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.

Nous étudions ici différents aspects de la sismicité du Sud-Est de la France, en nous aidant des données nouvelles disponibles aujourd'hui. L'apparition récente de nouveaux réseaux sismologiques (L.O.G., S.E.O., I.G.G.) dans les Alpes, et la multiplication d'études géophysiques (grands profils, aéromagnétisme,paléomagnetisme,photos satellites, nivellement) et géologiques devraient aboutir dans les prochaines années à une synthèse géodynamique des Alpes. Notre travail apporte certains éléments Sismologiques pour cette future synthèse. Nous présentons d'autre part une étude sur une nouvelle méthode de zonage sismique que nous appliquons en particulier au ca's du S.E. de la France. Les trois premiers chapitres concernent surtout l'acquisition ou le traitement de nouvelles données de sismologie. Dans le Chapitre l, on constitue un fichier de séismes historiques et récents, avec lequel on trace des cartes de sismicité et on étudie la loi magnitude-fréquence. Le Chapitre II livre des solutions focales nouvelles. Le Chapitre III donne les résultats d'une campagne d'enregistrement de petits séismes en Ubaye-Queyras en septembre-octobre 1977 . Le Chapitre IV est consacré à la synthèse des données acquises dans les trois premiers chapitres et à leur comparaison avec d'autres données (géophysiques et géologiques). Enfin, le Chapitre V expose notre méthode de zonation sismique. Nous présentons en annexe le fichier de séismes, les cartes de sismicité, ainsi qu'un exposé sur la loi magnitude-fréquence.

The deep ocean (> 200-m depth) covers more than 65 percent of earth's surface and is known as the largest active carbon sink of the planet. Photosynthesis fixes inorganic carbon into organic rich-compounds to fuel the biological production in the upper ocean. A small portion of the photosynthetic carbon eventually sinks to the seafloor to support diverse deep-sea life. In this dissertation, the phytoplankton production and export flux of particulate organic carbon (POC) to the seafloor were linked to standing stocks and compositional changes of the deep-sea soft bottom assemblages. The pattern and processes of energy transfer from the surface ocean to the deep sea was examined by modeling the global benthic bacteria, meiofauna, macrofauna, and megafauna biomass from remotely sensed ocean color images and the seafloor relief. The analysis was then scaled down to the macrofauna of the Gulf of Mexico (GoM) to examine the global pattern on regional oceanic features with contrasting productivity regimes. These results suggested a universal decline of benthic standing stocks down the continental margins that is caused by an exponential decrease of export POC flux with depth. A revisit of historical epibenthic invertebrate sampling in the North Atlantic showed that both individual species and multi-species assemblages occurred in narrow depth bands that hugged the topography from the upper continental slope out to the Hatteras Abyssal Plain. The continuum compositional change suggested that the continuous decline of benthic food supply with depth was the potential driving force for the pattern of bathymetric faunal zonation. A broad, systematic survey across multiple depth transects in the northern GoM suggested that macrofauna zonation is not only taking place across isobaths, but also form the northeast to the northwest GoM due to a horizontal productivity gradient created by the nutrient-laden Mississippi River. Analyses of long-term demersal fish data from 1964 to 2002 in the northern GoM showed no evidence of large-scale faunal change across different sampling times. Base on the pooled data, a shift in rate of fish species replacement may be caused by complex biological interactions or changes in environmental heterogeneity along depth or productivity gradients.

