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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.
61

Processus et dynamique de la recolonisation et de la bio-diversité dans les bras du Rhin et autres cours d'eau restaurés de la plaine d'Alsace après reconnexion / Processes and dynamics of recolonization and biodiversity in side-channels of the Rhine river (France) and other restored streams after reconnection

Meyer, Albin 12 December 2012 (has links)
Durant les 20 dernières années d'anciens bras latéraux du Rhin ont été restaurés par reconnexion au cours principal. L'objectif de cette thèse est d'évaluer l'efficacité de la restauration et de vérifier si l'écosystème aquatique a retrouvé sa fonctionnalité. Les communautés végétales aquatiques sont utilisées ici comme indicateurs de ces changements. De nombreux facteurs ont été mesurés : les communautés végétales, leurs traits biologiques, les flux et stocks de diaspores, la chimie de l'eau, du sédiment et des plantes, l'hydro-géomorphologie. Cette étude a été menée dans 9 sites restaurés et 3 sites de référence. Trois communautés végétales ont été identifiées : une "eutrophe", une "mésotrophe", et une "rhéophile". La composition de ces communautés est liée aux conditions physiques et trophiques, et aux flux de diaspores. Les reconnexions ont permis aux sites restaurés de retrouver des communautés et une fonctionnalité écologique semblables à celles des sites de référence. / During the last 20 years, side channels of the Rhine have been reconnected to the main course. The objective of this thesis is to assess the efficiency of restoration and the recovery of the ecosystems functionality. The aquatic plant communities were used as indicators of changes. Many factors were monitored: plant communities, their biological characteristics, flux and bank of propagules, the chemistry of water, sediment and plants, hydro-geomorphology. This study was conducted in 9 restored sites and 3 reference sites. Three aquatic plant communities were identified: eutrophic, mesotrophic and rheophilic. The composition of these communities is first linked to physical conditions and second to trophic level, together with flux of propagules. Reconnections allowed the restored sites to exhibit communities and ecological functioning similar to reference sites, in a relatively short time.
62

Effet des restaurations des écosystèmes, de la trophie et de la connectivité hydrologique sur la diversité génétique des plantes aquatiques / Impact of ecosystem restorations, trophy and hydrologic connectivity on aquatic plant genetic variability

Oudot-Canaff, Jehanne 06 February 2014 (has links)
La conservation des zones humides fortement modifiées par les pratiques anthropiques, nécessite l’acquisition de données scientifiques sur leur diversité et leur fonctionnement. Cette thèse vise à relier l’anthropisation des zones humides à la diversité génétique, niveau de base de la biodiversité lié à la capacité adaptative des populations et au maintien des espèces. L’effet de l’anthropisation sur la diversité génétique de végétaux aquatiques est étudié à plusieurs échelles d’espaces (zone humide et bassin versant) et de temps (études synchroniques et diachroniques). La diversité génétique de populations de deux espèces rudérales (Berula erecta et Apium nodiflorum) et une compétitive (Nuphar lutea) est comparée dans deux plaines alluviales contrastées (trophie, connectivité hydrologique et restauration), à l’aide de marqueurs microsatellites adaptés à l’étude d’espèces clonales. La diminution de la connectivité hydrologique augmente la différenciation génétique et diminue la diversité génétique pour les espèces rudérales étudiées alors qu’elle n’a pas d’effet sur l’espèce compétitive. L’impact de la connectivité est donc dépendant de la stratégie de reproduction. La diversité génétique des espèces rudérales diminue également dans les zones humides plus eutrophes. L’augmentation de la diversité génétique post-restauration chez B. erecta est corrélée à la fréquence des perturbations (assecs) qui créent des niches favorisant le recrutement des graines. Cette étude propose des préconisations de gestion pour les zones humides et apporte des connaissances sur la dynamique de la diversité génétique des plantes aquatiques en lien avec leur environnement / The conservation of wetlands which are strongly modified by human practices, requires the acquisition of knowledge about their diversity and functioning. This thesis aimed to link the human pressures and plant genetic diversity in wetlands, which is the basic level of biodiversity linked to the adaptive capacity of populations and species maintenance. The effect of anthropization on the genetic diversity of aquatic plants is studied at several spatial and temporal scales (wetland and watershed; synchronic vs. diachronic studies). The genetic diversity of populations of two ruderal (Berula erecta and Apium nodiflorum) and one competitive species (Nuphar lutea) in two contrasting floodplains (in terms of trophic status, hydrological connectivity and restoration) is compared using microsatellite markers suitable for the study of clonal species. A reduction in hydrological connectivity increases genetic differentiation and decreases genetic diversity for ruderal species studied, while it did not affect the competitive species. The impact of connectivity is related to plant reproductive strategy. The genetic diversity of ruderal species also decreases in most eutrophic wetlands. The increase of genetic diversity of B. erecta after restoration is correlated with the frequency of disturbances (dewatering) that create niches for seed recruitment. This study provides management recommendations for the impacted wetlands and provides knowledge about the dynamics of the genetic diversity of aquatic plants in relation to their environment
63

