xiii, 86 p. : ill. (some col.) / In the Pacific Northwest, populations of the Olympia oyster, Ostrea lurida, were once decimated by overharvesting and natural disasters. Their full recovery may now be limited by availability of hard substrata for larval settlement. I studied the timing of settlement and larval preferences for commonly available substrata, including conspecifics and the shells of Pacific oysters, Crassostrea gigas, which are often provided in restoration efforts. Settlement occurred from August-December with a peak in October. I found no significant settlement differences between live and dead oysters or between shells of Olympia or Pacific oysters. There was significantly higher settlement on bottoms of horizontal substrata than on tops. In the laboratory, larvae showed no clear preferences among various hard substrata. This lack of settlement preference has positive implications for restoration projects, since Pacific oyster shell is much easier to obtain and seems to be no less beneficial than the shells of conspecifics. / Committee in charge: Dr. Craig M. Young, Chairperson; Dr. Richard B. Emlet, Member; Dr. Steven S. Rumrill, Member

From January 2012 to December 2012 I collected adult oysters from two intertidal populations on a monthly basis in the Coos Bay estuary, Oregon for histological analysis of their gonads. Gametogenesis and spawning occur seasonally from May through September, when water temperatures exceed 14.5&deg C, with brooding oysters found from July through September. Oocyte diameters increased significantly from May to June, and from June to July within oyster populations at Haynes Inlet and Coalbank Slough, respectively. Male gametogenesis initiated in May at Haynes Inlet and in June at Coalbank Slough. Dry meat condition values increased significantly during periods of reproduction and decreased following the reproductive season's end. Condition index values for Coalbank Slough were consistently lower than those at Haynes Inlet, suggesting poor nutrition or physiological stress. Salinities below recorded physiological thresholds are believed to be the primary environmental factor influencing the discrepancy in reproductive activity at Coalbank Slough.

Made available in DSpace on 2016-09-27T13:40:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-09-15. Added 1 bitstream(s) on 2016-09-27T13:44:48Z : No. of bitstreams: 1 000542639.pdf: 751735 bytes, checksum: 334cd0b1e79c6259fc057d2892fc30d7 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A ostreicultura surgiu da necessidade em: atender a crescente demanda de ostras, sem ameaçar o estoque natural através do extrativismo. Os métodos de cultivo foram aperfeiçoados ao longo dos anos em diversos países permitindo um crescente aumento na produção deste molusco. Em alguns lugares este aumento da produção está sendo superior ao volume consumido in natura como conseqüência, toma-se necessário o aperfeiçoamento da tecnologia pós-colheita. Para alcançar tal objetivo, foi realizado congelamento de ostras inteiras (vivas) em túnel de ar forçado. Amostras de ostras frescas e congeladas, com ° (recém congelada), 30 e 60 e 90 dias foram submetidas às análises de composição química, testes sensoriais e estudo dos índices de condição. A composição química da ostra fresca mostrou teores médios de umidade de 81,7 I ± 0,56% e 83,25 ± 0,12; de proteína de 9,96 ± 0,48 e 11,02 ± 0,59; lipídeo de 0,51 ± 0,11 e 0,27 ±0,14; carboidrato de 6,06 e 3,22, para o I e II experimento, respectivamente. Com relação ao processamento da ostra, foram detectadas alterações em sua composição química, tanto em função do congelamento quanto do armazenamento, em ambos experimentos. Os três índices de condição estudados mostraram diferenças entre as ostras frescas e as congeladas, e de modo geral estão de acordo com os valores descritos na literatura. Com a análise sensorial foi possível verificar que a ostra congelada foi satisfatoriamente aceita para o consumo humano, com índices de aceitabilidade acima de 70%. / Oyster fanning appeared of the necessity in taking care of the increasing- demand of oysters, without threatening the natural supply through the extrativism. The farming had been improved to long of the years in diverse countries allowing a increase the production of this mollusc. Increase of the production is being incompatible to the consumed volume in natura, and as consequence, becomes necessary the perfectioning of the technology after¬ harvest. To reach such objective, the freezing of entire oysters (alive) in continuous air blast freezer was carried through. The changes of chemical composition, condition indices and sensorial tests were analyzed in response to different samples of oysters: fresh and frozen, with O (just frozen), 30 and 60 and 90 days. The chemical composition of the fresh oyster showed average texts of moisture of 81.71 ± 0.56 and 83.25 ± 0.12; of protein of 9.96 ± 0.48 and 11.02 ± 0.59; lipid of 0.51 ± 0.11 and 0.27 ± 0.14; carbohydrate of 6.06 and 3.22, for the I and II experiment, respective1y. Relating to the processing of the oyster, alterations in its chemical composition, as much in function of the freezing as of the storage had been detected, in both experiments. The studied indices of condition had shown to differences between the fresh oysters and the frozen ones, and in general way they are in accordance with the described va1ues in literature. With the sensorial analysis it was possible to verify that the frozen oyster was satisfactorily accepted for the human consumption, with situated indices of acceptability above of 70%.

