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1 Available online at International Journal of Research in Environmental Science and Technology Universal Research Publications. All rights reserved Original Article CYANOBACTERIAL DIVERSITY AND RELATED PHYSICO-CHEMICAL PARAMETERS IN PADDY FIELDS OF CUDDALORE DISTRICT, TAMILNADU K.Thamizh Selvi and K.Sivakumar Department of Botany, Annamalai University, Annamalainagar Tamilnadu Abstract Received 09 June 2011; accepted 22 June 2011 Cyanobacterium is an extremely diverse group of prokaryotic organism with valuable contribution to soil fertility by fixing atmospheric nitrogen and play very important role in all type of water bodies and soils whether they being heterocystous or non-heterocystous form. In the present study, the blue green algal samples were collected from paddy fields of Keerapalayam and Vallampadugai area investigated for their distribution. Totally 35 species were identified in which 14 species were heterocystous form belonging to genera Anabaena (9), Cylnidrospermum(1), Calothrix (2), Nostoc (2), and 21 species were non-heterocystous form belonging to genera Arthrospira(1), Gloeocapsa(1), Gloethece (2,)Lyngbya (2), Merismopedia (1), Oscillatoria (9), Phormidium (2), Spirulina( 3). The maximum numbers of blue green algae were found to be nonheterocystous forms. Heterocystous filamentous forms showed limited distribution and diversity. In the present study, physicochemical parameters such as Temperature, ph, salinity, dissolved oxygen and total dissolved solids were observed in Keerapalayam and Vallampadugai paddy fields in Cuddalore District of Tamilnadu Universal Research Publications. All rights reserved Keywords: Cyanobacterial diversity, physico-chemical parameters, Paddy fields Introduction Cyanobacteria are present abundantly in paddy fields and are important in maintaining rice fields fertility through nitrogen fixation. Soils of many rice fields contain a high density of cyanobacteria, and over 50% are heterocystous filamentous forms. Cyanobacteria or blue-green algae are group of ubiquitous photosynthetic prokaryotes possessing the ability to synthesize chlorophyll a and carry out an important role in nutrient recycling and the maintenance of organic matter in aquatic systems. The utilization of blue green algae in the rice fields has a great significance in increasing the rice field s fertility. Several reports are found on edaphic algae of rice fields of different states of India (Kolte and Goyal, 1986; Anand et al., 1995; Sing et al., 1997; Sahu et al., 1997; Amita Devi et al., 1999). The paddy field ecosystem consists of diverse habitats for microorganisms. These habitats are microenvironments physicochemically different to each other and could exhibit biologically distinct properties. Such heterogeneity of the habitats should influence the structure and diversity of microbial communities in the paddy field ecosystem as a whole and may support various microbiological processes occurring in paddy fields, most of which are agronomically and biogeochemically important (Kimura, 2000; Kirk, 2004).Though rice is cultivated in the Cuddalore District of Tamilnadu, no concerned attempt has so far been made to record the occurrence and distribution of blue green algae in paddy fields. However, the component of blue green algae in the paddy fields of Cuddalore District is not known. Therefore a systematic study on the distributional pattern of blue green algae and physico-chemical parameters in the paddy fields was undertaken to prepare a detailed account of cyanobacteria of the paddy fields in Cuddalore District of Tamilnadu. 7

2 Materials and methods Study Area N N N N W E Enlarged view of selected station S 8

3 Keerapalayam (Station I) which is located 5 Km from Chidambaram towards West (11 24 N Latitude and E Longitude) and Vallampadugai (Station II) is located 4 Km from Chidambaram towards East (11 24 N Latitude and E Longitude. The paddy fields soil samples were collected from Keerapalayam and Vallampadugai during January, 2010 to December, 2010 in the Cuddalore District of Tamilnadu. Collection and preservation of blue green algal samples Blue green algal samples were collected from paddy fields of both areas. Samples were collected by removing the surface debris from randomly selected spots and scrapping about 20 gm soil from 1 cm soil layer in 1 hectare area samples were collected in 100 ml pet bottles. The collected samples were preserved in 4% formaldehyde and Lugol s iodine solution. Cyanobacteria were observed by using a compound microscope. Blue green algal identification was done using the keys given by Desikachary (1959), Raju (1972), Anand (1989) and Biswal and Das (2004).The relative abundance studies of blue green algae of different genera was calculated by the following formula. Relative abundance = (X/Y) 100 Where X = number of individual cyanobacterial isolates and Y = total number of cyanobacterial isolates Analysis of Physico-chemical parameters The soil and water samples were collected from paddy field of both areas from January, 2010 to December, 2010 for estimation of physicochemical studies. The samples were taken in 100 ml pet bottle. The physico-chemical analysis of the samples was carried out by the method of APHA (1995) and Trivedy and Goel (1986). The statistical data were analyzed by ANOVA (DMRT). Results The distribution of cyanobacteria are shown in Table 1and 2 and its relative abundance are shown in Fig.1 and 2. Totally 35 species belonging to 12 genera of cyanobacteria were recorded in two study area in which 4 genera were heterocystous form and 8 genera were non-heterocystous form. Among 14 isolates Anabaena (9, 64.28%), Cylindrospermum(1,7.14%), Calothrix (2,14.28), and Nostoc (2,14.28) and also recorded 21 species were nonheterocystous form belonging to genera Arthrospira(1,4.76%), Gloeocapsa (1,4.76),Gloeothece (2,9.52), Lyngbya (2,9.52%), Merismopedia(1,4.76%) Oscillatoria (9, 42.85%) Phormidium (2, 9.52%), and Spirulina (3, 14.28%). Among four species of the cyanobacteria viz., Anabaena sp., Cylindrospermum musicola, Calothrix castellii and Nostoc sp., Anabaena and Nostoc were dominant and among 8 species of nonheterocystous form of cyanobacteria, Arthrospira jenneri, Gloeocapsa sp. Lyngbya sp., Merismopedia punctata, Oscillatoria sp., Phormidium sp.and Spirulina sp., Among which Oscillatoria and Spirulina were dominant. Fig.1. Cyanobacterial diversity (Heterocystous form) and its abundance in two paddy fields of cuddalore District, Tamilnadu The physico-chemical parameters were shown in Table 1 and 2. The physico-chemical analysis of water revealed that the temperature ranged from 22 o C to 35 o C in paddy field of Keerapalayam and Vallampadugai. The maximum soil temperature (35 o C) was observed during may, 2010 and minimum temperature (24 o C) was observed during Navember, The maximum water temperature (33 o C) was observed during may, 2010 and minimum temperature (24 o C) was observed during May and Navember, ph ranged from 7.8 to 8.4 was observed in Keerapalayam paddy field. The maximum ph (8.4) was observed during may, 2010 and minimum ph (7.8) was observed in January and November, ph ranged from 7.3 to 8.3 was observed in Vallampadugai paddy field. The maximum ph (8.3) was observed during July, 2010 and minimum ph (7.3) was observed in January, 2010 (Table 3and 4). The salinity was higher in March (1.9%) in both areas. The Dissolved oxygen ranged from 7.8 to 8.2 in Keerapalayam area and 7.47 to 8.27 in Vallampadugai area. The total dissolved solids ranged from 2.1 to 3.9 mg/l. Fig.2.Cyanobacterial diversity (Non-Heterocystous form) and its abundance in two paddy fields of cuddalore District, Tamilnadu 9

4 Tablei1.iCyanobacterial diversity (heterocystous form) in paddy fields of Keerapalayam (Station I) and Vallampadugai (Station II) S.NO Name of the Isolates Station I Station II 1 Anabaena constricta (Szafer Geitler) Anabaena dolibum (Bharadwaja) Anabaena macrospora(klebahn) Anabaena oryzae (Fritsch) Anabaena sp Anabaena volzii (Lemm) Anabaena laxa (Rabehn.) Anabaena ballygunglii (Benerji) Anabaena sp Cylindrospermum musicola(kuetz) Calothrix contarenii (Zanard) Calothrix fusca (Kutz) Nostoc coeruleunum Var.Plactonicum Nostoc calcicola( Breb) - + Discussion A total number of 35 blue green algae belonging to 12 genera were identified from the two paddy fields of Cuddalore District of Tamilnadu. The members observed were unicellular, colonial, filamentous hetrocystous and non heterocystous forms. Among the species, heterocystous forms showed clear dominance over non-heterocystous forms. The genus Nostoc showed wide distribution with 2 species and Anabaena 9 species. In non-heterocystous forms, Oscillatoria showed more distribution with 9 species The cyanobacterial distribution results are shown in Table 1and 2. Totally 35 species belonging to 12 genera of cyanobacteria were recorded in which 4 genera were heterocystous form and 8 genera were non-heterocystous form. 12 species of the cyanobacteria viz., Anabaena sp., and Osillotoria sp. were dominant in both paddy fields. The abundance and the distribution of the heterocystous forms might be indicating the lower nitrogen status in both the rice fields. Presence of these heterocystous cyanobacteria in the paddy fields might be contributing