<p> The interaction of biological and physical processes has resulted in distinct morphological and biological zonation across the Subarctic macrotidal tidal flats at the head of Frobisher Bay. The tidal flats have been divided into six morphological zones which are closely related to the three biological communities found there. </p> <p> Faunal species of the Upper Flat inhabit the beach and fines flat morphological zones where ice action during breakup and freezeup has the greatest influence. Species inhabiting these zones are hardy, and freshwater tolerant. Many are highly motile and recolonize the area after ice breakup. </p> <p> The Middle Flat extends from 5.0 m ALLT to 2.2 m ALLT. It is inhabited by motile polychaetes at its upper end (bouldery flat >4.5 m ALLT). with more sedentary species appearing towards its lower end (very bouldery flat). Below 2.2 m ALLT, on the Lower graded flat, sedentary infauna such as Cyrtodaria kurriana, Mya truncata and sabellid polychaetes, dominate the substrate. </p> <p> The three major processes acting on the tidal flats are, in order of importance, tidal, ice and wave action. Exposure indices, generated from tidal data, reveal 2 critical tidal heights at around 4 m and 7.5 m ALLT, in Frobisher Bay. The boundary between motile and less motile fauna, and bouldery and very bouldery morphological zones, occurs around 4.0 m ALLT. Of the flora and fauna only Fucus evanescens is found beyond the 7.5 m ALLT limit. </p> / Thesis / Master of Science (MSc)

The Belchertown Intrusive Complex is a ~164 km2 Devonian pluton that intruded Paleozoic metasedimentary and metavolcanic rocks in west-central Massachusetts. Intrusion of the pluton was synchronous with Acadian deformation (Ashwal, 1974). The complex is concentrically zoned, with a core of orthopyroxene-biotite monzodiorite, a middle zone of clinopyroxene-hornblende-biotite granodiorite, and an outermost zone of hornblende-biotite granodiorite. Zoning from a more to less hydrous mineral suite from the outside to the inside of the pluton led Ashwal (1974) to suggest that metamorphic hydration most strongly affected the outermost zones of the complex. Basaltic inclusions occur most commonly near the edges of the pluton. Many of these inclusions preserve textures suggestive of mafic-felsic magma interaction. The abundance of basaltic enclaves on the edges of the complex may suggest a bowl-shaped structure, with lower more mafic-dominated rocks exposed on the edges of the complex. Bulk rock major element analyses of granitoids, basalts and gabbros, and diorites from all zones of the complex show that intermediate samples, regardless of zone, plot on a mixing line between mafic and felsic end members, supporting a model in which mafic and felsic magmas may have mingled and mixed. Trace element analyses of intermediate-composition samples are similar across the entire complex, with enrichment in large ion lithophile elements and a pronounced Nb trough. In contrast, trace element concentrations in both the mafic rocks (basaltic enclaves and gabbroic inclusions), and in the granitoids, show considerable variation. The diversity of composition within both the mafic and felsic end-members suggests that either fractionation or differing degrees of partial melting of source rocks may account for these compositional ranges. Sanukitoids comprise a majority of the inner zone, and point to the mixing of parental melts at depth in a subduction tectonic regime as a likely model of petrogenesis for the complex.

In this work we develop and analyze algorithms motivated by the parameter estimation problem corresponding to a multilayer aquifer/interbed groundwater flow model. The parameter estimation problem is formulated as an optimization problem, then addressed with algorithms based on adjoint equations, quasi-Newton schemes, and multilevel optimization. In addition to the parameter estimation problem, we consider properties of the parameter to solution map. This includes invertibility (known as identifiability) and differentiability properties of the map. For differentiability, we expand existing results on Fréchet sensitivity analysis to convection diffusion equations and groundwater flow equations. This is achieved by proving that the Fréchet  derivative of the solution operator is Hilbert-Schmidt, under smoothness assumptions for the parameter space. In addition, we approximate this operator by time dependent matrices, where their singular values and singular vectors converge to their infinite dimension peers. This decomposition proves to be very useful as it provides vital information as to which perturbations in the distributed parameters lead to the most significant changes in the solutions, as well as applications to uncertainty quantification. Numerical results complement our theoretical findings. / Ph. D.