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-09-06T18:21:10Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE Patrícia Versão Final.pdf: 2205592 bytes, checksum: bd9cb29a5fbf4391919c2627525d91ef (MD5) / Made available in DSpace on 2016-09-06T18:21:10Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE Patrícia Versão Final.pdf: 2205592 bytes, checksum: bd9cb29a5fbf4391919c2627525d91ef (MD5) Previous issue date: 2015-07-09 / FACEPE / Toda atividade humana é por natureza geradora de resíduos, sejam sólidos, líquidos ou gasosos e estes devem ser gerenciados corretamente, para minimizar os custos e reduzir o potencial de geração de problemas sanitários e ambientais em comunidades. No Brasil, são produzidos anualmente cerca de 62 milhões de toneladas de resíduos sólidos urbanos, dos quais 6,4 milhões deixam de ser coletados e, por consequência, tiveram destino impróprio. Uma maneira apropriada para disposição desses resíduos são os aterros sanitários. A geração de lixiviados constitui-se na principal preocupação quanto à degradação ambiental de áreas localizadas próximas ao local de disposição final dos resíduos sólidos urbanos (RSU), uma vez que o tratamento desses efluentes tem se mostrado um grande desafio. Diante dessas questões, observou-se que para obter uma remoção de poluentes satisfatória, se faz necessário uma combinação de tratamentos físico-químicos devido à complexidade e o alto grau de poluição desse efluente. Neste trabalho foi utilizada a combinação das técnicas de coagulação/floculação e adsorção para o tratamento do lixiviado e posteriormente, realizado um estudo da geração de biogás do efluente. Inicialmente o lixiviado foi coletado do Aterro de Resíduos Sólidos da Muribeca-PE, e pré-tratado pelo processo de coagulação/floculação utilizando hidróxido de cálcio (cal comercial de São Paulo) como coagulante, nas condições já otimizadas por estudos realizados anteriormente. Após o lixiviado ter sido pré-tratado, foi submetido ao processo de adsorção com o intuito principal de remover as substancias húmicas (responsável pela cor do lixiviado) através do uso de resíduo do cultivo de ostras e mariscos como adsorventes, os quais foram comparados como o carvão ativado pulverizado. Os experimentos de adsorção foram realizados em batelada utilizando as melhores condições encontradas através da técnica de planejamento experimental fatorial: adsorvente com granulometria de 100 Mesh calcinado a 1000 °C durante 30 minutos e processo adsortivo a temperatura ambiente, com 3 g de adsorvente, sob de 300 rpm. A observação do comportamento cinético da adsorção da cor do lixiviado (substâncias húmicas) sobre as conchas de ostra e marisco resultou na determinação do tempo de equilíbrio que foi entre 40 e 50 minutos, todavia, para garantir o equilíbrio e a uniformidade dos ensaios foi utilizado o tempo de 60 minutos. As isotermas de adsorção se ajustaram ao modelo de Langmuir e capacidade máxima de adsorção foi de 45,45 Hazen.L/g para ostra. O pH do lixiviado que era de 8,7 passou a ser após a combinação de tratamento 12,55. A combinação dos processos de tratamento em questão foi bastante eficiente em diversos aspectos, obtendo uma redução de aproximadamente 95% da DBO, 40% da DQO, 70% e 80% da cor do lixiviado para ostra e marisco respectivamente. Mostrando que na técnica de adsorção as conchas da ostra e marisco são bons adsorventes para redução dos poluentes potenciais.. / All human activity is by nature generates waste, whether solid, liquid or gaseous, and these must be managed properly to minimize costs and reduce the potential for generation of health and environmental problems in communities. In Brazil, are produced annually about 62 million tons of municipal solid waste, of which 6.4 million are no longer collected and therefore had improper destination. An appropriate way for disposal of these wastes are landfill. The generation of leachate constitutes the main concern regarding the environmental degradation of areas located near the site of final disposal of municipal solid waste, since the treatment of these effluents has been a great challenge. In view of these issues, it was noted that to obtain a satisfactory removal of pollutants, it is necessary combination of physical-chemical treatments due to the complexity and high degree of pollution of the effluent. This work used a combination of techniques coagulation / flocculation and adsorption for the treatment of the leachate and thereafter, a study of the generation of biogas effluent. Initially the leachate was collected from the Landfill Solid Waste Muribeca-PE, and pre-treated by coagulation / flocculation using calcium hydroxide (lime commercial São Paulo) as coagulant, the conditions already optimized by previous studies. After the