Solen cylindraceus is an infaunal filter-feeding bivalve inhabiting the intertidal mud banks of many southern African estuaries. It is particularly abundant in the Kariega estuary (33°41'S; 26°42'E) where it reaches densities of 400m⁻² (192g shell-free dry wt. m⁻²). The Kariega is a permanently open, marine dominated estuary about 18km in length, and S. cylindraceus is most abundant in its middle and upper reaches. Some physical characteristics of the estuary (temperature, salinity, sediment and water turbidity) are described, and the possible role of these factors in determining the density and distribution of S. cylindraceus within the Kariega estuary, is discussed. The structure of the alimentary system, gills and labial palps of S. cylintfraceus is described, all of which showed no major variation from the "typical" eulamellibranchiate form. Solen cylintfraceus was found to be a euryhaline osmoconformer with a salinity tolerance range of 15-65%. When animals were removed from their burrows, osmotic equilibration of the haemolymph was rapid (1-2 hours). By contrast, in animals left undisturbed in their burrows, osmotic equilibration was retarded (72-204 hours). It is suggested that the observed decrease in the rate of change of haemolymph osmolarity for animals in their burrows is linked to the stability of the interstitial salinity. A temperature tolerance range of 5-44°C was determined for S. cylintfraceus (in situ), in which prolonged exposure to 5°C and 40-45°C (12-36 hours respectively) resulted in a decreased burrowing ability, coma and death. Animal burrowing responses were not affected by temperatures in the range 15-35°C. Field experiments were carried out over several tidal cycles, in which the measurement of crystalline style volume was used as a means of assessing extracellular digestive activity. No major variation in style volume was recorded and it appeared that S. cylindraceus did not exhibit any cyclical pattern of style dissolution and regeneration. It is suggested that S. cylindraceus feeds continuously from the water column during high tide and possibly within its burrow, at or below the water table, during low tide. At a suspensoid concentration of 5Omg l⁻¹, S. cylindraceus was found to filter water almost continuously (90-95% of the time). Time spent filtering dropped to 68% at 100mg l⁻¹ and 32% at 500mg l⁻¹. Filtration rates for summer collected animals (25°C) were 22.86 ± 4.36ml min.⁻¹, some 3ml min.⁻¹ greater than that recorded for winter (16°C) collected animals. Filtration rate may be expressed as a function of shell length by the equations: y=0.247x¹̇⁰⁶⁶ (winter) and y=0.758x⁰̇⁸²⁶ (summer). Solen cylindraceus was capable of acclimating its filtration rate to both high and low temperatures under laboratory conditions. Filtration rate exhibited a thermal optimum in the range 15-35°C, declining at higher and lower temperatures. Q₁₀ values of filtration decreased rapidly from greater than 4 to less than 2, when the thermal optimum was reached. Maximum rates generally occurred at approximately 5°C above the temperature to which the animal had been acclimated. Optimal filtration rates (19-23ml min.⁻¹) were recorded in the salinity range 15-45%. When subjected to abrupt changes in salinity, filtration rates were immediately depressed. The extent and duration of these decreased filtration rates were dependent upon the magnitude and direction of salinity change, and were always less in animals exposed to hyper- than hyposaline conditions. Animals exposed to increased temperature and simultaneous elevated or unchanged salinity, showed a slight increase in filtration rate followed by rapid acclimation. A decrease in both temperature and salinity resulted in an initial decrease in filtration rate and a longer acclimation period. The ability of S. cylindraceus to acclimate fully within a wide temperature and salinity range, and to filter maximally in hypersaline conditions may, in part, explain its unusually high abundance in the Kariega estuary, despite it being close to the southernmost limit of the animal's geographical distribution. No significant difference in flItration rate was recorded at suspensoid concentrations of 5-100mg 1⁻¹. However, at 250 and 500mg l⁻¹ filtration rates decreased significantly, and coincided with increased levels of pseudofaecal production. Solen cylindraceus retained particles down to 2.5-3.0µm with great efficiency (ca. 60-90% efficiency). Below this particle size, retention efficiency decreased rapidly and a net production of particles was recorded below 1.51µm. Particle retention was independent of temperature (15 and 25°C) and salinity (15 and 35%). Use was made of stable carbon isotope analyses (¹³C/¹²C ratios) in an attempt to determine the important food sources of S. cylindraceus within the Kariega estuary. The results obtained demonstrated an enrichment in δ¹³ values for S. cylindraceus from the upper (-27.9%) to the middle (-25%c) and lower (-21.6%o ) reaches of the estuary, with no seasonal variation apparent. The bivalve was substantially more depleted in ¹³C relative to the dominant aquatic macrophytes Zostera capensis (-9.1 to -15.6%o) and Spartina maritima (-12.5%o). The use of δ¹³ alone, however, to unequivocally "pin point" specific food sources of a filter feeder in a predominantly detritus based food web, is limited. It is suggested that in the Kariega estuary, riparian litter and other terrestrially derived vegetation contribute to the carbon pool. A possible contribution of ¹³C depleted food sources via chemoautotrophic and/or anaerobic pathways, to the diet of S. cylindraceus, is suggested.

