| 1 | Marine microbiological studies of mangrove swamps of Killai backwaters The bacterial populations of mangrove swamps of Killai backwaters (11 degrees 21' - 11 degrees 29'N, 79 degrees 46' - 79 degrees 50'E, South India) were studied during August 1968 (Pre monsoon period) and December (post monsoon period). The presence of these groups such as agar digesters, algin digesters, cellulose digesters, sulphate reducers etc., bring about transformation of organic matter in the mangrove swamps. The presence of denitrifiers in mangrove swamps and in association with the molluscs may bring about the precipitation of calcium carbonate by removing the acid radicals such as sulphate and nitrite, increasing alkalinity. The luminescent bacteria such as Vibrio and Aeromonas were also isolated in mangrove swamps of Killai backwaters. The iron bacteria like Leptothrix sp. and Gallionella sp. were also isolated from mangrove swamps of Killai backwaters Source: Venkatesan, V.; Ramamurthy, V.D. J. Oceanogr. Soc. Japan. 27(2); 1971; 51-54. 0047. | ||
| 2 | Arylsulfatase producing bacteria in marine sediments A total of 313 strains of bacteria which hydrolysed tripotassium phenolphthalein disulfate (PDS) were isolated from the sediments of three biotopes, namely, Vellar estuary, backwaters and mangrove during the period of investigation. They were identified to the generic level. The following genera were encountered, namely, Vibrio, Bacillus, Alcaligenes, Micrococcus, Pseudomonas, Cytophaga - Flavobacterium, Aeromonas, Corynebacterium and members of Enterobacteriaceae. Vibrio and Bacillus were found to be the dominant groups representing 29.26% and 41.80% respectively of the total isolates. Because of the importance of the Vibrio group in marine environment these isolates were further identified to the species level and it included V. parahaemolyticus, V. alginolyticus, V. consticola, V. anguillarum and V. fischeri. These observations suggest that different groups of arylsulfatase producing bacteria probably occur in marine sediments Source: Dhevendaran, K.; Chandramohan, D.; Natarajan, R. Fish. Technol.. 22(2); 1985; 121-125. 0248. | ||
| 3 | Studies on rhizosphere microflora of Acanthus ilicifolius The rhizosphere which occupies an important niche in the mangrove ecosystem, consists mainly of the mangrove plant root surfaces and the surrounding soil. They harbour a number of beneficial micro-organisms which enhance the productivity of the area. The mangrove plant Acanthus ilicifolius found abundantly in the swampy area along Cochin Coast was studied to estimate quantitatively and qualitatively the microorganisms inhabiting the rhizosphere and their role in enhancing productivity Source: Raman, M.; Chandrika, V. Mariculture research under the postgraduate programme in mariculture. Part 2. Rengarajan, K.; Noble, A.; Prathibha; Kripa, V.; Sridhar, N.; Zakhriah, M.; eds. CMFRI Spec. Publ.. 53; 1993; 100-102. 0807. | ||
| 4 | Chemoheterotrophy in the mangrove environment The unique characteristics of the mangrove ecosystem of the tropics are discussed. This ecosystem is endowed with a diversity of habitats within it and is chemoheterotrophic in nature. The production of photosynthetic prokaryotes under chemoheterotrophic conditions is discussed. Nitrogen fixation by planktonic cyanobacteria to augment nitrogen budget of the ecosystem has been worked out. The heterotrophic growth of photoautotrophic prokaryotes as a mechanism of natural evolution to survive in hostile coastal anaerobic and anoxic conditions is emphasized Source: Rao, C.S.V.R.; Krishnamurthy, K. Curr. Sci.. 66(5); 1994; 382-385. 0866. | ||
