19 resultados para Green algae

em Cochin University of Science


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This thesis entitled “Contribution of size fractions of planktonic algae to primary organic productivity in the coastal waters of cochin,south west coast of india”. Marine ecosystems planktonic algae are the most important primary producers on wliich considerable attention is being given on account of their supreme status in the marine food chain.The study of primary production in the Indian Ocean started With DANA (I928-30),, John Murray t I933-34). Discovery ( I934) and Albatross (I947-48) expeditions which tried to evaluate productivity from nutrients and standing crop of phytoplankton .The bioproductivity of the marine environment is dependent on various primary producers. ranging in size from picoplankton to larger macro phytoplankton. The quantity and quality of various size fractions of planktonic algae at any locality depend mainly on the hydrographic conditions of the area .In the coastal waters of Cochin- south west coast of lndia. Planktonic algal community is composed mainly of the diatoms, the dinoflagellates, the blue-green algae and the silicoflagellates, the former two contributing the major flora and found distributed in the all size fractions. The maximum number of species of diatoms at station 1 and station 2 was found in the pre-monsoon season.. The size groups of planktonic algae greater than 53 um are dominated by filamentous- chain forming and colonial diatoms. The coastal waters of Cochin. planktonic algae less than 53 um in size contribute significantly to primary productivity and the biodiversity of the microflora, indicating the presence of rich fishery resources in the south west coast of india.The study of different size fractions of planktonic algae and their relative contribution to the primary organic production is a useful tool for the estimation of the quantity and quality of fisheries.A deeper investigation on the occurrence of these microalgae and proper identification of their species would be of immense help for the assessment of the specificity and magnitude of fishery resources.

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The present work is the study of filamentous algae in the paddy fields of Kuttanad and Kole lands of Kerala. This investigation was initiated by sampling of filamentous algae in Kuttanad during December 2010 to February 2011. A second phase of sampling was done from November 2011 to February 2012. The sampling periodicity corresponded to the crop growth starting from field preparation through sowing, and continued till the harvest. Sampling locations were selected from the active paddy cultivation regions of the six agronomic zones of Kuttanad. The numbers of sampling locations were proportional to the area of each zone. Algae of the Kole lands were collected during from October 2011 to January 2012. It was observed that blue-green algae dominated in both Kuttanad and Kole lands. Thirty two species of blue-green algae and eight species of green algae were identified from Kuttanad. The highest number of algal species was observed from Kayal lands in Kuttanad throughout the cropping season. Among the thirty two species of blue-green algae twenty five species are nonheterocystous and seven species are heterocystous. Twenty eight species of blue-green and six species of green algae were identified from Kole lands, and highest number of species was observed in Palakkal throughout the cropping season. Among the twenty eight species of blue-green algae collected from Kole lands twenty one species are non-heterocystous, and only seven species are heterocystous filamentous algae. Blooms of Spirogyra were observed during the second phase of sampling in Kuttanad and also in the Kole lands. The results of the germination study revealed that the extract of Spirogyra sp. inhibited seed germination and reduced seedling vigour. The growth of the treated seedlings was evaluated by pot experiments. The results clearly showed that Spirogyra sp. can negatively affect the seed germination, seedling vigour, and the yield of rice.

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The present study was undertaken to observe the phytoplankton (distones,dinoflageliates,and blue green algae) blooms occurring along the south west coast of India at various seasons from February 1982 to august 1984.The centers selected for collection and observation were off Quilon, off Alleppey ,off Calicut. A total number of 25 phytoplankton blooms were studied. Characterisation of phytoplankton blooms include observing the cell counts from the day of its appearance to its day of disappearance. The appearance ,duration and locality of the blooms were also noted

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Sedimentary biomarker pigments around Cochin estuary situated in the southwest coast of India were determined by HPLC. Fucoxanthin, an indicator of diatom was observed to be the most abundant carotenoid pigment in the estuary. Dinoflagellate derived carotenoid pigment peridinin was confined in the southern part of estuary and zeaxanthin pigment indicative of cyanobacteria were more found in sites influenced by anthropogenic activities. One compound having close similarity to fucoxanthin was also detected. Alloxanthin (cryptophyceae), chl b (green algae), canthaxanthin, neoxanthin, lutein and peridinin isomer were also detected by spectra and corresponding algal class were identified. The highest concentration of chl a (11.01 mg g 1) found near to the anthropogenic affected area while the lowest chl a (0.65 mg g 1) was recorded in industrial area. Degradation products of chl a, such as pheophorbide and pheophytin were observed and principal mode of mechanism of degradation were derived. Higher pheopigments content than chl a, reflects a density trapping of dead cells and early degradation of phytopigments from grazing activities

