ALGAL BIODIVERSITY AND APPLICATION OF
INDICES
IN ASSESSING TWO LAKES OF
MYSORE DISTRICT
Mr. Sudeep. B.M* and Prof. Shankar P. Hosmani,
Department of Studies in Botany , University of Mysore,
Manasagangothri, Mysore - 570006, Karnataka , India .
Two perennial lakes in Mysore district (Hadhinarulake and Shettylake)
were studied for algal biodiversity.
To elucidate the community structure phytoplanktons in each lakes
Soyer’s (1980) Frequency index, Bellan - Santin’s (1969) Quantative
Dominance index, Pielou’s (1975) Evenness index, Shannon Weaver
(1949), Diversity index of Boyd’s index (1981) were calculated.
These indexes showed certain interesting features which have been
discussed .
BOYD’S DIVERSITY INDEX
The diversity index of Boyd indicates the order of pollution in a water body.
The main parameter in the index is the number of genera of phytoplankton in
a water body and is calculated using the mathematical formula.
H=S–1
In N
S is the number of genera of phytoplankton;
N is the total number of phytoplankton and In is the natural logarithm.
If the values obtained are >4 it indicates less pollution and clean water, values of 3 –2 indicate
moderate pollution and values <1 indicate that water is heavily polluted.
FREQUENCY INDEX AND DOMINANCE INDEX: SHANNON – WEAVER AND PIELOU’S
EVENNESS INDEX
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The Frequency index of a particular species was estimated by f= m/M x 100
where m = number of stations where the species were found and
M = number of all stations;
The Dominance index of a particular species was estimated by DI = m/M x 100
Where m = individual number of species in the stations and
M = total individual number of all the species.
Pielou’s (1975) evenness index was estimated by j = H′ / log 2S
Where H′=Shannon and Weaver Index (1949) and S= species number.
n
The Shannon and Weaver (1949) index was estimated by H′ = - ∑log pi. log 2pi
n-1
Where S = total individual number of species and
N = Total individual number of all species and
pi = S/N
Table 1.1: Total Number of Phytoplankton- Shettylake
Sl .No
Apri l
May
June
Jul y
Aug.
S e pt.
O ct.
Nov.
De c
1 Chlorophyceae
2 Cyanophyceae
Parame te r
16800 18200 19600 18200
Jan
Fe b
9800
11200
5600
9800
8400
9800
8400
9800
2800
2800
1400
15400 15400 11200 19600
Nil
5600
Nil
9800
4200
3 Bacillariophycea
Nil
8400
4200
2800
Mar
4200
4200
9800
9800
2800
Nil
8400
1400
1400
2800
4800
4800
4800
2800
1400
Nil
1400
2800
2800
4200
1400
1400
Nil
Nil
34
17
20
10
18
16
15
4 Euglenophyceae
4200
4200
2800
4200
5 Desmidaceae
2800
1400
2800
41
30
29
6 No of genera (S)
7 T ot al number of phyt oplankt on (N)
9800
16
19
43400 42000 40600 47600 23800 28000 14000 25200 23000 21600 23000 26600
Table 1.2: Total Number of Phytoplankton - Hadhinaru Lake
Parame te r
Jan
1 Chlorophyceae
2 Cyanophyceae
9800
1400
1400
1400
3 Bacillariophycea
8400
8400
4 Euglenophyceae
1400
5 Desmidaceae
1400
Nil
1400
2800
6 No of genera (S)
7 T ot al number of phyt oplankt on (N)
Fe b
Mar
Apri l
May
Ju n e
Ju l y
Au g.
S e pt.
O ct.
Nov.
De c
7000
12600
8400
5600
5600
5600
2800
2800
7000
2800
1400
1400
1400
8400
7000
7000
7000
Nil
7000
Nil
4200
Nil
4200
Nil
4200
2800
8400
1400
Nil
2800
Nil
2800
Nil
2800
1400
1400
1400
1400
1400
2800
1400
4200
2800
2800
Nil
2800
11200 14000
5600
16
16
21
15
17
14
18
14
15
13
14
13
22400 22400 28000 21000 23800 19600 18200 15400 15400 11200 11200 18200
AS PER THE DIVERSITY INDEX OF BOYD
Shetty lake is moderately polluted from January-June (2006) with the index reaching
1during July and becoming heavily polluted, however from August to December it
again becomes moderately polluted (Table 2.1).
