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Trinko, Tara Rae. "Bottom-Up and Top-Down Controls on Algal Bloom Frequency in Two Shallow Mesotrophic Lakes." Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/TrinkoTR2008.pdf.
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Misner, Ian. "Morphological & phylogenetic analysis of two species of heterokont alage [i.e. algae] /." Electronic version (Microsoft Word), 2004. http://dl.uncw.edu/etd/2004/misneri/ianmisner.html.
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Petrick, Ingolf, Lilli Dombrowski, Michael Kröger, Thomas Beckert, Thomas Kuchling, and Sven Kureti. "Algae Biorefinery – Material and energy use of algae." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-137259.
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Algae offer as much as 30 times greater biomass productivity than terrestrial plants, and are able to fix carbon and convert it into a number of interesting products.
The numerous challenges in algae production and use extend across the entire process chain. They include the selection of suitable algal phyla, cultivation (which takes place either in open ponds or in closed systems), extraction of the biomass from the suspension, through to optimal use of the obtained biomass. The basic suitability of aquatic biomass for material use and energy supply has been demonstrated in a large number of studies. Numerous research projects are concerned with identifying the optimal processes to enable its widespread implementation. [... aus der Einleitung]
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Petrick, Ingolf, Lilli Dombrowski, Michael Kröger, Thomas Beckert, Thomas Kuchling, and Sven Kureti. "Algae Biorefinery – Material and energy use of algae." DBFZ Deutsches Biomasseforschungszentrum, 2013. https://slub.qucosa.de/id/qucosa%3A4316.
Full textAbstract:
Algae offer as much as 30 times greater biomass productivity than terrestrial plants, and are able to fix carbon and convert it into a number of interesting products.
The numerous challenges in algae production and use extend across the entire process chain. They include the selection of suitable algal phyla, cultivation (which takes place either in open ponds or in closed systems), extraction of the biomass from the suspension, through to optimal use of the obtained biomass. The basic suitability of aquatic biomass for material use and energy supply has been demonstrated in a large number of studies. Numerous research projects are concerned with identifying the optimal processes to enable its widespread implementation. [... aus der Einleitung]
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Vercellino, Ilka Schincariol. "Resposta do perifíton aos pulsos de enriquecimento em níveis crescentes de fósforo e nitrogênio em represa tropical mesotrófica (Lago das Ninféias, São Paulo) /." Rio Claro : [s.n.], 2007. http://hdl.handle.net/11449/100626.
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Resumo: O estudo visou a (a) caracterizar as principais alteracoes estruturais da comunidade de algas perifiticas em condicoes de enriquecimento por pulsos de nitrogenio e fosforo (b) identificar a formacao de guildas de especies indicadoras; (c) avaliar a contribuicao do perifiton em relacao a outros compartimentos biologicos na retencao do fosforo. O experimento foi realizado em represa rasa tropical a partir de mesocosmos com controle de fluxo de agua, onde foram colocadas laminas de vidro para o perifiton, 78 L de agua da represa e 100 individuos de Ricciocarpus natans. O delineamento constou de controle e tres tratamentos (n = 3), com niveis crescentes de nutrientes (RN/P molar = 44): T1 - 100 ÊgP L-1 e 2000 ÊgN L- 1; T2 - 200 ÊgP L-1 e 4000 ÊgN L-1; T3 - 400 ÊgP L-1 e 8000 ÊgN L-1. Dezessete amostragens semanais foram realizadas durante 64 dias, sendo uma antes da adicao dos sais (preenriquecimento) e outra 24h apos adicao (pos-enriquecimento). A ACP separou as observacoes do controle e do pre-enriquecimento daquelas do pos-enriquecimento. Pela OECD, os tratamentos foram classificados em mesotrofico (C), eutrofico (T1, T2) e hipereutrofico (T3). O incremento de biomassa perifitica foi primordialmente direcionado pelas cargas crescentes de nutrientes e menos pelos pulsos de enriquecimento. O efeito cumulativo dos pulsos sobre a biomassa fitoplanctonica foi bem menor, sendo apenas evidente no T3 para as macrofitas. A composicao quimica da biota nao respondeu ao aumento das cargas de nutrientes e as comunidades autotroficas permaneceram P-limitadas. Em relacao ao balanco de massa, o seston foi o principal sequestrador de P, seguido pelo complexo macrofitas-perifiton e pelo perifiton. Entretanto, parte substancial de P ficou retida, muito provavelmente, no sedimento e sua microflora associada. Foram caracterizadas tres guildas indicadoras das condicoes ambientaisAbstract: The study aimed at (a) characterizing the main periphytic algae community structural modifications under nitrogen and phosphorus pulses enrichment conditions; (b) identifying the formation of indicating species guilds; and (c) evaluating the periphyton contribution towards phosphorus retention facing other biological compartments in the system. Experiment was carried out in a tropical shallow reservoir using water flux controled mesocosms where microscope glass slides were placed for periphyton attachment, 78 L reservoir water and 100 Ricciocarpus natans individuals. Experiment design included one control and three treatments (n = 3) with different nutrient concentrations (molar N/P ratio = 44): T1 - 100 ìgP L-1 and 2,000 ìgN L-1; T2 - 200 ìgP L-1 and 4,000 ìgN L-1; T3 - 400 ìgP L-1 and 8,000 ìgN L-1. Seventeen weekly samplings were performed during 64 consecutive days, one of them carried out before the enrichment (pre-enrichment) and the other one 24 hr after P addition (postenrichment). Principal Component Analysis separated observations of the control and preenrichment from those of the post-enrichment. According to OECD, treatments were classified as mesotrophic (C), eutrophic (T1, T2) and hypereutrophic (T3). Periphytic biomass increase was mostly directed by the increasing nutrient loads, and less by the enrichment pulses. Cumulative effect of pulses on the phytoplankton biomass was much lesser and evident only at T3 treatment for the macrophytes. Chemical decomposition of the biota did not respond to the increase in nutrient loads, and the autotrophic communities remained P-limited. Regarding to the mass balance, seston was the main P sequestrator, followed by the complex macrophytes-periphyton and the periphyton. Substantial part of P remained, however, trapped much probably in the sediments and its associated microflora. Three guilds indicative of environmental conditions were identified
Orientador: Denise de Campos Bicudo
Coorientador: Irineu Bianchini-Júnior
Banca: Liliana Rodrigues
Banca: Raoul Henry
Banca: Carla Ferragut
Banca: Antonio Fernando Monteiro Camargo
Doutor
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Brooke, C. M. "Calcareous algae and algal limestones from the Silurian of Gotland, Sweden." Thesis, Bucks New University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378104.
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Garcia, Filho Auro Silva. "Revisão das seções Acarporophytum, Aristata e Macrospora do gênero Batrachospermum (Rhodophyta, Batrachospermales) /." Rio Claro, 2014. http://hdl.handle.net/11449/108716.
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Orientador: Orlando Necchi JuniorBanca: Luis Henrique Branco
Banca: Valéria Cassano
Resumo: As três seções do gênero Batrachospermum - Acarposporophytum (com uma única espécie, B. brasiliense Necchi), Aristata (B. beraense Kumano, B. cayennense Montagne, B. longiarticulatum Necchi e B. turgidum Kumano) e Macrospora (B. equisetifolium Montagne, B. hypogynum Kumano & Ratnasabapathy e B. macrosporum Montagne) têm sido demonstradas como monofiléticas em estudos filogenéticos envolvendo pelo menos um representante de cada seção. As seguintes hipóteses foram testadas: 1) as seções Acarposporophytum, Aristata e Macrospora constituem grupos monofiléticos dentro do gênero Batrachospermum; as seções têm sido demonstradas como monofiléticas em estudos filogenéticos e com a adição de maior número de espécies e populações essa tendência deverá ser confirmada; 2) A maioria das espécies atualmente reconhecidas em cada seção com base em caracteres morfológicos será corroborada pelos dados moleculares. A presente revisão das três seções teve como objetivos: 1) inferir as relações filogenéticas, bem como os limites de variação intraespecíficas, das espécies dentro e entre as seções, bem como com outras seções do gênero, foram utilizados os caracteres morfológicos diagnósticos atualmente aceitos e três marcadores moleculares - rbcL, gene plastidial que codifica a subunidade grande da RUBISCO; região de "barcode" do gene mitocondrial cox1, que codifica a subunidade 1 da enzima citocromo c oxidase; e UPA - gene plastidial "universal plastid amplicon"; 2) elaborar estudo de revisão para as três seções por meio da realização dos caracteres taxonômicos diagnósticos para espécies desses grupos, à luz dos novos dados moleculares. Foram analisadas 19 amostras provenientes das regiões sudeste, centro-oeste, norte e nordeste do Brasil, além dos espécimes-tipo de cada seção e sequências disponíveis no "GenBank" para cada um dos marcadores utilizados. Os caracteres diagnósticos para o...