to certain extent towards the nitrogen budget. Moreover, they are able to colonize almost all biotopes with their inherent adaptation capacity in response to environmental conditions (Sinha and Hader, 1996; Zehr et al., 2000; Saha et al., 2003; Komárek, 2003). Singh et al., (1996) observed the genera Anabaena, Calothrix and Nostoc were encountered with maximum number of species in rice field of Tripura. However in our studies along with heterocystous genus, non heterocystous had maximum number of species. Anand and Hopper (1995) reported predominance of species of Oscillatoria and non heterocystous genera such as Phormidium and Lyngbya in rice field of Kerala. In rice fields of Nagaland, Singh et al., (1997a) recorded maximum number of species of Microcystis and heterocystous genera as Anabaena and Nostoc. Cyanobacteria increase the oxygen concentration and improve other physico-chemical parameters of the environment, in which they grow and flourish (Mandal et al., 1998).The physico-chemical changes in the environment may affect particular species and induce the growth and abundance of other species, which leads to the succession of several species in a course of time (Muthukumar et al., 2007). The crucial role of the physico-chemical parameters in the ecosystem on the distribution of algal community has been extensively analyzed in tropical and temperate fresh water ecosystem (Lund, 1965). In the present study, the physicochemical parameters ware analyzed in paddy fields of selected study areas. The temperature ranged from 22 o C to 35 o C was observed in both paddy fields. This may be due to optimal temperature for the growth of blue green algae. In this condition BGA grow because the range of temperatures permitting the growth of BGA is larger than that required by rice; however, it influences both algal biomass composition and productivity. Low temperatures decrease productivity and favour eukaryotic algae. Roger and Reynaud (1979) reported the high temperatures favour both the phytoplankton productivity and blue green algae. The present study correlates with BGA abundance. Allen and Stanies, (1968) observed temperature ranges between 25 o C to 35 o C in soil of the rice fields. The temperature was slightly higher in June and July at two stations of paddy fields when compared with other months. This may be due to the influence of summer season and the role of solar radiation. 10

5 Table 2. Cyanobacterial diversity(non-heterocystous form) in paddy fields of Keerapalayam (Station I) and Vallampaugai (Station II) S.No Name of the Isolates Station I Station II 1 Arthrospira jenneri(stizb) Gloeocapsa luteofusca (Martens) Gloeothece rupestris (Lyngb) Gloeothece rhodochlamys (Skuja) Lyngbya aestuarii (Liem) Lyngbya versicolor (Wartmann) Gomont Merismopedia punctata (Meyen) Oscillatoria limnotica (Ag. Ex Gomont) Oscillatoria tenuis (Ag.ex.Gomont) Oscillatoria cortiana (Meneghini ex Gomont) Oscillatoria sancta (Kutz)Gomont Oscillatoria curviceps (Ag.ex Gomont) Oscillatoria rubescens (DC) Oscillatoria jenensis (Komarek) Oscillatoria vizagapatensis (Rao,C.B) Oscillatoria sp Phormidium richardi (Drouet) Phormidium sp Spirulina meneiginiyana (Zanard) Spirulina gigantean(schmidle) Spirulina major( Kutz) + - Nouchi et al., (1990; 1994) reported that temperature variation observed in rice cultivation area. Uchijima (1959, 1963) investigated annual variations in water temperature and heat balance in shallow water with no rice plants and evaluated the climatic aspects of seasonal and spatial variations of paddy water temperature in Japan by using a simplified heat balance equation. Because the actual water temperature is influenced by the canopy density of rice plants (Uchijima, 1961), Takami et al., (1989) presented a simple scheme for evaluating the daily mean water temperature under a plant canopy by using a simplified heat balance equation. Similar models have been developed by Maruyama et al., (1998) and Ohta and Kimura (2007) to estimate the daily mean paddy water temperature under various weather conditions. Choudhury and Kennedy, (2004), DeLuca et al., (1996) reported that the cyanobacteria grew rapidly in the rice fields that contained ample organic matters in the soil and water as well as conditions such as ph, temperature, organic sources in various rice fields. In the present study Nostoc and Anbaena were dominant in both rice fields. ph is an essential parameter for the determination of water character and to differentiate the medium. The ph is a variable, influencing biochemical relations and possibly affecting species distribution. The present study showed the ph ranges from 7.3 to 8.4 in all paddy