Em seu habitat natural as algas estão sujeitas a ação simultânea de vários fatores, como radiação (fotossinteticamente ativa e ultravioleta), temperatura, salinidade e disponibilidade de nutrientes, entre outros. A variação desses fatores no ambiente natural ocorre de forma coletiva e uma rápida resposta do organismo é determinante pra sua sobrevivência. Neste trabalho foram conduzidos experimentos relacionados aos efeitos da variação nos parâmetros ambientais sobre a macroalga Gracilaria domingensis. Três linhagens cromáticas dessa espécie foram cultivadas no mar, em diferentes épocas do ano (estações chuvosa e seca). Os dados fotossintéticos e bioquímicos foram acessados em uma escala de tempo referente às variações observadas durante o período de luz do dia e em uma escala referente às variações observadas em semanas. Os resultados obtidos a partir de análises dos parâmetros fotossintéticos, conteúdo pigmentar, concentração de glutationa, concentração de aminoácidos tipo micosporina, conteúdo tecidual de carbono, nitrogênio e fósforo, teor de lipídeos e ácidos graxos e rendimento do ágar mostraram alterações no perfil bioquímico e fisiológico da macroalga. Essas alterações foram correlacionadas com os fatores abióticos e sugerem alterações no metabolismo como uma das estratégias de aclimatação da espécie. / In their natural habitat algae are exposed to simultaneous action of various factors, as radiation (photosynthetically active radiation and ultraviolet), temperature, salinity, nutrient availability and others. The variation in these factors in the natural environment occurs collectively and the algae capability for quick response is determinant for survival. In this work, studies related to the effects of environmental variation on the macroalgae Gracilaria domingensis were performed. Three chromatic strains were cultivated in the sea, at different times of the year (dry and rainy seasons). Biochemical and photosynthetic responses were accessed on a daylight time scale and on a week time scale. The reached results for photosynthetic parameters, pigment content, glutathione concentrations, mycosporine-like amino acids concentrations, carbon, nitrogen and phosphorus tissue content, lipids and fatty acids levels and agar yield, revealed the altered biochemical and physiological profile of macroalgae. These changes were environment related and suggest metabolism changes as a strategy used by this organism to acclimate.

Orientador: Rafael Silva Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T00:25:50Z (GMT). No. of bitstreams: 1 GuilhermePereira_Caio_M.pdf: 4423463 bytes, checksum: b3d0cccfd6c5f84a9df0f479651580a0 (MD5) Previous issue date: 2013 / Resumo: Plantas carnívoras são aquelas que apresentam a capacidade de capturar e digerir pequenos animais, geralmente invertebrados. Os estudos com essas plantas começaram há mais de um século e, ainda hoje, não são conhecidos os mecanismos que determinaram a evolução e a distribuição geográfica dessas singularidades vegetais. Os modelos de custos--benefícios vêm, nesse sentido, atuando como guias para diversos estudos nas últimas décadas e parecem esclarecer diversos pontos obscuros quanto à ecologia e evolução dessas plantas. O gênero Philcoxia (Plantaginaceae), endêmico de campos rupestres -- ambientes associados a afloramentos rochosos e a formações de areia branca, propensos a eventuais queimadas e pobres em nutrientes --, apresenta características que acabaram por levar a questionamentos quanto à sua fisiologia. Com o acúmulo crescente de evidências, estudiosos começaram a sugerir que tais espécies pudessem apresentar mecanismos ativos de captura e digestão de presas. O estudo em questão teve como objetivo determinar se Philcoxia minensis exibe a síndrome da carnivoria e analisar os custos e benefícios desse hábito no contexto teórico sugerido por Thomas J. Givnish para a evolução da carnivoria. Para isso, fizemos uma detalhada descrição anatômica das folhas de P. minensis, na qual pudemos observar padrões evidentes de produção enzimática associada à digestão de invertebrados, em especial de fosfatases. Caracterizamos as estruturas glandulares responsáveis pela produção dessas enzimas, assim como os nematódeos que são considerados, até o momento, as únicas presas de P. minensis. Por fim, quanto à absorção de nutrientes derivados dos nematódeos, pudemos observar uma incorporação de 5% do nitrogênio das presas (Caenorhabditis elegans) em apenas 24h, e 15% em 48h em um experimento com isótopos estáveis. Para avaliar o balanço energético dessa espécie, analisamos de que forma características foliares associadas aos processos de fotossíntese e respiração se correlacionam. De maneira geral, encontramos forte correlação entre as capacidades fotossintéticas (Aarea e Amass) e os valores de LMA (quantidade de massa seca por unidade de área foliar) para as espécies não carnívoras, com um claro distanciamento dos indivíduos de P. minensis, que apresentaram taxas fotossintéticas extremamente baixas. Quanto às correlações entre os conteúdos de nitrogênio e de fósforo com as capacidades fotossintéticas, vimos que os indivíduos de P. minensis apresentaram