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Department of Marine Biology, Microbiology and Biochemistry, Cochin University of Science and Technology

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Rare earth metal ion exchanged (La3+, Ce3+, RE3+) KFAU-Y zeolites were prepared by simple ion-exchange methods and have been characterized using different physico-chemical techniques. In this paper a novel application of solid acid catalysts in the dehydration/ Beckmann rearrangement of aldoximes; benzaldoxime and 4-methoxybenzaldoxime is reported. Dehydration/Beckmann rearrangement reactions of benzaldoxime and 4-methoxybenzaldoxime is carried out in a continuous down flow reactor at 473K. 4-Methoxybenzaldoxime gave both Beckmann rearrangement product (4-methoxyphenylformamide) and dehydration product (4-methoxybenzonitrile) in high overall yields. The difference in behavior of the aldoximes is explained in terms of electronic effects. The production of benzonitrile was near quantitative under heterogeneous reaction conditions. The optimal protocol allows nitriles to be synthesized in good yields through the dehydration of aldoximes. Time on stream studies show a fast decline in the activity of the catalyst due to neutralization of acid sites by the basic reactant and product molecules.

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In this paper, a novel application of solid acid catalysts in the Beckmann rearrangement of E,E-cinnamaldoxime in the synthesis of an important heterocyclic compound; isoquinoline is reported. E,E-Cinnamaldoxime under ambient reaction conditions on zeolite catalysts underwent Beckmann rearrangement to produce isoquinoline in yields of ca. 86–95%. Cinnamonitrile and cinnamaldehyde were formed as by-products. LaH-Y zeolite produces maximum amount of the desired product (yield 95.6%). However, the catalysts are susceptible for deactivation due to the basic nature of the reactants and products, which neutralize the active sites. H-Y zeolite is more susceptible (22% deactivation in 10 h) for deactivation compared to the cerium-exchanged counterpart (18% deactivation in 10 h). Thus, the optimal protocol allows isoquinoline to be synthesised in excellent yields through the Beckmann rearrangement of cinnamaldoxime. The reaction is simple, effective, does not involve any other additives, and environmentally benign.

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Variations in the decay times of the characteristic green emissions at 522.7, 551.3, 549.6, 547.6, 542.2, 540.2, 535.9 and 533.5nm from CaF2 :H03+ with concentration are studied at RT and LNT. A pulsed N2 laser beam of power density 1.5 MW cm-2 is used for the excitation. Temperature dependent concentration quenching of the decay times are observed for all the emission bands. But an increase in the decay time due to the reabsorption process is also observed for a few of the above bands.

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The thesis embodies the results of a study on the variations in the parameters of productivity of two test species, a chlorophycean alga and a diatom. The chlorophycean alga Scenedesmus abundans was isolated from a fresh water pond whereas the diatom Nitzschia clausii was from the Cochin backwaters. Their growth parameters and their variations due to the effect of addition of some heavy metals have been studied. The growth parameters include biomass, production, respiration, photosynthetic pigments and end products of photosynthesis. The cell numbers were estimated by using a haemocytometer and production and respiration by oxygen light and dark technique. Spectrophotometric analysis for pigments, anthrone method for carbohydrate and heated biuret method for protein were the different methods employed in the present investigation. The present study is confined to nickel, cobalt, trivalent and hexavalent chromium. Different metals are discharged from various industries in and around Cochin. The effects of these metals individually and in combination are studied. Experiments to determine the effects of interaction of metals in combination enabled the assessment of the antagonistic and synergistic effect of metals on test species. The concentration or accumulation of metals on algae was determined by Atomic Absorption Spectrophotometry. The thesis has been divided into seven chapters. The introductory chapter explains the relevance of the present investigation. Chapter two presents the review of literature based on the work in relation to toxicity. Third chapter gives a detailed description of the material and specialized methods followed for the study. The effects of various metals selected for study - nickel, cobalt, trivalent and hexavalent chromium on the qualitative and quantitative aspects of productivity forms the subject of matter of the fourth chapter. The fifth chapter gives the impact of metals in combination on two species of algae. A general discussion and summary are included in the sixth and seventh chapters

