Cyclotella, Hyalodiscus, and Aulacoseira and declining abundance of Diatoma
(Pandey et al. 2015b). Species such as Achnanthidium, Amphipleura, Asterionella,
Craticula, and Cyclotella were found to be more abundant at highly polluted
downstream sites; and nutrients and DOC were found to be the major regulator of
abundance variabilities. At high N/P and Si/P stoichiometric ratios, species such as
Hyalodiscus, Navicula, Nitzschia, etc. have been found in abundance (Pandey et al.
2015b).
Further, the abundance of Aulacoseira has been shown to correlate with high P
loading (Walsh and Wepener 2009), while that of Synedra and Cocconeis has been
linked with P-limiting condition (Walsh and Wepener 2009). The species such as
Pinnularia and Diatoma are able to tolerate mesotrophic to eutrophic conditions
(Muscio 2002; Walsh and Wepener 2009), and Gomphonema can tolerate eutrophic
to hypereutrophic condition (Walsh and Wepener 2009). Ponader and Potapova
a
l
p
C
n
e
m
C
f
f
a
C
i
x
e
E
n
l
u
S
d
e
p
C
l
u
v
D
l
a
h
C
Fint
a
r
g
A
n
i
m
A
Sele
r
a
p
G
u
c
a
G
l
a
p
N
i
x
e
A
p
m
a
N
r
o
f
A
Nlan
Nsim
Mvar
Ealp
Pvir
0
2
4
6
8
10
12
14
16
18
Dvul
Mvar
Fint
Gpar
Agra
Nsim
Caff
Suln
Cmen
Namp
Nlan
Aexi
Cpla
Npal
Eexi
Cped
Gacu
Amin
Pvir
Chal
Afor
Sele
Ealp
0
2
4
6
8
10
12
14
16
18
Species sequence
t
n
i
F
l
u
v
D
r
a
p
G
r
a
v
M
a
r
g
A
a
l
p
C
n
l
u
S
Nsim
n
i
m
A
i
x
e
E
f
f
a
C
p
m
a
N
n
e
m
C
Nlan
i
x
e
A
u
c
a
G
d
e
p
C
Sele
Pvir
l
a
h
C
Ealp
Afor
Npal
0
2
4
6
8
10
12
14
Species sequence
Npal
Pvir
Nsim
Nlan
Namp
Suln
Aexi
Afor
Amin
Chal
Caff
Cmen
Cped
Dvul
Gacu
Gpar
Mvar
Sele
Cpla
Eexi
Agra
Ealp
Fint
0
2
4
6
8
10
12
I
II
III
IV
Importance value
Importance value
Importance value
Importance value
Fig. 10.1 Dominance-diversity curve of benthic diatoms at four study sites (I, Yamuna; II, Assi;
III, Varuna; and IV, Gomti confluences with the Ganga River). (*Reprinted from Pandey et al.
2017, with permission from Current Science)
230
D. Jaiswal et al.
(Pandey et al. 2015b). Species such as Achnanthidium, Amphipleura, Asterionella,
Craticula, and Cyclotella were found to be more abundant at highly polluted
downstream sites; and nutrients and DOC were found to be the major regulator of
abundance variabilities. At high N/P and Si/P stoichiometric ratios, species such as
Hyalodiscus, Navicula, Nitzschia, etc. have been found in abundance (Pandey et al.
2015b).
Further, the abundance of Aulacoseira has been shown to correlate with high P
loading (Walsh and Wepener 2009), while that of Synedra and Cocconeis has been
linked with P-limiting condition (Walsh and Wepener 2009). The species such as
Pinnularia and Diatoma are able to tolerate mesotrophic to eutrophic conditions
(Muscio 2002; Walsh and Wepener 2009), and Gomphonema can tolerate eutrophic
to hypereutrophic condition (Walsh and Wepener 2009). Ponader and Potapova
a
l
p
C
n
e
m
C
f
f
a
C
i
x
e
E
n
l
u
S
d
e
p
C
l
u
v
D
l
a
h
C
Fint
a
r
g
A
n
i
m
A
Sele
r
a
p
G
u
c
a
G
l
a
p
N
i
x
e
A
p
m
a
N
r
o
f
A
Nlan
Nsim
Mvar
Ealp
Pvir
0
2
4
6
8
10
12
14
16
18
Dvul
Mvar
Fint
Gpar
Agra
Nsim
Caff
Suln
Cmen
Namp
Nlan
Aexi
Cpla
Npal
Eexi
Cped
Gacu
Amin
Pvir
Chal
Afor
Sele
Ealp
0
2
4
6
8
10
12
14
16
18
Species sequence
t
n
i
F
l
u
v
D
r
a
p
G
r
a
v
M
a
r
g
A
a
l
p
C
n
l
u
S
Nsim
n
i
m
A
i
x
e
E
f
f
a
C
p
m
a
N
n
e
m
C
Nlan
i
x
e
A
u
c
a
G
d
e
p
C
Sele
Pvir
l
a
h
C
Ealp
Afor
Npal
0
2
4
6
8
10
12
14
Species sequence
Npal
Pvir
Nsim
Nlan
Namp
Suln
Aexi
Afor
Amin
Chal
Caff
Cmen
Cped
Dvul
Gacu
Gpar
Mvar
Sele
Cpla
Eexi
Agra
Ealp
Fint
0
2
4
6
8
10
12
I
II
III
IV
Importance value
Importance value
Importance value
Importance value
Fig. 10.1 Dominance-diversity curve of benthic diatoms at four study sites (I, Yamuna; II, Assi;
III, Varuna; and IV, Gomti confluences with the Ganga River). (*Reprinted from Pandey et al.
2017, with permission from Current Science)
230
D. Jaiswal et al.