Abstract: he three sections of the genus Batrachospermum - Acarposporophytum (with the single species B. brasiliense Necchi), Aristata (B. beraense Kumano, B. cayennense Montagne, B. longiarticulatum Necchi and B. turgidum Kumano) and Macrospora (B. equisetifolium Montagne, B. hypogynum Kumano & Ratnasabapathy and B. macrosporum Montagne) - have been shown to be monophyletic in phylogenetic studies involving at least one member of each section. The following hypotheses were tested: 1) the sections Acarposporophytum, Aristata and Macrospora represent monophyletic groups within the genus Batrachospermum; the sections have been shown to be monophyletic and closely related in previous studies and with the addition of more species and populations this trend will be confirmed; 2) most species currently recognized in each section on the basis of morphological characters will be corroborated by molecular data. This revision of the three sections has the following aims: 1) to infere phylogenetic relationships and the intra-specific limits of variation of the species within and between sections, as well as with the other sections of the genus; the investigation used the morphological diagnostic characters currently applied and three molecular markers - rbcL, the plastidial gene encoding the large sub-unit of RUBISCO; the barcode region of the mithocondrial gene cox1, encoding sub-unit 1 of cythochorme c oxidase; and UPA, plastidial universal plastid amplicon; 2) to carry out a revisional study of the three sections by means of the reevaluation of taxonomic diagnostic characters for species within these groups, in the light of new molecular data. Nineteen new samples were analysed from the southeast, mid-west, north and northeast regions of Brazil, as well as the type specimens of each species and the sequences available in GenBank for each molecular marker. The diagnostic characters for section circumscription and species identification within the sections...
Mestre
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Saraiva, Anna Isabel Nassar Bautista. "Respostas fisiológicas de macroalgas continentais à radiação ultravioleta /." Rio Claro, 2017. http://hdl.handle.net/11449/151243.
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Orientador: Orlando Necchi JúniorResumo: Nos últimos séculos a história do ser humano no planeta Terra tem sido marcada por intensos impactos ambientais antropogênicos negativos, dentre os quais destaca-se a maior exposição da radiação ultravioleta (UV) na superfície terrestre devido à destruição da Camada de Ozônio ocasionada pela liberação de substâncias tais como os CFCs (clorofluorcarbonetos). A radiação UV tem sido considerada com um dos principais fatores que afetam a distribuição dos organismos fotossintetizantes em ambientes aquáticos, tendo efeitos biológicos diversos como danos no DNA e em moléculas proteicas, alteração dos pigmentos fotossintéticos, modificações nos parâmetros fotossintéticos e crescimento desses organismos. Torna-se evidente, portanto, que as mudanças da incidência de radiação UV na superfície terrestre podem levar a alterações ecofisiológicas nas comunidades algais. Nesse contexto, este trabalho teve como objetivo central analisar as respostas fisiológicas (parâmetros fotossintéticos, concentração de pigmentos fotossintéticos e de substâncias fotoprotetoras) à radiação ultravioleta (UVA e UVAB) em macroalgas continentais (ambientes lóticos e aerofíticos). A idéia geral foi avaliar o nível de resposta (tendência de aumento ou diminuição em maior ou menor grau) na performance em função da exposição à radiação ultravioleta. Duas hipóteses gerais foram formuladas: 1) as respostas das macroalgas consistirão essencialmente de tendência de diminuição de sua performance fisiológica (parâmetros fotossintéticos e concentração de pigmentos) e aumento de substâncias fotoprotetoras sob exposição à radiação UV; 2) o nível de resposta será diferente entre os grupos de algas, sendo que para as algas verdes (tipicamente algas de sol) espera-se que sejam mais tolerantes à ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The history of human on planet Earth has been marked by intense negative anthropogenic environmental impacts, which enhanced the exposure to ultraviolet (UV) radiation the Earth's surface due to depletion of the ozone layer caused by the release of substances, such as, CFCs (chlorofluorocarbons). UV radiation has been considered as one of the main factors that affect the distribution of photosynthetic organisms in aquatic environments, with varied biological effects, such as, damage to DNA and protein molecules, alteration of photosynthetic pigments, changes in photosynthetic parameters and growth of these organisms. Changes in the incidence of UV radiation on the Earth's surface can lead to ecophysiological alterations in algal communities. In this context, the objective of this investigation was to analyze the physiological responses (photosynthetic parameters, concentration of photosynthetic pigments and photoprotective substances) to ultraviolet radiation (UVA and UVAB) in inland macroalgae (lotic and aerophytic habitats). The general idea was to evaluate the level of response (trend of increase or decrease to greater or lesser degree) in photosynthetic performance to ultraviolet exposure. Two general hypotheses were formulated: 1) the responses of macroalgae will essentially consist of a trend to decrease in their physiological performance (photosynthetic parameters and pigment concentration) and increase photoprotective substances under UV exposure; 2) the response level will be different among algal groups, with green algae (typically sun-adapted algae) expected to be more tolerant to UV radiation, whereas red algae (typically shaded-adapted algae) to be more sensitive and the cyanobacteria having intermediate responses. Specific hypotheses were formulated for each part of the work (chapters). Experiments were performed under three ... (Complete abstract click electronic access below)
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com, n_moheimani@hotmail, and Navid Reza Moheimani. "The culture of coccolithophorid algae for carbon dioxide bioremediationn." Murdoch University, 2005. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20050901.140745.
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The culture of coccolithophorid algae is an attractive option for sequestration or
recycling of CO2 as they can fix carbon by photosynthesis as well as in calcium
carbonate scales known as coccoliths. They also produce high amounts of lipids which
have a potential application as a renewable fuel.
Five species of coccolithophorids (Pleurochrysis carterae, CCMP647, Pleurochrysis sp.
CCMP1211, Gephyrocapsa oceanica CS-335/2, Emiliania huxleyi CCMP371, and
Emiliania huxleyi CS-369) were screened for their ability to grow at high temperature.
All species grew up to 28oC except E. huxleyi CS-369. However, Pleurochrysis sp.
CCMP 1211 which was found to clump and can therefore not be recommended for
large-scale cultivation. The salinity tolerance of these species was also examined.
Growth of P. carterae, G. oceanica, and E. huxleyi in laboratory scale closed
photobioreactors (plate, carboy, airlift, and tubular photobioreactors) showed the plate
photobioreactor to be the best closed cultivation system. The highest productivities
were achieved by P. carterae in the plate photobioreactor and were 0.54 g.L-1.d-1, 0.12
g.L-1.d-1, 0.06 g.L-1.d-1 for total dry weight, lipid and CaCO3 respectively.
The growth of P. carterae and E. huxleyi was also examined in an outdoor raceway
pond. The E. huxleyi culture was easily contaminated resulting in the loss of the culture
in less than three weeks, but P. carterae grew well over a period of 13 months. The
overall total dry weight productivity of P. carterae was 0.19 g.L-1.d-1 with lipid and
CaCO3 contents of up to 33% and 10% of dry weight respectively. There was little
protozoan and bacterial contamination. Medium pH increased to pH 11 during the day
and was found to be a reliable variable for maintaining the health of the culture. A
maximum pH achieved during the day of less than pH 8.5 indicated the imminent collapse of the culture. Heavy rain and low temperature were the main reasons for
culture loss in mid winter, whereas high temperature during summer favoured P.
carterae growth. A comparison of the growth of P. carterae and Dunaliella salina
MUR8 in the raceway ponds showed no significant differences between these two
species with regard to areal total dry weight productivity and lipid content.
The effects of several limiting factors were also examined. A reduction in medium pH
resulting from CO2 addition inhibited the growth of E. huxleyi in the plate
photobioreactor, whereas P. carterae growth and productivities increased in the pH
range of pH 7.7 to 8.0 in the plate photobioreactor and pH 9.1 to 9.6 in the outdoor
raceway pond. The best operational pond depth for outdoor raceway culture of P.
carterae was between 16 cm and 21 cm. Early morning temperatures, especially during
the winter, highly affected the growth of P. carterae in the raceway pond, whereas
artificially increasing the medium temperature improved the health of the culture but
resulted in little increase in productivity. Photosynthesis of P. carterae was found to be
highly inhibited by high oxygen concentration in the medium irrespective of
temperature or irradiance.
An economic model of P. carterae in a 63 ha raceway plant resulted in a cost for the
biomass of between 7.35 Aus$.Kg-1 and 14.17 Aus$.Kg-1 depending on the harvesting
method used.
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Young, Ashton M. "Zeolite‐Based Algae Biofilm Rotating Photobioreactor for Algae and Biomass Production." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/986.
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Alkaline conditions induced by algae growth in wastewater stabilization ponds create deprotonated ammonium ions that result in ammonia gas (NH3) volatilization. If algae are utilized to remediate wastewater through uptake of phosphorus, the resulting nitrogen loss will hinder this process because algae generally require a stoichiometric molar ratio of N16P1. Lower ratios of N/P due to loss of ammonia gas will limit the growth and yield of algae, and therefore will reduce phosphorus removal from the water phase into the algae phase. In order to reduce nitrogen loss through volatilization, an ammonium selective zeolite, clinoptilolite, can be used to sequester nitrogen from the water phase as ammonium ion and in a form that is bioavailable for uptake and growth of algae. A novel algae biofilm rotating photo bioreactor (RPB) with clinoptilolite integrated to the outermost surface as the substratum for algae biofilm attachment and growth has been designed, constructed, and tested for ammonium capture and algae biomass production, with simultaneous removal of the algal nutrient phosphorus from water. The clinoptilolite‐based RPB (cRPB) provides algal biomass that can serve as feedstock for biofuel production through uptake of zeolite‐based nitrogen and water phase phosphorus.
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Shamsudin, L. B. "The benthic algae of the River Itchen with particular reference to epilithic algae and epilithic algae on selected macrophytes." Thesis, University of Southampton, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375372.