leachate has been pretreated was subjected to adsorption technique with the primary purpose of removing humic substances (responsible for the color of the leachate) by use of crop residue such as clams and oysters adsorbents, like activated charcoal sprayed. The adsorption experiments were carried out in batch using the best conditions found using the technique of factorial experimental design: adsorbent particle size of 100 mesh calcined at 1000 ° C for 30 minutes, 3 g quantity of adsorbent stirring at 300 rpm. The study of biogas production from leachate was carried out by analyzing the specific methanogenic activity (AME) and BMP tests with the use of sewage sludge as biomass Hose inoculated in the effluent. The observation of the kinetic behavior of adsorption of the color of the leachate (humic substances) on the oyster shells and shellfish resulted in determining a time. Although the process adsorptive adsorption kinetics followed in time between approximately 40 and 50 minutes, the balance study was performed in 60 minutes to ensure their full equilibrium. The adsorption isotherms followed the Langmuir model and the maximum adsorption capacity was 45.45 Hazen.L / g for oyster and ...... for shellfish. The pH of the leachate was 8.7 which is now following the combination treatment 12.55. The combination treatment process in question is very efficient in many ways, obtaining a reduction of approximately 95% of BOD, COD 40%, 70% and 80% of the color leached oyster and shellfish respectively. Showing that the adsorption technique of oyster shells and shellfish are good adsorbents for reducing potential pollutants. In general, the higher rate of biogas generation was obtained from the raw leachate + sewage sludge hose equal to 150.0 Nml. Based on these data, it can be suggested that the BMP test presents itself as an excellent experimental tool for obtaining characteristic curves biogas generation in municipal solid waste leachate. And according to the composition of the BMP test gas, which has higher concentration of methane (CH4) in the waste water + sludge hose, confirmed the results of the assay was also found AME where increased production of methane.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Física, Química e Geológica, Instituto de Oceanografia, 2007. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2013-02-18T16:41:32Z No. of bitstreams: 1 2007_gabriela_ignacio.pdf: 836041 bytes, checksum: bb374a70eb8e3a0915630c9ed8785c3f (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2013-06-12T17:10:38Z (GMT) No. of bitstreams: 1 2007_gabriela_ignacio.pdf: 836041 bytes, checksum: bb374a70eb8e3a0915630c9ed8785c3f (MD5) / Made available in DSpace on 2013-06-12T17:10:38Z (GMT). No. of bitstreams: 1 2007_gabriela_ignacio.pdf: 836041 bytes, checksum: bb374a70eb8e3a0915630c9ed8785c3f (MD5) Previous issue date: 2007 / Hidrocarbonetos naturais e antrópicos estão amplamente distribuídos no meio ambiente marinho, tendo sua origem biogênica, diagenética, pirolítica ou petrogênica. Com o objetivo de avaliar os níveis ambientais e fontes preferenciais de hidrocarbonetos alifáticos e policíclicos aromáticos (HPAs) ao longo do Complexo Estuarino da Baía de Paranaguá, foram coletadas 7 amostras de sedimento, 12 de água e 7 de ostras em áreas sob influência antropogênica e fora da área potencialmente contaminada (Controle). Os hidrocarbonetos alifáticos foram determinados em água e sedimento por cromatografia gasosa com detector de ionização de chama (CG/DIC) e os HPAs em água, sedimento e ostras por cromatografia gasosa com detector de massas (CG/EM). No sedimento, a distribuição individual e as relações entre n-alcanos sugerem uma contribuição preferencial de hidrocarbonetos de origem biogênica terrestre em todas as estações, refletindo a presença de manguezais. A mistura complexa não resolvida (MCNR) foi observada em todas as amostras, mas sua concentração não caracteriza claramente a existência de aportes crônicos de óleo. A distribuição de HPAs no sedimento mostrou uma mistura de fontes pirolíticas e petrogênicas, com grande predominância de fonte pirolítica. Na água, as relações encontradas sugerem uma mistura de hidrocarbonetos de origem biogênica, petrogênica e pirolítica. Nas ostras, a concentração dos compostos de 2 e 3 anéis foi predominante em relação aos compostos de 4 e 5 anéis em quase todas as amostras, indicando a assimilação de compostos mais leves pelos organismos. Os fatores de bioacumulação (água/ostra e sedimento/ostra) foram relativamente baixos, indicando uma baixa biodisponibilidade dos HPAs. Apesar das diferentes fontes encontradas para os compartimentos bióticos e abióticos estudados no Complexo Estuarino da Baía de Paranaguá, os níveis de hidrocarbonetos são considerados relativamente baixos