L’objectif général était d’évaluer la réponse du macrobenthos à la dynamique d’un herbier marin à Zostera noltii (colonisation, maturation, destruction, restauration), dans le Bassin d’Arcachon, une lagune du sud-ouest de la France. Quand l’herbier commence à se développer, la structure de la macrofaune diverge immédiatement entre habitats d’herbier et de sables nus, sans cependant que les indice biotiques testés (BENTIX, BOPA, AMBI) varient. De même, la population du bivalve dominant, la coque (Cerastoderma edule), souffre du développement de l’herbier. Sa communauté parasitaire (trématodes) est modifiée, sans que cela n’influe sur la dynamique des coques. A l’échelle du Bassin, le développement de l’herbier (considéré comme un signe de “bonne santé”) a été comparé à la santé de deux bivalves endogés dominants, la palourde japonaise (Ruditapes philippinarum) et la coque (C. edule), évaluée en termes de prévalence de maladie. Aucune corrélation n’existe entre le taux de recouvrement d’herbier et la prévalence de trois maladies (trématodiase, perkinsose, maladie du muscle marron). Entre 2002 et 2010, la surface d’herbier a diminué de 1/3. En termes de structure de communautés et d’espèces dominantes, peu de différences sont notées au sein de chaque année (entre les 12 stations) et entre années, indépendamment du déclin de l’herbier. Parmi les indicateurs biotiques, l’indice multivarié MISS est en adéquation avec la relative similarité de la structure de la macrofaune benthique entre les groupes discriminés par l’analyse MDS. En 2005, des activités de dragage dans le Bassin d’Arcachon ont abouti à l’enfouissement de 0,32 km2 d’herbier à Z. noltii. La structure du macrobenthos a été immédiatement modifiée sans retour à l’état initial sur les zones couvertes de sable. En revanche, le macrobenthos (endofaune) s’est rapidement rétabli dans les zones couvertes de vase alors que l’herbier n’a commencé à se développer qu’au bout de 5 ans après les travaux. Le dernier chapitre de cette thèse donne un bref aperçu des connaissances actuelles sur les herbiers vietnamiens et des possibles travaux scientifiques à mener. / The overall objective was to assess macrobenthos response to marine Zostera noltii seagrass dynamics (colonization, maturation, destruction, restoration), in Arcachon Bay, a French Southwestern lagoon.When seagrass starts to develop, the structure of macrofauna community immediately diverges between sand and seagrass habitats, without however modifying tested biotic indices (BENTIX, BOPA, AMBI). As well, population of the dominant bivalve, the cockle (Cerastoderma edule), suffers from seagrass development. Their parasite (trematode) community are impacted, but not sufficiently to explain cockle deficit in seagrass.At the scale of the Bay, seagrass development (considered as a sign of “good health”) is compared to the fitness of the two dominant infaunal bivalves, the Manila clam (Ruditapes philippinarum) and the cockle (Cerastoderma edule), measured in terms of disease prevalence. There was no correlation among seagrass cover rate and the prevalence of three diseases: trematodiosis, perkinsosis and Brown Muscle Disease.Between 2002 and 2010, seagrass cover decreased by 1/3. When looking at community structure and dominant species, there were moderate differences within (among 12 stations) and among years, independently of seagrass decline. Among biotic indicators, multivariate index MISS was in adequation with the relative similarity of macrofauna structure among groups discriminated by MISS analysis.In 2005, dredging activities in Arcachon Bay led in burying 0.32 km2 of Z. noltii. Macrobenthos structure was immediately modified and did not recover in places buried by sand. Conversely, macrobenthos (infauna) recovered rapidly in areas cover by mud, while seagrass began to develop again five years after work. The last chapter of the thesis provides a brief insight of the seagrass in Vietnam, the actual knowledge and what could be investigated.

