenthesis numerical ratio of L:S each quadrat against a fixed number (6) of Spirodela polyrrhiza
individuals