| 5 | Bacterial flora in mangroves of Andaman - Part 1: Isolation, identification and antibiogram studies Bacterial flora of mangrove litter fall and underneath sediments from South Andaman was investigated. Thirtyeight bacterial isolates were obtained from Rhizophora, Avicennia and Nypa species inhabited areas. The cultural, morphological and biochemical features revealed that most of the isolates belong to Bacillus spp (50%). In addition Aeromonas, Vibrio, Escherichia, Enterobacter, Corynebacterium, Kurthia, Staphylococcus, Micrococcus, and Listeria were also present. Most isolates were gram positive (76.3%), motile (87%) and fementative bacteria ranged from 6.9% for dulcitol to 82.1% for dextrose. Thirty percent isolates were pigment producer (either diffusible or cell associated). The bacterial isolates showed a minimum of 50% resistance against chloramphenicol and a maximum of 100% resistance against polymixin B. Source: Shome, R.; Shome, B.R.; Mandal, A.B.; Bandopadhyay, A.K. Indian J. Mar. Sci.. 24(2); 1995; 97-98. 0912. | ||
| 6 | In situ decomposition of Ulva lactuca and associated biochemical changes in a tropical mangrove environment Litter bag method was used to follow changes in mass and biochemical constituents during microbial decomposition of the seaweed, Ulva lactuca, L. in situ. Different groups of organisms involved at various stages of decomposition were investigated. Considerable loss in wet weight, ash content, carbohydrate, lipid and organic carbon contents and increase in protein and total nitrogen content was observed with the progress of decomposition. The carbon:nitrogen ratio decreased from 16.6 to 4.8. Readily leachable carbohydrates were completely lost from the thalli by 12 day. Slow build up of microbial populations on the seaweed thalli and degradation of their structural materials was also observed Source: Vasantha, K.; Kannan, L.; Udaiyan, K. Phykos . 36(1-2); 1998; 57-71. 1016. | ||
| 7 | Brackishwater shrimp farming: Possible impacts on estuarine ecosystem Aquaculture has been widely accepted as a practice that will supplement the capture fishery production, besides generating various types of job opportunities for the rural population. Coastal aquaculture has been given utmost priority in many developing and underdeveloped countries due to its potential for earning foreign exchange. However, aquatic systems have been under tremendous stress due to increased use to land and water resources, population growth and industrial development. Aquaculture as a user of water resources, may also be contributing to the stress and environmental imbalances if it is incorrectly conceived and/or operated. In India, shrimp aquaculture has developed as the largest aquaculture practice in within a decade. But, most the developments have been confined to the estuarine and brackishwater areas. Tropical estuaries being the most productive ecosystem and subjected to a variety of developmental activities, most of which bring in some environmental changes, it is important to look at the possible impacts the brackishwater shrimp aquaculture on the environment and the biota. In this paper, the improtant physical and biological processes influencing the estuarine ecosystem are briefly presented. The role of different types of flora and fauna (viz. phytoplankton, zooplankton, benthos, bacteria and fishes) in the estuarine productivity processes and their interdependence are highlighted. The importance of mangroves to the estuarine ecosystem in general and for the propagation of marine shrimps in particular is emphasised. Status of brackishwater shrimp farming in India, possible impacts of coastal aquaculture as a whole and shrimp aquaculture in particular on the ecosystem and dependant flora and fauna are described. Some areas which need special attention in making the brackishwater shrimp aquaculture into a sustainable and eco-friendly practice are listed Source: Achuthankutty, C.T.; Sreepada, R.A. Advances in aquatic biology and fishereis: Prof. N. Balakrishnan Nair felicitation volume. Natarajan, P. ed. 1998; 175-189. 1047. | ||