On an average the lake according to Boyd index is moderately polluted.
On the other hand Haninaru lake which is protected from major disturbances is always
moderately polluted (Table 2.2).
The Diversity index of Boyd (1981) indicates that both lakes are moderately polluted.
Shetty lake sometimes tends to become heavily polluted.
Table 2.1: Diversity Index of Boyd (1981) for Shetty lake
Sample Month’s
No of
Total number of In N Diversity inde x
Numbe r
genera (S) phytoplankton
(H) = S-1/n N
(N)
1
January
41
43400
10.74
3.99
O rder of pollution
Moderately polluted
2
February
30
42000
10. 64
2.72
Moderately polluted
3
March
29
40600
10. 61
2.63
Moderately polluted
4
April
34
47600
10. 77
3.06
Moderately polluted
5
May
17
23800
10. 07
1.58
Moderately polluted
6
June
20
23800
10. 07
1.88
Moderately polluted
7
July
10
14000
9. 54
0.94
Heavily polluted
8
August
18
25200
10.13
1.67
Moderately polluted
9
September
16
23000
10. 04
1.49
Moderately polluted
10
October
15
21600
9. 98
1.4
Moderately polluted
11
November
16
23000
10. 04
1.49
Moderately polluted
12
December
19
26600
10.19
1.76
Moderately polluted
4 = Clean water, 3-2 = moderately polluted, < 1 = heavily polluted
Table 2.2: Diversity Index of Boyd (1981) for Hadhinaru lake
Sample Month’s
Number
Total
No of
gener number of
a (S) phytoplan
kton (N)
In N
Diversit
y index
(H) =
S-1/In N
Order of pollution
1
January
16
22400
10.01
1.5
Moderately polluted
2
February
16
22400
10.01
1.5
Moderately polluted
3
March
21
28000
10.23
1.95
Moderately polluted
4
April
15
21000
9.95
1.4
Moderately polluted
5
May
17
23800
10.07
1.58
Moderately polluted
6
June
14
19600
9.88
1.31
Moderately polluted
7
July
18
18200
9.8
1.73
Moderately polluted
8
August
14
15400
9.64
1.34
Moderately polluted
9
September
15
15400
9.64
1.45
Moderately polluted
10
October
13
11200
9.32
1.28
Moderately polluted
11
November
14
11200
9.32
1.28
Moderately polluted
12
December
13
18200
9.8
1.22
Moderately polluted
4 = Clean water, 3-2 = moderately polluted, < 1 = heavily polluted
AS PER SOYER FREQUENCY INDEX
A total of 91 species were recorded in Shetty lake
As a result of the study carried out during 12 months in Shetty lake a total of 661 individuals were
recorded.
The highest numbers of species were observed during February (46), April (45) and January (42).
From the months of July to August the number of species ranged between 29 during December
and 20 during November.
The highest frequency index of Soyer recorded was for Synedra ulna, (91%), Euglenophysis vorax
(83%), Scenedesmus tricauda (83), Scenedesmus biflagelum, Clostorium validium, Cosmarium
tumidum, Cyclotella meheghinimna, Eunotia monodn, Scenedesmus quadricauda var. longispina,
Scenedesmus protrubesans, Cosmarium humicola with 75 % each. The third set of frequency
index with 66% were those of Chlorella vulgaris, Cymbella turgida, Gomphonema gracile,
Microsystis robosta, Phacus sp, Scenedesmus acutus, Spirogyra sp and Tetraedron duospinum.
This indicates that members of the Chlorococcales were more dominant and Cyanophyceae were
least.
In Hadhinaru lake total of 63 species were recorded.
As a result of the study carried out during 12 months 1298 individuals were recorded during the
12 months of study.
The highest number of species recoded were during the months of March (38) and May (36) and
during the rest of the months they varied between 32sp to a minimum of 17sp during October.