Title: Sytematics, palaeoecology and trophical structure of bivalve associations within the OAE2 in the Bohemian Cretaceous Basin (Upper Cenomanian): Pecínov quarry Author: Bc. Lucie Kunstmüllerová Department: Institute of geology and palaeontology Supervisor: doc. RNDr. Martin Košťák, Ph.D. Abstract: This master thesis provides an updated taxonomic inventory of the bivalve fauna of the Pecínov locality, places the fauna in its palaeobiogeographic setting, and addresses its palaeoecological significance. In the literature research part of the thesis the basic geology of the locality and an overview of the Bohemian Cretaceous Basin are presented. Processes connected to the ocean anoxic events, specifically to the OAE 2 are also discussed. The research part of the thesis describes the systematics of the bivalve assemblage (with the exception of Inoceramidae) and its statistical evaluation with the emphasis on the environment interpretations of the locality. In total, over 350 specimens have been considered and assigned to 20 genera within 15 families and 9 orders. Bivalve functional morphology and guilds are described to interpret palaeoecology. Guilds are based on life habit and feeding category. Four main guilds are recognized: epifaunal suspension-feeders, semi-infaunal suspension-feeders, infaunal...

The Pocket-book mussel, Lampsilis ovata, is a native freshwater bivalve species that is endemic to North America. The salinity tolerance of this species is of interest because anthropogenic salinization events and climate change factors threaten their natural freshwater habitats. Furthermore, the invasive freshwater bivalve species Corbicula fluminea has been shown to display significant salinity tolerance, which may lead to negative competitive interactions with native freshwater bivalve species if the salinization of freshwater habitats exceeds thresholds beyond which native species can effectively cope. It was hypothesized that L. ovata would be sensitive to salinity conditions above 1 g/L and respond by closing their valves. To investigate this, juvenile pocket-book mussels were subjected to three experiments which measured tissue-water content, hemolymph osmolality, and oxygen consumption after salinity exposure to 0, 2.5, 5, and 10 g/L. The 96-hour exposure study showed that the 2.5 g/L and 5 g/L treatment groups had significantly lower average percent tissue-water content than the control group. The average percent tissue-water content for mussels exposed to 2.5 g/L and 5 g/L dropped 2.4% and 2.2%, respectively. In the 24-hour time-course study, it was observed that changes in the average percent tissue-water content for all treatment groups primarily occurred after four hours of exposure. In the same study, the osmolality of the control group maintained an average of 31.2 mOsm/kg over the 24-hour period, despite the osmolality of the treatment water being 2 mOsm/kg. The hemolymph osmolality concentration of mussels exposed to the 2.5 g/L and 5 g/L treatments increased to osmotically conform to their treatment waters. After 24 hours, the hemolymph osmolality of the 2.5 g/L and 5 g/L treatment groups was 79 mOsm/kg and 163 mOsm/kg, respectively. Contrastingly, the osmolality of mussels exposed to the 10 g/L treatment maintained an average hemolymph osmolality of approximately 132 mOsm/kg, while the osmolality of the treatment water was 320 mOsm/kg. Lastly, the oxygen-consumption study showed that mussels exposed to the 5 g/L treatment consumed a significantly lower amount of dissolved oxygen than that of the control and the 2.5 g/L treatment by an average of 1.6 mg O2/mg/h. The control group consumed an average of 4.66 mg O2/mg/h, while the 2.5 g/L treatment group consumed the highest amount of dissolved oxygen with an average of 5.05 mg O2/mg/h. The data collected from these studies suggest that juvenile L. ovata might not be able to tolerate salinities greater than 2.5 g/L for an extended amount of time. Mussels exposed to the 5 g/L treatment and the 10 g/L treatment demonstrated varying degrees of behavioral avoidance and much higher morbidity rates. In contrast, the 2.5 g/L treatment group showed minimal behavioral avoidance and an elevated oxygen consumption rate. When compared to similar studies performed on C. fluminea, these results support the hypothesis that L. ovata is more sensitive to saline conditions than the invasive species and could be replaced by the invasive species if habitat conditions exceeded 2.5 g/L salinity.