Estimation des incertitudes associées aux indices macroinvertébrés et macrophytes pour l'évaluation de l'état écologique des cours d'eau / Uncertainty estimation associated to macroinvertebrates and macrophytes in ecological status assessment in waterbodies

Wiederkehr, Juliane 23 January 2015 (has links)
L’évaluation de l’état écologique des rivières est régie par l’application de protocoles sur le terrain et au laboratoire. Ceux-ci induisent de nombreuses incertitudes tant naturelles qu’humaines. L’objectif de cette thèse est (1) d’étudier l’impact de certaines incertitudes sur les indices biologiques basés sur les macroinvertébrés et les macrophytes en rivière, (2) de les estimer et (3) d’observer leur propagation jusqu’à l’évaluation de la qualité écologique des rivières. Pour les macroinvertébrés, nous nous sommes intéressés à l’impact de la variation intra-substrat et à l’effet des variabilités liées aux compétences de l’opérateur dans les indices IBGN, IBG DCE et I2M2. Pour les macrophytes, nous nous sommes focalisés sur l’effet opérateur dans l’IBMR. Des variations des indices ont été observées jusqu’à conduire à une évaluation globale erronée. Des solutions correctives peuvent être proposées afin de réduire les effets des sources de variabilités étudiées. / Ecological status assessment in waterbodies depends on standards application in the field and in the laboratory. They induce many uncertainties associated to natural or human variabilities. The aim is (1) to study the effect of some uncertainties on french indices based on macroinverterbrates and macrophytes, (2) to estimate them, and (3) to observe their propagation on final ecologica lstatus. Concerning macroinvertebrates, we are interested in the intrasubstrate variability and the surveyor effect in IBGN, IBG DCE and I2M2. Concerning the macrophytes, we focus on surveyor impact in IBMR. Indices variation appears and could lead to ecological status changes. Control quality approach could be proposed to reduce uncertainties effects.
64

Diversité des interactions trophiques à l'interface microorganismes - microcrustacés dans une zone littorale à macrophytes : conséquences sur le transfert des acides gras essentiels / Diversity of trophic interactions between microorganisms and microcrustaceans in a macrophyte littoral zone : consequences for essential fatty acid transfer

