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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Distribui??o espacial, em microescala, e sazonal das microalgas potencialmente tox?genas Dinophysis spp. (Ehremberg 1839) na ilha Gua?ba (Mangaratiba, RJ) e suas poss?veis implica??es no cultivo de moluscos bivalvos. / Spacial, in microscale, and sazonal distribution of toxic microalgae Dinophysis spp. (Ehremberg 1839) at Gua?ba island (Mangaratiba, RJ) and yours probably implications in bivalves culture.

Ferreira, Vanessa de Magalh?es 04 March 2009 (has links)
Made available in DSpace on 2016-04-28T20:16:30Z (GMT). No. of bitstreams: 1 2009 - Vanessa de Magalhaes Ferreira.pdf: 3832895 bytes, checksum: 54d34bf9e767ef211ef5b82de690ac7b (MD5) Previous issue date: 2009-03-04 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / At Guaiba island (Mangaratiba municipality, south coast of Rio de Janeiro) is located the Association of Marine Maricultores of Mangaratiba s farm. The region has excellent conditions for growth of molluscs bivalves: mild water temperatures, mesotrophic and with good sanitary conditions (under bacteriological aspects). The crop is the main shellfish mussel Perna perna, which feeds mainly phytoplanktonic organisms (microalgae). However, the phytoplankton community may be present harmful microalgae such as dinoflagellates Dinophysis spp. that can produce diarrhoetic toxins. The main diarrhoetic phycotoxin produced by these microalgae is okadaic acid (OA), previously detected in the region and associated with D. acuminata. This phycotoxin is implicated in the syndrome Diarrhoetic Shellfish Poisoning, which affects humans, showing the acute effect gastrointestinal symptoms (vomiting, abdominal pain and diarrhea) and chronic promotion of carcinogenesis in the stomach and intestine. Regarding the animal sanity OA affects the immune system of mussels making them susceptible to pathogens and pollutants. In addition is genotoxic and can lead to loss of genetic biodiversity of P. perna. This effect can generate mutations that compromise the future generations of shellfish can lead to disastrous consequences for the mitiliculture. Dinophysis as planktonic organism, has a limited ability to swim. However, under conditions of stability of the water column the dinoflagellate may attach to certain depths, which may become an aggravating factor in the contamination of shellfish if production of OA. This distribution on the microscale is from the interaction between biotic and abiotic factors. Thus the present work to identify and quantify the Dinophysis species present at Guaiba island and verify whether the formation of density along the water column over a year. Were collected monthly, in high tide, over a vertical profile of 8 meters deep. The microalgae were collected with Van-Dorn bottle and fixed with formalde?do for further work on microscopy. We measured temperature, salinity, Secchi depth. Climatological data of rainfall, intensity and direction of winds were released by Vale. We identified 6 species of Dinophysis: D. acuminata, D. caudata, D. fortii, D. ovum, D. tripos and D. rotundata. The Cluster analysis revealed D. acuminata was dominant (Fitopac v1.6, p <0001), besides being the most frequent and abundant throughout the year. Only the species during summer showed higher cell density (average of 297 c?lulas.l-1, a low relative abundance according literature) in the stratum of 0-4 meters deep, than in the stratum > 4 meters (160 c?lulas.l-1), significantly different from the rest of the year (ANOVA, p <0.0001). D. fortii and D. rotundata were codominant in summer and autumn/winter, respectively. The remaining species occurred as incidental. D. ovum only occurred in summer and this work is the first report of this species in Brazilian waters. Redundancy analysis showed that the hydrological and climatological parameters analyzed only salinity and wind (selected by the