O objetivo deste trabalho foi avaliar a biodisponibilidade de HPAs na água do mar no sistema estuarino de Santos e no sistema lagunar de Cananéia-Iguape, para isso foi feita a exposição de membranas semipermeáveis (SPMD) e de bivalves (Crassostrea brasiliana) a fim de se obter um melhor panorama das concentrações desse poluente nessas duas regiões. De forma complementar foram analisadas também amostras de água, material particulado em suspensão (MPS) e sedimentos. A bioacumulação de HPAs no tecido de bivalves foi cerca de quatro vezes superior às suas concentrações iniciais para a região de Santos. Foram também estimadas as concentrações de HPA na água do mar através das concentrações encontradas nos SPMDs e nos bivalves transplantados. Essas concentrações foram comparáveis às concentrações encontradas nas amostras de água. Através da análise de componentes principais juntamente com índices diagnósticos foi possível estabelecer as possíveis fonte de HPAs para as matrizes analisadas, identificando assim a predominância de HPAs pirolíticos em bivalves e sedimentos, enquanto que na água, MPS e SPMDs há predominância de HPAs petrogênicos. A comparação entre compartimentos mostrou a importância da avaliação de múltiplas matrizes, em função da concentração de HPAs cada grupo de compostos e de seus diferentes padrões de acumulação. Não foram observadas diferenças significativas entre as concentrações médias de HPAs nas duas regiões de estudo. O Complexo de Cananéia - Iguape antes considerada como área controle, apresentou concentrações de HPAs elevadas, indicando influencia antrópica para a região. / The aim of this work was to evaluate PAH\'s bioavailability in the sea water in Santos Estuarine System and Cananéia - Iguape Lagoon System. SemiPermeable Membrane Devices (SPMD) and bivalves (Crassostrea brasiliana) were deployed in both areas to obtain an overview of all these pollutants concentration, further than the potential of bioaccumulation of contaminants. Aiming comparative purposes, samples of water, suspended particulate matter (SMP) and sediments were also analyzed. PAHs bioaccumulation in bivalves tissues after deployment represented fourfold the initial concentration for Santos region. The estimated concentration of 16 priority PAHs in the water SPMD- and bivalve-based were within the concentration of PAH analyzed in the water samples, demonstrating the effectiveness of those tools to assessment of PAH in water. Through the Principal Components Analysis (PCA), and the diagnostic ratios it was possible to establish the potential sources of PAHs for analyzed compartments, identifying the pyrolytic PAH influence for bivalves and sediments under, while for water, MPS and SPMDs the mainly PAHs source were from petrogenic PAHs. Comparison between compartments showed the importance of multiple tools analyzes due to the concentration of PAH of each compound group and the different pattern of accumulation. It was not observed significant difference between the mean concentrations of PAHs in both studied regions. Cananéia - Iguape Complex was first considered as control area reported PAHs concentration higher PAH concentrations, suggesting anthropic influence in this area.