Made available in DSpace on 2016-12-23T13:48:26Z (GMT). No. of bitstreams: 1 DISSERTACAO.pdf: 3510917 bytes, checksum: 69a3d858b081edcac7d8bccf6547c8c3 (MD5) Previous issue date: 2007-02-27 / In the coastal plain vegetation (restinga) of Paulo Cezar Vinha State Park in Guarapari-ES, there are 12 restinga vegetation types or zones with very distinct physiognomies, following a species distribution and diversity gradient toward the continent interior. Thus, Canavalia rosea (Fabaceae) is restricted on creeping psammophytic zone, whereas Passiflora mucronata (Passifloraceae) is located on Palm scrub zone. There are several hypotheses about the vegetation zones stand, and the most outspread one is the saline gradient. Recently, the soil fertility factor has been also postulated. Trying to elucidate these questions, it was carried out the present study in order to investigate the salinity and mineral nutrition influence on the C. rosea and P. mucronata initial growth. Both species were grown with restinga soil in witch it was applied NaCl saline solution of 0, 200, 400 e 600mM. In nutritional experiment, the plants were grown in washed sand where it was applied weekly the Hoagland & Arnon (1936) nutritive solution at 20, 100 and 200% of ionic strength. The experiments were performed in a green house with natural light, temperature, and photoperiod. With the dry matter and leaf area data it was calculated the relative growth ratio (RGR), the net assimilation ratio (NAR), the leaf area ratio (LAR), the root/shoot ratio (RS), and the biomass allocation (root, stem and leaf fraction mass) according to Hunt (1982). It was also performed chemical and physical soil analyses of Creeping psammophytic and Palm scrub zone. The results showed that, on the whole, the increase of salinity affected both species growth. Both plants did not survive the highest levels of salinity (400 and 600mM), and C. rosea was later affected. The best performance was by the C. rosea plants growing in 0mM NaCl solution, whict reveled better biomass production. The C. rosea R:S ratio decreased in higher salinity levels, on the other hand, opposite effect was verified for P. mucronata plants. The soil analyses reveled that the sodium concentration was equivalent in both vegetations zones analyzed, and significant differences occurred as to the soil fertility. The Palm scrub vegetation develops on soils with higher organic matter and bases saturation values. This information confirms those results from the growth analysis, because P. mucronata plants have better growth (higher RGR and NAR) with the increase of nutrient availability, whereas C. rosea plants have a superior development in low ionic strength solution. The results allow-us to conclude that the fertility gradient must be a preponderant factor in the plant position of the vegetal zones studied at the restinga of Paulo Cezar Vinha State Park. / Na restinga do Parque Estadual Paulo Cezar Vinha, há 12 formações com fisionomias bem distintas, obedecendo a um gradiente de distribuição e diversidade de espécies no sentido praia-interior do continente. Canavalia rosea (Fabaceae) está situada na formação Psamófila-reptante, enquanto Passiflora mucronata (Passifloraceae) encontrase na formação Palmae. As hipóteses sobre o posicionamento das formações são diversas. A mais difundida seria a do gradiente salino. Mais recentemente, o fator fertilidade do solo também tem sido postulado. Buscando elucidar essas questões, foi conduzido o presente trabalho, tendo como objetivo principal investigar a influência da salinidade e da nutrição mineral no crescimento inicial de C. rosea e P. mucronata. Para verificar o efeito da salinidade, as plantas foram cultivadas em tubetes contendo solo da formação Psamófila-reptante encharcado com soluções de 0, 200, 400 e 600mM de NaCl. Na análise nutricional, as plantas foram cultivadas em vasos plásticos (3l) contendo areia lavada como substrato, onde foi aplicada, semanalmente, solução nutritiva de Hoagland e Arnon (1936) a 20, 100 e 200% de força iônica. Os experimentos foram conduzidos em casa de vegetação com luz, temperatura e fotoperíodo natural. Com os dados de massa seca e área foliar, foram calculadas as taxas de crescimento relativo (TCR), assimilatória líquida (TAL), razão de área foliar (RAF), razão raiz: parte aérea (R:Pa) e alocação de biomassa (fração de massa radicular, caulinar e foliar), segundo Hunt (1982). Também foram realizadas análises físicoquímicas do solo das formações Psamófila-reptante e Palmae. De modo geral, o aumento da salinidade afetou o crescimento das duas espécies. As plantas não sobreviveram aos tratamentos de 400 e 600mM, e esse efeito foi tardio em C. rosea. Melhor desempenho foi obtido por plantas de C. rosea em 0mM (solo de restinga), exibindo um maior rendimento na produção de biomassa. A razão R:Pa dessa espécie decresceu com o aumento dos níveis de salinidade, enquanto efeito oposto foi verificado para as plantas de P. mucronata. Maior rendimento na produção de biomassa da parte aérea e radicular, das duas espécies, ocorreu em 0 e 200mM de NaCl, respectivamente. As análises de solo revelaram que a concentração de sódio foi equivalente entre as formações analisadas, e diferenças significativas foram encontradas quanto à fertilidade. A formação Palmae desenvolve-se em solos com maiores valores de matéria orgânica e de saturação por bases. Essas informações confirmam os resultados obtidos experimentalmente em que plantas de P. mucronata crescem, proporcionalmente, à disponibilidade de nutrientes no solo, enquanto plantas de C. rosea desenvolvem-se melhor em deficiência nutricional. Os maiores valores de TAL e TCR de C. rosea foram obtidos na solução mais pobre em nutrientes, enquanto, para P. mucronata, maiores valores foram obtidos nas soluções mais ricas. Dessa forma, os resultados apresentados mostram que o gradiente de fertilidade deve ser o fator preponderante no posicionamento de plantas nos solos das formações estudadas na restinga do Parque Estadual Paulo César Vinha.