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Yee, Daniel P. "Nutrient bioremediation by algae and a light dependent model for predicting algal growth." Diss., [La Jolla] : University of California, San Diego, 2010. http://wwwlib.umi.com/cr/fullcit?p1477951.
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Thesis (M.S.)--University of California, San Diego, 2010.Title from first page of PDF file (viewed July 16, 2010). Available via ProQuest Digital Dissertations. Includes bibliographical references (leaves 54-59).
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Hiatt, Michael John. "Synergetic Algal Infrastructure: Investigating the Benefits of Algae Production in an Airport Environment." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366241697.
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Silva, Nadia Martins Lemes da. "Trentepohliales (Ulvophyceae, Chlorophyta) de biomas brasileiros : flora, taxonomia e filogenia /." Rio Claro, 2013. http://hdl.handle.net/11449/100679.
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Orientador: Luis Henrique Zanini BrancoBanca: Carlos Eduardo de Mattos Bicudo
Banca: Celia Leite Sant'Anna
Banca: Carla Ferragut
Banca: Valéria Cassano
Resumo: Os membros da ordem Trentepohliales são estritamente terrestres, crescendo em solo, rochas, troncos, folhas, frutos, folhas e vários tipos de construções artificiais. A ordem consiste de uma única família, Trentepohliaceae, e o número de gêneros é ainda conflitante entre os autores, alguns considerando a família com cinco gêneros (Trentepohlia, Printzina, Phycopeltis, Cephaleuros e Stomatochroon) e outros com seis (incluindo Physolinum, além dos gêneros citados). Esse grupo é um dos mais abundantes em ambientes terrestres e está entre os menos conhecidos e estudados, principalmente em regiões tropicais. Devido à sua morfologia relativamente simples, as Trentepohliales formam um grupo taxonomicamente difícil e sua grande plasticidade morfológica está relacionada a fatores ambientais, tornando confusa a distinção de espécies e gêneros. O presente estudo visou contribuir com o conhecimento taxonômico do grupo, por meio do levantamento florístico em cinco biomas brasileiros: Cerrado (Parque Nacional da Serra da Canastra e Parque Nacional da Chapada dos Veadeiros), Floresta Ombrófila Densa (Parque Estadual da Serra do Mar/Núcleo Picinguaba e Parque Nacional de Itatiaia), Floresta Ombrófila Mista (Região de Campos do Jordão) e Restinga (Parque Estadual da Serra do Mar/Núcleo Picinguaba), além de fragmentos de Floresta Estacional Semidecidual presentes na região noroeste do estado de São Paulo. Adicionalmente, objetivou-se a ampliação geográfica do registro de ocorrência das espécies já registradas em território nacional e descrição de aspectos ecológicos do habitat onde se desenvolvem. O material coletado foi utilizado para detalhamento da taxonomia do grupo, com a aplicação de estudos moleculares, além dos morfológicos clássicos. Os crescimentos de Trentepohliales... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Not available
Doutor
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Henderson, Rita Kay. "PosiDAF for algae removal." Thesis, Cranfield University, 2007. http://dspace.lib.cranfield.ac.uk/handle/1826/4472.
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During algac blooms, coagulation is frequently unsuccessful resulting in poor flotation duc to complex algal character. 11iis thesis cxplorcs tlic link between algal character and conventional treatment and the potential for developing morc appropriatc algac trcatmcnt tcclinologics. Specifically, dissolvcd air flotation (DAF) that has bccn adaptcd by dosing cationic clicmicals to the saturator to modiry bubbic surfaccs, such that it docs not rcly on coagulation, is invcstigatcd. 1'his proccss is tcrmcd PosiDAF. Analysis of dissolved algogcnic organic mattcr (AOM) extracted from problcmatic species enabled investigation of the impact of morphology and AOM on coagulation- flocculation-flotation. Both increasing surface area and charge density of algae systcrns, werc rclatcd to increasing coagulant dcmand. Application of the appropriate coagulant dcmand ensured removal of all thrcc components - cclls, AOM and coagulant. Maintaining the zcta potential bct-%vccn -10 mV and +2 mV ensured optimum rcmoval was obtained. PosiDAF trials were conducted by dosing chemicals that had previously been shown to alter bubble charge, including co3gulant, surfactant and polymer, to the saturator. Coagulants were unsuitable for use in PosiDAF as they did not remain at the bubble surface. Highly hydrophobic, cationic surfactants were observed to remove cells according to a theoretical model, such that removal improved with increasing bubbic: particic ratio and with cell size. The polymer, polyDADNIAC, achieved greater removal cfficiencies than those predicted theoretically, attributed to an increase in the swept volume of the bubble. However, polyDADMAC was sensitive to changes in AOM composition. A chemical that combines attributes of both surfactant and polyDADMAC may overcome the barriers to PosiDAF implementation.
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Beaty, Myron H. "Cryopreservation of eukaryote algae." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-07282008-135156/.
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Baloyi, Hope. "Algae liquefaction / Hope Baloyi." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8153.
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The liquefaction of algae for the recovery of bio–oil was studied. Algae oil is a non–edible feedstock and has minimal impact on food security and food prices; furthermore, it has been identified as a favourable feedstock for the production of biodiesel and this is attributed to its high oil yield per hectare. Algae oil can be potentially used for fuel blending for conventional diesel. The recovery step for algae oil for the production of biodiesel is costly and demands a lot of energy due to the high water content and size of the algae organism. In this study hydrothermal liquefaction was used for the recovery of oil from algae biomass. Hydrothermal liquefaction uses high water activity in sub–critical water conditions to convert wet biomass to liquid fuel which makes the process more cost effective than pyrolysis and gasification in terms of energy savings on biomass drying costs.
The main objective of this study was to determine suitable liquefaction reaction conditions (reaction temperature, biomass loading and reaction atmosphere) for producing bio–oil from algae and identifying the effects of these conditions on bio–oil yield and properties. Bio–oil properties are a good indication of the quality of the oil product and the significance of the liquefaction reaction conditions. The experiments were carried out in a SS316 stainless steel high pressure autoclave. An environmental scanning electron microscope with integrated energy dispersive spectroscopy was used for the characterisation of the raw algae biomass. The algae biomass was liquefied in water at various temperatures ranging from 280 to 360°C, at different biomass loadings (3 to 9 wt %) and a 5 wt% potassium hydroxide (KOH) for all experiments. The reaction time was held constant at 30 minutes in all experiments performed under CO2 and N2 atmospheres. Chloroform was used to recover the bio–oil oil from the reaction mixture following liquefaction, and the bio–oil was purified by removing chloroform using a vacuum distillation process.
The bio–oil sample was methylated to the fatty methyl esters using trimethyl sulfonium hydroxide solution to determine its composition using gas chromatography. The elemental composition of the bio–oil was analysed using a Flash 2000 organic analyser. The main organic components of the bio–oil were determined using Fourier–transform infrared (FT–IR) spectroscopy. The oil yield was found to be dependent on reaction temperature and biomass loading when liquefaction was done in an inert environment, showing a significant increase at high temperatures and biomass
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loadings. Biomass loading had no significant influence on bio–oil yields at high temperatures in a reducing atmosphere and an average oil yield of 25.28 wt% and 20.91 wt% was obtained under a CO2 atmosphere and a N2 atmosphere at 360°C, respectively. Higher yields of C16 fatty acid were obtained at 320°C at a 3 wt% biomass loading in a CO2 atmosphere. The FTIR analyses showed the presence of oxygenated compounds such as phenols, ketones, aldehydes and ethers. The bio–oil had a reduced O/C ratio as compared to that in the original feedstock, with improved heating values. The reduction in the O/C ratio in the bio–oil indicated that deoxygenation occurred during liquefaction and that the bio–oil produced has good properties for combustion. This study indicates that the bio–oil is well suited for further processing to biodiesel because of the high C16 fatty acid content. Hydrothermal liquefaction could thus be a feasible method for producing bio–oil from Scenedesmus acutus.Thesis (MSc Engineering Sciences (Chemical Engineering))--North-West University, Potchefstroom Campus, 2012.
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Watson, Anne Mary. "The filtration of algae." Thesis, University College London (University of London), 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403594.
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Croft, Martin Tom. "Vitamin B₁₂ in algae." Thesis, University of Cambridge, 2006. https://www.repository.cam.ac.uk/handle/1810/284053.
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Vitamin B12-dependent algae are unable to grow in medium made with natural filter-sterilized seawater or freshwater unless a vitamin B12 supplement is added to the culture, suggesting that the concentration of free vitamin B12 in the natural environment in generally too low to support the growth of vitamin B12-dependent algae. The source of cobalamin for algae appears to be vitamin B12-synthesizing bacteria, because when these organisms are grown in co-culture, the algae no longer require the vitamin. In return for vitamin B12, the bacteria are able to use the products of algal photosynthesis to grow, indicating an important and unsuspected symbiosis. Using the green alga Chlamydomonas reinhardtii as a model organism, RT-PCR analysis has demonstrated that vitamin B12 regulates the expression of the gene encoding the vitamin B12-independent methionine synthase. Cobalamin is likely to regulate the expression of this gene by binding directly to the mRNA and influencing its secondary structure, since affinity binding studies suggest that the mRNAs that encode for the methionine synthase proteins have a high affinity for cobalamin. Further work in C. reinhardtii and Euglena gracilis has shown that a cell wall protein is involved in the high affinity uptake of vitamin B12, since mutants deficient in cell wall biosynthesis are impaired in their ability to take up the vitamin. The C. reinhardtii protein has been purified by affinity chromatography, and identified by mass spectrometry. The complete cDNA encoding the C. reinhardtii vitamin B12 binding protein has been cloned, and the protein shown to be a member of the pherophorin family, a well-known group of green algal cell wall proteins. A combination of techniques has indicated that the protein is glycosylated, and that the sugar moieties are attached to a central domain that contains a significant number of hydroxyproline residues.