O objetivo deste trabalho foi avaliar a biodisponibilidade de HPAs na água do mar no sistema estuarino de Santos e no sistema lagunar de Cananéia-Iguape, para isso foi feita a exposição de membranas semipermeáveis (SPMD) e de bivalves (Crassostrea brasiliana) a fim de se obter um melhor panorama das concentrações desse poluente nessas duas regiões. De forma complementar foram analisadas também amostras de água, material particulado em suspensão (MPS) e sedimentos. A bioacumulação de HPAs no tecido de bivalves foi cerca de quatro vezes superior às suas concentrações iniciais para a região de Santos. Foram também estimadas as concentrações de HPA na água do mar através das concentrações encontradas nos SPMDs e nos bivalves transplantados. Essas concentrações foram comparáveis às concentrações encontradas nas amostras de água. Através da análise de componentes principais juntamente com índices diagnósticos foi possível estabelecer as possíveis fonte de HPAs para as matrizes analisadas, identificando assim a predominância de HPAs pirolíticos em bivalves e sedimentos, enquanto que na água, MPS e SPMDs há predominância de HPAs petrogênicos. A comparação entre compartimentos mostrou a importância da avaliação de múltiplas matrizes, em função da concentração de HPAs cada grupo de compostos e de seus diferentes padrões de acumulação. Não foram observadas diferenças significativas entre as concentrações médias de HPAs nas duas regiões de estudo. O Complexo de Cananéia - Iguape antes considerada como área controle, apresentou concentrações de HPAs elevadas, indicando influencia antrópica para a região. / The aim of this work was to evaluate PAH\'s bioavailability in the sea water in Santos Estuarine System and Cananéia - Iguape Lagoon System. SemiPermeable Membrane Devices (SPMD) and bivalves (Crassostrea brasiliana) were deployed in both areas to obtain an overview of all these pollutants concentration, further than the potential of bioaccumulation of contaminants. Aiming comparative purposes, samples of water, suspended particulate matter (SMP) and sediments were also analyzed. PAHs bioaccumulation in bivalves tissues after deployment represented fourfold the initial concentration for Santos region. The estimated concentration of 16 priority PAHs in the water SPMD- and bivalve-based were within the concentration of PAH analyzed in the water samples, demonstrating the effectiveness of those tools to assessment of PAH in water. Through the Principal Components Analysis (PCA), and the diagnostic ratios it was possible to establish the potential sources of PAHs for analyzed compartments, identifying the pyrolytic PAH influence for bivalves and sediments under, while for water, MPS and SPMDs the mainly PAHs source were from petrogenic PAHs. Comparison between compartments showed the importance of multiple tools analyzes due to the concentration of PAH of each compound group and the different pattern of accumulation. It was not observed significant difference between the mean concentrations of PAHs in both studied regions. Cananéia - Iguape Complex was first considered as control area reported PAHs concentration higher PAH concentrations, suggesting anthropic influence in this area.

Ce doctorat repose sur l'utilisation de Glycymeris glycymeris, un bivalve de la famille des Glycymerididae, pour reconstruire la variabilité environnementale en rade de Brest (France). Il vise à comparer des données géochimiques archivées dans ces coquilles avec diverses variables biologiques et écologiques. Les objectifs sont d'identifier de potentiels proxys et d'étendre notre connaissance de la variabilité environnementale avant les premières mesures instrumentales.Au total, 38 spécimens (vivants ou morts) ont été utilisés pour construire une chronologie s'étendant de 1891 à 2014.Les indices de croissance standardisés suggèrent que la croissance coquillière est principalement influencée par le débit de l'Elorn, la salinité et la matière particulaire en suspension.Des analyses isotopiques, réalisées sur les portions juvéniles de 24 spécimens, mettent en évidence que les variations de δ18Oaragonite enregistrent fidèlement la température de surface, permettant sa reconstruction sur 45 ans en rade de Brest. En terme de forçage climatique, ces variations de température en rade semblent contrôlées par le gyre subpolaire et l'East Atlantic Pattern.Cinq coquilles (3 d'âge inférieur à 10 ans et 2 âgées de 45 ans) ont ensuite été analysées pour leurs concentrations en strontium et magnésium par LA-ICP-MSLes concentrations en Mg et Sr, quant à elles, sont positivement corrélées à la température de l'eau à une échelle sub-annuelle, mais négativement à l'échelle annuelle.Cette étude met en lumière le potentiel de G. glycymeris comme archive de la variabilité climatique et environnementale en rade de Brest. Du fait du nombre important de spécimens sub-fossiles en rade, cette thèse fournit une base de travail pour l'extension de ces reconstructions dans un passé encore plus lointain. / This PhD thesis uses Glycymeris glycymeris, a temperate bivalve in the Glycymerididae family, to reconstruct environmental variability in the Bay of Brest, France. This work comprises of geochemical data archived within shells, compared with several biological and ecological variables. The aims of this study were to assess for potential proxies and expand environmental knowledge prior to local observational records.Thirty-eight live- and dead-collected specimens were used to create a chronology spanning 1891 to 2014. When the standardised growth index was correlated with local environmental factors, it showed that the predominant drivers of growth were Elorn inflow, salinity and suspended particulate matter.Isotopic analysis was undertaken on the juvenile increments of 24 shells. Our results highlight that variations in δ18Oaragonite accurately record local sea surface temperatures, leading to the creation of a 45-year SST reconstruction for the Bay of Brest. Correlations between this and climate forcings show that SSTs in this area are controlled by the subpolar gyre and the East Atlantic Pattern.Five shells (three under the age of 10 and two aged 45) were analysed using a LA-ICP-MS to determine the quantity of strontium and magnesium. Mg and Sr intensities are positively correlated with temperature sub-annually, but on an annual scale there is a negative correlation.This study conveys the potential of G. glycymeris as an archive of climatic and environmental variability in the Bay of Brest. As there are a large number of sub-fossil specimens in the area, this study also provides an anchored base for expansion further back in time.

