Essay: Bacillariophyceae as Indictors of Ecological Status in Kabini River, Nanjangud.

Abstract: Bacillariophyceae are widely used for the bioassessment of lakes and river due to their broad distribution and their ability to integrate changes occurring in water composition and quality. The objective of current research is to evaluate the Kabini river ecology using diatoms communities as indicators. Water and diatoms samples were collected from Kabini river, Mysuru (Karnataka). Louis Laclercq IDSE/5 index is derived from the OMINIDIA 5.3 software. In the currents study total 11 species of diatoms are identified. Variations and abundance in the number of species is observed throughout the study period. The number of species and population was high in the month of December and January.
The current study states that Kabini river water is Circumneutral throughout the period of study with high levels of chloride. According to the salinity values the water is considered as fresh/brackish with chloride levels always less than 500mg-1 and the salinity values are less than 0.9. The river water supports nitrogen autotrophic diatoms that tolerate elevated levels of organically bound nitrogen. Oxygen requirements of diatoms quite often vary from season to season. Alpha ‘ meso-saprabous conditions prevails, where the water class becomes III, oxygen saturation reaches 25-85% and BOD levels become 4-13 mg/L. All diatom species occurring in the river are strictly moisture tolerant. Although organic pollution in the river ranges between nonexistent to moderate, the indicator species of organic pollution are Gomphonema Paravalum, Amphora Ovalis, Synedra Acus and Synedra Ulna and the percentage of organic pollution ranges between a minimum of 9.14 during summer and 28.57 during monsoon. Synedra Acus, Synedra Ulna, Amphora Ovalis are the prime indicators of anthropogenic eutrophication. The number of diatom species is high during summer and least during winter; evenness of species with small variations is predominant.
Keywords : Bacillariophyceae, Biomonitoring, Ecological Indicators, pollution.
I. INTRODUCTION
Change in water quality and hydrology are rapid in the fresh water bodies, causing difficulties in the estimating the ecology. Biomonitoring has been proven to be very effective due to its integrative nature [13]. Bioindicators are powerful tools for the monitoring of the water quality, since they exhibit the cumulative effects of the current and past conditions, whereas chemical and physical properties apply only to the moment of the sampling [6]. Phytoplanktons are generally used to study the ecology of the water body [12]. In recent days use of diatoms as a bioindicators has been advanced due to their broad distribution and the variation in species composition that can
be attributed to the ecological parameters of the river [2]. The study of diatoms as the indicator of water ecology has 60 years old history [5]. Diatoms are extensively used to determine the ecology of the water body, since they can occur in all aquatic environments and they are found at almost all the levels of pollution. The wide distribution, high reproduction rate, and sensitivity of the individual species towards organic pollution qualify the diatoms as suitable bio-indicators[14]
Ecological indicators have widespread applications in environmental monitoring. The fluctuation of diatom species to various environmental changes can be an early warning towards freshwater ecological problems. The present paper emphasizes on ecology of Kabini river. The OMNIDA software has been used to derive the ecological values. The design of OMNIDA software for computation of diatom indices has facilitated the use of diatom based biomonitoring[9]. The software has an inbuilt ecological data for 13000 diatom species and is a comprehensive data base, which is used to derive the ecological values. The Louis-Laclercq Diatomic Index of Saprobity- Eutrophication (IDSE/5) 2008 is an advanced pollution index among all the other indices and is mainly based on the occurrence of only diatom species in aquatic ecosystems[11]. Degradation levels, evenness, percentage indicators of organic and anthropogenic pollution and the species indicating organic and anthropogenic pollution are estimated by this index. It also determines the ecological indicator values which in turn help to know the trophic state of an ecosystem based on the prevailing conditions of that ecosystem.[5]&[6].
II. MATERIALS AND METHODS
A. Sited description:
The Kabini (Kapila) is a river of southern India. The Kabini river is an eastern flowing river from the Western Ghats, and is the main river that drains the Wayanad Plateau flowing into the Cauvery system in Karnataka at Tirumakudalu Narasipura. A stretch of Kabini river is selected for the study, near Kembalu water treatment plant (WTP) at Nanjangud, which is depicted in Fig.1. Nanjangud is one of the most important industrial area situated near Mysuru, which is located on the bank of Kabini River. Nanjangud is spread over 1207’12’ N longitude to 760 40′ 48′ E latitude with average elevation of 656 m and having population about 50,598 as per 2011 census.
Fig. 1 : Geographical depiction of intake point of Kembalu water treatment plant and Kabini River.
B. Sampling and analysis
Samples were collected once in 15 days for a period of six months (Dec 2014 to June 2015) from the Kabini river. Collection of samples, preservation, identification and enumeration of diatoms were done by Lackey’s drop method [7] which is been modified by Suxena in 1987. The photographs were obtained under 40*10X magnification under the digital photographic microscope (make/model; ADI LAB TECH/ EU3490). Bacillariophyceae were enumerated as per the methods described by Welch and tabulated as Cells/L.
III. RESULTS AND DISCUSSION
A. Distribution of Diatoms in Kabini river.
In the current study total 11 species of diatoms were identified which are subjected to OMNIDIA GB 5.3 to derive IDSE/5 and ecology indices. Variations and abundance in the number of species is observed throughout the study period, which is shown in Table I. The number of species and population was high in the month of December and January. This may be due to the high level of disturbance due to human activities (Anthropogenic pollution). The dominant species of Kabini river were Navicula sp, Synedra sp, Gomphonema sp, Cymbella sp, Pinnularia sp., Cocconies sp., Pleurosigma sp., Nistzchia sp., Fragilariophyceae and Amphora which are depicted in Fig.2.