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Tumilar, Aldric. "Algae-Centred Industrial Symbiosis." Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/17173.
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This thesis describes a unique industrial symbiosis employing algae at the core of a novel industrial system that integrates fossil-power generation, carbon capture, biofuel production, aquaculture, and wastewater treatment. A new modelling framework capable of designing and evaluating material and energy exchanges within an industrial ecosystem is introduced. Results, focusing on CO2 flows, demonstrate the potential for CO2 emissions reduction through carbon reuse and recycling. Significantly, this thesis shows the positive potential of this new complex industrial symbiosis and of the modelling framework by demonstrating a high degree of flexibility in terms of integrated material and energy flow analysis. Details of this algae-centred eco-industrial park and a demonstration of its workings through preliminary techno-economic calculations are presented. Results show that a proposed eco-park that generates 660 MW power plant and several material co-product streams (biofuel, chemicals), reduces net CO2 emissions significantly by 62% (equivalent to 1,9 million t/yr) as compared to a 660 MW stand-alone power plant. This reduction is achieved through the recycling and utilisation of captured CO2 in the algae feed. Using a 100% renewable option, zero CO2 emissions may be targeted, but noting that this option is limited because it comes without materials co-production. Also, the overall unit production cost of algae-centred eco-industrial park proposed significantly lowered by 60% compared to the overall unit production cost needed from combining all stand-alone plants together. Feedstock and equipment overall budgets have more impacts compared to other sensitivity analysis carried. The effectiveness of evaluating energy technology transitions towards future low-emission energy and chemical systems is discussed.
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Tonetto, Aurélio Fajar. "Efeito das relações bióticas sobre o estabelecimento de macroalgas de ecossistemas lóticos tropicais : interação com microalgas e pressão por herbivoria /." Rio Claro, 2014. http://hdl.handle.net/11449/132717.
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Orientador: Ciro Cesar Zaini BrancoBanca: Carla Ferragut
Banca: Cleto Kaveski Peres
Banca: Denise de Campos Bicudo
Banca: Orlando Necchi Junior
Resumo: As macroalgas lóticas têm sido consideradas, juntamente com perifíton, briófitas e macrófitas, um dos principais produtores primários de ambientes de riachos. Por essa razão, nas últimas décadas muitos trabalhos vêm sendo realizados na tentativa de entender-se a distribuição espaço-temporal desses organismos. A grande maioria desses trabalhos tem investigado exclusivamente os efeitos de variáveis ambientais sobre os padrões de distribuição ecológica das macroalgas de riachos. Entretanto, apenas a relação entre a ocorrência e distribuição desses organismos e as variações do ambiente tem demostrado ser pouco preditiva em relação ao estabelecimento e manutenção das macroalgas nestes ecossistemas. Assim, parece claro que, além do mosaico dinâmico de condições ambientais, outras forças que atuam sobre estes organismos devem ser consideradas na análise de suas distribuições ecológicas. Neste sentido, é possível imaginar que as interações bióticas, em pequena escala, que ocorrem entre os organismos que coexistem em um mesmo trecho de riacho também possam interferir de maneira significativa nas respostas ecológias desses organismos. As microalgas e macro-invertebrados herbívoros, por exemplo, são organismos que coexistem intimamente com as macroalgas e, portanto, devem possuir papel relevante na distribuição desses organismos no ambiente. De fato, alguns estudos têm sugerido que os fatores internos de uma comunidade parecem ser mais importantes para determinar as suas variações do que os fatores externos, pontuais ou sazonais, que atuam durante o período de colonização. Neste contexto, o presente estudo investigou as possíveis interações bióticas existentes entre as micro e macroalgas de riachos tropicais, através da condução de um estudo experimental. De forma mais específica, o primeiro objetivo foi avaliar a existência de competitição ou cooperação entre as algas bentônicas (micro e...
Abstract: The stream macroalgae have been considered, along with periphyton, bryophytes and macrophytes, one of the main primary producers in streams environments. For this reason, in recent decades many studies have been performed to understand the spatiotemporal distribution of these organisms. Most of these studies have only investigated the effects of environmental variables on patterns of ecological distribution of macroalgae streams. However, only the relationship between the occurrence and distribution of these organisms and the changes in environment has been shown to be poorly predictive in relation to the establishment and maintenance of macroalgae in these ecosystems. Thus, it seems clear that, beyond the dynamic mosaic of environmental conditions, other forces acting on these organisms should be considered in the analysis of their ecological distributions. In this sense, it is possible to imagine that biotic interactions on a small scale, that occur between coexistent organisms in the same stream stretch can also significantly influence on the ecological responses of these organisms. Microalgae and herbivorous, for example, are organisms that coexist intimately with macroalgae and therefore must have a relevant role in the distribution of these organisms in the environment. In fact, some studies have suggested that the internal factors of community seem to be more important in determining their variations than external, occasional or seasonal factors that act during the period of colonization. In this context, the present study investigated the possible existing biotic interactions between micro and macroalgae in tropical streams, by conducting an experimental study. More specifically, the first objective was to evaluate the existence of competition or cooperation between benthic algae (micro and macroalgae) over a process of colonization on artificial substrates. In addition, we tried to correlate these interactions with the dynamic ...
Doutor
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Madikiza, Liwalam Onwabile. "The role of grazers and basal sustrate cover in the control of intertidal algal distribution." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&.
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Tonetto, Aurélio Fajar [UNESP]. "Efeito das relações bióticas sobre o estabelecimento de macroalgas de ecossistemas lóticos tropicais: interação com microalgas e pressão por herbivoria." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/132717.
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000856267.pdf: 2565945 bytes, checksum: 07754b874d035f18e023aeb27c324535 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
As macroalgas lóticas têm sido consideradas, juntamente com perifíton, briófitas e macrófitas, um dos principais produtores primários de ambientes de riachos. Por essa razão, nas últimas décadas muitos trabalhos vêm sendo realizados na tentativa de entender-se a distribuição espaço-temporal desses organismos. A grande maioria desses trabalhos tem investigado exclusivamente os efeitos de variáveis ambientais sobre os padrões de distribuição ecológica das macroalgas de riachos. Entretanto, apenas a relação entre a ocorrência e distribuição desses organismos e as variações do ambiente tem demostrado ser pouco preditiva em relação ao estabelecimento e manutenção das macroalgas nestes ecossistemas. Assim, parece claro que, além do mosaico dinâmico de condições ambientais, outras forças que atuam sobre estes organismos devem ser consideradas na análise de suas distribuições ecológicas. Neste sentido, é possível imaginar que as interações bióticas, em pequena escala, que ocorrem entre os organismos que coexistem em um mesmo trecho de riacho também possam interferir de maneira significativa nas respostas ecológias desses organismos. As microalgas e macro-invertebrados herbívoros, por exemplo, são organismos que coexistem intimamente com as macroalgas e, portanto, devem possuir papel relevante na distribuição desses organismos no ambiente. De fato, alguns estudos têm sugerido que os fatores internos de uma comunidade parecem ser mais importantes para determinar as suas variações do que os fatores externos, pontuais ou sazonais, que atuam durante o período de colonização. Neste contexto, o presente estudo investigou as possíveis interações bióticas existentes entre as micro e macroalgas de riachos tropicais, através da condução de um estudo experimental. De forma mais específica, o primeiro objetivo foi avaliar a existência de competitição ou cooperação entre as algas bentônicas (micro e...
The stream macroalgae have been considered, along with periphyton, bryophytes and macrophytes, one of the main primary producers in streams environments. For this reason, in recent decades many studies have been performed to understand the spatiotemporal distribution of these organisms. Most of these studies have only investigated the effects of environmental variables on patterns of ecological distribution of macroalgae streams. However, only the relationship between the occurrence and distribution of these organisms and the changes in environment has been shown to be poorly predictive in relation to the establishment and maintenance of macroalgae in these ecosystems. Thus, it seems clear that, beyond the dynamic mosaic of environmental conditions, other forces acting on these organisms should be considered in the analysis of their ecological distributions. In this sense, it is possible to imagine that biotic interactions on a small scale, that occur between coexistent organisms in the same stream stretch can also significantly influence on the ecological responses of these organisms. Microalgae and herbivorous, for example, are organisms that coexist intimately with macroalgae and therefore must have a relevant role in the distribution of these organisms in the environment. In fact, some studies have suggested that the internal factors of community seem to be more important in determining their variations than external, occasional or seasonal factors that act during the period of colonization. In this context, the present study investigated the possible existing biotic interactions between micro and macroalgae in tropical streams, by conducting an experimental study. More specifically, the first objective was to evaluate the existence of competition or cooperation between benthic algae (micro and macroalgae) over a process of colonization on artificial substrates. In addition, we tried to correlate these interactions with the dynamic ...
