No description available.

<p>The aims of this study were therefore: 1) to test the suitability of various seaweed-based diets against that of the formulated feed Abfeed&reg / -S34 on the growth of the abalone H. midae / and 2) to compare the growth of H. midae fed protein-enriched U. lactuca as opposed to those fed wild, naturally low protein U. lactuca in both single-species and mixed feeds.</p>

<p>The aims of this study were therefore: 1) to test the suitability of various seaweed-based diets against that of the formulated feed Abfeed&reg / -S34 on the growth of the abalone H. midae / and 2) to compare the growth of H. midae fed protein-enriched U. lactuca as opposed to those fed wild, naturally low protein U. lactuca in both single-species and mixed feeds.</p>

Magister Scientiae - MSc / The direct methanol fuel cell or DMFC is emerging as a promising alternative energy source for many applications. Developed and developing countries, through research, are fast seeking a cheap and stable supply of energy for an ever-increasing number of energyconsuming portable devices. The research focus is to have DMFCs meet this need at an affordable cost is problematic. There are means and ways of making this a reality as the DMFC is found to be complementary to secondary batteries when used as a trickle charger, full charger, or in some other hybrid fuel cell combination. The core functioning component is a catalyst containing MEA, where when pure platinum is used, carbon monoxide is the thermodynamic sink and poisons by preventing further reactions at catalytic sites decreasing the life span of the catalyst if the CO is not removed. Research has shown that the bi-functional mechanism of a platinum-ruthenium catalyst is best because methanol dehydrogenates best on platinum and water dehydrogenation is best facilitated on ruthenium. It is also evident that the addition of other metals to that of PtRu/C can make the catalyst more effective and increase the life span even further. In addition to this, my research has attempted to reduce catalyst cost for DMFCs by developing a low-cost manufacturing technique for catalysts, identify potential non-noble metal catalytic systems and develop a basic process to combine various non-noblel, less expensive metallic systems to form binary, ternary and quaternary catalysts. The initial research focused on the identification of a suitable Pt/C preparation method, and characterization of the resulting catalysts by electrochemical methods (including voltammetry), elemental analysis (by EDS), and morphological characterization (by TEM). Once the preparation method for Pt/C had been established, binary (Pt–M/C), ternary (Pt–M1M2 /C) and quaternary (Pt–M1M2M3 /C) catalysts were prepared by modifying the initial Pt/C preparation method. These multi-metallic catalysts primarily function in preventing CO poisoning and allowing MeOH oxidation at the anode. To determine the effectiveness of the in-house multi-metallic catalysts the catalysts were then compared to the commercially available bench mark JM commercially available catalyst. Cyclic voltammetric and chronoamperommetric analysis revealed that the in-house catalysts electrochemical catalytic activity were similair to that of the commercially available catalysts. The Fuel application testing revealed similair trends to that of the EC activity at 0,5V (Ag/AgCl) test results, with the quaternary catalyst proving to be the most active anode catalyst producing the highest power density. The quaternary catalysts proved to be superior with its increased mass activity and high surface area (80% of the catalytic particles < 3nm). / South Africa

Brown algae are an important group of organisms inhabiting coastal ecosystems worldwide. Because of their sessile nature, they are exposed to natural abiotic stresses such as high and low irradiances, desiccation, thermal fluctuations and mechanical stress, as well as anthropogenic-derived stresses such as chemical pollution. While the impacts of metal pollution affect brown algae on a local scale, there is growing concern on the potential interactions between pollutants and abiotic pressures resulting from global climate change. The main objective of this study was to determine the nature of the interactions (synergistic, additive or antagonistic) of different concentrations of copper in combination with increased temperatures in controlled laboratory experiments using the model brown alga Ectocarpus siliculosus as a proxy for brown seaweeds, which are globally important primary producers and bioengineers of near-shore waters. The responses in E. siliculosus were evaluated at different levels of biological organisation. At the whole organism level Cu or temperature affected growth but no interactions occurred. Antagonistic interactions occurred between stressors in the photosynthetic efficiency response (measured as chlorophyll a fluorescence), being less affected by Cu at higher temperatures. The bioaccumulation of Cu ions showed and antagonistic response to temperature as less Cu ions were accumulated at elevated temperature. The concentrations of H2O2 and lipid peroxides (TBARS), which are indicators of oxidative stress, were synergistically affected by interactions of stressors. In contrast, the concentrations of antioxidants ascorbate and glutathione reflected both additive and antagonistic interactions respectively. This also occurred in the activity of antioxidant 8 enzymes (superoxide dismutase, ascorbate peroxidase, catalase and glutathione reductase) and the expression of related genes. Finally, the results of the biochemical and physiological tests were integrated with the whole transcriptome response to temperature and Cu stress. These results showed that interactions between temperatures and Cu stress could be highly complex, but also lead to the discovery of potential stress markers such as light harvesting complex proteins and several transporters. This research provides new insights into the responses of brown macroalgae to metal and thermal stress. Those responses indicate that synergistic or antagonistic interactions can occur at different levels of organisation, being the regulation of antioxidant metabolism, photosynthetic physiology and related gene expression, the most important mechanisms involved. This information will aid to understand potential effects of climate change on the toxicity of metals for macroalgae in estuaries and coasts affected by pollution.