se comparados a ambientes sabidamente contaminados. / Natural and anthropogenic hydrocarbons are ubiquitously distributed in the aquatic environments, with biogenic, diagenetic, pyrolitic and petrogenic origins. Thus, the aim of this study was to evaluate the environmental levels and preferential sources of aliphatic and polycyclic aromatic (PAH) hydrocarbons in the Estuarine Complex of Paranaguá Bay. Seven samples of sediment, 12 of water and 7 of oysters were collected in areas under the influence of and away from anthropogenic inputs (Control site). Aliphatic hydrocarbons were determined in water and sediment samples by gas chromatography with flame ionization detector (GC/FID), while polycyclic aromatic hydrocarbon (PAH) in water, sediment and oyster samples were determined by gas chromatography with mass spectrometer detector (GC/MS). In sediment samples, the nalkanes suggested a great contribution of continental hydrocarbons in all the stations, reflecting the presence of mangroves. The unresolved complex mixture (UCM) was observed in all samples, but its concentration did not characterize the existence of chronic inputs of oil. The distribution of PAHs in the sediment showed a mixture of pirolitic and petrogenic sources, with a predominance of pirolitic sources. In water samples, the relations suggested a mixture of hydrocarbons of biogenic, petrogenic and pirolitic origin. In oysters, 2 and 3 rings were predominant over 4 and 5 ring PAHs in almost all samples, indicating the assimilation of lighter compound by the organisms. The low bioaccumulation factors (water/oyster and sediment/oyster) indicated a reduced bioavailability of the PAHs. Despite different sources were found in biotic and abiotic compartments from the Estuarine Complex of Paranaguá Bay, the levels of hydrocarbons were relatively low in comparison to contaminated areas.

A partir do diagnóstico da viabilidade e ordenamento da ostreicultura na região de Cananéia-SP, estruturou-se o projeto "Ostra de Cananéia". Este projeto teve como principais estratégias: a introdução da criação de ostra, a regularização sanitária do produto, com a criação de uma Estação Depuradora e, principalmente, a organização da comunidade com a criação de uma entidade comunitária, a COOPEROSTRA. Apesar do projeto já apresentar resultados dentro da comunidade atingida, faltava realizar um diagnóstico sócio-econômico e com isso a caracterização do público pós-projeto. Esta dissertação pretende contribuir com informações sobre a transformação da realidade e condições de vida do grupo-alvo, o que vem a ser o objetivo maior da proposta inicial de ordenamento. Para tanto, foram realizadas entrevistas com os cooperados e com o corpo técnico que assessoram a cooperativa. Em seguida, os cooperados foram submetidos a um questionário fechado que buscou avaliar os impactos das novas tecnologias de produção de ostras e na geração de renda. Os cooperados apresentaram dificuldade na participação em atividades de gestão da cooperativa, no entanto, aqueles que participavam, obtiveram incremento de renda ou conseguiram mantê-la. Foi observado um aumento de auto-estima, dignidade, visão de mundo e reconhecimento da profissão, no entanto, ainda é necessário incorporar princípios democráticos em sua prática associativista. As técnicas de engorda em viveiros são amplamente utilizadas e a desmariscagem deixou de ser uma prática constante. O Estado desempenha um papel fundamental na criação e manutenção deste empreendimento, até que conquiste autonomia. A metodologia utilizada para atendimento dos objetivos propostos se mostrou eficiente. A COOPEROSTRA constitui modelo interessante para outras iniciativas comunitárias do mesmo tipo / A diagnostic study on the viability and organizational aspects of oyster aquaculture in the region of Cananéia, São Paulo, led to the development of the project "Oysters from Cananéia". This project’s main goals were to introduce oyster rearing, regulate the sanitary quality of the product by creating a depuration station, and, principally, organize the community through the creation of communitarian entity, COOPEROSTRA. Although the project had already shown results within the community it has reached, a socio-economic diagnosis had not been conducted nor a post-project analysis of the cooperative members. This dissertation intends to contribute with information on the transformation of reality and livelihood conditions of the target group, which is the major objective since the initial proposal for ordering. Consequently, interviews were conducted with the cooperative members and technical experts that assist the cooperative. Afterwards, the cooperative members were submitted to a closed questionnaire to help evaluate the impacts of new technology for