Masclaux, Hélène 24 June 2011 (has links)
Les zones littorales à macrophytes ont un rôle fonctionnel important dans les hydrosystèmes fluviaux. Outre leur forte productivité, ces milieux se caractérisent également par une forte biodiversité. Cependant, les liens pouvant exister entre hétérogénéité spatiale, biodiversité et flux de matière restent encore peu connus. En milieu aquatique, les microcrustacés représentent un maillon clef entre les microorganismes eucaryotes, qui sont les principaux producteurs d’acide gras polyinsaturés (AGPI), et le compartiment piscicole. Dans ce travail de thèse, nous avons donc cherché à savoir comment la diversité des cladocères rencontrée dans une zone littorale à macrophytes pouvait affecter le transfert des AGPI dans les réseaux trophiques. L’approche vers laquelle s’est orienté ce travail combine à la fois des études menées en milieu contrôlé, permettant des expériences de nutrition, ainsi que des études menées en milieu naturel. Cette double approche permet de faciliter l’interprétation des résultats issus des analyses lipidiques, isotopiques et isotopiques de composés spécifiques. Nos résultats montrent ainsi qu’il n’existe pas de variabilité dans les capacités d’accumulation et de bioconversion des AGPI chez les cladocères coexistant dans une zone littorale à macrophytes. D’après ces résultats, il semble donc que le principal facteur influençant la variabilité des transferts d’AGPI vers le compartiment piscicole soit la stratégie alimentaire et le compartiment trophique exploité par les différentes espèces de microcrustacés. En effet, outre le seston, notre étude montre que certaines espèces de cladocères rencontrées en zone littorale sont capables d’exploiter l’épiphyton et le neuston. Les analyses lipidiques mettent de plus en évidence, que la diversité des compartiments trophiques exploités s’accompagne d’une variabilité d’apports en AGPI. Dans notre étude, l’épiphyton est ainsi significativement plus concentré en AGPI que le seston. A l’interface air-eau, le neuston se caractérise de plus, par une forte accumulation de matière organique d’origine allochtone qui, dans le cas d’une pluie de pollen, représente une source de carbone et d’AGPI non négligeable pour certaines espèces de microcrustacés. Dans les zones littorales à macrophytes, la complémentarité des espèces de cladocères entraine donc une utilisation plus complète des ressources. La diversité des compartiments trophiques, associée à la diversité des microcrustacés, permet donc probablement une optimisation du transfert des AGPI vers les niveaux trophiques supérieurs. / Areas with littoral macrophytes play an important functional role in freshwater systems. In addition to the high productivity recorded in such areas, they also shelter a high diversity of organisms. However, possible links between spatial heterogeneity, biodiversity and energy pathways are still poorly known. As they constitute the major link between microorganisms and species higher in the food web, microcrustaceans play a key role in the transfer of polyunsaturated fatty acids (PUFA) to organisms at higher trophic levels. In this study, we wanted to assess if microcrustaceans diversity encountered in macrophytes littoral zones would lead to a variability of PUFA transfer in the food web. This work combined controlled conditions experiment and studies run in natural environments in order to help the interpretation of results from lipid analysis, isotopic analysis and fatty acid isotope analysis. Our results indicate that there are no differences of PUFA concentrations between cladocerans from a macrophyte littoral zone when they were exposed to the same pool of dietary PUFA. Hence, in heterogeneous feeding habitats such as macrophytes zones where these cladocerans often co-exist, foraging behavior of cladoceran species more than differences of metabolism may be crucial for determining PUFA transfer to upper trophic levels. In addition to seston, our study shows indeed that some cladoceran species are able to forage on the epiphytic and neustonic compartments. Lipid analyses highlight moreover that the diversity of trophic compartments lead to a variability of PUFA inputs to primary consumers. In our study, the epiphytic compartment is indeed significantly more concentrated in PUFA than seston. At the air-water interface, neuston is moreover characterized by important allochthonous organic matter accumulation. During a pollen rain, this organic matter represents an important source of carbon and PUFA for some microcrustacean species. In macrophytes littoral zones, cladocerans complementarity leads to a more complete use of PUFA sources. The association of trophic compartment diversity and microcrustacean diversity probably allows an optimization of PUFA transfer to higher trophic levels.
65

Facteurs environnementaux, éléments du paysage et structure spatiale dans la composition des herbiers submergés du lac Saint-François, fleuve Saint-Laurent

