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.

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: David A. Hutchins, College of Marine & Earth Studies. Includes bibliographical references.

Thesis (M. Sc.)--University of Hong Kong, 2006.

Made available in DSpace on 2014-06-12T23:01:27Z (GMT). No. of bitstreams: 2 arquivo8255_1.pdf: 2570452 bytes, checksum: be2dd849a8c65c04e76f16d631f91864 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2007 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O sistema estuarino de Barra das Jangadas (8º12 30 e 34º55 00 ), localizado em Jaboatão dos Guararapes, é caracterizado pela forte influência dos rios Jaboatão e Pirapama, que contribuem com a entrada de nutrientes enriquecendo a área e conseqüentemente a pesca. Suas margens apresentam, por um lado, manguezal bastante preservado, e por outro, intenso desmatamento, como conseqüência do crescimento demográfico. A análise da estrutura da comunidade fitoplanctônica é relevante para se conhecer a composição, biomassa, densidade e produtividade do ecossistema aquático, além de diagnosticá-lo, uma vez que algumas espécies são bioindicadoras da qualidade ambiental. Baseado nisto, o presente trabalho teve como objetivo principal diagnosticar este ecossistema através da estrutura e dinâmica da comunidade fitoplanctônica e variáveis ambientais. As coletas, dos parâmetros hidrológicos e biológicos, foram realizadas em junho, julho e agosto de 2003 (período chuvoso) e dezembro de 2003, janeiro e março de 2004 (período seco), em quatro estações fixas, durante preamar e baixa-mar diurna. Para o fitoplâncton foi feito arrasto horizontal com rede de 65μm. Estatisticamente, as marés apresentaram maior significância, destacando-se oxigênio dissolvido, saturação do oxigênio dissolvido, transparência da água, salinidade e pH na preamar, e material em suspensão e os sais nutrientes na baixa-mar. Sazonalmente oxigênio dissolvido e nitrato foram significativos no período chuvoso e silicato e temperatura no período seco. O ambiente variou de limnético a eualino sendo verticalmente homogêneo, na maioria das vezes. Quanto à taxa de saturação do oxigênio o sistema estuarino variou de zona poluída a supersaturada. Levando-se em conta o fracionamento da biomassa algal, verificou-se que a fração do pico/nanofitoplâncton foi a que mais contribuiu com o meio. Foram identificados 214 táxons distribuídos em cinco grupos, porém o dominante foi o da Bacillariophyta, destacando-se as espécies Coscinodiscus centralis Ehrenberg e Bellerochea malleus (Brightwell) Van Heurck como as mais representativas. A diversidade, eqüitabilidade, biomassa e densidade algais foram típicas de ambiente que vem sofrendo forte ação antrópica proporcionando a predominância de poucas espécies oportunistas que se adaptam rapidamente às condições eutróficas encontradas na área estudada

published_or_final_version / Ecology and Biodiversity / Doctoral / Doctor of Philosophy

Due to a number of factors, the biodiesel industry in the United States is surging in growth. Traditionally, oil seed crops such as soybean are used as the feedstock to create biodiesel. However, the crop production can no longer safely keep up with the demand for the growing biodiesel industry. Using algae as a feedstock has been considered for a number of years, but it has always had limitations. These limitations were mainly due to the production methods used to grow and harvest the algae, rather than the reaction methods of creating the biodiesel, which are the same as when using traditional crops. Algae is a promising alternative to other crops for a number of reasons: it can be grown on non arable land, is not a food crop, and produces much more oil than other crops. In this project, we propose a novel attached growth method to produce the algae while recycling dairy farm wastewater using the microalga Chlorella sp. The first part of the study provided a feasibility study as the attachment of the alga onto the supporting substrate as well as determining the pretreatment options necessary for the alga to grow on wastewater. The results showed that wastewater filtered through cheesecloth to remove large particles was feasible for production of Chlorella sp, with pure wastewater producing the highest biomass yield. Most importantly, the attached culture system largely exceeded suspended culture systems as a potentially feasible and practical method to produce microalgae. The algae grew quickly and were able to produce more than 3.2 g/m2-day with lipid contents of about 9% dry weight, while treating dairy farm wastewater and removing upwards of 90% of the total phosphorus and 79% of the nitrogen contained within the wastewater. Once the "proof-of-concept" work was completed, we investigated the effects of repeat harvests and intervals on the biomass and lipid production of the microalgae. The alga, once established, was harvested every 6, 10, or 15 days, with the remaining algae on the substrate material functioning as inoculums for repeated growth. Using this method, a single alga colony produced biomass and lipids for well over six months time in a laboratory setting. The second part of this study investigated another aspect of biodiesel production from algae. Rather than focus solely on biomass production, we looked into biodiesel creation methods as well. Biodiesel is created through a chemical reaction known as transesterification, alcoholysis, or commonly, methylation, when methanol is the alcohol used. There are several different transesterification methods. By simplifying the reaction conditions and examining the effects in terms of maximum fatty acid methyl esters (FAME) produced, we were able to determine that a direct transesterification with chloroform solvent was more effective than the traditional extraction-transesterification method first popularized by Bligh & Dyer in 1959 and widely used. This synergistic research helps to create a more complete picture of where algal biodiesel research and development is going in the future. / Master of Science

This study investigated the factors that maintain the patchiness of various rocky shore communities, particularly the roles of physical disturbance and biological interactions. Three communities were studied: a rnidshore red algal turf dominated by Laurencia pinnatifida, a Cladophora rupestris turf that dominated an area of the lowshore'and a fucoidbarnacle mosaic in the rnidshore that was interspersed by limpets. The study of the Laurencia turf showed it to be extremely stable once established and that its primary mode of recolonisation was by vegetative encroachment. Because of its slow growth L. pinnatifida did not recolonise and dominate any gaps that occurred in the turf within the timescale of this study. The Cladophora rupestris community was not only extremely stable, but was also persistent. Cladophora rupestris returned as the dominant alga to disturbed areas irrespective of the size, shape or season of the disturbance and this may have been because of processes involving the inhibition of other species such as Fucus serratus by early successional species which Cladophora rupestris could tolerate. Repeated disturbance events may have broken such inhibitions, enabling other species to colonise the substratum to higher levels of abundance than would normally have occurred. In the Laurencia and Cladophora turfs few limpets were required to maintain gaps in the turf, but these areas were rapidly recolonised by algae if all limpets were removed. The gaps in the Cladophora turf became dominated by Cladophora rupestris, however, in the Laurencia turf Laurencia pinnatifida did not recolonise the gaps that had been kept clear by limpet grazing. In the midshore fucoid, barnacle and limpet community the limpet densities had to be reduced to half of the natural levels to permit the colonisation of barnacle matrix by algae. The cover by FUCllS vesiculosus was .inversely related to the density of limpets, with the largest values being obtained in areas that were devoid of limpets. The effect of modifying the environmental conditions, by shading and watering the barnacle matrix, on the establishment of Fucus vesiculosus germlings was also studied. This showed that more shade tended to result in a greater number of fucoid escapes, possibly because of insolation stress and photoinhibition of the germlings on the unshaded substratum. The persistence offucoid patches was found to be affected by both the size of the area and the duration for which it was protected from limpet grazing. From the studies I carried out it is apparent that there were several forms of patchiness on the moderately exposed rocky shores on the south coast of the Isle of Man. These result from the vertical environmental stress gradient and interactions between plants and animals and in each case the exact sequence of events that followed a disturbance, depended on the species involved.

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