Submitted by Izabel Franco (izabel-franco@ufscar.br) on 2016-09-12T13:55:20Z No. of bitstreams: 1 DissTZ.pdf: 3737067 bytes, checksum: 3b8fbeeaf9b22bee8d5df8d70aff841b (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-12T18:41:00Z (GMT) No. of bitstreams: 1 DissTZ.pdf: 3737067 bytes, checksum: 3b8fbeeaf9b22bee8d5df8d70aff841b (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-12T18:41:22Z (GMT) No. of bitstreams: 1 DissTZ.pdf: 3737067 bytes, checksum: 3b8fbeeaf9b22bee8d5df8d70aff841b (MD5) / Made available in DSpace on 2016-09-12T18:41:34Z (GMT). No. of bitstreams: 1 DissTZ.pdf: 3737067 bytes, checksum: 3b8fbeeaf9b22bee8d5df8d70aff841b (MD5) Previous issue date: 2015-04-06 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / There are several factors that may influence the richness and distribution in the subterranean fauna, just as resource avaiability and distribution, the local climate characteristics, the quality of the habitat and the vegetation surrounding it. Hypogean systems present high degree of endemism and their populations present as intrinsic characteristics a reduced number of individuals and are usually dependent on nutrients imported from the surface. These factors, among other results in an extremely fragile hypogean environment. This study aimed to verify the taxonomics groups that occur in Presidente Olegário caves, located at northwestern of Minas Gerais, Brazil. Along with that it aimed to verify through statistical tests as the biotics and abiotics variables influence the distribution and composition of subterranean fauna of this region. For these purposes, collections using combinated sampling methods occured in five different visiting occasions, contemplating both dry and rainy periods. The Presidente Olegário karst area presented high richness (386 species in seven caves sampled). Four new species and three new records besides four troglomorphic morphotypes were registrated. It was also verified how essential the execution of replics are, since the detection of rare species increases with the number of samplings. The caves presented high taxonomic distinctness and therefore, presented high faunistic singularity. The species distribution is positively associated to abiotics variables (temperature, relative humidity and precipitation), which can promote niche diversification when changed and consequently increase the local diversity. Therefore faunistic patterns can be changed for sazonality influence in the subterranean environment. High values of richness and abundance were registered at the entrance and twilight zones, where higher amounts of organic matter were found. The fauna stratification occurred with some taxa occurring preferentially in certain substrates types, which is probably related to food resources availability. Therefore, the terrestrials communities studied seem to be strutured based on energy resources and thus, a food web was built for these caves. Several impacts are present in Presidente Olegário, such as pasture, agriculture and future projects of gas extration and hidreletrics. Thus, this region with high richness and faunistic singularity and its area of influence should be considered as priority for conservation. / Há diversos fatores que influenciam a riqueza e a distribuição da fauna no ambiente subterrâneo, como a disponibilidade e distribuição dos recursos, as características climáticas locais, a qualidade do habitat e a cobertura vegetal do entorno. Sistemas hipógeos apresentam elevado grau de endemismo, e suas populações apresentam como características intrínsecas um número reduzido de indivíduos e, geralmente, são dependentes de nutrientes importados da superfície. Estes fatores, dentre outros, tornam o meio hipógeo extremamente frágil. Este estudo teve como objetivos verificar quais grupos taxonômicos ocorrem em cavernas de Presidente Olegário, noroeste de Minas Gerais, Brasil, além de verificar, por meio de testes estatísticos, como as variáveis bióticas e abióticas influenciam na distribuição e composição da fauna subterrânea dessa região. Para isso, foram realizadas coletas utilizando métodos combinados de amostragem ao longo de cinco ocasiões de visita, contemplando períodos secos e chuvosos. A área cárstica de Presidente Olegário apresentou elevada riqueza (386 espécies em sete cavernas amostradas). Foi registrada a ocorrência de quatro espécies novas, três registros novos, além de quatro morfotipos troglomórficos. Também se verificou a necessidade e importância da realização de réplicas, uma vez que a detecção de espécies raras