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Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2017-02-09T13:57:16Z No. of bitstreams: 1 PDF - Climélia da Nóbrega Silva.pdf: 2378682 bytes, checksum: bc27dc4732d9c3146e265bcaaa7cece6 (MD5) / Made available in DSpace on 2017-02-09T13:57:16Z (GMT). No. of bitstreams: 1 PDF - Climélia da Nóbrega Silva.pdf: 2378682 bytes, checksum: bc27dc4732d9c3146e265bcaaa7cece6 (MD5) Previous issue date: 2014-12-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Estuaries are environments that run important ecosystem services, such as nurseries and feeding places for numerous species. However, are subject to various anthropogenic impacts that directly affect their operation. This study aimed to test which taxonomic level is sufficient to evaluate the environmental condition as well as assess the relative efficacy of ecological indicators in estuaries assumed as subject to anthropogenic pressures of different intensities. The research was conducted in the estuaries of the River Paraíba do Norte and Mamanguape River (Northeastern Brazil), in November 2013, totaling 27 sampling sites, parted into four zones according to the values of salinity, sediment composition and depth. The organisms collected were sorted and identified to the lowest possible taxonomic level. This study is divided into two chapters, the first taxonomic depicts sufficiency by addressing the hypothesis that the family level would be more efficient to detect the environmental condition and the second test whether the combined use of the thermodynamically oriented indicators, functional trophic groups wealth rate and diversity index Shannon-Wiener would provide consistent answers in the evaluation of the ecological condition of estuaries. Fill Taxonomic showed that for the purpose of this study, both the family level as gender were enough to detect changes in environmental conditions, for this sample period. Regarding the use of associated ecological indicators to detect changes in ecological conditions of the estuaries, the indicators based on taxa richness, diversity, specific eco- exergy and functional feeding groups did not respond concurrently in the detection of changes in the ecological condition of estuaries with different levels of human impacts. Only eco-exergy index indicated differences in the ecological condition of the assessed ecosystems. Thus, the results obtained from the survey showed the importance of the study on the taxonomic sufficiency and ecological indicators based on benthic communities as a biomonitoring tool, which aims to understand the variations and fluctuations of ecosystems as well as the basis for measures proposed to mitigation of human impacts, conservation and environmental management. / Os estuários são ambientes que prestam serviços ecossistêmicos importantes, como berçários e locais de alimentação para inúmeras espécies. Porém, estão sujeitos a diversos impactos antrópicos que afetam diretamente seu funcionamento. O objetivo do trabalho foi testar qual nível taxonômico é suficiente para avaliar a condição ambiental, assim como verificar a eficácia relativa de indicadores ecológicos em estuários assumidos como sujeitos às pressões antrópicas de diferentes intensidades. A pesquisa foi realizada nos Estuários do Rio Paraíba do Norte e do Rio Mamanguape (Nordeste brasileiro), em novembro de 2013, totalizando 27 pontos de amostragem, divididos em quatro zonas de acordo com os valores de salinidade, composição do sedimento e profundidade. Os organismos coletados foram triados e identificados ao menor nível taxonômico possível. Este estudo está dividido em dois capítulos, o primeiro retrata a suficiência taxonômica, abordando a hipótese de que o nível de família seria mais eficiente em detectar a condição ambiental e o segundo testou se o uso associado dos indicadores termodinamicamente orientados, grupos tróficos funcionais, riqueza de taxa e índice de diversidade de Shannon-Wiener forneceriam respostas concordantes na avaliação da condição ecológica dos estuários. A suficiência taxonômica demonstrou que, para o objetivo desta pesquisa, tanto o nível de família quanto o de gênero foram suficientes em detectar alterações nas condições ambientais, para este período amostral. Em relação à utilização associada de indicadores ecológicos para detectar as mudanças nas condições ecológicas dos estuários, os indicadores baseados na riqueza de taxa, diversidade, eco-exergia específica e grupos tróficos funcionais não responderam de forma concordante na detecção das variações na condição ecológica dos estuários com níveis de impactos antrópicos distintos. Apenas o índice da eco-exergia indicou diferenças na condição ecológica dos ecossistemas avaliados. Assim, os resultados obtidos pela pesquisa evidenciaram a importância do estudo sobre a suficiência taxonômica e indicadores ecológicos baseados nas comunidades bentônicas como um instrumento de biomonitoramento, cujo intuito é entender as variações e flutuações dos ecossistemas, assim como servir de base para propostas de medidas para mitigação dos impactos antrópicos, conservação e gestão ambiental.