Léonard, Rosalie January 2005 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
66

Beach-cast deposition, food provision, and commercial harvesting of a non-indigenous seaweed, Mazzaella japonica, in Baynes Sound, British Columbia

Holden, Jessica 09 September 2016 (has links)
This thesis examines the contribution of a non-indigenous red alga, Mazzaella japonica, to wrack subsidies in Baynes Sound, British Columbia, and the effects of its removal by a commercial beach-cast harvest. Field and laboratory work was conducted to determine: 1) How large wrack inputs are in terms of biomass and spatial extent within the harvest region, and what proportion of this is comprised of M. japonica; 2) how wrack characteristics influence associated macrofauna communities; 3) if there is any detectable effect of beach-cast harvesting on either the wrack characteristics or macrofauna communities; and 4) if M. japonica provides a food source for native invertebrate consumers within the subtidal and supralittoral zones. Field surveys conducted from November 2014 through March 2015 found that wrack biomass within the harvest region could reach as much as 853 kg (±173 SD) per meter of shoreline, and cover up to 35 m2 (± 3 SD) of beach surface within this area. The macrophyte composition of the wrack was dominated by M. japonica, which accounted for 90% of the identifiable macrophyte biomass on average. Wrack in the later stages of decomposition hosted the most speciose and diverse assemblages of macrofauna, though community composition also differed among collection sites and with depth of the wrack. Though we were limited in our ability to disentangle the effects of beach-cast harvesting due to a concentration of effort at one site, we failed to detect any large influence on wrack biomass or macrofauna communities. Harvesting does, however, appear to be associated with a greater area of wrack cover and decreased mean depth. Stable isotope mixing models estimated that M. japonica contributed no more than 22% and 17% on average to the diets of supralittoral and subtidal consumers respectively, despite its overwhelming dominance in both environments. These results suggest that the non-indigenous red alga may experience a reprieve from herbivory within the subtidal environment. A lack of consumption within the supralittoral zone could influence nutrient cycling on recipient beaches and increase propagule pressure in the surrounding regions. Results from these studies are intended to help inform the management of M. japonica and its commercial harvesting. Combined, they indicate that this non-indigenous seaweed does not provide a substantial subsidy in the form of food provision for resident invertebrates. Furthermore, the commercial removal of M. japonica is small compared to the total biomass available, and had no detectable effect on the wrack-associated macrofauna communities examined. / Graduate / 2017-08-19 / jjulin.holden@gmail.com
67

Análise do desempenho de redes neurais artificiais no monitoramento sazonal de macrófitas no reservatório de Salto Grande e nas mudanças no uso e cobertura da terra do entorno /