This thesis examines the interactions of two non-indigenous algae, Mazzaella japonica and Sargassum muticum, where they co-exist and their impacts on native species in their recipient habitats. Field and lab experiments were conducted to determine if they impact native seaweed communities, marine invertebrates, and supralittoral regions. In situ studies conducted in areas where Mazzaella japonica exists without Sargassum muticum found that removal of M. japonica allowed for an increase of native seaweed abundance and richness growing in fully subtidal regions, but had no detectable impact on native seaweeds growing in intertidal regions. Additionally, at the intertidal site, removal of M. japonica resulted in the recruitment of S. muticum. In regions where the two non-indigenous seaweeds co-exist, removal of both non-indigenous seaweeds negatively impacted native seaweeds. The magnitude of this negative impact was greater in subtidal compared to intertidal regions. M. japonica removal had a greater impact on native seaweed recovery than did S. muticum removal in areas of co-existence. Removal of Mazzaella japonica also allowed for a significant increase in percent cover of Sargassum muticum at both sites where these two seaweeds co-exist. An increase in percent cover of M. japonica was found at the subtidal site when S. muticum was removed. Though both species increased when reprieved from competition with the other non-indigenous species, removal of M. japonica had a far greater influence on the increase in cover of S. muticum. This suggests that M. japonica is the dominant competitor in the ecosystem outcompeting S. muticum. Field surveys found Mazzaella japonica was the dominant wrack species washing up on beaches in Baynes Sound. Though Sargassum muticum is also a component of the wrack, it has a disproportionately large influence as a spatial subsidy on beach habitats. S. muticum decayed and decomposed at a faster rate than M. japonica and all native seaweeds tested except for Chondracanthus exasperatus. Additionally, S. muticum was colonized by significantly more invertebrates than either M. japonica or Fucus spp. Results from these studies are intended to provide information for resource managers making policy decisions regarding the fate of these two non-indigenous species. / Graduate / 0329

Submitted by (edna.saturno@ufrpe.br) on 2016-07-04T15:05:36Z No. of bitstreams: 1 Suellem Gomes Brayner.pdf: 663746 bytes, checksum: 8d3c2e49906ff30da1805ed4af222d6a (MD5) / Made available in DSpace on 2016-07-04T15:05:36Z (GMT). No. of bitstreams: 1 Suellem Gomes Brayner.pdf: 663746 bytes, checksum: 8d3c2e49906ff30da1805ed4af222d6a (MD5) Previous issue date: 2007-02-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This paper analyze the taxonomy and distribution of the Genus Caulerpa in the coast of Pernambuco (07º30’S and 09º00’W) and in the Archipelago of Fernando de Noronha (03º51’S and 32º25’W). Sampling was carried out at the coast of Pernambuco from April/2004 to November/2005, in the intertidal zone of 32 beaches. In Fernando de Noronha collections were made in June/2006 in the intertidal and infralittoral (10, 15 and 21m depth) regions of eight beaches. Exsiccates of Caulerpa from the Professor Vasconcelos Sobrinho Herbarium (PEUFR) were also examined. The results showed that the Genus Caulerpa is represented in the coast of Pernambuco State by 16 infrageneric taxa and some species presented restricted distribution such as: C. kempfii Joly & Pereira, C. lanuginosa J. Agardh and C. serrulata (Forssk.) J. Agardh.. To Fernando de Noronha Archipelago it was registered three infrageneric taxa. In both studied localities the highest species diversity occurred on sandy substrate. / Este trabalho analisa a taxonomia e distribuição do gênero Caulerpa na costa de Pernambuco (07º30’ S e 09º00’ W) e no Arquipélago de Fernando de Noronha (03º51’ S e 32º25’ W). As coletas foram realizadas na costa de Pernambuco de abril/2004 a novembro/2005, na região entre-marés, de 32 praias. Em Fernando de Noronha as coletas foram feitas em junho/2006, na região entre marés e no infralitoral ( 10, 15 e 21 m de profundidade) de oito praias. Foram, também, analisadas as exsicatas de Caulerpa depositadas no Herbário Professor Vasconcelos Sobrinho (PEUFR) da Universidade Federal Rural de Pernambuco. Os resultados mostram que o gênero Caulerpa está representado na costa de Pernambuco, por 16 táxons infragenéricos e algumas espécies apresentaram uma distribuição restrita como C. kempfii Joly & Pereira, C. lanuginosa J. Agardh e C. serrulata (Forssk.) J. Agardh. Para o Arquipélago de Fernando de Noronha foram registrados três táxons infragenéricos. Em ambas localidades estudadas a maior diversidade de espécies ocorreu em substrato arenoso.