Reservoirs are generally created by damming rivers. The upper reaches of any reservoir is generally narrow and winding like the parent river. This is the riverine zone of the reservoir. The reservoir is deepest and widest near the dam. Here, lake-like conditions exist and the water is quiescent. This is the lacustrine zone. The transitional zone separates the lacustrine and riverine zone. It has intermediate characteristics. There are many characteristics, both physical and chemical, that differentiate between these three zones. Based on the differences in characteristics between the three zones, a method has been developed to successfully divide any reservoir into three zones. The method developed was applied to Lake Manassas and the Occoquan Reservoir located in the Occoquan watershed in Virginia. Both are man-made impoundments. Analysis of data, based on the method developed, was successfully in dividing both reservoirs into the three zones. This method may therefore be successfully applied to obtain zonation in reservoirs. / Master of Science

Dans le cadre de l'installation d'un réseau de surveillance sismique en Provence Occidentale, notre étude consiste dans un premier temps : - à localiser, par différentes méthodologies d'approche de la déformation récente, les accidents tectoniques susceptibles d'être sismiquement actifs, - à caractériser les mécanismes des déformations tectoniques affectant cette région ainsi que leur répartition depuis environ 10 millions d'années, - à reconstituer le(s) champ(s) de contraintes à l'origine de ces déformations, en vue d'établir une zonation tectonique cohérente à l'échelle de la région étudiée. Dans un deuxième temps, nous définissons les relations existantes entre notre zonation tectonique, les accidents majeurs et la sismicité historique et instrumentale afin d'obtenir les caractères généraux permettant un découpage de la Provence en différents domaines sismotectoniques.

Face à l’érosion globale de la biodiversité des écosystèmes aquatiques continentaux, l’identification des mesures de gestion les plus urgentes à mettre en place est cruciale. En s’appuyant sur une approche innovante et multi-facettes de la diversité, les priorités de conservation pour les assemblages de poissons de rivière ont pu être déterminées à l’échelle de la France. La durabilité de ces priorités de conservation face aux principales composantes des changements globaux a ensuite été évaluée afin d’identifier les zones qui protégeront efficacement la biodiversité actuelle dans le futur. La méthodologie développée a finalement été appliquée au réseau hydrographique du département du Pas-de-Calais dans le but d’identifier précisément les priorités locales de conservation et de restauration. Ces outils pourront par la suite être utilisés comme support d’aide à la décision et adaptés selon les besoins des gestionnaires des milieux aquatiques. / The global loss of biodiversity affects freshwater ecosystems, making it crucial to identify the priority management actions in order to protect freshwater biodiversity in an effective and sustainable way. Based on an innovative multi-faceted framework of diversity, the spatial priorities for the conservation of stream fish assemblages have been identified at the scale of France. Their robustness to several drivers of global changes has then been assessed to identify the areas that are likely to efficiently protect the present-day biodiversity in the future. The methodological framework proposed herein has finally been applied to the river network of the Pas-de-Calais department located in northern France to accurately identify the local conservation and restoration priorities. These management tools can be used to support the establishment of management actions in accordance with the needs of the local environmental decision-makers.

Salt marshes provide critical ecosystem services, such as shoreline stabilization, biogeochemical cycling and habitat for wildlife, to much of the world's population living on the coasts. Emergent vascular plants are a critical component of these ecosystems. This study was a comprehensive effort to gain a better understanding of the ecology of salt marsh plants in the Nueces River delta on the south Texas coast. This knowledge is essential to understand the potential anthropogenic impacts on salt marshes, including sea-level rise, global warming, reduced freshwater inflow and coastal erosion. A combination of remote sensing analysis, field studies and experiments were used to allow analysis across spatial scales ranging from landscape patterns of vegetation to leaf level measurements of the dominant species. A novel method of image classification was developed using high-resolution multi-spectral imagery integrated with ancillary data to map the major plant communities at a landscape scale. This included a high marsh assemblage composed primarily of Spartina spartinae and a low marsh community dominated by Borrichia frutescens and Salicornia virginica. Geospatial analysis determined that the location of these plant communities was related to the distance from the tidal creek network and elevation. The B. frutescens and S. virginica assemblage was more abundant at lower elevations along the waters edge, making it vulnerable to loss from shoreline erosion. At a finer spatial scale, gradient analysis was utilized to examine the relationship between elevation, which creates environmental gradients in salt marshes, and species distribution. I discovered that elevation differences of less than 5 cm can influence both individual species and plant community distribution. One interesting finding was that the two dominant species, B. frutescens and S. virginica, share similar responses along an elevation gradient yet are observed growing in monotypic adjacent zones. I constructed a large reciprocal transplant experiment, using 160 plants at 4 sites throughout the marsh, to determine what causes the zonation between these two species. The results of this study found that S. virginica fared well wherever it was transplanted but was a weak competitor. B. frutescens survival was significantly lower in the S. virginica zone than in its own zone suggesting that abiotic factors are important in determining the zonation of this species. However, high spatial and temporal variability existed in environmental parameters such as salinity. This variability may have been caused by the semi-arid climate and irregular flooding typical in the Nueces Marsh. Therefore, I utilized a greenhouse experiment to directly test the importance of the two dominant physical factors in salt marshes, flooding and salinity. The results found that for B. frutescens the effects of flooding were not significant, however salinity at 30% reduced growth. Salinity did not influence growth of S. virginica. The greater ability of S. virginica to tolerate salinity stress has important implications because reduced freshwater inflow or climate change can increase porewater salinity, thus favoring the expansion of S. virginica, and altering the plant community structure. / text