Tolentino, Franciele Marques January 2019 (has links)
Orientador: Maria de Lourdes Boeno Trindade Galo / Resumo: As formas de uso e cobertura da terra no entorno de corpos d’água é um dos fatores que mais impactam águas continentais. Diante disso, é que ambientes aquáticos se tornam cada vez mais susceptíveis a processos de eutrofização, o que favorece a proliferação de macrófitas. Uma maneira de monitorar a proliferação de macrófitas, assim como alterações nas formas de uso e cobertura da terra no entorno de reservatórios é a partir de dados de sensoriamento remoto. Sensores remotos surgem como uma alternativa com grande potencial para a análise da variabilidade espaço-temporal de macrófitas aquáticas. Classificadores baseados em aprendizado máquina são cada vez mais utilizados em alternativa às técnicas tradicionais, uma vez que alguns desses algoritmos não requerem a distribuição estatística dos dados permitindo assim a inclusão de atributos não espectrais no processo de classificação. Este estudo teve por objetivo avaliar o potencial de redes neurais artificiais (RNAs) no monitoramento sazonal da dispersão de macrófitas aquáticas no reservatório de Salto Grande, Americana (SP), simultaneamente às alterações no uso e cobertura da terra do seu entorno. No processo de classificação, foram realizados diversos experimentos a fim de selecionar os atributos e arquiteturas de RNA mais adequados para discriminar tanto as macrófitas no corpo hídrico, quanto os tipos de uso e cobertura da terra no seu entorno. Os dados de entrada constituíram-se de bandas espectrais do sistema OLI/Landsat-8, i... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The land use/cover surrounding water bodies is one of the factors that most impact continental waters. Thus, aquatic environments become increasingly susceptible to eutrophication processes, which favors the growth of macrophytes. One way to monitor the growth of macrophytes as well as changes in the forms of land use/cover surrounding reservoirs, is from remote sensing data. Remote sensors emerge as an alternative with great potential for the analysis of spatio-temporal variability of aquatic macrophytes. Classifiers based on machine learning are alternatives increasingly used in detriment to traditional techniques. Those algorithms do not require the statistical distribution of the data, thus allowing the inclusion of non-spectral attributes in the classification process. In this sense, this wok aims to evaluate the potential of artificial neural network (ANN) in the seasonal monitoring of aquatic macrophytes dispersion in Salto Grande, Americana (SP), simultaneously with the changes monitoring in the land use/cover of the surrounding areas. In the classification process, several experiments were performed to select the most appropriate attributes, as well as the best ANN architecture to discriminate the macrophytes in the water body and the types of land use/cover of the surrounding. The input data consisted of OLI / Landsat-8 system spectral bands, texture images derived from OLI images, normalized spectral indices for vegetation enhancement (NDVI), moisture content (MNDW... (Complete abstract click electronic access below) / Mestre
68

Avaliação da qualidade ecológica de ambientes aquáticos da bacia hidrográfica do Rio Itanhaém através da assembleia de macrófitas aquáticas : proposta para a formulação de um índice de integridade biótica /

Umetsu, Cristiane Akemi. January 2016 (has links)