FAPESP: 10/17563-0
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Zacher, Katharina. "Effects of UV radiation on Antarctic benthic algae : with emphasis on early successional stages and communities = Effekte von UV-Strahlung auf antarktische benthische Algen : mit schwerpunkt auf jungen Entwicklungsstadien und Gemeinschaften /." Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 2007. http://www.loc.gov/catdir/toc/fy0804/2008422507.html.
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Whitton, Rachel Louise. "Algae reactors for wastewater treatment." Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/10289.
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The onset of the Water Framework Directive (WFD) will challenge water utilities to further reduce their wastewater phosphorus discharges to < 0.5 mg.L- 1. Whilst conventional treatments, such as chemical dosing, are able to meet these new discharge consents, the strategies are representative of a linear economy model where resources are unrecovered and disposed. An alternative solution which can contribute to the aspiration of a circular economy is microalgae. Microalgae are ubiquitous in wastewater environments and assimilate phosphorus during their growth, to residual concentrations complementary of the WFD. Furthermore, microalgal biomass can be anaerobically digested to produce biomethane offering the potential for an energy neutral approach. However, uptake of microalgal systems are lacking in the UK through limited knowledge of operation; and the belief that such solutions are synonymous to large, shallow open ponds with extensive treatment times. The development of alternative microalgal reactors are increasingly investigated to overcome these implementation challenges. Of these, immobilised microalgae has shown great potential; and whilst within its infancy demonstrates the greatest opportunity for development and optimisation. This thesis determines the critical operational parameters that influence the remediation efficacy of immobilised microalgae for tertiary nutrient removal; including species selection, biomass concentration, treatment period and lighting; with recommendations for optimal performance. These recommendations are then applied to the design and operation of an immobilised bioreactor (IBR) to understand the key design and operating components that influence the overall economic viability. In doing so, the potential for an IBR to be economically viable, within the next decade, in comparison to traditional approaches are discussed.
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Emil, Axelsson. "Up-scaling of algae cultivation." Thesis, Luleå tekniska universitet, Industriell miljö- och processteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-60493.
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Microalgae are one of the oldest types of lifeforms on this planet and dead algae are one source for the oil that we extract from the ground. This oil has a major part in the technology advances of humanity, to levels unimaginable not long ago. Unfortunately, this oil is one of the major reasons for the global warming and other environmental issues caused by humans. Therefore, much effort is made on new technologies to decrease the use of fossil oil and other fossil material in favor for so called renewable sources. In this work focus is on production of biomass that can be used for processing to other bulk materials, mainly chemicals. This is also a highly potential market, the amount of materials derived from fossil sources are at least 422 million metric tons per year. The issue though is that the production costs for algae are still fairly high and can’t compete with the market price of fossil raw materials. Two algae species, Scenedesmus obliquus and Coelastrella sp., were cultivated in 6 pilot size ponds (500 L) and the results were compared to a lab experiment (0.5 L). The lab experiment was earlier performed by the author’s supervisors with the same species. The algae in the ponds were cultivated outdoor with flue gas in semi-closed ponds and the resulting biomass was allowed to sediment spontaneously. Scenedesmus obliquus was successfully cultivated in the pilot, but the system was not suitable for cultivation of Coelastrella sp. The main aim of this work was to evaluate if it is possible to predict the amount of biomass produced in the pilot cultivation based on the results from the previously performed lab cultivation. The conclusion based on the results in this work is that it not possible to predict the biomass production in the pilot based on lab experiments. The properties and behavior of different algae species can be very different in different systems, and the setups in this study differed too much. However, the results indicate that the pilot system has a high efficiency and can maintain a monoculture outdoors for at least 18 days as well as that the supply of flue gas highly affects the growth of the algae Scenedesmus obliquus.
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Ress, Jennifer Ann. "The Ecology of Aerial Algae." Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1332874801.
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Bosley, Amber L. "Algae Characterization and Processing Techniques." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1321538296.
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Girme, Gauri Manik. "Algae powered Microbial Desalination Cells." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397735584.
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Cherad, Ramzi. "Supercritical water gasification of algae." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/11442/.
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Diversification of our energy supplies – especially in the transport and electricity generation sectors – is required to meet decarbonisation targets. Algae have been identified as suitable alternative feedstocks for third generation biofuels due to their fast growth rates and non-competitiveness with land for food crops. Hydrothermal processing of algae is an appropriate conversion route as it allows the processing of wet feedstock thus removing the energy penalty of drying. In this study, supercritical water gasification was used for (i) the hydrothermal processing of macroalgae for the production of gaseous fuel – mainly hydrogen and methane – and (ii) the upgrading of the process water from hydrothermal liquefaction of microalgae for hydrogen production for biocrude hydrotreating. The supercritical water gasification (SCWG) of the four macroalgae species investigated (Saccharina latissima, Laminaria digitata, Laminaria hyperborea, and Alaria esculenta) produced a gas that mainly consisted of hydrogen, methane and carbon dioxide. Non-catalytic SCWG resulted in hydrogen yields of 3.3-4.2 mol/kg macroalgae and methane yields of 1.6-3.3 mol/kg macroalgae. Catalytic SCWG (using ruthenium) resulted in hydrogen yields of 7.8-10.2 mol/kg macroalgae and methane yields of 4.7-6.4 mol/kg macroalgae. The yield of hydrogen was approximately three times higher when using sodium hydroxide as catalyst (16.3 mol H2 / kg macroalgae) compared to non-catalysed SCWG of L. hyperborea (5.18 mol H2 / kg macroalgae). The energy recovery (an expression of how much chemical energy of the feedstock is recovered in the desired product following hydrothermal processing) was 83% when sodium hydroxide was used as a catalyst, compared to 52% for the non-catalytic SCWG of L. hyperborea. The yield of methane was approximately 2.5 times higher (9.0 mol CH4 kg 1macroalgae) when using ruthenium catalyst compared to the non-catalysed experiment (3.36 mol CH4 / kg macroalgae) and the energy recovery increased by 22% to 74%. The selectivity of methane or hydrogen production during the SCWG of macroalgae can be controlled using ruthenium or sodium hydroxide respectively. Longer hold times and increased reaction temperature favoured methane production when using ruthenium. An increase in catalyst loading had no significant effect on the methane yield. Higher hydrogen yields were obtained through using higher concentrations of sodium hydroxide, lower algal feed concentration and shorter hold times (30 min). Increasing reaction times ( > 30 min) with a base catalyst (sodium hydroxide) decreased the hydrogen yield. Overall energy recovery was highest at the lowest feed concentrations; 90.5% using ruthenium and 111% using sodium hydroxide. The process waters from the hydrothermal liquefaction (HTL) of microalgae (Chlorella, Pseudochoricystis, and Spirulina) were gasified under supercritical water conditions to maximise hydrogen production. Hydrogen yields ranged from 0.18-0.29 g H2 / g biocrude from SCWG of the process water of HTL along with near complete gasification of the organics (~98%). Compared to the hydrogen requirements for hydrotreating algal biocrude (~0.05 g H2 / g biocrude), excess hydrogen can be produced from upgrading the process water through SCWG. The results indicate that process waters following SCWG are still rich in nutrients that can be recycled for algal cultivation.
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Vinikoor, Conner Reid. "Life History of Volvocine Algae." Thesis, The University of Arizona, 2010. http://hdl.handle.net/10150/146595.
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The evolution of somatic cells is a key aspect in the evolution of single to multicellular life forms. Our model is based on an empirically tested model of the growth of unicellular Chlamydomonas algae and a suggestion by Koufopanou (1994) that the basic mechanism underlying Chlamydomonas growth and reproduction may better explain the diversity of more complex volvocine algae morphologies. Six strains of Pleodorina starrii investigated in terms of the parameters of the model, yielded data for the proportion somatic (p) at various cell number sizes.
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Novitski, Linda Nicole. "BENTHIC ALGAL COMMUNITY STRUCTURE ALONG AN ELEVATIONAL AND CHEMICAL GRADIENT IN THE HAZEL CREEK WATERSHED, GREAT SMOKY MOUNTAINS NATIONAL PARK." Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1155742200.
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Pande, Nilesh Navalkishor. "Interactions between the toxic alga, Alexandrium fundyense, and its bacterial associates stimulation, inhibition, and specificity /." Restricted access (UM), 2008. http://libraries.maine.edu/gateway/oroauth.asp?file=orono/etheses/37803141.pdf.
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These (Ph.D.)--University of Massachuesetts Lowell, 2008.Title from PDF title page. Available through UMI ProQuest Digital Dissertations. Includes bibliographical references (leaves 55-66). Also issued in print.
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Vilas, Boas Lucas Kortz. "Efeitos das variações de temperatura relacionados às mudanças climáticas globais sobre as respostas fotossintéticas de macroalgas lóticas tropicais /." Rio Claro, 2016. http://hdl.handle.net/11449/143878.
