Fresh water diatom (Bacillariophyceae) diversity in the Willingdan lake Cuddalore district of Tamil Nadu in India
Aranganathan, K Sivakumar
Department of Botany, Division of algal biotechnology, Annamalai University, Annamalai Naga, Tamil Nadu, India
The diversity of diatoms in the river has been investigated for a period of one years ( ) collection of algal samples from willingdon lake surface water and algal samples were collected in velar river The present paper deals with 18 taxa of freshwater diatoms collected from Willingdon lake cuddalore district of Tamil Nadu (Lat. 11̊ 25' 32.91" N and Long. 79̊ 6' 12. 89" E) light microscope analysis Actinocyclus normanii, Tabellaria flocculosa, Synedra famelica, Navicula schroeteri var. Escambia, Synedra acus, Synedra ulna, Navicula pupula, Navicula nunivakiana, Navicula radiosa, Navicula reinhardtii, Frustulia vulgaris, Pinnularia joculata, Pinnularia brevicostata, Encyonema hustedtii Nitzschia palea, Caloneis bacillum, Stauroneis anceps, Diatoma vulgare. And Scanning electron microscopic (SEM) Studies Discostella asterocostata, Discostella stelligera, Surirella robusta, Navicula symmetrica, Gomphonema biceps, Discostella stelligera, Cyclotella meneghiniana, all the taxa were recorded for the first time from this lake
Keywords: bacillariophyceae, freshwater, Willigdon Lake, light microscope, scanning electron microscopic
The bacillariophyceae are unicellular algae characterized by having a cell wall of silica. The wall consists of two vales that have more or less flat surfaces, held together by a band or girdle. The are found in freshwater and marine habitats, and also on moits soil surface. They are only few published recoreds on the systematic account of freshwater diatom flora of the Indian sub-continent.
Taxonomy of Indian Fresh-water diatoms from a literature survey on freshwater diatoms it is seen that algal studies are put to a number of different purposes like taxonomy, diversity, pollution etc., Purely taxonomic works with proper descriptions and taxonomic positions are limited. Many deal with lists of diatoms from a particular region. Various indices like the Margalef index, Nygaard's trophic status index, Shannon species diversity inden, Pilelou's evenness index, Species richness, Palmer's pollution tolerant index etc., have been used by different workers. Studies pertaining to the freshwater diatom flora of different parts of India are not regular. Ehrenberg (1851, 54) was the first to give the floristic account of diatoms some parts of India and Nicobar Islands. West & West (1902, 1907) described for the first time 59 freshwater diatoms from the Punjab & Kashmir regions well as from Bengal and Madras. Carter (1926) added 49 species. Abdul Majeed (1935) gave an account of 62 diatoms from the undivided Punjab. Skvortzow (1935) listed the diatoms from Calcutta, Chennai region (Composite Madras state):- Venkatraman (1939)  gave the first systematic account of diatoms in his paper "A systematic account of some south Indian diatoms". He had described in all 98 taza in 32 genera with 6 new varieties and 6 new forms collected from Madras (Chennai), OOty, Kodaikanal Hills, Vandalur in Chingleput district. Krishnamurthy (1954) recorded 58 species of which 2 species, 4 varieties and 4 forms were new reports. His work did not contain those already published by Venkatraman. Suzena studied the Kodaikanal diatoms besides other algae and reported 46 forms in “Bibliotheca Phycologica" (1983). Gajarat-Rajasthan-Bombay, Mysore (Karnataka) regions: Gonzalves and Gandhi (1952, 53, 454) listed the diatoms from Bombay and Saisette Islands. H.P. Gandhi (1955-1998) had published papers on the freshwater diatom flora of different parts of South India like Sagar, Jog Falls, Hirebhaskar Dam Area, Kolhapur in Karnataka state, Vasna Village near Ahmedabad Baroda -Ahmedabad regions of Gujarat. He had written a book on “Fresh water diatoms of Central Gujarat with a review and some others"(1998). He had reported the occurrence of diatoms from Bombay and Salsette islands and was the first to study the freshwater diatoms from Rajasthan. He had recorded many new forms and species from all these places. His publications are full of neatly hand-drawn diagrams with scale. Rashmi Pareek et al., (2011) investigated freshwater diatoms from Galta Kund in Jaipur and reported the occurrence of 24 taxa of diatoms. These diatoms appear to be commonly present in many of the freshwater collections from South India as well. Uttar Pradesh region: - Singh (1961-1963) studied the diatom flora from 3 ponds situated at Banarus Hindu University campus and another permanent pond at Deoria district of Uttar Pradesh as well as from the rivers Ganges & Barna at Varanasi, Uttar Pradesh. Pratap Singh et al., (1978)  have worked on the Freshwater diatom flora of Kankawati river in Gujarat. They have recorded 8 genera and 9 species. Vidharba region: - From Vidharba, Sarode and Kamat recorded 119 species of diatoms. (1983) Andhra-Pradesh region: -Venkateswarlu (2006) gave a special lecture on algae of aquatic environments. He has described and classified the freshwaters into two basic types flowing (lentic) and nonflowing (lotic). Benthic attached forms of diatoms predominate in lentic waters and planktonic floating diatoms and other unicellular forms of algae in from the Moosi River lotic waters. Venkateswarlu recorded Hyderabad 78 species of diatoms (1983). At Pakistan: - Syed Tariq-Ali et al., (2006) made a taxonomic study of 10 Cymbella species from Punjab and Azad Kashmir. Syed Tariq-Ali et al., (2006) identified 9 species of Nitszchia from Kasur and Lahore districts of Pakistan. Orissa region: - Jena et al., (2006)  reported the freshwater diatom flora from Orissa state and neighbouring regions. They reported the presence of 78 diatom taxa belonging to 26 genera. Of these nearly 22 taxa of diatoms are new reports. Jena et al., (2008) studied the Algal diversity in Rushikullya River, Orissa. They reported on the occurrence of 42 taxa, 29 genera of algae; 10genera and 11 species of diatoms reported. Diadesmis confervacea Kutzing. Is a new name. Maharashtra region:- Dhande &Gunale (2008): studied two genera namely Fragilaria and Synedra from Artak Lake, Majharashtra. Sudhir et al., (2009) reported 58 taxa of freshwater diatoms in 17 genera without figures and descriptions from Aurangabad in Maharashtra. More recently, Andhale, S.B,, S.S. Harane and G.B. Kohle (2012) reported the presence of freshwater diatoms from Jayakwadi Bird Sanctuary of the Godhavari river at Pathan, Maharashtra. Common genera such as Gomphonema, Fragilaria, Synedra, Achnanthes, Stauroneis, Neidium, Mastogloia, Licmophora, Nitszchia and Surirella are reported by them. Thisparticular reference shows diagrams and descriptions of species. Himalayan Region: - P.K. Mishra, et al., (2009): Reported on the freshwater diatoms from Terai mountains and Himalaya regions of Eastern Nepal. They recorded about 36 taxa of diatoms in 9 genera with 20 new reports’. Subha et al., (2009) reported on some freshwater diatoms from the Trans-Himalaya region at Mustang numbering 19 taxa with beautiful colour photographs but without description. Central high land region: - Jyoti Verma and Praksh Nautiyal (2010)  have studied the floristic composition of the epilithic diatoms belonging to Thallassiosiraceae, Fragilariaceae, Eunotiaceae and Achnanthaceae. of Central Highland region: They have recorded a total of 293 species, varieties and forms of which only 3 species are from the centric. A total of 47 genera and 290 species belong to the Pennate groups. They were concerned more with percentage composition of each group. No descriptions of species were given. Calcutta region: - Bhattacharya et al., (2011): Reported on the Freshwater diatoms from Kolkata with special reference to their taxonomy. A total of 15 genera and 61speices were recorded by them. There is a new report of Amphiprora sp., in freshwater. Tamilnadu region: - Sridharan (former Head, Dept. of Botany, National College, Trichy) has been working on the freshwater algae of different parts of South India (1986-2012) Karthick & al. (2009, 2010, 2013), like Trichy City -Karumandapam, Pirattiyur, surrounding areas of Bharathidasan University (Suriyur Campus); Pudukkottai district. Pudukkottai City, Keeranur, Narthamalai, Kudumiyanmalai; Karaikudi, Kundrakudi, Pillaiyarpatti and surroundings; Dharmapuri district -Kaveri Falls at Hogenakkal; Pollachi District- Parambikulam areas; Namakkal district- Kolli Hills; Dindugal District- Udumalpet, Thirumoorthy Hills, Perambalur District -Ariyalur, Nakkambadi village etc., He has studied several new reports for the different collection localities. Similarly, there are many reports of freshwater algae and diatoms from different parts of India published all these years. Several papers are without figures or photographs of diatoms as well as without descriptions of species. Hence it is difficult to consider them as purely taxonomic.
Materials and Methods
Description of study area Willingdon Lake
willingdon Lake is a lake situated in the keelachiruvoi village tittakudi taluk of the cuddalore district in the india state of tamilnadu.it is the second-largest lake in tamilnadu after the Willingdon lake, which also is situated in the cuddalore district. The Willingdon Lake also has about 27 arcillary lakes and together They from the primary source of irrgaton for nearly 25,000 actes (10,000) hectares of land and over 67 village depondent on it for cultivation.
Fig 1: flow chart of Analysis
Sample collection from the study area
Fig 2: Map showing the sampling station of the Willingdon lake Cuddalore district (Tamil Nadu).
Surface water samples were collected from Willingdon Lake in the second week of every month during October 2018 to September 2019. A liter of water sample was collected every month separately for the qualitative and quantitative estimation of phytoplankton and studies of physical and chemical properties were also made.