As macroalgas marinhas constituem uma importante fonte de produtos naturais, devido à sua composição química, rica em substâncias fenólicas, terpenos e polissacarídeos sulfatados, apresentando potencial biotecnológico como fonte de substâncias com atividade antioxidante, antiviral, antitumoral e antibacteriana. Nesse sentido, o objetivo do presente estudo foi avaliar o potencial de prospecção de macroalgas do litoral do Espírito Santo (ES), mediante estudos dos potenciais antioxidante e bioativo de extratos brutos de quatro espécies de algas pardas (Chnoospora minima, Dictyopteris plagiogramma, Padina gymnospora e Sargassum cymosum) e de uma espécie de alga verde (Codium isthmocladum). A caracterização inicial dos extratos acetato de etila e metanólico das algas pardas, demonstrou a presença de constituintes com características distintas, indicando que pertencem à diferentes classes fenólicas. Os extratos metanólicos e aquosos das cinco espécies apresentaram os maiores rendimentos, sendo utilizados para análise do potencial antioxidante e bioativo. O extrato metanólico de P. gymnospora apresentou o maior potencial antioxidante e o maior teor de substâncias fenólicas totais pelo ensaio Folin-Ciocalteu, indicando o potencial dessa espécie como ingrediente funcional e na busca de substâncias antioxidantes naturais. As espécies analisadas apresentaram potencial bioativo (antiviral e antitumoral), sendo que os extratos aquosos foram mais ativos, quando comparados aos metanólicos. O maior potencial antiviral foi encontrado nos extratos aquosos de P. gymnospora, S. cymosum e C. isthmocladum, e o maior potencial antitumoral nos extratos aquosos de D. plagiogramma e C. isthmocladum. Tanto o potencial antiviral, como antitumoral podem estar relacionados à presença de substâncias fenólicas e polissacarídeos sulfatados nos extratos. Os resultados obtidos demonstram que as espécies estudadas, principalmente D. plagiogramma, P. gymnospora, S. cymosum e C. isthmocladum, apresentam potencial para prospecção de produtos naturais / Marine macroalgae are an important source of natural products, due to their chemical composition, rich in phenolic substances, terpenes and sulphated polysaccharides, presenting biotechnological potential as a source of substances with antioxidant, antiviral, antitumor and antibacterial activity. In this sense, the objective of the present study was to evaluate the potential of macroalgae prospecting on the coast of Espírito Santo (ES), through studies of the antioxidant and bioactive potentials of crude extracts of four species of brown seaweeds (Chnoospora minima, Dictyopteris plagiogramma, Padina gymnospora and Sargassum cymosum) and a species of green seaweed (Codium isthmocladum). The initial characterization of the ethyl acetate and methanolic extracts of the brown seaweeds, showed the presence of constituents with distinct characteristics, indicating that they belong to the different phenolic classes. The methanolic and aqueous extracts of the five species presented the highest yields, being used for analysis of the antioxidant and bioactive potential. The methanolic extract of P. gymnospora presented the highest antioxidant potential and the highest content of total phenolic substances by the Folin-Ciocalteu assay, indicating the potential of this species as a functional ingredient and the search for natural antioxidant substances. The analyzed species presented bioactive potential (antiviral and antitumor), and the aqueous extracts were more active when compared to methanolic. The highest antiviral potential was found in aqueous extracts of P. gymnospora, S. cymosum and C. isthmocladum, and the highest antitumor potential in aqueous extracts of D. plagiogramma and C. isthmocladum. Both antiviral and antitumoral potential may be related to the presence of phenolic substances and sulfated polysaccharides in the extracts. The results showed that the studied species, especially D. plagiogramma, P. gymnospora, S. cymosum and C. isthmocladum, present potential for the prospection of natural products