taxas fotossintéticas extremamente baixas para os valores desses dois nutrientes e, embora uma tendência possa ser observada, não observamos correlações entre capacidades fotossintéticas e os conteúdos foliares de nitrogênio e fósforo. Por fim, conseguimos determinar conclusivamente a natureza carnívora de P. minensis, assim como pudemos posicionar essa espécie ao longo do espectro de economia foliar, tanto de forma local quanto em uma escala global. Nossos resultados ilustram o quanto ainda há para ser descoberto quanto à origem, à distribuição e à frequência da síndrome da carnivoria / Abstract: Carnivorous plants are plants that have the ability to capture and digest small animals, usually insects and other invertebrates. The studies with these plants began in the nineteenth century and until today it is unknown the underlying mechanisms that determine the evolution and the geographical distribution of these singularities. The cost--benefit models are, accordingly, acting as guidelines to various studies in recent decades and seem to be able to clarify many obscure points concerning the ecology and the evolution of these plants. The three species of the genus Philcoxia, endemic to campos rupestres -- fire prone and nutrient--poor environments usually associated with rocky outcrops and white sand formations -- have unique characteristics and adaptations that eventually led to several questions regarding the physiology of these plants. With growing accumulation of evidence, scholars started to consider the possibility that such plants could present active mechanisms for capturing and digesting prey. The present study aimed to determine if Philcoxia minensis exhibits the syndrome of carnivory and to analyze the costs and benefits of this habit in the theoretical context suggested by Thomas J. Givnish for the evolution of carnivory. In order to do so, we have made a detailed anatomical description of the leaves of P. minensis, in which we observed a clear pattern of enzyme production possibly associated with prey digestion, including phosphatases. We also characterized the glandular structures that are responsible for the production of the enzymes as well as the nematodes that are considered, until now, the only prey of P. minensis. Concerning the absorption of nutrients derived from prey, we observed an incorporation of 5% of the nitrogen of the nematodes (Caenorhabditis elegans) in 24h, and 15% in 48h in an experiment with stable isotopes. To evaluate the energy balance of this species, we analyzed correlations between leaf traits associated with the processes of photosynthesis and respiration. Generally speaking, we found a strong correlation between the photosynthetic capacity (Amass and Aarea) and the LMA (leaf mass per area) values for neighboring non--?carnivorous plants, with a distancing of P. minensis individuals, which showed very low photosynthetic rates. Regarding the correlations between the contents of nitrogen and phosphorus with photosynthetic capacities, we observed that the individuals of P. minensis showed extremely low photosynthetic rates for their nutrient concentrations and, although a tendency could be observed, there is no correlation between photosynthetic capacity and the foliar contents of nitrogen and phosphorus. Finally, we have conclusively determined the carnivorous nature of P. minensis and we placed this species along the leaf economics spectrum, both in local and global scale. Our results illustrate how much there is still to be discovered about the origin, distribution and frequency of the carnivorous syndrome / Mestrado / Ecologia / Mestre em Ecologia

Orientador: Eduardo Caruso Machado / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-21T03:39:07Z (GMT). No. of bitstreams: 1 Dovis_VeronicaLorena_D.pdf: 1810872 bytes, checksum: 889e3b63cede2d73563ccbfb91cdd3e1 (MD5) Previous issue date: 2012 / Resumo: As hipóteses deste estudo foram: a presença de frutos nas variedades de laranja tardia e as variações sazonais no ambiente afetam o desenvolvimento reprodutivo, o metabolismo de carbono e nitrogênio e o acúmulo e remobilização de reservas nos órgãos da planta; cada estádio fenológico tem necessidades nutritivas específicas, que afetariam a assimilação de CO2 e o metabolismo de carboidratos e nitrogênio. Estas hipóteses foram testadas em plantas que sofreram ou não desbaste total de frutos com o intuito de induzir variações na demanda de assimilados. O experimento foi executado em Cordeirópolis (SP) em plantas de laranjeira "Valência? de 2,5 anos de idade, crescidas em vasos de 100 L. Em maio de 2009, a metade das plantas foi completamente desbastada de frutos. A partir de julho e ao longo do ciclo produtivo avaliaram-se a dinâmica de assimilação de CO2, carboidratos e compostos nitrogenados, e a atividade de enzimas da assimilação de nitrogênio. O experimento foi inteiramente casualizado com três ou quatro repetições, segundo o parâmetro avaliado, o tratamento estatístico dos dados foi como parcelas subdivididas no tempo. Em relação à primavera a fotossíntese é reduzida no inverno e no verão, como consequência da ocorrência de temperaturas mais baixas e mais