aumenta com o número de amostragens. As cavernas apresentaram elevada distinção taxonômica e, portanto, possuem elevada singularidade faunística. A distribuição das espécies está associada de forma positiva às variáveis abióticas (temperatura, umidade relativa e precipitação), as quais podem promover a diversificação de nichos quando alteradas e, consequentemente, aumentar a diversidade local. Ainda, padrões faunísticos podem ser alterados por influência da sazonalidade no ambiente subterrâneo. Maiores valores de riqueza e abundância foram registrados nas zonas de entrada e penumbra, onde havia maior quantidade de matéria orgânica. Foi observada a estratificação da fauna subterrânea, com alguns táxons ocorrendo preferencialmente em determinados tipos de substratos, o que provavelmente está relacionado à disponibilidade de recursos alimentares. Portanto, as comunidades terrestres das cavernas estudadas parecem ser estruturadas com base em recursos energéticos e, assim, foi proposta uma teia alimentar para essas cavernas. Diversos impactos e ameaças estão presentes em Presidente Olegário, como atividades agropecuárias, projetos futuros de extração de gás e construção de pequenas centrais hidrelétricas. Assim, essa região com elevada riqueza e singularidade faunística e toda sua área de influência deve ser considerada como prioritária para conservação.

Orientadores: Luiz Francisco Lembo Duarte, Vera Nisaka Solferini / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-09T03:13:57Z (GMT). No. of bitstreams: 1 DeCapitani_JoanaDutilh_M.pdf: 5636529 bytes, checksum: 9756e9e22fb0418a7a5cd700c6e0c60d (MD5) Previous issue date: 2007 / Resumo: A riqueza de espécies, abundância, proporção de jovens, crescimento corporal, seleção de microhabitat, diversidade genotípica, variabilidade e estrutura genética de anêmonas-do-mar da região entremarés foram estudados no período de agosto de 2005 a julho de 2006. Cinco espécies foram encontradas e tiveram as suas populações acompanhadas em duas praias do município de São Sebastião, SP: Bunodosoma caissarum, Bunodosoma cangicum, Anthopleura cascaia, Actinia bermudensis e Phyllactis flosculifera. Destas, as mais abundantes foram Bunodosoma caissarum, Bunodosoma cangicum e Anthopleura cascaia. Estas três espécies mostraram oscilações muito grandes em seus tamanhos populacionais, padrão não esperado considerando a longevidade de anêmonas-do-mar. As espécies B. caissarum e B. cangicum mostraram um padrão de recrutamento aparentemente contínuo e pequeno enquanto A. bermudensis e A. cascaia apresentaram um maior número de jovens principalmente na primavera. Não foi verificado um padrão claro de crescimento corporal das espécies estudadas, devido, possivelmente, à variação no número de indivíduos amostrados em cada mês, ou a uma taxa de crescimento muito pequena para ser detectada no período de um ano. Os microhabitats ocupados pelas espécies foram significativamente relacionados às suas preferências, mostrando que a localização espacial não acontece aleatoriamente. Bunodosoma caissarum, B. cangicum e Phyllactis flosculifera foram as espécies escolhidas para as análises genéticas. Cada uma delas teve duas populações amostradas, e as populações de B. caissarum foram também organizadas localmente em subgrupos. As três espécies apresentaram altos valores de diversidade genética e todas as populações apresentaram déficits de heterozigotos. Os valores de diferenciação genética encontrados para B. caissarum (? = 0.039) são significativos, considerando que a espécie apresenta larva planctônica e as populações amostradas estavam separadas por apenas 13 km. Além disso, foi encontrada evidência de estruturação microgeográfica para esta espécie. Bunodosoma cangicum apresentou valores baixos de estruturação genética (? = 0.021) e P. flosculifera valores moderados (? = 0.080). Phyllactis flosculifera e B. cangicum apresentam populações distantes (1000 km e 1300 km, respectivamente) geneticamente conectadas, o que sugere que ambas as espécies tenham larvas com capacidade de dispersão em grandes distâncias. Todos os indivíduos das populações estudadas das três espécies apresentaram genótipos únicos, o que sugere que nenhuma delas tenha reprodução assexuada / Abstract: We studied the richness of species, abundance, proportion of juveniles, growth, microhabitat selection, genotypic diversity, genetic variability and structure of intertidal sea anemones between August 2005 and July 2006. Five species were found and their populations were studied in São Sebastião, SP: Bunodosoma caissarum, B. cangicum, Anthopleura