Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Física, Química e Geológica, Instituto de Oceanografia, 2006. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2013-02-11T23:17:32Z No. of bitstreams: 1 2006_juliana_braun.pdf: 1619378 bytes, checksum: 75d9d7dd8973d75d6d9d22ee9e2b139e (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2013-06-11T22:00:40Z (GMT) No. of bitstreams: 1 2006_juliana_braun.pdf: 1619378 bytes, checksum: 75d9d7dd8973d75d6d9d22ee9e2b139e (MD5) / Made available in DSpace on 2013-06-11T22:00:40Z (GMT). No. of bitstreams: 1 2006_juliana_braun.pdf: 1619378 bytes, checksum: 75d9d7dd8973d75d6d9d22ee9e2b139e (MD5) Previous issue date: 2006 / As regiões costeira do Complexo da Baía de Paranaguá têm sofrido um crescente desenvolvimento industrial, comercial e turístico, que acarreta em aportes de origem industrial, rural e urbana. A determinação da contaminação por esgoto urbano é normalmente realizada por indicadores microbiológicos (ex.: coliformes fecais), mas existem indicadores químicos como os esteróides (ex.: coprostanol) que são menos sensíveis a variações ambientais. Visando avaliar a introdução de matéria orgânica de origem antrópica e biogênica, 9 esteróides fecais foram analisados em 39 sedimentos coletados ao longo do Complexo Estuarino de Paranaguá (PR) entre 2003 e 2005. As concentrações de coprostanol variaram entre 0,02 e 2222 ng.g-1, sendo que o eixo leste-oeste foi a mais contaminado por esteróis de origem antrópica. Os esteróis campesterol, estigmasterol e β-sitosterol, normalmente associados ao aporte de matéria orgânica de origem biogênica, foram identificados em todos os sedimentos analisados. β-sitosterol foi o mais abundante entre os marcadores biogênicos, chegando a representar 58% dos esteróides totais. Isso indica que aportes biogênicas (principalmente terrígenas) são importantes fontes de matéria orgânica para o Complexo Estuarino de Paranaguá, principalmente onde não foi encontrada contaminação antropogênica. / The coastal area of Paranaguá Bay (PR) has been receiving an increasing industrial, commercial and tourist development. As a consequence, its waters have been receiving different sorts of industrial, rural and urban inputs. The determination of the contamination from urban sewage is normally evaluated using microorganisms such as fecal coliforms, but molecular markers such as coprostanol are less sensitive to environmental variability. Thus, the present work aimed to evaluate the introduction of organic matter from anthropogenic and natural sources by analyzing 9 sterols (fecal and biogenic) in 39 sediments sampled from the Paranaguá Bay between 2003 and 2005. The concentrations of coprostanol varied between 0.02 and 2222 ng.g-1, and the east-west axis of the Paranaguá Bay was more contaminated by fecal sterols. The sterols campesterol, estigmasterol and β-sitosterol, normally associated with biogenic inputs, were detected in all sediments analyzed. β-sitosterol was dominant, reaching up to 58% of the total sterols. Thus, biogenic inputs are an important source of organic matter to the Paranaguá Bay, mainly where anthropogenic contamination is less important.

Les mangroves sont des forêts côtières des régions tropicales et subtropicales, situées dans la zone de balancement des marées. Elles fournissent un grand nombre de services écosystémiques aux sociétés humaines et aux milieux adjacents (ressources, habitats, protection). Les mangroves sont continuellement affectées par des variations environnementales naturelles (salinité, température, cycle des marées) mais elles sont également le réceptacle d'effluents anthropiques (aquacultures, centres urbains). Il a été suggéré que ces forêts humides pourraient participer à la bio-épuration d'eaux usées domestiques (EUD). Les objectifs de la thèse étaient à la fois d'apporter des éléments pouvant ultérieurement servir à définir un cadre pour cet usage spécifique d'un écosystème naturel, et, sur le plan plus fondamental, d'évaluer les capacités de résistance et de résilience à court et long termes d'une mangrove soumise à une perturbation anthropique contrôlée. Le travail de thèse s'est appuyé sur un système expérimental fonctionnant depuis 2008 dans la plus grande mangrove de l'île de Mayotte. Dans ce système pilote, des EUD prétraitées sont quotidiennement déversées dans deux zones de mangroves dominées par les palétuviers Ceriops tagal ou Rhizophora mucronata et ayant des caractéristiques contrastées. Plusieurs campagnes d'échantillonnage ont permis de suivre in situ l'impact de l'excès de nutriments et d'eau douce sur la végétation, les crabes, la méiofaune et les communautés microbiennes, et de déterminer leurs capacités de résistance et de résilience. Dans ce travail, les EUD ont fortement stimulé la croissance de la végétation, modifié la structure des populations de crabes, de méiofaune, et des communautés microbiennes, et induit une hausse des densités et des activités des microorganismes impliqués dans le cycle de l'azote. Ceci n'a cependant pas entrainé de dysfonctionnement majeur de l'écosystème (perte massive de couvert végétal ou forte régression des populations de crabes). L'observation de l'écosystème sur deux ans après l'arrêt d'apports d'EUD a également mis en évidence une capacité notable de résilience de la mangrove. Enfin, les résultats de cette étude indiquent que la zone dominée par R. mucronata serait plus apte à recevoir les EUD prétraitées dans le cadre de leur bio-épuration par la mangrove car moins impactée. / Mangroves are coastal forests in (sub)tropical regions, located in the intertidal zone. They provide a many ecosystem services to human societies and neighboring ecosystems (resources, habitats, protection). Mangroves are continually affected by natural stresses (salinity, temperature, tidal cycle) but they are also subjected to anthropogenic effluents (aquaculture, urban centers). It was suggested that mangroves may be used for the bio-epuration of domestic wastewaters. This thesis aims at providing elements that will help defining the framework for this specific usage of a natural ecosystem and evaluating the long- and short-term resistance and resilience abilities of mangroves subjected to an anthropic disturbance. To reach these objectives, we used an experimental system set up in the largest mangrove of the island Mayotte. In this system, pretreated wastewaters (PW) are daily discharged in two mangrove zones dominated by Ceriops tagal or Rhizophora mucronata. Several sampling campaigns allowed to monitor in situ the impact of nutrient and freshwater excess on vegetation, crabs, meiofauna, and microbial communities and to determine their resistance and resilience capacities. In this work, PW strongly stimulated vegetation growth, altered the structure of crabs and meiofauna, modified the microbial structure and increased microbial density and activity of microorganisms involved in nitrogen cycle. However, no major dysfunction of the ecosystem (loss of vegetation, strong decrease in crab density) was observed. The monitoring of the ecosystem during two years after the PW discharge was stopped showed a marked ability of the mangrove to recover from the disturbance. Finally, the results indicate that R. mucronata mangrove zone, less disturbed, is more able to receive discharges for bio-epuration of domestic PW by mangrove ecosystem.