Three species of Sargassum are the P10st abundant intertidal macroalgae at Puerto Penasco, Sonora, Mexico. Sargassum johnstonii Setchell & Gardner, S. herporhizum Setchell & Gardner, and S. sinicola Setchell & Gardner var. camouii (Dawson) Norris & Yensen are zoned on emergent reef in low intertidal areas. Sargassum johnstonii occurs in a zone above dense stands of S. herporhizum, and scattered patches of S. 8inicola occur on the lowest emergent reef. Sargassum sinicola, the most abundant species, predominates in pools throughout the intertidal zone. In mid-intertidal pools the species show the same zonation with respect to water depth that they do on emergent reef. Ecological separation is clear, the species occurring in different vertical zones or different habitats (pools or emergent reef). At some sites where S. herporhizum is rare or absent, the upper limit of emergent S. sinicola plants shifts upward probably because of a combination of physical and biological factors. The three species in this highly seasonal region reach maximum size and canopy cover in early spring. All produce fertile receptacles in the spring and shed their branches and die back in summer. Surviving S. sinicola persist through the summer at larger sizes, recommence growth and produce a second crop of receptacles in the fall; the other two species grow but are not fertile until the following spring. The species differ in allocation of biomass to vegetative and sexual reproductive structures. Sargassum herporhizum invests a high proportion of its wet and dry biomass into extensively branched, rhizoidal holdfasts. The holdfasts of the other two species are smaller relative to their upper branches, and are not rhizoidal. Experimental clearings showed that S. herporhizum was the most effective at recovering continuous space after disturbance and also after normal summer dieback. Sargassum johnstonii and S. sinicola produce large volumes of sexual receptacles on buoyant branches, which have the potential for wide dispersal, whereas S. herporhizum produces a relatively small volume. A trade-off between short-range vegetative encroachment abilities and potential for long-range dispersal of sexual propagules may have occurred in the evolution of reproductive strategies of these Sargassum species.

Dentre os ecossistemas presentes na região entre-marés e habitats da zona costeira, os costões rochosos são considerados um dos mais importantes por conter uma alta riqueza de espécies de grande importância ecológica e econômica. Desta forma estudos biogeográficos e paleogeograficos são importantes ferramentas para o entendimento dos padrões de distribuição da biota: o espaço (área geográfica de ocorrência dos organismos), o tempo (eventos históricos que influenciaram os padrões atuais de ocorrência) e a forma dos grupos de organismos. Este estudo teve como objetivo principal abordar a distribuição da biota relacionando-a com a geologia e a morfologia dos costões rochosos alem de caracterizar a presença de indicadores de paleoníveis marinhos de três costões rochosos localizados nas Baías do Flamengo e da Fortaleza, em Ubatuba (SP). Os resultados desse estudo indicam que as distribuição da fauna foi muito homogênea sendo encontrado em todos os costões estudados as cracas do genêro Chtamalus, Balanus e Tetraclita, moluscos do genêro Thais, Littorina (mais abundantes), alem de colonias de Phragmatopoma e extensas bancos de algas do gênero Sargassum que estiveram presentes durante toda amostragem. A ocupação das zonas pela biota vai depender mais do declive da rocha do que da composição mineralógica, juntamente com o regime de ondas atuante no local, que vai ditar a amplitude das faixas de ocupação dos organismos, essa inclinação da rocha pode diretamente interferir nos padrões de distribuição, alterando a taxa de substituição das espécies. Um grupo de moluscos gastrópodes vermetideos do gênero Petaloconchus merece especial destaque, pois, foi registrada a primeira ocorrência deste grupo no Estado de São Paulo, além disso seu remanescentes fósseis são importantes indicadores de paleoníveis marinhos. As estimativas de variações de nível do mar foram mais eficientes com a utilização de vermetídeos e paleotocas de ouriços somada as medições de campo dos vermetideos vivos e sua localização geográfica, permite determinar paleoníveis mais precisos, foram registrados níveis mais elevados no período de 3810 ± 30 Cal. anos AP, atingindo o máximo de 3,87m ± 0,5 m e o menor em 1340 ± 30 Cal. anos AP, registrando 1,00m ± 0,5 m. / Among the ecosystems in the region and intertidal habitats of the coastal zone, the rocky shores are considered one of the most important because it contains a high number of species of great ecological and economic importance. Thus paleogeographic and biogeographic studies are important tools for understanding the distribution patterns of biota: space (geographical area of occurrence of organisms), time (historical events that influenced the patterns of occurrence) and the form of groups of organisms.The present study aimed to approach the distribution of biota relating it to the geology and morphology of rocky coasts in addition to characterize the presence of indicators of marine paleolevels three rocky shores located in Bays Flamengo and Fortaleza, Ubatuba (SP) . The results indicate that the distribution of the fauna was very homogeneous being found in all the studied shores, barnacles of the genus Chtamalus, Balanus and Tetraclita, clams genus Thais, Littorina (most abundant), in addition to extensive colonies Phragmatopoma and banks Sargassum algae that were present during the whole sampling. The occupation of areas for biota will depend more on the slope of the rock that the mineralogical composition, together with the active wave regime in place that will dictate the extent of occupancy ranges of organisms, the inclination of the rock can directly interfere with the patterns distribution changing the rate of substitution of species. A group of gastropod mollusks vermetids of the genus Petaloconchus deserves special mention because it was the first recorded occurrence of this group in the State of São Paulo, besides its fossil remains are important indicators of marine paleolevels. Estimates of changes in sea level were more efficient with the use of vermetid and paleotocas urchins added field measurements of vermetid alive and their geographic location, to determine paleolevels most accurate, highest levels were recorded in the period 3810 ± 30 Cal. years BP, reaching a maximum of 3.87 m ± 0.5 m lower in 1340 ± 30 Cal. years BP, registering 1.00 m ± 0.5 m.