Sample preparation for light microscopic studies of phytoplankton
This was prepared by dissolving 10 gm of iodine and 20 gm of potassium iodine in 200 mL of water. To this was added 20 mL of glacial acetic acid. Lugol’s iodine solution prepared in this method was stored in a darkened bottle; it was mixed with plankton samples to yield a final concentration of 1% to preserve the sample better. Lugol’s iodine fixed samples were mixed with equal amount of formalin glycerine preservative.
Formalin-acetic acid-Alcohol mixtures: Rawlin’s formula (F.A.A.)
Ethyl alcohol 95%: 50 mL
Glacial acetic acid: 5 mL
Formalin: 10 mL
Water: 35 mL
Recommended for algal materials for histological studies.
5-15 ml each sample containing freshwater diatoms was taken in a centrifuge tube, concentrated and given distilled water wash twice by centrifuging and decanting the supernatant solutions in a laboratory centrifuge at 1500 rpm. To the pellet in the centrifuge tube, 5-10 ml of 100 volumes of hydrogen peroxide solution was added and kept in a hot-air oven set at 60° C for 4-8 hours. The material is allowed to cool to room temperature and washed with distilled water by a similar method 5-6 times to remove every trace of hydrogen peroxide. Now the sample is said ti be cleaned or free from organic matter leaving only the silica-shell of diatom frustules that only are useful in diatom identification. Finally, the cleaned sample were stored in 70% alcohol in suitable airtight containers.
Freshwater algae studies
Freshwater microalgae samples were collected towing a plankton net (mouth diameter 0.35 M) made up of bolting silk (No. 30 mesh size 48 m) for half an hour. The samples were in black polythene bags and immediately preserved with 4% formalin for quantitative analysis. Photomicrographs were taken selectively from computer screen fresh water algae was identified by referring to the standard keys of Desikachary (1959), Prescott (1964), Bongale and Bharathi (1980), Gonzalves (1981), Cox (1996), Anand (1998)  and Siva kumar and Senthil kumar (2008).
Scanning electron microscope with Energy Dispersive Spectroscopic analysis (EDS)
Phytoplankton samples were fixed in 3% glutaraldehyde in 0.1 M phosphate buffer at pH 6.8. Specimens were dehydrated through a graded series of alcohol at 12-15 minutes interval at 4°C up to 70% of alcohol. Then dehydrated phytoplankton sample was treated with critical point drier (CPD) and fixed on a stub and the specimens were coated to examine in Joel JSM-56010 LV (INSA-EDS). Electron micrographs was taken selectively from the computer screen. Simultaneously selected portions of micrograph was subjected to Energy Dispersive Spectroscopic analysis (EDS). This was conducted with an EDS 700 series interfaced with a data general NOVA2 computer and a Texas instrument silent 700 ASR. The EDS X-ray spectrometer was interfaced with a scanning electron microscope (20 kV) stage. The area of different components such as cell wall and cellular inclusion was analysed. To find out the fluxes of particular mineral, both the counts per second (S-1 or CPS) value and the apparent relative atomic percentage of weight in different components of the cell wall and cellular inclusion details were documented.
Results and Discussion
Centric in outline with a relatively shallow mantle. Diameter 68 m, marginal tubules visible, hexagonal aeriolae are equally spaced in rows of variable length.
Valves are linear with inflation in the center of the valve and capitate to slightly capitate apices. The medial inflation of the valve is wider than the apices. Striae are usually parallel but can be slightly radiate in the medial inflation. The st riae are alternate. The axial area is narrow and linear. The central area is small and rhombic. Short marginal spines are present.
Valves are narrow and linear, not swollen in the middle, with gradually tapered and rounded apices; ranges from 18-65µm in length and 2.4-3.1 µm in width. Axial area is straight and very narrow. Central area is ovoid, often offset to one side of the valve and with ghost striae. Short striae are typically found at one or both sides of the central area; 18-20 in 10 µm. Striae are parallel throughout.
Valves are linear-elliptical with rounded apices, length 28.1-48.6 m, width 6.3-9.1 m with 12-13 striae per 10 m. Axial area is narrow, linear and distinct; a distinct central nodule is present. The central area is asymmetrically rounded, wider on the secondary side of the valve, the raphe is filiform with enlarged proximal raphe ends deflected towards the primary side of the valve, and distal fissures are distinctly hooked towards the primary side extending from the valve face onto the mantle. Striae are radiate.
Valves are narrow and linear ranges from 90-130 µm in length and 3-5µm in width; narrowly lanceolate in outline, with a central area that is longer than broad;valves tapering to rounded or sub-capitate apices. Distinct rectangular central area, reaching to the valve margin, a little longer than broad.
Cells robust; linear or sometimes linear-lanceolate valves narrowing toblunt sub-rostrate or rostrate apices; ranges from 12–250 µm in length and 5-6µm in length.Central area is distinct, roughly square in outline and usually reaching the valve margin, striae visible within the central area.
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