altas, respectivamente. Porém, a condição fisiológica da planta também afeta a assimilação de CO2, a qual é incrementada pela alta demanda de carboidratos antes e durante a floração, mesmo sob baixa temperatura. A presença de frutos inibe parcialmente a brotação e floração visto que plantas desbastadas têm sete vezes mais flores; fixam 31% mais frutos e eles são 6% maiores. A floração é o processo de maior consumo de assimilados, e quanto mais intensa, maior o consumo de amido. Floração e frutificação são os únicos estádios nos quais se observaram diferenças entre os tratamentos; plantas com maior quantidade de flores têm maior consumo de assimilados. O amido continua a ser consumido até o fim da queda fisiológica dos frutos no verão, quando atinge o teor mínimo. Ramos e raízes maiores que 1 mm de diâmetro aportam amido durante o desenvolvimento das brotações e dos frutos. Entre o desbaste e a frutificação há aumento no teor de nitrogênio total nas folhas do último fluxo, ramos e raízes, ainda com baixa temperatura, resultado da maior demanda. O aumento no metabolismo induz maior síntese de proteína nas folhas e raízes menores que 1 mm de diâmetro. A enzima redutase do nitrato (RN) tem a menor atividade quando comparada com o sistema glutamina sintetase/glutamato sintase, sugerindo ser a que limita a taxa de assimilação de NO3-. Nas folhas a atividade in vitro da RN incrementa até a frutificação, e segue o padrão de variação sazonal observado na fotossíntese; nas raízes sua atividade é constante ao longo do ano / Abstract: The hypotheses of the study are that seasonal variations in environmental conditions affect the assimilation rate of resources while there is accumulation and remobilization of reserves in all the organs of plant to attend variations in nutrients demand. Each phenological stage has different needs, which would affect CO2 assimilation rate and metabolism of carbohydrates and nitrogen. To analyzer these hypotheses the objective was to evaluate the photosynthesis, flowering and fruit production, accumulation and remobilization of carbohydrates during of production cycle, in plants with and without fruit. Also it was objective to evaluate the annual dynamics of nitrogenous compounds and activity of enzymes of nitrogen assimilation. The study was conducted in Cordeirópolis (SP) in plants 'Valencia' orange of 2.5 years old, grown in pots of 100 L. In may 2009, at the start of the trial, half of plants was completely defruit, and starting from july and throughout the production cycle were evaluated photosynthesis, budding, flowering and fruit production, status of reserves of sugars, nitrogen compounds and enzymatic activities. The experimental design was completely randomized with three or four replications, with three or four repetitions, depending on the variable assessed, with split plots in time. It is observed that photosynthesis decreased in winter and summer, consequence of low and high temperature and radiation, respectively. However, the physiological condition of plant also affects the uptake, inducing an increase in photosynthesis prior to flowering, even at low temperatures. The largest demand of plants with fruits results in an increase on efficiency of energy use which comes of the assimilation and reserves. The presence of fruits partially inhibits the sprouting and blooming, even with high leaves starch content, defruited plants have seven times more flowers, fruit set is 31% higher and they are 6% greater. The flowering has the greater consumption of all phenological stages, when it is more intense, largest starch consumption. The flowering and fruiting are the only stages with differences between the treatments; plants with the more fruits and demand have more assimilates consumption. Starch is consumed until the end of june drop, in summer, when it reaches minimum content. Starch for development of flowers and fruits can be contributed by younger shoots, shoots older than one year and roots larger than 1 mm across. From the defruited plants until fruiting the total nitrogen content increases in mature leaves, shoots and roots, even at low temperatures, as result of the higher demand. Soluble protein is accumulated in mature leaves and roots smaller than 1 mm across as a result of increased metabolism. The nitrate reductase enzyme has the lowest activity when compared with the system glutamine synthetase/glutamate synthase, which would indicate that nitrate reductase activity controls the assimilation rate of NO3-. Nitrate reductase in vitro activity in leaves is increased until fruiting, and has seasonal variations similar like was observed in photosynthesis. Nitrate reductase in vitro activity in roots is constitutive throughout the year / Doutorado / Biologia Vegetal / Doutor em Biologia Vegetal

The chlorophyll a/b binding (CAB) genes play a very central role in all photosynthetic systems and are for Avena sativa (oat) totally unexplored. This dissertation investigates a large number of EST sequences and this investigation characterises the CAB genes in oat, with help from the evolutionary background of oat and the comparison to a reference organism and similar species.