As atividades humanas nos últimos dois séculos vêm provocando um aumento na concentração de dióxido de carbono (CO2) atmosférico. Um dos efeitos desse aumento é um incremento na produtividade primária de algumas espécies vegetais terrestres, que dessa maneira atuam como sequestradoras de carbono. Nos oceanos, o CO2 é armazenado principalmente na forma de carbonato de cálcio (CaCO3), e o aumento na sua concentração leva a uma acidificação da água do mar e a uma menor disponibilidade de íons carbonato. Os animais que precipitam CaCO3 não serviriam como sequestradores de carbono porque o processo de calcificação produz CO2. Porém, a maioria das medidas de balanço de CO2 em comunidades calcárias marinhas negligenciam as formações de algas. Nas algas calcárias o CO2 produzido pela calcificação é aproveitado pela fotossíntese. Além disso, aumentos na concentração de CO2 podem levar a aumentos na taxa de crescimento, embora essas taxas possam ser afetadas por uma queda na disponibilidade de íons carbonato. O objetivo deste trabalho foi verificar se o aumento na concentração de CO2, e a acidificação da água do mar por ela causada, afetam o crescimento de algas calcárias. Tendo em vista a ausência de referências sobre trabalhos desse tipo com algas calcárias e considerando que as coralináceas não-articuladas, grupo de algas com maior calcificação, são difíceis de trabalhar em laboratório, a primeira etapa do projeto foi dedicada ao estabelecimento de cultivos e de metodologias de trabalho. Foram analisadas algas calcárias de diversos grupos, sendo escolhidas as coralináceas não-articuladas pois sua calcificação, além de constante em relação ao crescimento, é bastante alta, o que compensa seu lento crescimento. Para os experimentos de injeção de CO2 estabeleceu-se o uso de frascos de 50 mL com 35 mL de meio artificial MCM, irradiância de 42 &#956;mol.m-2.s-1, temperatura de 25°C e período de incubação de uma semana. Os experimentos de enriquecimento com CO2 foram feitos com nódulos de Lithophyllum sp. incubados após borbulhamento com diferentes volumes desse gás. Para isolar o efeito da acidificação foram feitas injeções de CO2 em meio com e sem adição de CaCO3 como tampão. Também foram feitas incubações em meio acidificado com HCl de modo a verificar o efeito da acidificação independente de um aumento de CO2. O crescimento foi estimado pela calcificação, medida através da técnica de anomalia de alcalinidade. Para os grupos experimentais em meio tamponado, a injeção de quantidades cada vez maiores de CO2 levou a um aumento proporcional nas taxas de crescimentos para volumes até 0,2 L, acima dos quais essas taxas permanecem as mesmas independente do aumento de CO2; esse limite é provavelmente devido à saturação do meio e não da alga, uma vez que o borbulhamento foi feito apenas no início do período de incubação. Nos grupos sem tamponamento, pequenos volumes de CO2 (0,06 L) provocam um aumento na taxa de calcificação; volumes um pouco maiores (0,2 L) provocam queda na taxa de crescimento; acima desse valor ocorre a morte das algas após algumas semanas. Os resultados das injeções em meio sem adição de tampão são consistentes com os valores obtidos com a acidificação do meio sem enriquecimento com CO2. Lithophyllum sp. não apresenta variação na taxa de crescimento entre pH 8,0 e 7,5. Em pH 7,0 ocorre queda da taxa de crescimento e morte em pH abaixo de 6,5. Os resultados, embora não sejam conclusivos devido à limitações metodológicas, indicam que Lithophyllum sp., e provavelmente as demais algas coralináceas, podem sequestrar carbono dentro de certos valores de pH. Devido à utilização de meio de cultura artificial rico em carbonatos, o limite obtido de pH 7,0 para crescimento deve ser maior em ambiente natural. Este estudo mostrou ser necessária a realização de trabalhos mais extensos, para os quais as técnicas e procedimentos aqui descritos trabalho podem ser utilizados. / Human activities over the last two centuries provoked an increase in the concentration of carbon dioxide (CO2) in the atmosphere. One of the effects of this increase is an increment in the primary production of some terrestrial plants which in this way act carbon sinks. In the oceans the CO2 is stored mainly as calcium carbonate (CaCO3). An increase in the concentration of CO2 leads to seawater acidification and to a decrease in carbonate ions availability. Calcareous organisms, in principle, does not act as carbon sinks because the calcification process produces CO2. However, the majority of CO2 measurements in marine communities neglect the calcareous seaweed formations. In calcareous seaweeds the CO2 produced during the calcification process is utilized by photosynthesis. Moreover, increases in the CO2 concentration can lead to an increase in growth rates, although these rates can be negatively affected by a decrease in the availability of carbonate ions. The objective of this work is to test if an increase in the CO2 concentration, and seawater acidification, affects the growth rate of marine calcareous seaweeds. Information on seaweed calcification is scarce, specially on the non-articulated coralline algae, which are the main group of calcareous seaweeds. This group is difficult to work with in laboratory, and therefore the first stage of the project was dedicated to establish seaweed cultures and work methodologies. We tested different calcareous seaweeds including non Corallinaceae, articulated and non articulated coralline algae. Calcification presents a constant relation with growth and is higher on non articulated corallines, what compensates their slow growth. For the experiments of CO2 injection we utilizes vials of 50 mL with 35 mL of MCM artificial medium, irradiance of 42 &#956;mol.m-2·s-1, temperature of 25°C and one week incubation time. The experiments of CO2 enrichment were made with nodules of Lithophyllum sp. incubated after bubbling different volumes of CO2. To isolate the acidification effect from the effect of CO2, injections were made in media with, and without, addition of CaCO3 as buffer. Incubations in medium acidified with HCl were also performed to verify the effect of acidification independent of CO2 increment. The growth was estimated by calcification, measured trough the alkalinity anomaly technique. For the buffered medium, injections of gradually higher volumes of CO2 led to a proportional increase in growth rates until the limit of 0.2 L; above this limit the growth rates remained the same, regardless the increase of CO2. This limit is probably due to saturation of the medium and not of the seaweed, once the bubbling was limited only to the beginning of the incubation time. In the groups without buffering, small volumes of CO2 (0.06 L) resulted in an increase in the growth rate. Volumes slightly higher (0.2 L) resulted in a decrease in the growth rate. In higher volumes seaweed began to die. These results are consistent with those obtained by acidifying with HCl. Lithophyllum sp. presented no variation in growth rate between pH 8.0 and 7.5. A decrease in growth rates occurred at pH 7.0, and death occurred at pH below 6.5. The results are not conclusive due to methodological limitations, but indicate that Lithophyllum sp., and probably other coralline algae, can act as carbon sinks under certain pH values. Due to the utilization of a carbonate rich artificial culture medium the observed pH 7.0 limit for growth must be higher in natural environment. More extensive work is necessary to understand the role of these seaweeds on the global atmospheric CO2 increase, for which the techniques and procedures described in this work can be utilized.