cascaia, Actinia bermudensis and Phyllactis flosculifera. The most abundant ones were Bunodosoma caissarum, B. cangicum and Anthopleura cascaia. These three species showed important oscillations in their populations sizes, a pattern that was not expected considering the long life of sea anemones. Bunodosoma caissarum and B. cangicum showed small and continuous recruitment, while A. bermudensis and A. Cascaia presented a bigger number of juveniles mainly in the spring. A clear pattern of growth was not observed for any of the species studied, probably due to the variation in populations¿ size during the study or it could have been caused by a growth rate too small to be detected in one year time. The microhabitats occupied by all five species were related to their preferences, indicating that the spatial distribution found was not at random. Bunodosoma caissarum, B. cangicum and P. flosculifera were also genetically analyzed. Each one of them had two populations sampled, and the ones of B. caissarum were sampled in subgroups following spatial distribution in situ. All the species showed high levels of genetic diversity and all the populations presented a deficit of heterozygotes. The values of genetic differentiation found for B. caissarum (? = 0.039) are significant given the long-lived planktonic larva of the species and the small distance between the samples (13 km) and we also found evidence of microgeographic structuring in this species. Bunodosoma cangicum showed low levels of genetic structuring (? = 0.021) while P. flosculifera presented a moderate value of structuring (? = 0.080). Phyllactis flosculifera and B. cangicum present distant populations (1000 km and 1300 km apart, respectively) genetically connected suggesting that both species have larvae capable of good dispersal distances. All of the individuals of the three species showed unique genotypes, suggesting that none of them have asexual reproduction / Mestrado / Ecologia / Mestre em Ecologia

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.

En milieu intertidal rocheux, les communautés dominées par des canopées d'algues brunes (Phaeophyceae) sont particulièrement répandues. Malgré leur accessibilité, leur fonctionnement reste encore largement méconnu. En particulier, l'influence de la saisonnalité et du gradient d'émersion sur le métabolisme, le réseau trophique ou encore le processus de succession a été peu étudiée. Ce travail de thèse a donc eu pour objectif d'analyser le fonctionnement de deux communautés de Fucus établies à des niveaux marégraphiques différents, en portant une attention particulière aux conditions environnementales. Sur les côtes bretonnes (France), les communautés de Fucus vesiculosus Linnaeus et de Fucus serratus Linnaeus sont respectivement caractéristiques des étages médiolittoral moyen et inférieur. Des mesures de métabolisme (production primaire et respiration) réalisées in situ à différentes périodes de l'année ont mis en évidence une forte influence de la saisonnalité et le rôle primordial de la canopée dans les flux de carbone. Le métabolisme s'est avéré être plus élevé à l'émersion qu'à l'immersion, où l'intensité lumineuse constitue régulièrement un facteur limitant pour la production primaire. Par une approche de modélisation basée sur ces mesures et sur des données environnementales acquises à haute fréquence, un bilan annuel de production primaire a été calculé pour chaque communauté. Ces bilans confirment que ces systèmes sont fortement productifs et permettent de préciser leur régulation à l'échelle des cycles de marées. Le réseau trophique de ces communautés, analysé via les isotopes stables du carbone et de l'azote, apparait basé sur l'utilisation de nombreuses sources. / Along intertidal rocky shores, communities dominated by canopy-forming brown algae (Phaeophyceae) are particularly widespread. Their functioning is however largely understudied, especially concerning the influence of seasonality and shore height on primary production and respiration, on food webs or on successional process. The aim of this study was to investigate the functioning of two intertidal Fucus communities which are established at different tidal levels. During this study, a special consideration was given to the effects of environmental conditions. On the coasts of Brittany (France), communities dominated by Fucus vesiculosus Linnaeus and Fucus serratus Linnaeus are characteristic of mid-intertidal and low mid-intertidal levels, respectively. In situ measurements of metabolism (primary production and respiration) carried