Situé en France dans l’Aveyron, le bassin minier de Viviez a été soumis pendant plus d’un siècle à des rejets métalliques (principalement Cd et Zn) et est à l’origine de la contamination de l’estuaire de la Gironde, mise en évidence dans les années 1970. C’est dans ce contexte de pollution avérée que d’importants travaux de remédiation des sols ont été entrepris dès 2007. Les principaux objectifs de cette thèse résidaient en la caractérisation des premiers impacts de la remédiation sur l’amélioration de l’état chimique et écologique de l’hydrosystème via l’étude des biofilms périphytiques et des bivalves filtreurs Corbicula fluminea. En prévision des effets à plus long terme de la remédiation, il s’agissait en second lieu d’évaluer les capacités de décontamination des deux modèles biologiques et de s’intéresser à la restructuration des communautés diatomiques en réponse à une levée du stress métallique par transplantations in situ ou en laboratoire. Le suivi des bioaccumulations métalliques in situ réalisé entre 2008 et 2010 a révélé la rémanence d’un très fort gradient de contamination, à l’origine d’importants clivages communautaires dans les biofilms diatomiques. De plus, une augmentation de la pression métallique a été mesurée in situ en aval du site industriel en 2010 certainement en relation avec les travaux d’excavation. Des études de décontamination ont été menées en laboratoire après l’exposition des organismes in situ au cours de deux saisons. Chez Corbicula fluminea le Zn a été très rapidement dépuré, tandis que 15 mois n’ont pas suffi à obtenir la décontamination totale du Cd, estimée complète par modélisation après 740 à 1360 jours en fonction des saisons d’exposition. Bien que le potentiel de récupération des biofilms soit apparu rapidement en conditions naturelles après transplantation, les études de laboratoire menées sur plusieurs semaines en canaux n’ont pas abouti à une décontamination complète du Cd après 100 jours, qui a été estimée totale après 150 à 450 jours en fonction des saisons d’exposition. Malgré des prémices de restructuration, aucun retour vers des communautés de type témoin n’a pu être mis en évidence. Ces études ont souligné l’importance des phénomènes de migration d’espèces dans le potentiel de récupération des biofilms. Enfin, une étude portant sur les tératologies de diatomées a révélé leur maintien prolongé dans la population malgré l’arrêt de la contamination. L’ensemble de ces études a mis en évidence la complémentarité de l’utilisation des deux modèles biologiques, capables d’intégrer et de réguler différemment les contaminants, pour évaluer leur potentiel de récupération dans un contexte de gestion corrective de l’hydrosystème. / Located in France, in Aveyron, the mining basin of Viviez was submitted for over a century to metal discharges (mainly Cd and Zn) and was proven in the 1970s to be the source of the contamination of the Gironde estuary. In this context, significant soil remediation works were initiated in 2007. The main objectives of this thesis focused on the characterization of the first impacts of remediation on the chemical and ecological improvement status of the hydrosystem via the study of periphytic biofilms and filter-feeding bivalves Corbicula fluminea. In anticipation of the long-term effects of the remediation, a second part was devoted to evaluate the decontamination capabilities of the two biological models and to focus on the restructuring capacities of diatomcommunities in response to metal stress by translocations in situ or to laboratory. Monitoring of metal bioaccumulation carried out in situ between 2008 and 2010 revealed the persistence of a strong gradient of contamination, causing major shifts in the diatom communities of biofilms. In addition, an increase in metal contamination pressure was measured down streams the industrial site in 2010, certainly in relation with the excavation works. Decontamination studies were conducted in the laboratory after in situ exposure of organisms during two seasons. Corbicula fluminea showed fast depuration of Zn, while 15 months were not long enough to get the total decontamination of Cd, estimated complete after 740 to 1360 days according to the exposure season. Although the potential for metal decontamination of biofilms appeared to be rapid under natural conditions after transplantation, laboratory studies conducted over several weeks in artificial streams did not result in complete decontamination of Cd after 100 days, and was estimated complete after 150 to 450 days according to the exposure season. Despite the beginnings of restructuration, no return to communities similar to controls could be observed. These studies have emphasized the importance of the phenomena of species migration in the recoverypotential of biofilms. Finally, a study focussing on diatom teratologies revealed their long persistence in the population despite the stop of the contamination. All these studies demonstrated the complementary usefulness of both biological models, which differently integrate and regulate contaminants, to assess their recovery potential in a remediation context of the hydrosystem.