B. IDSE/5 and Ecology Indicators.
The Louis-Laclercq IDSE/5 index (2008) derived from the OMNIDIA GB 5.3 software is presented in Table II [11] and Ecological values are given in table IV. The classification of the ecological indicators values of Van Dam et al., (1994) are presented in Table III [15]. The indicator values for diatom taxa have been derived from Hustedt (1938)[3] The salinity classification is according to Vander Werff and Huls (1957-1974) and is based on the concentration of chloride in water [16] The nitrogen uptake metabolism is based on Cholonoky (1968) and Van Dam (1975) where diatoms are capable of assimilating organic nitrogen compounds[17] & [1]. Classification of oxygen requirements is based on Hustedt (1938) which indicate saturation levels of oxygen in water [3]. The Saprobity system combines indicator properties for the presence of biodegradable organic matter and oxygen concentrations. The term meta-eutrophic indicates indifferent species present in both oligotrophic and eutrophic waters [10]. These values mainly indicate the conditions required for the growth and survival of Bacillariophyceae and also determine the trophic state of the water.
Table I: Distribution of diatoms in Kabini river
December
January
February
March
April
June
Sl. no.
Spices
Acronym
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
S12
1
Navicula rhombic
NRHO
28000
56000
56000
84000
84000
112000
84000
140000
112000
56000
56000
56000
2
Synedra ulna
SULN
28000
0
28000
28000
28000
56000
56000
56000
56000
84000
28000
28000
3
Gomphonema paravalum
GPAR
56000
28000
28000
84000
84000
168000
84000
84000
84000
84000
56000
28000
4
Cymbella cymbelliformis
CCYM
56000
56000
84000
56000
84000
84000
84000
84000
56000
28000
28000
28000
5
Pinnularia Gibba
PGIB
0
0
28000
0
28000
28000
0
28000
28000
0
0
0
6
Cocconies placentula
CPLA
0
56000
28000
28000
56000
0
0
0
0
28000
28000
28000
7
Pleurosigma hippocampus
PLEU
0
0
28000
0
56000
28000
0
0
0
28000
28000
28000
8
Nistzsia pelea
NPAL
0
28000
56000
56000
28000
28000
112000
56000
84000
84000
112000
56000
9
Amphora ovalis
AOVA
28000
28000
28000
56000
56000
56000
84000
28000
28000
56000
56000
56000
10
Flagelleria capucina
FCAP
84000
56000
84000
84000
56000
168000
168000
140000
196000
168000
168000
112000
11
Synedra acus
SACU
56000
28000
28000
56000
56000
28000
56000
28000
28000
56000
28000
0
Table II : ISDE/5 and Diversity Indices of Kabini river
Sl.No.
Particulars
Dec
Jan
Feb
Mar
May
Jun
1
No. of species
7
8
11
9
11
10
8
9
9
10
10
9
2
Population
59500
33600
40040
53200
61600
75633
72800
64400
67200
67300
58800
29120
3
Diversity
2.28
2.98
3.26
3.08
3.36
2.99
2.91
2.93
2.87
3.10
2.99
3.04
4
Evenness
0.81
0.97
0.94
0.97
0.97
0.90
0.97
0.92
0.91
0.92
0.90
0.96
5
No. of genera
6
8
10
8
9
9
8
9
9
10
10
9
6
IDSE/5
3.72
3.66
3.44
3.38
3.35
3.55
3.45
3.59
3.56
2.89
3.40
3.20
7
Degradation
Low
Low
Mod
Mod
Mod
Low
Mod
Low
Low
High
Mod
Mod
8
% indication of organic pollution
9.41%
16.67%
20.98%
26.32%
18.189%
25.91%
28.92%
21.74%
25.0%
24.96%
28.5%
19.2%
9
% indicators of anthropogenic eutrophication
18.82%
16.67%
20.98%
26.32%
31.82%
18.51%
26.92%
17.39%
16.67%
29.12%
19.05%
28.85%
10
Organic pollution
Nil
LOW
MOD
MOD
LOW
MOD
MOD
MOD
MOD
MOD
MOD
LOW
11
% of Anthropogenic eutrophication
LOW
LOW
MOD
MOD
MOD
LOW
MOD
LOW
LOW
MOD
LOW
MOD
12
Organic pollution indicators
GPAR,
AOVE,
SACU,
SULN
GPAR,
NPAL
GPAR,
NPAL
GPAR,
NPAL
GPAR,
NPAL
GPAR,
NPAL
GPAR,
NPAL
GPAR,
NPAL
GPAR,
NPAL
GPAR,
NPAL
GPAR,
NPAL
GPAR,
NPAL
13
Anthropogenic pollution indicators
AOVA,
SACU,
SULU
AOVA,
SACU,
SULN
AOVA,
SACU,
SULN
AOVA,
SACU,
SEAP,
SULN
A0VA, SACU,
FCAP,
SULN
AOVA,
SACU,
SULN
AOVA,
SACU,
SULN
AOVA,
SACU,
SULN
AOVA,
SACU,
SULN
AOVA,
SACU,
SULN
AOVA,
SACU,
SULN
AOVA,
SULN
Table III: Classification of Ecological Indicator values (VanDam, Martens and Sinkeldam (1994)
a. pH
species
pH
1
Acidobiontic
Optional occurrence at pH 7
5
Alkalibiontic
Exclusively occurring at pH >7
6
Indifferent
No apparent optimum
b. Salinity
Water Quality
Cl- (mg/L)
Salinity
1
Fresh