Les zones côtières sont des milieux privilégiés pour l’ostréiculture. L’espèce la plus cultivée au monde est l’huître creuse Crassostrea gigas, qui a été introduite dans de nombreux pays à des fins d’exploitation et qui, lorsqu’elle trouve des conditions climatiques favorables dans son nouveau milieu, se développe naturellement, en constituant des récifs. Dans le Bassin d’Arcachon, l’huître existe ainsi sous deux formes, cultivée et sauvage. La forme récifale est une structure tridimensionnelle complexe (huîtres agglomérées, au contact du sédiment, plusieurs classes d’âge présentes), alors que les huîtres cultivées sont placées en sur-élévation dans des poches ostréicoles (spécimens isolés, classe d’âge unique). L’effet respectif de ces deux configurations a été étudié selon trois approches : (1) comparaison de la dynamique des deux types de population d’huîtres (croissance, reproduction, composition biochimique), (2) effet de l’activité alimentaire sur les proies accessibles dans le milieu et les flux particulaires associés, et (3) effets des huîtres sur le sédiment et les communautés benthiques. Les deux années d’échantillonnage ont été marquées par un retard de la ponte (année 1) et un défaut de croissance (année 2) des huîtres, qui ont été rapprochées d’un déficit thermique en période estivale (année 1) et d’une disponibilité alimentaire plus faible au printemps (année 2) ; les cycles de reproduction sont apparus en léger décalage entre huîtres cultivées et sauvages. Une expérimentation in situ en tunnels benthiques à trois périodes de l’année a permis de quantifier les flux de matière et la consommation de nutriments et d’espèces planctoniques par les deux populations d’huître durant un cycle de marée. Le sédiment à proximité des huîtres est enrichi en particules fines et en matière organique, par suite de modifications locales de l’hydrodynamisme et de la production de fèces par les huîtres. Il en résulte une modification de la structure des peuplements de l’endofaune benthique. Les récifs d’huîtres sauvages constituent un nouvel habitat de substrat dur dans le Bassin d’Arcachon où n’existent naturellement que des habitats sédimentaires ; ils supportent une épifaune à fortes biomasse et diversité, qui accroît la biodiversité locale. / Coastal areas are favourable environments for oyster farming. The most commonly farmed species in the world is the cupped oyster Crassostrea gigas, which was introduced in many countries for aquaculture purposes. When it finds suitable climatic conditions in its new environment, the species develops naturally, thereby creating oyster reefs. In Arcachon Bay (SW France), the cupped oyster develops as both farmed and feral populations. Oyster reefs are complex tridimensional structures (agglomerated oysters, in contact with the sediment, populations with many any classes), while farmed oysters are cultivated off-bottom in plastic bags (isolated oysters, populations with a single age class). The respective effects of these two oyster configurations were studied according to three research axes: (1) a comparison of the dynamics of farmed and wild oyster populations, in terms of growth, reproduction, and biochemical composition; (2) the effect of oyster feeding on accessible preys and the associated particulate fluxes; and (3) the effects of oysters on the sediment and benthic communities. The two years of study were characterized by a delay in the spawning periods (year 1) and an unusually low growth rate (year 2) in oysters, which were related to low summer water temperatures (year 1) and a low food availability in spring (year 2); reproduction cycles also appeared slightly shifted between farmed and wild oysters. An in situ experiment with benthic tunnels at three periods of the year was designed to quantify the flux of matter and the consumption of nutrients and planktonic species by the two oyster populations during a tidal cycle. Sediment in the vicinity of oysters contained more fine particles and organic matter, due to changes in local hydrodynamism and oyster production of faeces. These sedimentary changes modified the structure of benthic infaunal assemblages. Oyster reefs form a new habitat of hard substrate in Arcachon Bay, where only sedimentary habitats naturally occur; they have an epifauna with high biomass and diversity, that increases the local biodiversity.