Orientador: Antonio Fernando Monteiro Camargo / Banca: Irineu Bianchini Júnior / Banca: Dalva Maria Silva Matos / Banca: Fábio Cop Ferreira / Banca: Tadeu de Siqueira Barros / Resumo: Este trabalho teve como principal objetivo avaliar questões referentes à avaliação da qualidade ecológica de ambientes aquáticos, com ênfase em macrófitas aquáticas. Inicialmente fizemos uma análise cienciométrica a fim de verificar o panorama global dos estudos sobre qualidade ecológica e índices de integridade biótica e tentamos fornecer uma visão geral sobre os ecossistemas, organismos e regiões que mais utilizam esses indicadores, bem como uma análise crítica sobre as tendências, aplicações e limitações dessa abordagem. Nossos resultados indicam que há uma falta de uniformidade na distribuição do número de estudos por continente, principalmente em regiões tropicais. Além disso, poucos estudos consideram mais do que um grupo de organismos para avaliar a qualidade ecológica de ambientes aquáticos. Em seguida, utilizamos dados de macrófitas aquáticas presentes na bacia hidrográfica do Rio Itanhaém, situada no litoral sul do Estado de São Paulo, para desenvolver mais dois estudos. O primeiro deles avaliou a influência das variáveis ambientais sobre a riqueza de espécies e riqueza de formas de vida, com o intuito de verificar quais fatores naturais e antropogênicos são mais importantes na estruturação da assembleia de macrófitas aquáticas. Tanto fatores naturais quanto antrópicos foram responsáveis por explicar a riqueza de espécies e formas de vida nos ambientes aquáticos estudados. Por fim, nós exploramos o uso de macrófitas aquáticas como indicadoras da integridade ecológica dos ambientes aquáticos da bacia do Rio Itanhaém, a fim de desenvolver um índice multimétrico. Nossos resultados mostraram que a estrutura da assembleia de macrófitas é distinta em locais degradados e não impactados, permitindo o desenvolvimento do índice. Embora o processo de validação do índice não tenha apresentado bons resultados, este estudo permitiu um melhor entendimento das condições ecológicas... / Abstract: This study aimed to evaluate issues related to ecological quality of aquatic environments, with emphasis in aquatic macrophytes. Initially we developed a scientometric analysis in order to verify the global view of the studies dealing with ecological quality and index of biotic integrity (IBI), and try to provide an overview of ecosystems, organisms and regions that mostly used these indicators, as well as a critical analysis of the trends, applications and limitations of this approach. Our results indicate a lack of uniformity in the distribution of the number of studies by continent, mainly in tropical regions. Moreover, few studies have focused in more than one biological group to assess the ecological quality of aquatic environments. After, we used macrophyte aquatic data from Itanhaém River Basin, located in the south littoral of São Paulo State, to develop two more studies. First, we evaluated the influence of environmental variables on species richness and life form richness in order to verify which natural and anthropogenic factors are most important in structuring the plant assemblages. Both natural and anthropogenic factors were responsible for explaining the species richness and life forms richness in aquatic environments studied. Finally, we explored the use of macrophytes as indicators of the river ecological conditions in tropical rivers, in order to develop a multimetric IBI. Our results showed that the macrophyte assemblage structure is distinct in degraded and undisturbed sites, allowing the development of an IBI. Although the validation of the IBI has not shown good results, this study allowed a better understanding of ecological conditions in these aquatic environments and consists in a relevant contribution for future studies involving assessment and biomonitoring in tropical aquatic ecosystems / Doutor
69