The highest Soyer’s Index of frequency was recorded for Achanthes inflata (91%), Cateria sp,
Closterium Cambrium, Desmidium (100%), Gomphonema subapiculatum. The next frequently
recorded organisms were Cymbella bharathenesis (83%) and those between 75% and 66%
included Amphora ovalis, Arthrodesmus, Coelastrus chodati, Cyclotella meheghimiana, Diatoma
laifor, Docidium sp and Synedre ulna.
This indicates that the members of the Bacillariophyceae are more abundant and
Cyanophyceae and Euglenophyceae were not prominent in this lake.
AS PER SHANNON AND WEAVER DIVERSITY INDEX AND PIELOUS INDEX
The Diversity and Evenness index (Table 3.1 &3.2 )are plotted and shown in the Figure 1.1 & 1.2.
The Diversity index is high (0.04) only during January but reduces to 0.1 during February and
remains between 0.1 and 0.2 upto December.
Similarly Pielous Evenness is high during January and reduces during the rest of the months.
Except for the months of January the Diversity and Eveness (Table 3.1) in Shettylake go hand in
hand (Fig 1.1)
Therefore the frequency occurrence of phytoplankton in Shettylake is high for members of
Chlorococcales and Diatoms.
The diversity and evenness is high during January indicating that the lake is less polluted during
this month and the pollution level fluctuates during the rest of the months.
Since, according to Shannon and Weaver greater the diversity, lesser is the pollution level.
The Diversity index gradually rises from 0. 5 to nearly 1.5 during May. Also the Diversity index
rises during August and October and reducing to a very low value during December.
This is an indication that the lake experiences growth of diverse organisms during the summer
months.
The lake is retaining its oligotrophic nature but however during other months it is turning
oligotrophic.
Table 3.1: - Calculated values of Shannon and Weaver’s Index - Shetty lake and Hadhinaru lake
Parameter
Jan
Feb
Mar
April
May
June
July
Aug.
Sept.
O ct.
Nov.
Dec
Shettylake
0.379
0.061
0.12
0.095
0.126
0.12
0.145
0.095
0.106
0.077
0.108
0.092
Hadhinarulake
0.491
0.504
0.91
0.973
1.358
0.96
0.848
1.097
0.667
0.887
0.558
0.328
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
0.12
0.1
0.08
0.06
0.04
0.02
0
jan
feb
mar
apr
may
jun
jul
M ONTHS
auj
sep
oct
divers ity
evennes s
nov
dec
EVENNESS
DIVERSITY
FIG 1.1: SHETTY LAKE - DIVERSITY AND EVENNESS INDEX
The Evenness index does not vary much. The Diversity index and Evenness index do not go hand
in hand (Fig1.2).
The comparison of the diversity indices in both lakes leads us to the fact that the members of
Chlorococcales are dominant and the Diversity and Species Eveness go hand in hand.
This means that diversity is low in this lake, which is a sign of more pollution.
Hadhinaru lake has more Diversity index and the Evenness index also differs and this lake is
dominated by more numbers of Bacillariophyceae.
Table 3.2: - Calculated values of Pieolu’s Evenness Index (1975) – Shetty lake and Hadhinaru lake
Parameter
S hettylake
Hadhinarulake
Jan
Feb
Mar April
May
June
July Aug.
S ept.
Oct.
Nov.
Dec
0.101 0.016
0.03
0.025 0.035
0.03
0.04
0.03
0.033 0.025 0.036 0.027
0.144 0.146
0.25
0.286 0.379
0.28
0.27 0.382
0.21
0.31
0.19 0.101
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0.5
0.4
0.3
0.2
0.1
0
jan
feb
mar
apr
may
jun
jul
M ONTHS
auj
sep
oct
divers ity
evennes s
nov
dec
E
V
E
N
N
E
S
S
D
IV
E
R
S
ITY
FIG 1.2 HADHINARU LAKE - DIVERSIT Y AND EVENNESS INDEX
CONCLUSION
The Boyd’s index (1981) indicates that Shetty lake and Hadhinaru lake
ranges from moderate to heavily polluted;
The Shannon and Weaver (1949) Diversity Index is an important aspect
indicating the distribution of phytoplankton and their relation to pollution.
Soyer’s Frequency Index and Pieolu’s Eveness Index, clearly signify the
distribution of plankton all through the year and the relation between the
frequency of species and their Eveness in distribution in the two lakes.