Monte Carlo test) explained 11% of the variance of the data distribution of Dinophysis. Although no analysis has been performed for the presence of okadaic acid that all identified species are reported as potential producers of toxins diarrhea. Thus it is necessary for an evaluation of risk for diarrhoetic toxins aimed at animal health and safety to public health in the region. / Na ilha Gua?ba (munic?pio de Mangaratiba, litoral sul do Rio de Janeiro) localiza-se a fazenda marinha da Associa??o de Maricultores de Mangaratiba. O principal molusco cultivado ? o mexilh?o Perna perna, que se alimenta principalmente de organismos fitoplanct?nicos (microalgas). No entanto, na comunidade fitoplanct?nica podem estar presentes microalgas nocivas, como os dinoflagelados Dinophysis spp. que podem produzir toxinas diarr?icas. A principal ficotoxina diarr?ica produzida por essas microalgas ? o ?cido okadaico (AO), j? anteriormente detectado na regi?o e associado ? D. acuminata. Tal ficotoxina encontra-se implicada na s?ndrome Envenenamento Diarr?ico por Moluscos, que acomete humanos, apresentando como efeito agudo sintomatologia gastrintestinal (v?mito, dor abdominal e diarr?ia) e cr?nico promo??o de carcinog?nese no est?mago e intestino. Em rela??o ? sanidade animal o AO afeta o sistema imune dos mexilh?es tornando-os suscept?veis ? pat?genos e poluentes. Al?m disso, ? genot?xico e pode levar ? perda de biodiversidade gen?tica de P. perna. Dinophysis, como todo organismo planct?nico, apresenta uma restrita capacidade de nata??o. No entanto, sob condi??es de estabilidade da coluna d ?gua o dinoflagelado pode agregar-se em determinadas profundidades, o que pode vir a se tornar um agravante na contamina??o de moluscos se houver produ??o de AO. Tal distribui??o em microescala resulta da intera??o entre fatores bi?ticos e abi?ticos. Dessa forma o presente trabalho buscou identificar e quantificar as esp?cies de Dinophysis presentes na ilha Gua?ba, bem como verificar se houve a forma??o de adensamentos ao longo da coluna d ?gua ao longo de um ano. Foram realizadas coletas mensais, ao longo de um perfil vertical de 8 metros de profundidade, sempre na preamar. As microalgas foram coletadas com garrafa Van- Dorn e fixadas com formalde?do para posterior realiza??o de microscopia em campo claro e contraste de fase. Foram mensuradas: temperatura, salinidade, profundidade Secchi. Dados climatol?gicos de pluviosidade, intensidade e dire??o dos ventos foram cedidos pela Cia. Vale. Foram identificadas 6 esp?cies de Dinophysis: D. acuminata, D. caudata, D. fortii, D. cf ovum, D. tripos e D. rotundata. A an?lise de classifica??o revelou que D. acuminata foi dominante (Fitopac v1.6, p<0,001), al?m de ser a esp?cie mais frequente e abundante ao longo de todo o ano. Apenas durante o ver?o a esp?cie apresentou maior densidade celular (m?dia de 297 c?lulas.l-1, uma abund?ncia relativa considerada baixa pela literatura) no estrato de 0-4 metros de profundidade, do que no estrato > 4 metros (160 c?lulas.l-1), significativamente diferente do resto do ano (ANOVA, p<0.0001). D. fortii e D. rotundata foram co-dominantes no ver?o e outono/inverno, respectivamente. As demais esp?cies ocorreram como acess?rias. D. ovum apenas ocorreu no ver?o e o presente trabalho ? o primeiro relato da esp?cie em ?guas brasileiras. An?lise de redund?ncia revelou que dos par?metros hidrol?gicos e climatol?gicos analisados apenas salinidade e vento (selecionadas pelo Teste de Monte Carlo) explicaram 11% da vari?ncia dos dados de distribui??o de Dinophysis. Embora n?o tenha sido realizada an?lise para a presen?a do ?cido okadaico salienta-se que todas as esp?cies identificadas s?o relatadas como potenciais produtoras de toxinas diarr?icas. Dessa forma faz-se necess?rio a realiza??o de uma avalia??o de risco em rela??o ?s toxinas diarr?icas com vistas ? sanidade animal e ? seguran?a para a sa?de p?blica.

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