| 8 | Growth inhibition of fish pathogens by antagonistic actinomycetes isolated from mangrove environment Solvent extracts of 6 strains actinomycetes isolated from mangrove environment were found to inhibit the growth of fish bacterial pathogens, filamentous and non-filamentous fungi. Out of the 104 actinomycetes tested 56% of the isolates exhibited antagonistic effect towards gram-negative bacteria and 35.6% towards gram-positive bacteria. The concentrations required to bring about 100% inhibition of filamentous fungi was 500-760 ~kg in crude extracts. The same concentration produced inhibition zone in bacteria ranging from 2 mm to 10 mm in diameter against various test pathogens. Antibiogram of the actinomycetes against test pathogens showed two extreme zones (category 1 and category X) of inhibition by most of the antagonistic actinomycetes. The results suggest that the crude extract of these antagonistic actinomycetes possesses both antibacterial and antifungal properties. Therefore the extract promises to be a potential source of antibiotics against fish bacterial pathogens Source: Rathnakala, R.; Chandrika, V. The Fourth Indian Fisheries Forum, Proceedings. 24-28 November, 1996, Kochi, Kerala. Joseph, M.M. ; Menon, N.R.; Nair, N.U. eds. 1999; 337-341. 1074. | ||
| 9 | Seasonal variations of sediment phenolics and aerobic heterotrophs in mangrove swamps In the sediments of the mangrove swamps of Cochin, Kerala, India phenolic compounds and total plate count (TPC) ranged from 0.018 ppm to 16.75 ppm, and 25 x 104/g to 110 x 104/g respectively and showed distinct seasonal variations. Phenol concentration was highest (16.75 ppm) during monsoon month, when the bacterial abundance was the lowest (24.5 x 104). The diversity of bacteria and their numbers were higher when phenol concentration was less in the sediment ( 2 ppm). Both the parameters showed inverse correlation with each other (r Source: Joseph, I.; Chandrika, V. Indian J. Mar. Sci.. 29(1); 2000; 52-56. 1123. | ||
| 10 | Antibacterials from marine organisms: Potential for fish disease control It is well established that sea is a rich source of biologically active materials which an be exploited for the benefit of mankind. An attempt is made to discuss marine antibacterials with emphasis on fish disease control. Exploration of RRL, Bhubaneswar, Orissa, India in finding out the marine antibacterials in the field of aquaculture in controlling bacterial pathogens had generated encouraging results. The fish bacterial pathogens are Aeromonas hydrophila-1 (AH-1), A. hydrophila - 2 (AH- 2), Pseudomonas aeruginosa (PA), P. flourescens (PF), Edwardsiella tarda (ET), Vibrio alginolyticus (VA). It had shown out of in vitro screening of crude extracts from 15 sponges, extracts belonging to 11 sponges; 9 extracts of 5 soft corals, 2 gorgonians and 2 antipatharians had shown antibacterial activity in varying degrees with species specificity. In vivo toxicity and in vivo challenge studies of active extracts / fractions were carried out in experimental tanks on Cirrihinus mrigala. The crude extract of sponge Epipolasis topsenti had shown 80% survivability against E. tarda infection whereas two fractions showed 100% survivability against P. fluorescens and A. hydrophila - 2. Crude extract and fraction of mangrove plant, Cynomera spp. Exhibited 100% survivability of the test fish against E. tarda respectively. One fraction of soft coral, Sinularia flexibilis fraction showed 50% and 80% efficacy against P. fluorescens and A. hydrophila - 2 respectively. Fraction of algae Gracilaria corticata and shown 100% activity against A. hydrophila - 2. It is noteworthy to mention here that when use of antibiotics in the environment or in the feed has come under severe comments and scrutiny in the global scenario today and environment protection has become the key word, it is pertinent to think about these marine bioactives as an alternate method of controlling disease problems in aqua-farming. Thus, "drugs from the sea" will be not only an encouraging proposition but will be an entrepreneurial venture. Source: Choudhury, S.; Sree, A.; Mukherijee, S.C.; Bapuji, M.; Pattnaik, P. Proceedings of the National Conference on Utilization of Bioresources - NATCUB-2002, October 24-25, 2002, Regional Research Laboratory, Bhubaneswar. Sree, A. ; Rao, Y.R.; Nanda, B.; Misra, V.N. eds. 2002; 129-139. 1248.
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