Orientador: Marcello Guimarães Simões / Resumo: Bakevelliidae (Bivalvia, Pterioidea) são bivalves extintos, marinhos, de epifauna a semiinfauna, bissados, suspensívoros, com pelo menos 20 gêneros descritos e inúmeras ocorrências em todo o mundo. Eles prosperaram do Paleozoico tardio ao Eoceno, atingindo máxima diversidade durante o Mesozoico (principalmente no Jurássico Inferior e Médio). Eles também foram abundantes e bem distribuídos em sucessões sedimentares cretáceas, como àquelas das bacias do Araripe e Sergipe-Alagoas, ocorrendo também de forma pontual na bacia de Pernambuco-Paraíba, no nordeste do Brasil. Neste documento, novos Bakevelliidae aptianos (Cretáceo Inferior) são descritos para a Formação Romualdo, Grupo Santana, Bacia do Araripe, nordeste do Brasil. A análise está fundamentada no exame detalhado de 361 espécimes, provenientes do terço superior da Formação Romualdo, principalmente das seções geológicas nas bordas sudoeste e sudeste da bacia, tendo sido, porém, registrados em toda a Bacia do Araripe. Juntamente com outros membros conhecidos da família Bakevelliidae, já registrados na Formação Romualdo (i.e., Aguileria dissita), os novos bivalves (Araripevellia musculosa gen. et sp. nov., Aguileria romualdoensis sp. nov. e Gen et sp. Indet.) indicam que a fauna de Bakevelliidae desta unidade foi mais diversa do que se imaginava anteriormente. Calcários ricos em conchas de Bakevelliidae, alguns com espécimes preservados in situ, estão restritos ao terço superior desta unidade, o mesmo intervalo estratigráfic... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Bakevelliids (Bivalvia, Pterioidea) are extinct, marine, stationary epifaunal to semi-infaunal, suspension feeding bivalves with at least 20 described genera and numerous occurrences worldwide. They thrived from the Late Paleozoic to Eocene, reaching the maximum diversity during the Mesozoic (mainly Early and Middle Jurassic). They were also abundant and widespread in many Cretaceous sedimentary successions, as in the Araripe and Sergipe- Alagoas basins, also occurring occasionally in Pernambuco-Paraíba basin, in NE Brazil. In this document, new Aptian (Lower Cretaceous) bakevelliid bivalves are described for the Romualdo Formation, Santana Group, Araripe Basin, northeastern Brazil. Analysis is based on the detailed examination of 361 specimens all from the upper third interval of the Romualdo Formation, mainly from geological sections in the southwestern and southeastern borders of the basin, but they were recorded in all four corners of the Araripe Basin. Together with the other known members of the family Bakevelliidae, already record in the unit (i.e., Aguileria dissita), the new bivalves (Araripevellia musculosa gen. et sp. nov., Aguileria romualdoensis sp. nov., and Gen et sp. indet.) indicate that the Romualdo bakevelliid fauna was more diverse than previously realized. Bakevelliid-rich carbonates, some with in situ specimens, are restrict to the upper third of this unit, the same stratigraphic interval yielding echinoderm-, gastropod- and stromatolitebearing limestone... (Complete abstract click electronic access below) / Mestre

A poluição, alteração física do habitat e a introdução de espécies invasoras via água de lastro, representam os maiores impactos antropogênicos para os ambientes costeiros. Foram pesquisadas em amostras da região costeira de S. Paulo, regiões portuárias brasileiras e de tanques de lastro de navios, bactérias das espécies Vibrio cholerae (Vc), V. parahaemolyticus (Vp) e V. vulnificus (Vv) que são as que têm maior implicação na saúde pública. As amostras foram avaliadas levando-se em conta parâmetros físico-químicos e microbiológicos e suas relações com a presença de Vc, Vp e Vv. As relações clonais foram verificadas através das técnicas de ERIC, BOX e REP-PCR. Foram identificadas 90 cepas de Vp e 11 de Vc. Foram observadas correlações entre alguns parâmetros microbiológicos e a presença de vibrios. A análise clonal permitiu verificar a alta diversidade das cepas. Concluiu-se que Vc e Vp são autóctones do ambiente costeiro brasileiro e podem ser tornar reservatórios para determinados fatores associados à virulência, gerando cepas com potencial epidêmico. / Pollution, physical alteration of habitat and the