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A study of the reproductive physiology of P. (P). semisulcatus wasundertaken as this information is an essential prerequisite for brood stock development for hatchery operations, and the results are embodied in this thesis. The thesis is presented in seven chapters. The protein, lipid and carbohydrate contents of ovary were estimated for the different vitellogenic phases. The protein, lipid, carbohydrate and cholesterol contents were estimated in testes and spermatophore.The thesis present the results of induced maturation experiments by eyestalk ablation, CNS extract injection and UV rays application on immature female prawns.

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The present research is based on two broader aspects of pollution assessment ,and treatability of petroleum and petrochemical effluents by algae. The objectives of the investigation are to study the algal ecology and trophic status of an oil refinery effluent holding pond , isolate and identify pure cultures of algae, study the role of algae in petroleum and petrochemical effluent treatment, develop strains of algae tolerant to toxic effluents, study the biotreatment potential of the tolerant algal strains developed The thesis comprises of six chapters. The first chapter gives the significance and objectives of the present study. The second chapter describes the methodology, and results of studies on the algal ecology, and trophic status of the effluent holding pond of Cochin Refineries Ltd., Ambalamugal, Kochi. The third chapter deals with the isolation, and development of pure cultures of algae, the algal bioassay of the refinery effluent, and the analyses of Chitrapuzha river water. The analysis, and assessment of the algal growth potential of the petrochemical effluent of Hindustan Organic Chemicals Ltd., Ambalamugal, Kochi. are summarised in the fourth chapter The fifth chapter deals with the algal growth potential in phenol and phenolic effluent, and subsequent absorption of phenol and total dissolved solids. The summary and conclusion of the present study are given in the sixth chapter.

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Light emitting polymers (LEPs) are considered as the second generation of conducting polymers. A Prototype LEP device based on electroluminescence emission of poly(p-phenylenevinylene) (PPV) was first assembled in 1990. LEPs have progressed tremendously over the past 20 years. The development of new LEP derivatives are important because polymer light emitting diodes (PLEDs) can be used for the manufacture of next-generation displays and other optoelectronic applications such as lasers, photovoltaic cells and sensors. Under this circumstance, it is important to understand thermal, structural, morphological, electrochemical and photophysical characteristics of luminescent polymers. In this thesis the author synthesizes a series of light emitting polymers that can emit three primary colors (RGB) with high efficiency

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Existing method of culture were largely based on empirical knowledge. Lacking a scientific basis as such methods did, they were often wasteful and suffered severe limitation. Modern methods of fish and prawn culture based on scientific research, have revolutioned the industry in recent years and not only extended its scope to cover the whole country but led to increased fish and prawn production. An understanding of the biological capability of the water in the perennial and seasonal culture ponds, and the nature and extent of the influence of the abiotic factors on the production of organisms in the primary level of food chain would contribute to effectively implement management measures in the stocking strategies and in the evaluation of economics of production of prawns. It is against this background that the present topic of investigation "Studies on the ecology and production of algae in prawn culture systems” was selected.

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The estuaries are highly productive ecosystems and characteristically are more productive than the adjacent river or sea. Estuarine producers which include planktonic algae, periphyton, herpobenthos as well as macrophytes are capable of nearly year round photosynthesis. Productivity of an environment is mainly the contribution of various groups of autotrophic flora. Any quantitative estimation excluding any one of these would be an underestimation. Periphyton plays a very important role in the productivity of estuarine and coastal waters. It has been reported that periphytic algae attain high biomass (Moss, 1968; Hansson, 1988a) and may contribute up to 80% of the primary production (Persson gt gtt, 1977); Considerable amount of work has been done on the productivity in Cochin backwaters by different investigators (Qasim, 1973, 1979; Nair gt gtt, 1975; Gopi— nathan gt gtt, 1984). All of them have estimated the primary production based only on phytoplankton of the estuary. Considering the contribution of other autotrophic components of the estuary such as periphyton (haptobenthos), sediment flora (herpebenthos) and macropytes, the productivity estimated by earlier authors were essentially underestimations. The present work is an attempt inter glig to assess the contribution of periphytic flora towards the total organic production in the estuary