The C₄ photosynthetic pathway acts to concentrate CO₂ around the enzyme Ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco), ensuring that it catalyses a carboxylation rather than oxygenation reaction, which in turn suppresses photorespiration. In nearly all cases C₄ photosynthesis is underpinned by characteristic Kranz anatomy, with concentric wreaths of bundle sheath (BS) and mesophyll (M) cells surrounding closely spaced veins. The increased yields associated with the C₄ pathway have lead to the suggestion that C₃ crops such as rice should be engineered to undertake C₄ photosynthesis, however, this goal is currently held back by a lack of understanding about how the development of Kranz anatomy is regulated. Recently, a number of candidate Kranz regulators have been identified in an RNA-seq study that compared leaf development in maize foliar (Kranz) and husk (non-Kranz) leaves. However, this study did not consider the impact of a recent whole genome duplication in the maize lineage on the gene expression patterns analysed. Therefore, in this thesis maize homeolog gene-pair divergence during early leaf development was assessed. This revealed that expression divergence of homeolog gene-pairs is a significant evolutionary phenomenon. Functional validation of a subset of Kranz candidates revealed that a Zmscr1-1; Zmscr1h-1 double mutant exhibited defects in Kranz patterning, including increased formation of extra BS cells and veins with no separating M cells. Furthermore, Zmnkd1; Zmnkd2 double mutants exhibited a subtle increase in extra BS cell formation. Taken together, this indicates that both ZmSCR1/ZmSCR1h and ZmNKD1/ZmNKD2 function redundantly during Kranz development. No evidence was obtained that two additional genes, ZmSHR2 and ZmRVN1, play a role in Kranz development, and expression of candidate Kranz regulators in rice did not alter leaf anatomy. Together, this work has confirmed roles for a number of genes in Kranz regulation, and has provided insight into the complex regulation underpinning Kranz development in maize.

Les microalgues constituent une source prometteuse de biocarburants dits de troisième génération. L'intérêt de ces micro-organismes photosynthétiques réside également dans l'étendue de la palette de molécules qu'elles peuvent produire, telles que les protéines, les pigments ou encore les vitamines. Néanmoins, des progrès sont encore nécessaires pour diminuer les coûts économiques et environnementaux des procédés de culture et assurer ainsi la viabilité de la filière. En particulier, mieux comprendre l'effet de la lumière sur la productivité des cultures denses est une étape essentielle pour optimiser ces procédés. L'objectif de cette thèse est d'étudier les effets quantitatifs et qualitatifs de la lumière sur la croissance et les mécanismes d'acclimatation de deux espèces de microalgues à fort intérêt biotechnologique, Dunaliella salina et Tisochrysis lutea. La première partie de cette thèse examine la réponse de Dunaliella salina à des variations rapides de la lumière, reproduisant les fluctuations de l'éclairement typiquement perçues par les cellules microalgales brassées au sein des systèmes de cultures industriels à haute densité de type raceway. Dans la seconde partie, nous avons analysé la réponse de Dunaliella salina et Tisochrysis lutea à différentes compositions du spectre lumineux. L'approche à la fois expérimentale et théorique nous a permis d'identifier les effets d'une lumière colorée sur la productivité et la composition pigmentaire des microalgues. Nos résultats offrent des perspectives encourageantes et des pistes concrètes permettant d'optimiser l'utilisation de la lumière pour produire des microalgues et d'améliorer le bilan énergétique de ces procédés. / Microalgae are a promising source of third generation biofuels. The interest on these photosynthetic microorganisms also lies within the extent of the spectrum of molecules that they can produce, such as proteins, pigments, and vitamins. Nevertheless, further progress is still necessary to reduce the economic and environmental costs of cultivation processes and to ensure the viability of this sector. In particular, better understanding of the effect of light on the productivity of dense cultures is an essential step to optimize these processes. The aim of this thesis is to study the quantitative and qualitative effects of light on growth and acclimation mechanisms of two species of microalgae with high biotechnological interest ; Dunaliella salina and Tisochrysis lutea. The first part of this thesis examines the response of Dunaliella salina to rapid light changes, by reproducing irradiance fluctuations typically experienced by microalgal cells in a highly turbid suspension in raceway ponds. In the second part, we analyzed the response of Dunaliella salina and Tisochrysis lutea to different light spectra. Our experimental and theoretical approach allowed us to identify the effect of colored light on productivity and pigment composition of microalgae. Furthermore, our results offer encouraging prospects for elevate understanding and use of light and improve the energy performance of these processes.