introduction of alien species through ballast water constitute the biggest anthropogenic impacts on coastal environments. We examined samples taken from the coastal region of S. Paulo state, Brazilian ports and ship ballast tanks, for bacteria of the species Vibrio cholerae (Vc), V. parahaemolyticus (Vp) and V. vulnificus (Vv) which have the most significant implication for public health. The samples were evaluated for microbiological and physical-chemical parameters as well as the presence of Vc, Vp and Vv. Clonal relationships of bacterial isolates were determined through ERIC, BOX and REP-PCR. A total of 90 strains of Vp and 11 of Vc were identified. Correlations between some microbiological parameters and the presence of vibrios were observed. The clonal analysis revealed extensive strain diversity. We concluded that Vc and Vp are autochthonous bacteria of the Brazilian coastal environment that can become reservoirs for factors associated with virulence, and are capable of generating strains with epidemic potential.

Le littoral est l’objet d’une contamination chimique chronique par de nombreux polluants (résidus de pesticides, résidus médicamenteux, métaux lourds…), qui sont toxiques et qui sont impliqués dans des problématiques de santé publique et de dégradations environnementales. Certains contaminants agissent à faibles doses, tandis que d’autres induisent des effets cocktails redoutables sur les organismes. Les principaux contaminants sont régulièrement dosés dans différents points stratégiques liés à la ressource en eau, surtout celle de distribution et dans certains aliments. Mais face au foisonnement des contaminants qui sont déversés dans l’environnement, il n’existe aucun système de veille efficace qui tienne compte de l’étendue réelle du problème. Par ailleurs, contrairement à ce qui existe pour l’homme, il n’y a pas de démarches finalisées et normalisables pour évaluer l’état de santé des invertébrés aquatiques, alors qu’ils représentent plus de 95% de la biodiversité. L’objectif de ce travail de thèse interdisciplinaire a consisté à évaluer l’impact des polluants chimiques sur des espèces littorales (frange littorale et zones portuaires). Un premier champ d’études a visé à mettre au point des méthodes efficaces pour évaluer la contamination des bivalves par des polluants organiques et inorganiques (volet écotoxicologie) ; un second volet a eu pour but d’analyser les effets biologiques des polluants en développant une utilisation conjointe de plusieurs biomarqueurs (volet écophysiologie). Ainsi, à l’image de ce qui est fait en santé publique, ce projet de thèse a défini pour la première fois plusieurs démarches analytiques et statistiques pour le suivi de la qualité de l’eau en milieu littoral. / The coastline faces chronic chemical contamination due to numerous toxic pollutants (residues of pesticides and medicines, heavy metals, etc.) causing public health issues and environmental degradation. Whereas some contaminants are efficacious at low doses, others lead to dangerous cocktail effects on organisms. The main contaminants are assayed regularly among strategic stages linked to water resource. There is a particular focus on supply and food. Nonetheless, due to the proliferation of contaminants released in the environment, there is no effective monitoring system taking the real extent of the problem into consideration. Moreover, unlike existing methods for humans, there is no finalised or standardised approach to assessing the health of state of aquatic invertebrates, while they represent more than 95% of the biodiversity. The purpose of this thesis work involving interdisciplinary research was to evaluate the pollution impacts on the coastline species (coastal fringe and port areas). A first part of the study aimed at designing effective methods of contamination assessment on bivalves by organic and inorganic pollutants (ecotoxicology). Another part focused on analysing biological effects of pollutants by developing a joint use of several biomarkers (ecophysiology). Thus, like work carried out by public health, this thesis project defined for the first time several analytical and statistical steps on monitoring the state of health of marine organisms and the water quality in coastal areas.