fields. The ph of these soils was very acidic ( ), which is much lower than optimum ph (7 10). This is because BGA can grow normally in alkaline soil. The ph of water was relatively high in the winter months and low in the monsoon and summers. The lower ph during monsoon is due to high turbidity, and in summers, the high temperature enhances microbial activity, causing excessive productivity leads to increase production of CO 2 and reduced ph (Khan and Khan, 1985; Narayani, 1990). The higher value of ph recorded during winter months could be attributed to increased primary productivity. Higher value of ph can be attributed to higher growth rate of algal population which utilized CO 2 through photosynthesis (Chaterjee and Raziuddin, 2006). Rippka et al., (1979) observed the ph variation recorded in soil. Aiyer, (1965) observed Alosira ferrilissitiia and Calothrix brevessima have been reported to be ubiquitous in Kerala rice fields with ph from 3.5 to 6.5. In the present investigation, soil samples were collected from two paddy fields. The ph values are evaluated for cyanobacterial abundance and their generic diversity. In summer season the ph was high due to the evaporation of surface water from the paddy fields and in 11

6 Table 3. Seasonal variation of physico-chemical parameters in paddy field of Keerapalayam (Station I) Period Surface Temperature (⁰C) Water Temperature (⁰C) Table 4. Seasonal variation of physico-chemical parameters in paddy field of Vallampadugai (Station II) ph Salinity (%) Dissolved oxygen(o 2 )(mg/l) Total dissolved solids(mg/l) January 28± ± ± ± ± ±1.02 February 29± ± ± ± ± ±1.04 March 30± ± ± ± ± ±1.07 April 32± ± ± ± ± ±0.9 May 35.4± ± ± ± ± ±0.8 June 34± ± ± ± ± ±1.1 July 32± ± ± ± ± ±1.2 August 30± ± ± ± ± ±1.4 September 29± ± ± ± ± ±0.9 October 28± ± ± ± ± ±0.8 November 26± ± ± ± ± ±0.8 December 27± ± ± ± ± ±0.9 Values are expressed as the mean ±S.D; n=3 Period Surface Temperature (⁰C) Water Temperature (⁰C) ph Salinity (%) Dissolved oxygen(o 2 )(mg/l) Total dissolved solids(mg/l) January 26.2± ± ± ± ± ±1.2 February 25.4± ± ± ± ± ±1.5 March 26.2± ± ± ± ± ±0.9 April 27.6± ± ± ± ± ±0.8 May 30± ± ± ± ± ±1.2 June 30± ± ± ± ± ±1.1 July 28± ± ± ± ± ±1.4 August 26.8± ± ± ± ± ±1.0 September 25± ± ± ± ± ±1.1 October 24± ± ± ± ± ±1.0 November 24.8± ± ± ± ± ±1.2 December 25.4± ± ± ± ± ±1.0 Values are expressed as the mean ±S.D; n=3 rainy season the ph was low due to association with low salinity by the dilution of the fresh water. Anbazhagan, (1908) reported that the ph was low in rainy season and high in summer season in the paddy fields. Subhashini and Kaushik (1981) reported that the ph of the alkaline soil decreased when treated with cyanobacteria. Nayak and Prasanna (2007) investigated the cyanobacteria were more in number at high ph in rice fields. Cyanobacteria have been found not only to grow in highly saline-alkali soils, but also improve the physico-chemical properties of the soil by enriching them with carbon, nitrogen and available phosphorus (Kaushik, 1994). Among soil properties, ph is a very important factor in growth, establishment and diversity of cyanobacteria, which have generally been reported to prefer neutral to slightly alkaline ph for optimum growth (Singh, 1961; Koushik, 1994). Acidic soils are therefore one of the stressed environments for these organisms and they are normally absent at ph values below 4 or 5; eukaryotic algae, however, flourish under these conditions. Soil ph is also known to have a selective effect on the indigenous algal flora, especially cyanobacterial succession and their abundance in soil. The species of cyanobacteria and several other genera are widespread in Indian rice field soils and are known to 12

7 contribute significantly to their fertility (Koushik, 1991; Nayak et al., 2004). There are very few reports on the existence of cyanobacteria at low ph (acidic range) as they are in general, intolerant to low ph conditions (Hunt et al., 1979; Dominic and.madhusoodanan, 1999). In the present study the level of salinity, dissolved oxygen and total dissolved solids were observed during The salinity ranged from 1.5 to 1.9% during the study period in both the study area. In both the study area the lower amount of salinity was observed. This may be nature of the salt accumulated in the soil and also flooded condition. Yung et al., (1999) reported the salinity level observed in the water samples. The dissolved oxygen and total dissolved solids were observed in the present study. The present study shows that the dissolved oxygen and total dissolved solids were increased. This may be due to cultivation of BGA in rice field which produce oxygen