Les picocyanobactéries marines sont les organismes photosynthétiques les plus abondants de la planète. Parmi celles-ci, les Synechococcus marins sont détectés de l’équateur aux cercles polaires, suggérant qu’ils ont évolué des stratégies adaptatives très efficaces à la température. La première partie de ce travail de thèse a visé à étudier la thermophysiologie de différentes lignées de la radiation des Synechococcus marins. Les résultats d’expériences de variations thermiques à court et long terme associées à une étude de phyloécologie ont démontré l’existence de clades physiologiquement spécialisées dans des niches thermiques distinctes, i.e des thermotypes. Ces travaux ont de plus mis en évidence l’importance de l’optimisation de l’efficacité de l’appareil photosynthétique dans l’acclimatation à la température. Ainsi, la thermostabilité du photosystème II, complexe clé de la régulation de l’énergie, a été comparée chez différentes souches de Synechococcus marins. Ces travaux ont révélé de grandes différences de thermostabilité de l’antenne photosynthétique et de ses constituants, qui sont corrélées à la latitude d’isolement des souches. L’étude de modèles d’homologie de structure de phycobiliprotéines a permis de révéler certaines des adaptations moléculaires de ce complexe à la température. La fonctionnalité des complexes photosynthétiques est directement dépendante de la fluidité des membranes au sein desquelles ils sont insérés, un facteur physique très influencé par la température. Le troisième volet de cette thèse a permis de mieux comprendre les mécanismes de régulation des lipides membranaires chez les Synechococcus marins. Les résultats montrent que la composition en acides gras joue un rôle important durant l’acclimatation à différentes températures. De plus, par une approche de génomique comparative, ce travail de thèse montre que les Synechococcus marins présentent des équipements différents en enzymes désaturases, qui ont très probablement joué un rôle dans la colonisation de différentes niches thermiques. Les résultats de ce travail de thèse, discutés dans un contexte d’évolution de l’adaptation au gradient latitudinal de température chez les picocyanobactéries marines, soulèvent de nouvelles hypothèses exaltantes pour les travaux futurs. / Marine picocyanobacteria are the most abundant photosynthetic organisms on Earth. Among them, Synechococcus displays a wide latitudinal distribution, ranging from the equator to polar circles, suggesting that they have evolved efficient adaptive strategies to cope with the latitudinal temperature gradient. The first part of this PhD work aimed at studying the thermophysiology of different lineages of the marine Synechococcus radiation. The combination of thermal acclimation and stress experiments with a phyloecology study allowed unveiling the existence of lineages physiologically specialized in distinct thermal niches, i.e. thermotypes. This work furthermore pointed out the importance of the capacities to optimize the photosynthetic apparatus efficiency for successful temperature acclimation. The thermostability of photosystem II, a key complex to the regulation of light energy utilisation, was compared within several marine Synechococcus strains. The results revealed that the photosynthetic antenna and its components have distinct thermostabilities, which are related to the strain isolation latitude. Structural homology models of phycobiliproteins thus revealed sites of molecular adaptation of the antenna to temperature. The function of the photosynthetic complexes is dependent on the fluidity of the membranes in which they are embedded, a physical factor regulated by temperature. The results a first lipidomic study suggested that the regulation of the composition in acyl chains plays an important role in temperature acclimation in marine Synechococcus. Furthermore, genomic comparative analyses revealed notably that marine Synechococcus have distinct sets of desaturase enzymes which have likely played a role in the colonization of different thermal niches. The results of this PhD thesis, which are discussed in the context of the Synechococcus adaptive evolution to the latitudinal gradient of temperature, raise new hypotheses for some future exciting work.