L’objectif de cette thèse concerne la quantification des flux benthos-pélagiques dans une lagune soumise à un régime climatique tropical rythmé de périodes humides et périodes sèches. La lagune de Terminos, située au sud du golfe du Mexique est le plus vaste écosystème laguno-estuarien du Mexique (2000 km2). Du fait de sa faible profondeur (3.5 m en moyenne), les processus benthiques sont sensés participer activement à l’ensemble du cycle biogéochimique de cet Ecosystème. Les mesures de flux benthiques ont eu lieu au cours de un réseau de 13 stations pendant une saison sèche (mars 2009 et 2010) et une saison humide (octobre 2009 et novembre 2010). Quatre stations ont fait l’objet de mesures plus fréquentes du 2008 au 2010. Des incubations ex-situ de carottes de sédiment prélevées ont permis de mesurer la variabilité spatio-temporelle des taux de respiration benthique (SOD) et des flux de sels nutritifs. Les SOD sont significativement différents entre les périodes sèches et humides (1327±161 et 2248±359 µmol m-2 h-1 respectivement). Les flux de silicates sont significativement plus importants pendant la saison des pluies (89.4±15.9 µmol m-2 h-1) que pendant la saison sèche (46.5±11.4 µmol m-2 h-1). Les flux de phosphates, faibles tout au long des périodes étudiées, n’ont pas montré de différence significative. Les flux d’azote dissous (DIN) sont de même intensité mais de sens opposé (2.9±18.8 µmol m-2 h-1 et 24.3±7.3 µmol m-2 h-1). Ces flux caractérisés par un fort signal saisonnier sont fortement corrélés avec les caractéristiques biogéochimiques des sédiments (Corg, N et chloropigments) et contribuent significativement au bilan du carbone et des éléments associés. / The goal of this study concerns the quantification of sediment-water fluxes in a tropical lagoon under climatic forcing regulated by successive dry and wet periods. Terminos lagoon on the South coast of Gulf of Mexico (Campeche sound) is a shallow (3.5 m) but vast estuarine system (2000 km2) where the sediments are supposed to contribute largely to the overall biogeochemical cycling. Benthic flux measurements were performed twice over a network of 13 stations during dry (March 2009 and 2010) and wet periods (October 2009 and November 2010). A selection of 4 stations from this network were visited more frequently between 2008 and 2010. Sediment Oxygen Demand (SOD) and nutrient fluxes were measured through ex-situ incubations of sediment cores sampled manually. SOD were significantly different between both dry and wet seasons (1327±161 and 2248±359 µmol m-2 h-1 respectively). Silicates fluxes were significantly more intense during the wet season (89.4±15.9 µmol m-2 h-1) than during the dry one (46.5±11.4 µmol m-2 h-1). Phosphate fluxes, low during all periods did not show a temporal trend. Finally DIN fluxes showed a net uptake during the wet season (2.9±18.8 µmol m-2 h-1) and conversely an efflux during the dry season (24.3±7.3 µmol m-2 h-1). These fluxes depicted a pronounced seasonal signal, showed a significant correlation to sediment characteristics (Corg, N and chloropigments) and finally contributed to the overall carbon and nutrient budget of the lagoon.

En la presente tesis doctoral se aborda el estudio de las comunidades de peces presentes en las zonas someras litorales del Mar Menor. La comunidad objeto de estudio estuvo conformada principalmente por individuos en estado de postlarva e individuos juveniles, junto con los adultos de especies de talla pequeña.Los objetivos planteados fueron:A) Caracterización específica de la ictiofauna.B) Análisis de la biología poblacional y relaciones con el hábitat de especies de peces bentónicos.C) Análisis de las relaciones entre los tipos de hábitats litorales y la comunidad de peces.Los resultados obtenidos ponen de manifiesto la elevada importancia de las zonas someras litorales de la laguna como hábitats esenciales para la multitud de especies ícticas, tanto aquellas que poseen interés pesquero comercial (familias Atherinidae, Mugilidae y Sparidae) como aquellas que presentan interés conservacionista (familias Cyprinodontidae y Syngnathidae). / The present PhD thesis investigates the small-sized fish assemblages in the shallow littoral areas of the Mar Menor coastal lagoon. The study was focused on juveniles of migrant fish species that recruit into the lagoon and short-lived resident fish species that spend their entire lives in it.The objectives were:A) To characterize the fish assemblages.B) To examine population biology and habitat associations of benthic fish species.C) To analyse the relationship between littoral habitat types and fish assemblages.The results pointed out the importance of shallow littoral areas of the lagoon as essential habitats for many fish species, both juvenile fish species of commercial interest (Atherinidae, Mugilidae and Sparidae families) and threatened fish species (Cyprinodontidae and Syngnathidae families).