out at different periods of a year highlighted a strong seasonal influence on carbon fluxes and emphasized the importance of canopies in the metabolism of whole communities. Metabolism was higher during emersion than during immersion periods, for which light intensity regularly limits the primary production. Based on these measurements and on high-frequency measurements of environmental parameters, an annual primary production was calculated by modelling for both communities. These annual estimations confirmed that these communities are among the most productive systems of coastal region and specify their regulation at the tidal cycles scale. Food webs, which were analysed through carbon and nitrogen stable isotopes, are based on the use of almost all available sources of organic matter by consumers, and revealed a strong conservation of food webs across seasons. Thecolonisation survey of bare substrates shows that Fucus species improve the settlement success of numerous species and increase rapidly primary production of whole assemblages. Overall, despite some differences in metabolism and successional sequences according to the shore height at whichthey are located, these communities exhibited similar functioning due to the canopy which damns the environmental conditions.

Polychaetes are important components of the intertidal sandflat community in Lawson’s Flat, Dillon Beach, California. Little is known about the factors that control the relative abundance of these species. In view of the extensive evidence of the importance of interactions between component species in intertidal communities it is of interest to obtain information that would facilitate future experimental work of such interactions. This study documents seasonal changes in the abundance of the polychaete component of the intertidal community. Attention is directed at possible factors that might affect seasonal changes in distribution. A major finding is that certain herbivorous polychaetes exhibit seasonal fluctuations in abundance that appear to be correlated with changes in algal cover. These findings might suggest more detailed future experimentation. Some aspects of recruitment of major species are considered and the presence of a parasite in one of the species is noted. Aspects of benthic community ecology are discussed.

Populations of the sympatric intertidal bivalves, Macoma secta and M. nasuta are compared as to reproductive ecology and population dynamics. Histological examination of seasonal gonadal changes indicate that both species undergo dormancy in the winter months and rapid gamete proliferation in the spring. However, the timing of spawning differs. The M. secta population synchronously spawned in August while the M. nasuta population spawned lightly in late spring and more heavily in the fall. Fecundity estimates indicate M. nasuta adds 140% of winter weight in gametes and M. secta only adds 43% of winter weight in gametes. Spat fall was detected in January for both species and was light in intensity, for either species only 24 per m2. Nursery areas were determined for M. nasuta, which corresponds to adult distributions, and for M. secta, which correspond to the upper and lower fringes of the intertidal distribution but not the center. Analysis of variance on distributional data indicate the temporal stability of density and size for M. secta. M. nasuta densities were also temporally stable but sizes were not. Both species demonstrated significant changes in density with tidal height. A measure of seasonal population variability, the Population-Time Mean Square, was found to have zero correlation with tidal height for M. secta, meaning that environmental stress was the same for individuals at each tidal height . This is believed related to the gradient of calm size to tidal height. An argument for density dependence in M. secta is given with emphasis on individual growth and realized population fecundity; the null hypothesis: As density increases, the resources per individual decrease, therefore the growth rate of individuals decreases. Analysis of sympatric populations indicate differing patterns of life history, pointing out that selection has favored these two species coexistence. Analysis of population dynamics indicated that in comparison to M. nasuta (Low Tide Horizon), M. secta (Mid Tide Horizon) was more stable (terminology from Ricketts, Calvin and Hedgpeth, 1969). This supports Castenholz’ (1967) idea that where climates are mild, the intertidal communities are more stable than the subtidal communities.