in dissolved form. Muthukumar et al., (2007) reported the level of dissolved oxygen observed in various pond of Thanjavur. In the present study, the low amount of dissolved oxygen was observed in June, This result may be due to the increased temperature salinity and total dissolved solids. The low dissolved oxygen is common in aquatic system especially estuarine and marine system that have high nutrient loading and are seasonally stratified into water with different densities. This stratification allows microbial degradation of organic matter to deplete dissolved oxygen and reaction of water (Kolar and Rahal, 1993). In the present study, it is shown that the rate of dissolved oxygen is more in the September, October and November periods. The influx of freshwater may be the cause for the high rate of dissolved oxygen content. The decreased level of dissolved oxygen content recorded in November month may be due to the release of industrial effluents from various industries. The rate of dissolved oxygen is controlled by various factors such as temperature, salinity and dissolved solids (Patnaik and Misra, 1990). The present study concludes that the normal range of various physico-chemical parameters favorably increase the cyanobacterial growth which enhance the growth of paddy. Acknowledgement We are thankful to Professor and Head, Department of Botany, Annamalai University for providing necessary laboratory facilities and also first author (K.Thamizh Selvi) gratefully acknowledge University authorities for sanctioning Studentship to carry out work successfully. References Abdul Jameel.A Physico-chemical studies in Uyyakondan channel water of river cauvery. Poll..Res.17(2): Aiyer, R.S Comparative algological studies in rice fields in Kerala state. Agricultural Research Journal of Kerala.3(1): Allen, M.M. and Stanies, R.Y Selective isolation of blue green algae from water and soil. Journal of General Microbiology. 51: Amita Devi,G.H., Dorycanta,H and Sing,N.I Cyanobacterial flora of rice fields in Kerala State. Agri. Res. J.Keala. 3: Anad, N., Hopper,R.S. and Shanthakumar, H Distribution of blue green algae in rice fields of Kerala State, India. Phykos. 35: Anad,N Hand book of blue green algae. Bishen Singh and Mahendrapal Singh Publishers. Dehradum. APHA-AWWA-WPCA Standard methods for examinations of water and waste water. American Public Health Association. 18 th Ed. Washington, DC. Biswal, R. and Das,M.K Diversity of cyanobacteria in the rice fields of Rairakhol sub-division of Sambalpur District of Orissa. Bull Biol. Sci. 1: Chaterjee, G and Raziuddin,M Status of water body in relation to some physico-chemical parameters in Asansol Town, West Bengal, Proc. Zool. Soc. India. 5(2): Choudhury, A. T. M. A. and L. R. Kennedy Prospects and potentials for systems of biological nitrogen fixation in sustainable rice production. Soil Biol. Biochem. 39: DeLuca, T.H., Drindwater, L.E., Wiefling, B.A. and DeNicola, D.M Free-living nitrogen-fixing bacteria in temperate cropping system: influence of nitrogen source. Biology and Fertility of Soils. 23: Desikachary,T.V Cyanophyta, Indian Council of Agricultural Research.New Delhi.pp 700. Dominic, T.K,.Madhusoodanan, P.V. 1999: Cyanobacteria from extreme acidic environments. Current Science 77(8): Hunt, M.E., Floyd, G.L. Stout, B.B Soil algae in field and forest environments. Ecology. 60(2): Kaushik, B.D Cyanobacterial response of crops in saline irrigated with saline ground water. In: Shastree, N.K (ed.) Current Trends in Limnology, Vol. 1. Narendra Publishing House, New Delhi. Kaushik, B.D Algalization of rice in salt-affected soils. Annales of Agricultural Research 14: Khan, I.A. and Khan, A.A Physico-chemical conductions in Selkha Jheel at Aligarh. J. Environment Ecology, 3: Kimura, M., Anaerobic microbiology in waterlogged rice fields. In: Bollag, J.M., Stotzky, G. (Eds.), Soil Biochemistry, vol. 10. Marcel Dekker, New York, pp

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9 water layer under paddy plant cover. Bull. Nat. Inst. Agric. Sci., Series A 8: Uchijima, Z., An investigation on annual variations in water temperature and heat balance items of shallow water. Bull. Nat. Inst. Agric. Sci., Series A 10: Yung, Y.K.,Yauà, K., Wong,C.K.,Chan,K.K., Yeung,I., Kueh, C. S. W. and M. J. Broom Some Observations on the Changes of Physico-Chemical and Biological Factors in Victoria Harbour and Vicinity, Hong Kong, Marine Pollution Bulletin. 39: 1-2, pp Zehr JP., Carpenter, EJ. and Villareal, TA New perspectives on nitrogen-fi xing microorganisms in tropical andsubtropical oceans. Trends Microbiol. 8 (2): Source of support: Nil; Conflict of interest: None declared 15