oyster production and income generation. The cooperative members, did not seem comfortable whit the participate management activities of the cooperative, however, those who participated, were able to rise their income to keep it. Positive increases were observed in the cooperative members, notably with their self-esteem, dignity, world vision and recognition for their profession, however, it still is necessary to incorporate democratic principals to their association practices. The techniques for growing oysters in rearing beds are widely used and the practice of shelling oysters is no longer used. The State plays and important role in the creation and maintenance of this enterprise, until it attains autonomy. The methodology used to reach the proposed objectives proved to be efficient. COOPEROSTRA serves as an interesting model for other, similar community-based initiatives

This research evaluates two different Biological Nitrogen Removal (BNR) systems for enhanced nitrogen removal in decentralized wastewater treatment. The first study evaluated the performance of Hybrid Adsorption and Biological Treatment Systems (HABiTS) at the pilot scale with and without stage 1 effluent recirculation. HABiTS is a system developed at the bench scale in our laboratory and was designed for enhanced BNR under transient loading conditions. It consists of two stages; an ion exchange (IX) onto clinoptilolite media coupled with biological nitrification in the aerobic nitrification stage 1 and a Tire-Sulfur Adsorption Denitrification (T-SHAD) system in the anoxic denitrification stage 2. The T-SHAD process incorporates NO3- adsorption onto tire chips and Sulfur Oxidizing Denitrification (SOD) using elemental sulfur as the electron donor for NO3- reduction. Previous bench scale studies evaluated HABiTS performance under transient loadings and found significantly higher removal of nitrogen with the incorporation of adsorptive media in stage 1 and 2 compared with controls (80% compared to 73%) under transient loading conditions. In this study, we hypothesize that a HABiTS system with effluent recirculation in nitrification stage 1 may enhance nitrogen removal performance compared to that without recirculation. The following were the expected advantages of Stage 1 effluent recirculation for enhanced nitrogen removal: 1) Pre-denitrification driven by the mixture of nitrified effluent from stage 1 with high concentrations of biochemical oxygen demand (BOD) septic tank effluent. 2) Moisture maintenance in stage 1 for enhanced biofilm growth. 3) Increased mass transfer of substrates to the biofilm in stage 1. 4) Decreased ratio of BOD to Total Kjeldahl Nitrogen (TKN) in the influent of stage 1. Two side-by-side systems were run with the same media composition and fed by the same septic tank. One had a nitrification stage 1 effluent recirculation component (R-system), which operated at a 7:1 stage 1 effluent recirculation ratio for the first 49 days of the study and at 3:1 beginning on day 50 and one was operated under forward flow only conditions (FF-system). The R system removed a higher percentage of TIN (35.4%) in nitrification stage 1 compared to FF (28.8%) and had an overall TIN removal efficiency of 88.8% compared to 54.6% in FF system. As complete denitrification was observed in stage 2 throughout the study, overall removal was dependent on nitrification efficiency, and R-1 had a significantly higher NH4+ removal (87%) compared to FF-1 (70%). Alkalinity concentrations remained constant from stage 1 to stage 2, indicating that some heterotrophic denitrification was occurring along with SOD, as high amounts of sCOD leached from the tire chips in the beginning of the study, reaching sCOD concentrations of 120-160 mg L-1 then decreasing after day 10 of operation of stage 2. Sulfate concentrations from stage 2 for each side were low until the last 10 days of the study, with an average of 16.43 ± 11.36 mg L-1 SO42--S from R-2 and an average of 16.80 ± 7.98 SO42--S for FF-2 for the duration of the study, however at the end of the study when forward flow rates increased, SO42--S concentrations increased to 32 mg L-1 for R-2 and 40 mg L-1 for FF-2. Similar performance was observed in the FF system as the bench scale reactor tests. The second part of the research focused on the findings from a study of a Particulate Pyrite Autotrophic Denitrification (PPAD) process that uses pyrite as the electron donor and nitrate as the terminal electron acceptor in upflow packed bed bioreactors. The advantages of using pyrite as an electron donor for denitrification include less sulfate production and lower alkalinity requirements compared with SOD. The low alkalinity consumption of the PPAD process led to comparison of PPAD performance with and without oyster