Because organisms have limited resources to allocate to multiple life history traits, the Optimal Defense Theory (ODT) and the Growth-Differentiation Balance Hypothesis (GDBH) were developed by terrestrial plant ecologists to predict intraindividual defense allocation based on the cost of defense and these life history trade-offs. However, these theories have garnered equivocal experimental support over the years and are rarely experimentally extended from predictions of plant physiology to the palatability of the tissues an herbivore experiences. We therefore examined tissue palatability, nutritional value, and defense mechanisms in multiple Dictyotalean seaweeds in two Caribbean locations, using two herbivores. Relative palatability of tissues varied greatly with algal species, grazer species, and location. Because older bases were not consistently defended, GDBH did not predict relative palatability. We could not reject ODT without intensive measures of tissue fitness value and herbivore risk, and this theory was therefore not useful in making broad predictions of tissue palatability. In testing the physiological predictions of these theories, we found the young, growing apices of these seaweeds to be generally more nutritionally valuable than the old, anchoring bases and found organic-rich apices to be more chemically deterrent, thus supporting ODT. However, the combined chemical, nutritional, and structural traits of these algae all influenced herbivore choice. As a result, these patterns of apical value and chemical defense reflected palatability of live tissues for only one of five algal species, which rendered ODT and GDBH poor predictors of relative palatability for most algae.