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Orientador: Ciro Cesar Zanini BrancoBanca: Renata Giassi Udulutsch
Banca: Edson Fontes de Oliveira
Resumo: Apesar da existência de ciclos de alterações da temperatura média global na história da Terra, atividades antrópicas têm causado um aumento das concentrações de gases do efeito estufa na atmosfera desde a revolução industrial, causando mudanças climáticas já observadas nas últimas décadas. Tais mudanças climáticas afetam os organismos de ambientes aquáticos continentais, incluindo os produtores primários (p.ex., macroalgas). Utilizando as técnicas da evolução da concentração de oxigênio dissolvido, da concentração de pigmentos fotossintetizantes e da fluorescência da clorofila a, avaliou-se o efeito do aumento de temperatura devido ao aquecimento global, previsto em dois cenários futuros (RCP 4.5 e RCP 8.5 do Painel Intergovernamental de Mudanças Climáticas - IPCC) sobre as respostas fotossintéticas de macroalgas lóticas. As temperaturas controle foram determinadas, para os períodos de inverno e verão, a partir da temperatura média de riachos da região onde as amostras de macroalgas (Filos Rhodophyta, Cyanobacteria e Chlorophyta) foram coletadas e as temperaturas experimentais calculadas adicionando-se os aumentos previstos pelos cenários testados do IPCC. A resposta à simulação dos cenários do IPCC se deu de modo espécie-específico, contudo, os resultados gerais indicaram que dentre as espécies testadas, as Rhodophyta (Batrachospermum helminthosum Bory, Sirodotia delicatula Skuja e estágio "Chantransia") teriam sua eficiência fotossintética prejudicada com o aumento de tempe... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Despite the existence of global mean temperature shift cycles in Earth's history, anthropogenic activities have been causing an increase in the concentration of greenhouse gases since the industrial revolution, inducing the climate changes already observed over the last decades. Such climate changes affect freshwater organisms, including primary producers (i.e. macroalgae). Using the techniques of dissolved oxygen evolution, photosynthetic pigments concentration and chlorophyll a fluorescence, we evaluated the effect of projected temperature increase due to global warming of two future scenarios (RCP 4.5 and RCP 8.5 of the Intergovernmental Panel on Climate Change - IPCC) on the photosynthetic response of lotic macroalgae. Control temperatures were determined, for summer and winter seasons, from the mean temperature of streams of the region where macroalgae samples (phyla Rhodophyta, Cyanobacteria and Chlorophyta) were collected and experimental temperatures were calculated adding the projected increase of the tested IPCC scenarios. The response to the IPCC scenarios simulation showed a species-specific pattern, although results in general indicated that within tested species, the red algae (Batrachospermum helminthosum Bory, Sirodotia delicatula Skuja and "Chantransia" stage) would have their photosynthetic efficiency impaired with temperature increase, especially in scenario RCP 8.5 during the summer. In addition, most Chlorophyta investigated did not show a significant pro... (Complete abstract click electronic access below)
Mestre
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Nylund, Göran M. "Epibiosis of red algae and algal metabolites as settlement inhibitors of the barnacle Balanus improvisus Darwin." Göteborg [Sweden] : Dept. of Marine Botany, Göteborg University, 1999. http://bibpurl.oclc.org/web/20311.
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Thesis (master's)--Göteborg University, 1999.Title from PDF t.p. (viewed on Sept. 25, 2007). At head of title: Tjärno Marine Biological Laboratory. Includes bibliographical references (p. 13-14).
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Kaehler, Sven. "Causes and consequences of the spatial and temporal distribution of encrusting algae on tropical rocky shores." Thesis, Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17505616.
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Dunmore, Robyn Ann. "Demography of early life stages of habitat-forming intertidal fucoid algae." Thesis, University of Canterbury. Biological Sciences, 2006. http://hdl.handle.net/10092/1364.
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The intertidal zone is finely partitioned in species distributions and abundances. The demographies of key species over varying spatial and temporal scales are fundamental to understanding the population structure and overall dynamics of habitats and assemblages. In this thesis, settlement, dispersal and early life stage survival and growth were examined in several habitat-forming intertidal fucoid algae in New Zealand and Oregon, U.S.A. Natural settlement patterns of Hormosira banksii, Cystophora torulosa and Cystophora scalaris were quantified for over three years at a semi-protected shore in southern New Zealand. Settlement was monitored in four tidal zones, within bare rock and algal habitats. Settlement was synchronous between tidal zones but the density of settlement varied spatially and temporally. There were significant differences between tidal zones, habitats and times of the year. For H. banksii, small pulses of settlement occurred year-round with greatest densities during spring and early summer. Greatest settlement occurred at low tidal zones and under adult canopies. Both Cystophora species also reproduced year-round, but had much lower settlement densities than H. banksii. Most settlement occurred during spring and summer, while only small pulses occurred in autumn and winter months. Most settlement was in the lowest tidal zone (0.4 m above chart datum), with only a few zygotes settling at higher shore zones. Canopy cover had no significant effect on settlement densities. Dispersal was examined in Durvillaea spp., H. banksii, C. torulosa and Fucus gardneri. For all species, settlement densities declined with distance from the source populations, but densities were variable between species. Durvillaea spp. dispersal was more extensive than expected, with significant settlement occurring 32 m from the source population, the maximum sample range of the study. However, settlement densities were much higher within 8 m from the source. The extensive dispersal of Durvillaea spp. is a result of the combination of small, slowly sinking eggs and the presence of buoyant mucilage. The other species studied showed far more restrictive dispersal, and much lower settlement densities. Settlement occurred 2 m from the source, but most settlement occurred under or near the canopy. The eggs of these species are much larger and sink faster than the eggs of Durvillaea spp. The consequences of settling at different shore heights and seasons were examined in H. banksii and D. antarctica in New Zealand, and F. gardneri and Pelvetiopsis limitata in Oregon. Transplant experiments tested the effects of grazing and heat/desiccation stress on survival and growth of germlings at different shore heights, during different seasons. High germling mortality was a feature of all species, but rate of mortality depended on conditions and species. There is a trade-off for settling at different times of the year; overall, growth was faster in warmer seasons, but survival was better in cooler seasons. During cooler seasons, germlings are exposed to less heat/desiccation stress, but their slow growth exposes them to grazing and competitive interactions for longer periods. For New Zealand species, shore height had large effects, with better survival and growth in the low shore. Grazers were very effective in the low shore, and heat/desiccation stress had strong effects in the mid and high shores. For Oregon species, effects of grazing and heat/desiccation stress were generally weaker than for New Zealand species. Shore height had weak effects, but ultimately low shore germlings had poor survival, primarily because of overgrowth by ephemeral algae. This is in contrast to the generalisation that survival and growth in the low shore should be better due to a more benign environment. In this study, species had specific demographies that related to their life history characteristics and responses to the local environment. Differences in settlement, dispersal abilities, survival and growth over small spatial and temporal scales clearly underpinned large scale differences in recruitment and adult distribution and abundances.
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Park, Sichoon. "The selective use of chlorine to inhibit algal predators and avoid pond crashes for the algae-biodiesel industry." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51867.
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As algae-derived biofuel is a promising renewable energy source, it is well-established that micro-algae have the potential to make a significant contribution to transportation fuel demand. Although it has many advantages including high areal productivity, there are many negative factors. One of these factors is the predation of algae by amoebas, protozoans, ciliates and rotifers, particularly in open pond systems. For example, the rotifer Brachionus plicatilis, is able to eat as much as 12,000 algae cells per hour and can be responsible for an entire pond crash within days. Thus, these higher organisms need to be controlled in order to satisfy large-scale algae crop and biofuel production demand. One method of predation control involves the introduction of a toxic chemical to an algal culture that the predator has a higher sensitivity to with respect to algae. Ideally, predation could be minimized or eliminated without a substantial effect on the algal culture growth. Chlorella kessleri was used as the algal culture and Brachionus calyciflorus as the source of predation. Research was conducted in five stages. First, chlorine dissipation tests were carried out using spring water, distilled water, Bolds Basal Medium (BBM), and three different dry weights of algal suspension in order to analyze the dissipation rate of the residual chlorine. The results showed that chlorine in distilled water and spring water rarely dissipated while chlorine concentration in algal suspension rapidly decreased by a maximum of 90% within the second hour. Second, acute chlorine toxicity tests were conducted in order to find the 24-hr LC50 of B. calyciflorus. The 24-hr LC50 of the test animal was 0.198 mg Cl/L. Third, chlorine toxicity tests were conducted in order to find the LC50 of Chlorella kessleri. The 24-hr LC50 of C. kessleri was 0.321 mg Cl/L. Based on these results, the test animal was more sensitive to chlorine than the test algae; therefore chlorine may be used to avoid algae pond crashes by B. calyciflorus. Fourth, C. kessleri and B. calyciflorus were combined into one test to determine how long it would take to observe an algal culture crash. The result demonstrated that the higher the population of predators in algal suspension, the faster it crashed. Finally, chlorine, C. kessleri, and B. calyciflorus were combined into one test to determine what chlorine concentration and dosing interval was needed to significantly reduce predation without significantly reducing algae growth. The results of the fifth experiment showed that the effective intermittent chlorine concentration was between 0.45 and 0.60 mg Cl/L, and a short interval of chlorine dosing was effective in inhibiting rotifers in algal suspension. Even though the rotifers in algal suspension were inhibited by 0.45 to 0.60 mg Cl/L, algae growth was greatly inhibited by chlorine. In this respect, future work is needed to reduce the effect on algae by chlorine or alternative chemicals.
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Lekan, Danelle Kara. "Influence of temperature, salinity and nutrients on growth and toxin of Karenia brevis clones." View electronic thesis, 2008. http://dl.uncw.edu/etd/2008-2/r3/lekand/danellelekan.pdf.
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Lees, Fiona M. "Studies on metal-tolerant estuarine algae." Thesis, Heriot-Watt University, 1985. http://hdl.handle.net/10399/1620.
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Ball, Lucy Ann. "Carbon acquisition in the chrysophyte algae." Thesis, University of Dundee, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403161.