shell addition. Two columns were operated side-by-side, one packed with pyrite and sand only (P+S), while another one was packed with pyrite, sand and oyster shell (P+S+OS). Sand was used as a nonreactive biofilm carrier in the columns. My contribution to this research was to carry out Scanning Electron Microscopy-Energy-Dispersive X-Ray Spectroscopy (SEM-EDS) analysis to support the hypothesis that oyster shell contributes to nitrogen removal because it has a high capacity for biofilm attachment. SEM analysis showed that oyster shell has a rough surface, supported by its high specific surface area, and that there was more biofilm attached to oyster shell than pyrite or sand in the influent to the column. EDS results showed a decrease in atomic percentages for pyrite sulfur in the effluent of both columns (59.91% ± 0.10% to 53.94% ± 0.37% in P+S+OS column and to 57.61% ± 4.21% in P+S column). This finding indicated that sulfur was oxidized more than iron and/or the accumulation of iron species on the pyrite surface and supports the coupling of NO3- reduction with pyrite oxidation.

L’huître plate, Ostrea edulis, est l’espèce d’huître endémique européenne. Sa production est aujourd’hui réduite en raison de surpêches historiques et de maladies dont la bonamiose. En raison des fortes mortalités observées chez l’huître creuse ces dernières années les conchyliculteurs tendent à vouloir diversifier leur production et manifestent un regain d’intérêt pour cette espèce patrimoniale. Néanmoins, la bonamiose, maladie due au parasite protozoaire, Bonamia ostreae, reste un problème majeur pour la production de cette espèce. Les moyens de lutte contre cette maladie sont limités, mais nécessitent de meilleures connaissances sur les interactions entre l’huître plate et le parasite. De précédentes études ont suggéré que l’apoptose est activée par l’huître plate pour se défendre contre le parasite. Ce mécanisme est connu pour être impliqué dans de nombreux processus biologiques dont la défense contre des organismes pathogènes. Dans ce contexte, l’objectif général de ce travail de thèse est de mieux caractériser l’implication de l’apoptose dans la réponse de l’huître plate à une infection à B. ostreae. Des outils ont tout d’abord été développés afin d’étudier le processus apoptotique d’un point de vue cellulaire en cytométrie en flux et microscopie ainsi que d’un point de vue moléculaire en mesurant l’expression de gènes impliqués dans l’apoptose. Ces outils ont alors été utilisés pour étudier les interactions entre O. edulis et B. ostreae in vitro et in vivo. Les résultats obtenus confirment l’implication de l’apoptose dans les mécanismes de défense de l’huître plate en réponse à B. ostreae et mettent en évidence la capacité du parasite à déjouer ce mécanisme afin de survivre et se multiplier dans les hémocytes. Enfin, la réponse apoptotique a été appréhendée chez l’huître plate et l’huître creuse dans le cadre d’expositions à divers micro-organismes : OsHV-1, Vibrio aestuarianus et des micro-algues. / The flat oyster, Ostrea edulis, is the European endemic oyster species. Its production has been reduced because of overfishing and diseases including bonamiosis. Massive mortalities observed on the Pacific cupped oyster these last years explained the wish of shellfish farmers to diversify their production and their revival of interest for this patrimonial oyster species. However, bonamiosis due to the protozoan, Bonamia ostreae, is still a major problem for the production of this species. Measures to control the disease are limited and require a better knowledge of the interactions between the flat oyster and the parasite. Previous studies have suggested the involvement of apoptosis in flat oyster defense mechanisms against B. ostreae. This mechanism is involved in various biological mechanisms including defense against pathogens. In this context, the main objective of this PhD work was to better characterize the involvement of the apoptosis during interactions between the flat oyster and the parasite B. ostreae. In a first step, some tools were developed in order to study the apoptotic process at the cellular level using flow cytometry and microscopy as well as at the molecular level by measuring apoptotic gene expression. In a second step, these tools were used to study O. edulis-B. ostreae interactions in vitro and in vivo. Obtained results confirm the involvement of apoptosis in the response of the flat oyster to B. ostreae and demonstrate the ability of the parasite to inhibit the apoptosis pathway in order to survive and multiply within the hemocytes. Finally, the apoptotic response has been investigated in the flat and Pacific oysters after exposure to diverse micro-organism: OsHV-1, Vibrio aestuarianus and micro-algae.