Estudo de bioacumulação de metais tóxicos e elementos traço em amostras de macrófitas aquáticas flutuantes do Reservatório Guarapiranga, São Paulo - SP, Brasil / Bioaccumulation of toxic elements in floating aquatic macrophytes of Guarapiranga Reservoir, São Paulo - SP, Brazil

Coutinho, Suellen Nobrega 06 February 2018 (has links)
As macrófitas desempenham um papel de extrema relevância em ambientes aquáticos, pois acumulam elementos metálicos e podem ser utilizadas para biomonitoramento desses ecossistemas, principalmente quando se trata de um importante reservatório para abastecimento público de água, assim como o Reservatório Guarapiranga. Neste estudo, foram avaliados os teores dos elementos potencialmente tóxicos As, Cd, Cr, Cu, Hg, Ni, Pb e Zn e outros elementos de interesse, em amostras de quatro espécies de macrófitas flutuantes (E. crassipes, P. stratiotes, S. herzogii e S. molesta), e nos compartimentos ambientais sedimentos e água. Foram coletadas amostras de macrófitas, sedimentos e água, em três pontos ao longo do Reservatório Guarapiranga em duas campanhas de coleta realizadas nas épocas chuvosa (março) e seca (setembro), em três semanas consecutivas para cada época de coleta, com o objetivo de avaliar a extensão da contaminação por elementos metálicos neste ecossistema. Para tal, foram aplicadas as seguintes técnicas analíticas: INAA, GF AAS, Análise Direta de Mercúrio, ICP OES e ICP MS para as análises das macrófitas e as técnicas ICP OES e CV AAS para as análises de água e sedimentos. Os resultados dos elementos tóxicos determinados nas macrófitas apresentaram valores acima dos valores de referência para plantas vasculares aquáticas para a maioria dos elementos, especialmente para o Cu, que apresentou teores extremamente elevados (10 a 802 mg kg-1), em especial no ponto P-03, onde foram encontradas as concentrações mais elevadas deste metal. A ANOVA mostrou diferenças estatisticamente significativas entre as concentrações nos locais de coleta, para a maioria dos elementos, porém não indicou diferenças estatisticamente significativas em relação ao acúmulo desses elementos entre as espécies de macrófitas flutuantes, em ambas as épocas (chuvosa e seca). Os teores dos elementos tóxicos determinados nas amostras de água mostraram-se abaixo dos limites de quantificação das técnicas analíticas aplicadas. No entanto, a avaliação das concentrações desses elementos nas amostras de sedimentos revelou valores que ultrapassaram os valores de TEL (Threshold Effect Level) para a maioria dos elementos analisados e os altos teores de Cu (32 a 4567 mg kg-1) ultrapassaram o valor de PEL (Probable Effect Level), especialmente no ponto P-03. O índice de geoacumulação demonstrou sedimentos de moderadamente a muito poluídos por Zn e de moderadamente a altamente poluídos por Cu. A contaminação de cobre no reservatório é explicada pela frequente aplicação deste metal na forma de sulfato de cobre, como algicida, em especial no ponto de coleta (P-03) que está localizado próximo ao local onde a Companhia de Saneamento Básico do Estado de São Paulo (SABESP) realiza a captação de água no reservatório. A comparação entre os teores dos elementos As, Cd, Cr, Cu, Hg, Ni, Pb e Zn analisados nas amostras de sedimentos e macrófitas apresentou uma correlação positiva, indicando a bioacumulação desses elementos pelas macrófitas. Os resultados podem indicar potencial risco da qualidade da água no reservatório. / Macrophytes play a relevant role in aquatic environments since they may accumulate metallic elements and can be an important tool for bioaccumulation studies, especially concerning an important and strategic water supply as Guarapiranga Reservoir. In this study, the contents of the potentially toxic elements As, Cd, Cr, Cu, Hg, Ni, Pb, Zn, and other elements of interest, were determined in samples of four species of macrophytes (E. crassipes, P. stratiotes, S. herzogii e S. molesta), sediments and water samples, aiming to assess metallic elements contamination. Samples were collected at three sites of the Guarapiranga Reservoir, in two sampling campaigns on wet (March) and dry (September) seasons, in three consecutive weeks for each season. The analytical techniques employed were: INAA, GF AAS, Mercury Direct Analysis, ICP OES and ICP MS, for macrophyte analysis, and ICP OES and CV AAS for sediment and water analysis. Toxic element concentration results in macrophytes presented higher values than reference values for aquatic plants for most elements, mainly for Cu, which presented extremely high values (10 to 802 mg kg-1), especially at site P-03, where the highest contents were observed. ANOVA showed significant differences among sampling sites. However, there were no significant statistical differences in the accumulation of the analyzed elements among the macrophyte species for both season campaigns (wet and dry). The toxic elements content in water samples were below the quantification limits of the analytical techniques applied. Nevertheless, the level of the toxic elements analyzed in sediment samples exceeded TEL values (Threshold Effect Level) for most elements. Besides, Cu presented high concentrations (32 a 4567 mg kg-1) that surpassed PEL value (Probable Effect Level), especially at site P-03. The geoaccumulation index indicated sediments moderate to highly polluted by Zn and moderate to extremely polluted by Cu. The contamination by Cu in the reservoir is explained by the frequent use of this metal as algicide (copper sulphate), especially at the site (P-03) located near the State Company of Water Supply (SABESP) catchment point. The results obtained for As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in the sediment samples were compared to the results obtained for the macrophyte samples, and a positive correlation was obtained, indicating bioaccumulation of these elements in aquatic macrophytes. These results may indicate potential risk of the reservoir water quality.
70

Ecologia de Anopheles darlingi Root (1926) no reservatório de Porto Primavera, Estados de São Paulo e Mato Grosso do Sul / Ecology of Anopheles darlingi, Root (1926) in Porto Primavera's reservoir, São Paulo and Mato Grosso do Sul States.