A portable infra red gas analyzer was used to investigate the interactive effects of light, temperature, and CO,jO, ratios under controlled environmental conditions in an attempt to model gas exchange characteristics of Coix Iachryma-jobi L. Plotting light response curves as a function of temperature (20, 25 30 and 35°C) revealed no sign of light saturation even at a photosynthetic photon flux density (PPFD) close to 2000 !Lmol m-' sol. High net assimilation rates (A) of approximately 24 !Lmol CO, m"s'! were realized at 30-35°C. Assimilation (A) versus internal CO, partial pressure (C,) curves showed a steep rise with increase in C, but saturated at approximately 150 (JLII-!) and all the results, either in the absence or presence of 0" showed a similar response under all temperature regimes. C. Iachryma-jobi exhibited low CO, compensation points cr ) between 0 and 10 JLlI-! under similar experimental temperatures and either at 0 or 21%0,. The slopes of double reciprocal plots of llA versus llCi, were nearly identical and crossed the yintercept at almost identical points under all 0, concentrations. These data indicate first; that there was no apparent 0, inhibition and second; indicated that the apparent inhIbitor constant (K,) for 0, at the site of carboxylation did not change with increase in [OJ from 0 to 21% oxygen. These observations were further confirmed by results obtained from the analysis of apparent carboxylation efficiency (CE, as defined as the slope of response of A to increasing CO,), as no inhibition of A with increase of [OJ occurred. These characteristics were consistent with typical features of C,photosynthesis. The absence of 0, inhibition and low r values indicated that an efficient CO, concentrating mechanism which eliminates photorespiration exists in C. Iachryma-jobi. At the light microscope level, leaf anatomy exhibited typical C, structure viz. bundle sheath with large chloroplasts and this sheath is further surrounded by a radiate Kranz mesophyU cells. Furthermore the anatomical features suggested that C. wchryma-jobi was an NADP-ME species. Stomatal conductance (g,) to assimilation (g,/A) indicated an increase in A with decrease in g" an essential feature of improving water use efficiency (WUE), but one which drastically reduces CO, diffusion rate. The physical lintitation (stomatal lintitation, t) to CO, diffusion under various [0,] and temperatures, but constant PPFD, did not exhibit statistically significant change in t values at either 0 or 21% a, within each temperature regime, however there was a marked decrease in t as the plant approached its optimum photosynthetic temperature.

Photosynthesis in the world's oceans by marine algae is responsible for approximately 50% of CO2 fixed into organic carbon. Aquatic primary producers are intricately linked to the climate system due to their reliance on CO2 as a substrate for photosynthesis and role in the removal and export of carbon from the surface ocean to marine sediments. The evolutionary history of marine algae was shaped by changes in the climate system. As a result, fossilized marine algae and modern representatives of ancient groups have the potential to unlock information about the Earth’s climatic past. To use this information and fully understand the role of marine algae in the carbon cycle, however, it is essential to develop an in-depth understanding of CO2 fixation in these organisms. In this thesis I look at carbon fixation in biomineralizing marine algae from a geological and a biological perspective. First I apply a carbon isotope proxy for CO2 to organic material preserved in marine diatom frustules from an extremely transformative period in geological history, the Eocene-Oligocene boundary. Subsequently, this thesis aims to address gaps in our understanding of carbon fixation in eukaryotic marine algae. I present a novel dataset of kinetics of the carbon fixing enzyme, Rubisco, in eukaryotic algae, investigate the role of a pyrenoid-based carbon concentrating mechanism, and identify plastic changes in carbon fixing machinery in response to changing CO2. The findings from this thesis refine our understanding of primary production in the oceans and how we apply algae-based CO2 proxies to understand ancient climates.

Die Dissertation beschäftigt sich mit der Untersuchung und Entwicklung definiert beleuchteter Photobioreaktorsysteme (klassische Systeme wie Schüttelkolben und Blasensäule als auch neuartige Konzepte) für reaktionskinetische Untersuchungen. Diese dienen zur Untersuchung des Einflusses des Lichts auf das Wachstum phototropher Organismen, als Modellorganismus wurde das Cyanobakterium Arthrospira platensis ausgewählt.