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Patel, Bhavish. "Wet algae processing for biofuel production." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/62984.
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Microalgae is seen as a sustainable source of chemicals and biofuels, but its processing to low value fuels is expensive, particularly due to drying, and thus the feasibility of a wet processing route is necessary. This thesis presents experimental research and life cycle assessment on the conversion of microalgal biomass to liquid biofuel (precursor) using high temperature and pressure processing technologies. The bulk of the work is related to Hydrothermal Liquefaction of algal biomass at various residence time (0.5 - 60 min) and temperatures within the Hydrothermal regime (275 - 380°C), using both batch and novel in-house built continuous flow reactor systems. Several analytical tools were deployed to assist with analysis of the formed biocrude to help understand the effect of the reaction conditions on the formed products. Having analysed the biocrude, it became apparent that the aqueous phase contained substantial matter and as such an investigation to quantitate the inorganics in the aqueous phase was conducted. As for the biocrude, detailed analysis showed that further treatment was necessary to make it amenable for utility directly or as a blended fuel and thus, Hydrotreatment using commercially available catalyst under H2 in a batch reactor was conducted. Lastly, the conversion of algal lipids to biodiesel as well as other constituents was investigated under Hydrothermal conditions in presence of methanol, leading to in situ Supercritical Transesterification. The reaction conditions used were found to be too severe for stable yield of methyl esters and consequently degradation kinetics of methyl esters was calculated. Lastly, to understand the environmental profile of the investigated processes, a life cycle assessment was conducted based on experimental data combined with literature values for a conceptual biorefinery in 5 different countries with differing energy mixture. The thesis ends with concluding remarks on the investigation and potential direction for future work.
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O'Rourke, Christina Margaret. "Cell wall polysaccharides in charophytic algae." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/17868.
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Plants colonised land 460 million years ago and charophytes represent the closest living relatives of land plants. The ability to live on land may depend on the presence of certain cell wall polysaccharides such as xyloglucan, a hemicellulose exclusively found in land plants (Popper and Fry, 2003). The cell walls of charophytes are poorly characterised. The aim of this project was to use biochemical techniques to characterise the cell wall polysaccharides of charophytic algae in relation to early land plant phylogeny. Hydrolysis of Coleochaete scutata and Chara vulgaris cell walls in 2 M trifluoroacetic acid yielded predominantly GalA, Gal, Glc and Man residues and also some Ara, Xyl and traces of Fuc and Rha. In addition, hydrolysis of Chara pectin revealed an abundance of an unusual monosaccharide, 3-O-methyl-D-galactose, which was structurally identified by a series of 1-D and 2D NMR spectroscopy by COSY, TOCSY, NOESY and HSQC. 3-O-Methyl-D-galactose is more commonly found in lycophyte cell walls where its presence has been suggested to be related to lycophytes’ evolutionarily isolated position (Popper et al., 2001). The newly discovered presence of 3-O-methyl-D-galactose in charophyte pectin suggests that this polymer may be more complex than previously thought. Coleochaete and Chara hemicellulose extracts were fractionated by anion-exchange chromatography into five classes. A strongly anionic fraction from Chara hemicellulose was found to be rich in Glc, Xyl, Gal and Fuc suggestive of a xyloglucan-like polysaccharide. However, XEG was unable to produce diagnostic xyloglucan oligosaccharides in either Coleochaete or Chara hemicelluloses. Xylanase and mannanase digestion of Coleochaete and Chara hemicelluloses gave xylan- and mannan-oligosaccharides. Furthermore, lichenase digestion of Coleochaete hemicellulose yielded an unusual octasaccharide composed of approximately equimolar xylose and glucose. My work has shown that charophyte cell walls are a source of undiscovered monosaccharides and potentially novel pectic and hemicellulosic domains which may have important functions in enabling the successful colonisation of land by plants.
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Ayarza-León, Jorge Luis. "Alginates: 20000 applications of submarine algae." Revista de Química, 2014. http://repositorio.pucp.edu.pe/index/handle/123456789/100618.
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Desde la antigüedad, el ser humano ha encontrado recursos de gran utilidad en el mar. Las algas pardas marinas de la clase Phaeophyceae son la fuente de un biopolímero con propiedades muy interesantes, denominado alginato. En la actualidad, el alginato es extraído y comercializado en muchos lugares del mundo, es un componente importante en muchos productos de uso diario, e incluso se le emplea a nivel de investigación académica.Since antiquity, mankind has depended on the sea to obtain valuable resources. Marine brown algae from the class Phaeophyceae are the source of a biopolymer with very interesting properties called alginate. Nowadays, alginate is extracted and commercialized around the world, it is an essential component in many everyday products, and it is even used in academic research.
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Venkatagiri, Avinash. "Materials and Methods for Algae Preconcentration." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1406313094.
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Hong, Yu. "Microwave-enhanced thermal processing of algae." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/46682/.
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Algae are promising substitutes to the widely-used fossil fuels. The thermochemical conversion of algae has been investigated extensively in the past two decades. In this study, systematic investigation of microwave-enhanced pyrolysis of algae together with catalytic reforming was conducted aiming at developing a new approach for the production of more syngas-enriched gas product from algae and other marine biomass. Firstly, the characterisation of algae was conducted to show the nature of the raw materials followed by the kinetic study of the decomposition of a suite of micro- and macro-algae, i.e., spirulina, chlorella and porphyra. The kinetic study was carried out using model algae, i.e. the use of ovalbumin as protein, oil droplets as lipid and cellulose as polysaccharides or carbohydrate to simulate a real alga. The thermogravimetric characteristics of algal samples were studied based on the analysis of TG and DTG curves. Kissinger-Akahira-Sunose method was used to derive the activation energy and pre-exponential factor. Moreover, the optimal reaction mechanism was determined by using Coats-Redfern method of the decomposition of different samples. The morphology and composition of char after TG analysis were characterised by using SEM/EDS. By comparing the characteristics of chars prepared in N2 and CO2 atmosphere, it was found that CO2 atmosphere favored the pyrolysis of algal protein with lower required activation energy (about 235 kJ mol-1) and shortened the pyrolysis time by 5.9-20.2%. But it was also found that the algal lipid increased the difficulty for the pyrolysis of algae with relatively higher activation energy around 200 kJ mol-1 (>180 kJ mol-1 under N2). However, the activation energy of cellulose decomposition remained almost the same around 310 kJ mol-1 in N2 and CO2. Therefore, CO2 atmosphere is more suitable for the pyrolysis of algae with high protein content and low lipid content. It was also found that protein in algae decomposes first, which is followed by the decomposition of carbohydrates and then lipids. Secondly, in order to obtain a high yield of syngas-enriched gas product from algae, microwave-enhanced pyrolysis of algae (spirulina, chlorella, dunaliella, laminaria and porphyra) and primary model algal compounds, i.e. cellulose and ovalbumin, at 400, 550 and 700°C in N2 atmosphere was conducted. The distribution and composition of gaseous, liquid and solid products were also studied in detail. Amongst the five algae, porphyra is the most promising raw material for high syngas-enriched gas production with more than 85 wt.%, while protein-rich spirulina and chlorella favored bio-oil production which yielded in about 10 wt.%. Meanwhile, with 94 wt.% carbohydrate, dunaliella converted most of its carbohydrates into C1-C3 gases. With a high portion of incombustible components (14.7-23.3 vol.% of CO2), laminaria has relatively lower gaseous production which was less than 80 wt.%. It also found that the optimal pyrolysis temperature was in the range of 400 to 550 °C for most of the samples except for spirulina which was at 700 °C. For the production of bio-oil, microalgae, with high protein content, were favored to be the raw materials (oil yield of 5.2-15.4 wt.%), compared to macroalgae (oil yield of 1.8-5.2 wt.%). Moreover, microalgae- spirulina and chlorella-favoured the formation of more phenols and nitrogenated compounds (10.8-17.8% and 20.9- 28.7% respectively) primarily from protein content, while less PAHs of 11.4-29.9% which mainly derived from algal carbohydrates. Finally, microwave-enhanced reforming of algae under CO2 atmosphere was conducted at 400, 550 and 700°C, together with the comparison of the results including the distribution and composition of gas, bio-oil and char in N2 and CO2 atmospheres. Compared with the product distribution derived under N2, the bio-oil yield from most algae in CO2 increased by 50- 170%, whilst the production of gas slightly decreased by 1-7%. Under CO2 atmosphere, the syngas in spirulina and chlorella gas product dramatically decreased by 60.8-69.7% and 7.1-17.6% respectively, while that from dunaliella increased by 23.4-30.4%. The percentage of syngas for the other samples remained similar. For the bio-oil derived from all the five algae samples, there were nearly no PAHs contained. In addition, the ash of algae was used as catalyst and introduced into the pyrolysis of five algae respectively under N2 atmosphere at 550°C. Compared with the non-catalytic pyrolysis, the weight percent of char from most algae increased by 20-90% using laminaria and porphyra ash, due to the decomposition of compounds in bio-oil. The syngas percentage from microalgae significantly increased by 6-45%, while that from macroalgae slightly decreased by 2-15% with the addition of spirulina, chlorella and porphyra ash. The content of PAHs in the bio-oil of spirulina, chlorella, laminaria and porphyra considerably reduced by 29-94%, while the amount of aromatics from spirulina and chlorella increased to around 1.3-7.1 times. In summary, the microwave-enhanced pyrolysis of algae favored the production of more CO/H2 rich gas at lower pyrolysis temperature under N2 atmosphere, while under CO2 atmosphere the yield of bio-oil increased. With the addition of algal ash as catalysts, the CO+H2 percentage in gas production from microalgae increased significantly. Therefore, it can be concluded that the microwave-enhanced pyrolysis of algae is an effective and efficient process for the conversion of algal biomass into value-added fuels.