Mucci, Luis Filipe 29 July 2008 (has links)
Problemas de saúde pública advindos da proliferação de vetores de agentes patogênicos são frequentemente relatados após a construção de grandes barragens nas regiões tropicais. Porto Primavera é um dos últimos grandes projetos hidrelétricos implementados no Brasil, abrangendo uma faixa de cerca 200 km do Rio Paraná, entre os Estados de São Paulo e Mato Grosso do Sul. Resultados preliminares de projetos de pesquisa desenvolvidos na região desde 1997 apontam para um aumento na densidade de Anopheles darlingi, coincidindo com uma intensificação dos fluxos e atividades humanas na área, como turismo, pesca e transporte. Diante disso, a preocupação com a ocorrência de surtos de malária nas localidades à margem do lago motivou a busca de um maior conhecimento sobre as populações destes vetores. O objetivo desta pesquisa foi investigar a associação entre a abundância das formas imaturas e adultas de An. darlingi com variáveis do microhabitat e da ecologia da paisagem (respectivamente), após a formação do reservatório. Em relação ao microhabitat, foram selecionados o pH, condutividade, o sombreamento, a presença de cianofíceas filamentosas, detritos flutuantes, matéria orgânica galhos ou raízes e a composição das assembléias de macrófitas aquáticas. Quanto à ecologia da paisagem, foram analisados o comprimento da borda abrigo-criadouro e o tamanho das áreas dos habitats através das técnicas de sensoriamento remoto e SIG. Para a verificação de associações entre variáveis do microhabitat e imaturos de An. darlingi foi empregada a análise de correspondência canônica e para as métricas da paisagem e formas adultas, a regressão linear simples. As formas imaturas de An. darlingi apresentaram associação positiva com todas as variáveis do microhabitat, exceto com a abundância de cianofíceas filamentosas. As associações mais fortes se deram na seguinte ordem: abundância de Wolffia sp. e profundidade no primeiro eixo canônico e presença de material flutuante tipo II, pH e grupo de macrófitas e componentes da superfície no segundo eixo. Foi encontrada associação positiva entre abundância de espécimes adultos de An. darlingi e o comprimento da borda fragmento florestal-coleção hídrica, mas não em relação às áreas dos fragmentos florestais. De acordo com estes resultados, novos referenciais teóricos podem ser aplicados no mapeamento do risco da transmissão da malária em escala regional e na vigilância e controle entomológicos em nível local. / Public Health problems raised up from vector-borne diseases proliferation are frequently related after the construction of big dams in tropical regions. Porto Primavera is one of these greats hydroeletric projects stabilished recently in Brazil, occuping aproximately 200 km of Paraná river between São Paulo and Mato Grosso do Sul States. Preliminary results on developping investigations up to 1997 showed an Anopheles darlingi increase simultaneously the intensification of human moviment and activities in region, such as turism, fishing and transport. In face to the worry about the possibility of occurrence of malaria outbreaks in localities around the Lake raised the motivation to investigate a better knowledge about the populations of this vectors. In general, the objective was to investigate the association between the abundances of immatures and adult forms of Anopheles darlingi with microhabitat variables and landscape ecology respectively, after filling the reservoir. In relation to microhabitat variables was selected: pH, condutivity, shadow, deep, presence of filamentous cianoficeas, floating debris, and composition of aquatic macrophytes. In relation to landscape ecology it was analysed the perimeter of the florested shelters and breeding sites-edge and the area of florestal fragments, based on remote sensing and GIS technologies. Cannonical Correspondance analysis was the method to verify the association between microhabitat variables and immatures abundance. A large distribution of An. darlingi was noted because was find in all surveyed locations. Immature forms it was be positively associated with all microhabitat variables except filamentous cianoficea. The strongly association were in order: Wolffia sp. and deep to the first cannonical axis and floating debris of Type II, pH and macrophytes groups and surface components for the second. The Simple Linear Regression was the method to verify associations between landscape ecology variables and adult forms was find positive association between the abundance of An. darlingi and the perimeter of the florested shelters and breeding sites-edge, but not to the area of florestal fragments. According to this results, new theoretical knowledges are able to apply in the risk maps elaboration for malaria transmission in regional scale and to enthomological vigilance and control in local scale.

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