Manguezais desenvolvem-se de formas distintas, em função dos cenários ambiental e geomorfológico. O desenvolvimento espaço-temporal de bosques de mangue, no Sistema Costeiro Cananéia-Iguape, foi estudado no contexto da ecologia da paisagem. Manguezais foram analisados nos níveis hierárquicos Stand (unidade de paisagem) e Site (bosque ou parcela). No nível Stand, o tratamento de fotografias aéreas com uso de Sistema de Informação Geográfica (SIG), indicou variação espacial distinta, em duas áreas de estudo do Mar de Cananéia, no mesmo intervalo temporal, 16 anos (1981 – 1997). No nível Site, bosques de mangue adjacentes ao Mar de Cananéia e à Baía do Trapandé foram monitorados durante 2 anos (2002 – 2004), em parcelas fixas, fornecendo informações sobre o desenvolvimento destes. Bancos de sedimento emersos são, primeiramente, colonizados pela gramínea Spartina alterniflora, espécie pioneira e determinante no estabelecimento de propágulos. Os bosques de mangue, estudados no Mar de Cananéia, nas fases inicial e jovem são dominados por Laguncularia racemosa, em áreas em progradação, como proposto na literatura. Na área de estudo da Baía do Trapandé, a espécie dominante é Rhizophora mangle. Bosques maduros são dominados pelas espécies R. mangle ou Avicennia schauerianna, em função das características das áreas de estudo. Padrões de sucessão dos bosques de mangue estudados seguem modelo proposto na literatura. / Mangrove forests get developed in distinct patterns, depending on geomorphological and environmental scenarios. Its spatial and temporal development was studied in a landscape ecology context, at the Cananéia-Iguape Coastal System. Stand and Site hierarchical levels had been used to analyze mangrove forests. At Stand level, aerial photography processing along with Geographical Information System (GIS) showed distinct spatial variations during the same 16 years period (1981-1997) in the two case areas: Mar de Cananéia and Baia de Trapandé. At Site level, mangrove forests surrounding Mar de Cananéia and Baia de Trapandé had been monitored during 2 years (2002-2004) using fixed plots, providing information on its development. Gramineous Spartina alterniflora, pioneer species and determinative for propagule establishment, colonize at first emerged sandbanks. Studied mangrove forests surrounding Mar de Cananéia are, during initial and youth phases, dominated by Laguncularia racemosa, in deposition areas, as suggested in bibliography. At Baia de Trapandé surround, the dominant species was Rhizophora mangle. Mature forests are dominated by R. mangle or Avicennia schauerianna, depending on area’s characteristics. Studied mangrove forests follow model of succession seen in bibliography.