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Foltz, Garrett. "Algae Lysis with Pulsed Electric Fields." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/732.
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With growing interest in alternative fuels, algae lipid harvesting is seen as a possible source of biofuel. Algae species under consideration include Chlorella vulgaris, Chlamydomonas reinhardtii and Dunaliella salina due to lipid contents as high as 30% to 56% of their dry weight (depending on growth conditions) and availability [5], [6]. In order to harvest lipids from algae, the cells must first be lysed.
Lysing is achieved by breaking the algal cell wall or membrane to separate oil from the rest of the algae biomass. Current lysing procedures use enzymes, pressure homogenization, and/or sonication to lyse cells; however, these methods are costly and complicate oil extraction [9], [10].
This project examines a novel method of cell lysis through pulsed electric field (PEF) application that enables cost-effective extraction methods relative to current enzyme and sonication techniques.
A theoretical model for cell membrane potential in the presence of electric field was developed, and PEF chambers were manufactured on microscope slides to enable microscope viewing and cell lysis recording during PEF application. Additionally, larger static chambers were created for testing higher volumes of algal solution. Electric field characteristics, such as pulse width, pulse number and magnitude, sufficient for lysis of Dunaliella salina and Chlorella vulgaris were found.
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Graham, Sylvia Lynne. "Growth and grazing of microzooplankton in response to the harmful alga Heterosigma akashiwo in prey mixtures /." Online version, 2008. http://content.wwu.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=305&CISOBOX=1&REC=8.
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Peres, Cleto Kaveski. "Taxonomia, distribuição ambiental e considerações biogeográficas de algas verdes macroscópicas em ambientes lóticos de unidades de conservação do sul do Brasil /." Rio Claro : [s.n.], 2011. http://hdl.handle.net/11449/100618.
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Orientador: Ciro Cesar Zanini BrancoBanca: Carlos Eduardo de Mattos Bicudo
Banca: Orlando Necchi Junior
Banca: Ina de Souza Nogueira
Banca: Celia Leite Sant'Anna
Resumo: Algas verdes são organismos presentes em todo o mundo, ocorrendo em uma grande amplitude de condições ecológicas. Em ambientes lóticos, elas são importantes tanto para a produção primária quanto para a criação e manutenção de habitats para outros organismos. Neste contexto, o presente estudo teve como objetivo abordar a taxonomia, distribuição ambiental e considerações biogeográficas das algas verdes macroscópicas de ambientes lóticos localizados em Unidades de Conservação (UC) na região Sul do Brasil. Para tanto, foram amostradas 10 UC's dos quatro principais biomas desta região, totalizando 105 riachos. Na abordagem taxonômica foram tratadas 16 espécies pertencentes às ordens Chaetophorales, Cladophorales, Klebsormidiales, Microsporales e Ulotrichales, além de três espécies de algas verdes coloniais. Uma espécie do gênero Basicladia foi considerada como novo registro para a ciência e Cladophora sterrocladia foi registrada pela primeira vez no Brasil. Na abordagem teórica foram discutidos os aspectos reprodutivos das famílias Oedogoniaceae e Zygnemataceae e a sua implicação em estudos taxonômicos e ecológicos. Uma hipótese relacionada à poliploidia foi sugerida para explicar a baixa frequência de ocorrência de espécimes portadores de estruturas reprodutivas em ambientes lóticos. A partir dos materiais destas duas famílias encontrados nos riachos do Sul do Brasil foi conduzida uma separação em 12 morfotipos baseados essencialmente no diâmetro celular. Estes morfotipos foram testados quanto a sua relação com as variáveis ambientais. Por fim, considerando o aspecto ecológico foi abordada a distribuição ambiental das algas verdes macroscópicas de riachos nos principais biomas da região Sul do Brasil, levando em consideração os padrões de riqueza, abundância e composição de espécies e a sua relação com a distância geográfica e as ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Green algae are organisms found throughout the world, occurring in a wide range of ecological conditions. In lotic environments, green algae are important both for primary production and for the creation and maintaining of habitats for other organisms. In this context, this study aimed to addressing the taxonomy, ecological distribution and biogeographical considerations of lotic macroscopic green algae in conservation units (UC) in Southern Brazil. For this purpose, 10 UC's in four principal biomes of this region were sampled, amounting 105 streams. In the taxonomic approach were treated 16 species belonging to the orders Chaetophorales, Cladophorales, Klebsormidiales, Microsporales and Ulotrichales, and three species of colonial green algae. One species of the genus Basicladia was considered as a new record to the science and Cladophora sterrocladia was first recorded in Brazil. In the theoretical approach were discussed the reproductive aspects of Oedogoniaceae and Zygnemataceae families and their implication in the taxonomic and ecological studies. One hypothesis related to polyploidy was suggested to explain the low frequency of specimens bearing reproductive structures in lotic environments. Based on the materials found in southern Brazil was made a division into 12 morphotypes based essentially on cell diameter. These morphotypes were tested for their relationship with environmental variables. Finally, the ecological aspect addressed the environmental distribution of macroscopic green algae from streams of the main biomes of Southern Brazil, taking into account the richness, abundance and species composition and their relation to geographic distance and the environment variables. The results showed that the presence or absence of the group was essentially related to shading and, to a lesser degree, to pH and current velocity of the sampling segment. Once occurring in a given ... (Complete abstract click electronic access below)
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Crulhas, Bruno Pereira. "Avaliação das respostas fotossintéticas de macroalgas lóticas sobre diferentes composições espectrais da radiação incidente /." Rio Claro, 2013. http://hdl.handle.net/11449/87866.
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Orientador: Ciro Cesar Zanini BrancoCoorientador: Orlando Necchi Júnior
Banca: Rosana Marta Kolb
Banca: Rogerio Antonio Krupek
Resumo: A luz incidente é certamente uma das principais variáveis ambientais que influenciam a distribuição, estrutura e funcionamento das comunidades de macroalgas de ecossistemas lóticos. Por isso, a influência da variação qualitativa e quantitativa da luz incidente sobre as respostas fotossintéticas foi analisada em onze táxons macroalgais pertencentes aos Filos Chlorophyta, Cyanobacteria, Rhodophyta e Xanthophyta, utilizando as técnicas de oxigênio dissolvido e fluorescência da clorofila a. Através destas técnicas foram produzidas curvas de fotossíntese-irradiância e então calculados vários parâmetros fotossintéticos. As espécies do Filo Chlorophyta registraram uma preferência pela luz verde, com altos valores de Pmax, eficiência fotossintética e rendimento quântico efetivo, nesta faixa do espectro luminoso. Em relação à quantidade de luz disponível, o grupo apresentou padrões espécie-específicos, tanto com espécies tidas como de sombra como de sol. O Filo Cyanobacteria apresentou melhor aproveitamento fotossintético quando exposto à luz vermelha, pois, obteve altos valores de rendimento quântico efetivo e eficiência fotossintética neste tratamento. Quanto à quantidade de luz incidente, o grupo demonstrou resposta indiferente, sem uma clara tendência nos seus parâmetros fotossintéticos nos tratamentos de atenuação. O Filo Rhodophyta demonstrou altos valores de eficiência fotossintética e rendimento quântico efetivo nos espectros luminosos azul e vermelho e, considerando os dados quantitativos, o grupo apresentou respostas fotossintéticas típicas de plantas de sombra, com baixos valores de Pmax, e do ponto de saturação e altos valores de rendimento quântico efetivo e eficiência fotossintética sob menores irradiâncias. O Filo Xanthophyta, no experimento qualitativo, obteve... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The incident light is certainly one of the main environmental variables which influence the distribution, structure and functioning of lotic macroalgae communities. Therefore, the influence of qualitative and quantitative variation of incident light on the photosynthetic responses were analyzed in eleven especies pertaining to Chlorophyta, Cyanobacteria, Rhodophyta and Xanthophyta, using the techniques of dissolved oxygen and chlorophyll a fluorescence. Through these techniques the irradiance curves were made and then the photosynthetic parameters were analyzed. The species of Chlorophyta recorded a preference for the green light, with high Pmax, photosynthetic efficiency and quantum yield, in this range of the light spectrum. Relative to the quantity of light available, the group presented speciesespecific patterns with both sun and shade species. The Cyanobacteria showed better exploitations when exposed to red light, whereas, obtained high values of effective quantum yield and photosynthetic efficiency in this treatment. Regarding to the amount of incident light, the group showed indifferent response, with no clear trend in its photosynthetic parameters in the attenuation treatments. The Rhodophyta, in the qualitative experiment demonstrated high values of photosynthetic efficiency and effective quantum yield in the blue and red spectrum, and in the quantitative experiment, the group presented photosynthetic results typical of shade plants due to low Pmax and saturation point, and high values of effective quantum yield and photosynthetic efficiency under lower irradiances. The Xanthophyta obtained milder and similar values of photosynthetic parameters among the tested treatments in the qualitative experiment, being indifferent to the type of available spectrum. In the quantitative experiment, it showed a preference... (Complete abstract click electronic access below)
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