Use of antibiotics in the aquaculture industry for the control of bacterial infections in salmon has led to public concern regarding antibiotic residues in salmon tissue and the potential health risk this poses to humans. Oxytetracycline and Romet-30 are two common antibacterial agents utilized to control disease in the local finfish aquaculture industry of British Columbia, Canada. Many fish farms in British Columbia are located within close proximity to existing shellfish stocks. The potential for antibiotic bioconcentration and the production of bacterial resistance to the drugs in bivalves is a concern. The development of a solid phase extraction technique for these two drugs from Pacific oysters, Crassostrea gigas was accomplished. Analysis of whole oysters via HPLC revealed detectable levels of oxytetracycline and Romet-30 up to 4 weeks after antibiotic treatment at the salmon farm site. Oysters suspended in the salmon net pens and surrounding waters were sampled over a 5 month period. Concentration of oxytetracycline residues in oyster tissue reached a maximum of 0.11 ppm (n=2). Levels of sulphadimethoxine in oyster tissue reached a maximum concentration of 1.27 ppm (n=2). Maximum detectable concentrations of ormetoprim in oysters were 0.26 ppm (n=2). A controlled study investigating uptake and depuration of oxytetracycline and Romet-30 in the Pacific oyster revealed results similar to those described for the salmon farm. A flow through drug delivery system for the Pacific oyster was utilized over a ten day uptake and thirty day depuration period. Levels of oxytetracycline in whole animal tissue increased in a linear fashion (r²=0.984) over the uptake period. This indicates that the drug was bioaccumulated in the oyster reaching a maximum concentration of 10.72 ± 2.4 s.e. ppm (n= 3) on day 10 of uptake. Depuration of the drug was rapid. After thirteen days a concentration of 0.21 ± 0.04 s.e. ppm (n=7) was detected. The detection of Romet-30 in the uptake and depuration in the oyster was more erratic. Day 7 of uptake revealed a maximum concentration of sulphadimethoxine and ormetoprim of 1.092 ± 0.24 s.e. ppm (n=7) and 0.21 ppm (n=3) respectively. Depuration of Romet-30 was rapid. The concentration decreased to 0.029 ppm (n=3) by day 13. Condition indices of oysters sampled before and after antibiotic treatment indicated a significant increase (p<0.05) in condition index after treatment with medicated feed. A quantitative survey of bacteria associated with the gut of the oyster was performed. Relative numbers of endogenous bacteria were compared to oysters before and after antibiotic treatment. Numbers of bacteria significantly decreased (p< 0.05) following treatment. / Land and Food Systems, Faculty of / Graduate

Saprophytic fungi can be paired with companion crops in interplant systems to increase production efficiency. However, fungal species/strain, substrate, and inoculation rate can affect the growth of companion crops. This project investigated the viability of open-field mushroom production by interplanting three strains of Pleurotus ostreatus (Elm A, Elm B, and 8801) with kale (B. oleracea var. acephala) and forage radish (Raphanus raphanistrub sub. sativus), and measured the effect of interplanting on plant yield over two field seasons. In the field, Elm A showed an increase in plant yield at a low inoculation rate and decrease in plant yield at a high inoculation rate, compared to the untreated. Conversely, 8801 showed a reduction in plant yield at high and low inoculation rates in the field. Elm B at a high rate showed a reduction in plant yield both in the field and greenhouse. Kale was grown in hydroponics with fungal secretions added at a range of concentrations (10, 100, 1,000 and 10,000 ppm). Elm A showed an overall increase in plant yield in hydroponics, and Elm B showed an overall decrease in plant yield, compared to the untreated. Mushroom production was low in field plots and was not a commercially viable option. Pleurotus ostreatus interplanting methods with companion crops need improvement to make this a commercially viable practice.