Les vasières intertidales sont des environnements complexes et changeants, qui abritent des invertébrés enfouis dans le sédiment (la macrofaune benthique) et sont visités de manière saisonnière par de grands migrateurs : les oiseaux limicoles. Ce travail de recherche s’intéresse aux relations proie-prédateur entre les oiseaux limicoles et leur ressource alimentaire : la macrofaune benthique. La thèse est articulée en 8 chapitres qui présentent des études à différentes échelles spatio-temporelles : des saisons à la décennie, et de la baie à la route migratoire. Ces études sont basées sur un échantillonnage régulier des vasières intertidales du Golfe de Gascogne (France) ainsi que d’échantillonnages en mer des Wadden (Pays-Bas) et au Banc d’Arguin (Mauritanie). Les données de macrofaune (qualité, taille, densité, biomasse) sont couplées aux données de comptages de leurs prédateurs ainsi qu’à leur comportement alimentaire (reconstruction du régime alimentaire d’après les isotopes, les fécès, la modélisation ou l’observation de vidéos). Ces huit études apportent un éclairage sur l’écologie de leurs interactions (en intégrant des variables environnementales telles que le temps d’inondation, la granulométrie, la température, la production primaire, ou encore la latitude). Une attention particulière est portée à la variabilité des proies et du comportement alimentaire de leurs prédateurs, dans l’espace et le temps. Des encarts viennent illustrer pour l’un les techniques de reconstruction du régime alimentaire, pour l’autre les défenses développées par les mollusques marins, ou encore la relation entre énergie à disposition et sélection du site pour les limicoles. / Intertidal mudflats are complex ecosystems undergoing constant changes, home to infaunal invertebrates (benthic macrofauna), and migratory sites for particular birds : shorebirds. This research focuses on predator-prey interactions between shorebirds and their macrobenthic prey. The present thesis is composed of 8 chapters which illustrate different spatio-temporal scales : from seasons to the decade, and from the bay to the migratory flyway. These studies are based on regular benthic sampling of intertidal flats along the Bay of Biscay (France), as well as sampling data from the Dutch Wadden Sea and the Mauritanian Banc d’Arguin. Macrobenthic data (quality, sizes, densities, biomass) are linked with shorebird counts and data about their feeding behaviour (diet reconstruction from isotopes, faeces, modeling and video observations). These eight studies shed light on particular relationships between some prey and their predators, and the ecology of these interactions (including environmental variables such as inundation time, grain size, temperature, primary production, or even latitude). Particular attention is given to the variability of prey and predator behaviour in time and space. Inserts are included in between chapters to illustrate for instance different diet reconstruction techniques, anti-predation traits in marine molluscs, or relation between energy available and site selection in shorebirds.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-08-09T15:15:28Z No. of bitstreams: 1 Ericka Brasil Wanderlei.pdf: 1492969 bytes, checksum: 4c9c3d5a5c4a27c148d71157b6ac13a4 (MD5) / Made available in DSpace on 2016-08-09T15:15:28Z (GMT). No. of bitstreams: 1 Ericka Brasil Wanderlei.pdf: 1492969 bytes, checksum: 4c9c3d5a5c4a27c148d71157b6ac13a4 (MD5) Previous issue date: 2015-02-20 / The release of effluents, with or without treatment, in aquatic environments isthe most common form of pollution in coastal areas, altering the ideal conditions for the survival of organisms and affecting the human health. This study evaluates changes in the structure of the macrobenthic community near a domestic sewage discharge (after treatment) released in the estuary of Ariquindá river, south coast of Pernambuco. Samples were taken from 10 points (triplicates), five upstream and five downstream of the release point. To each side the points were distributed according to the distance, in meters, from the launch point: P0, P50, P100, P200 and P350, totaling 30 samples collected with a cylinder of 10 cm radius 20 cm length, and sieved through a 0.3 mm mesh opening. Taxa were identified to the lowest possible level and trophic groups were analyzed. Particle size data were analyzed, organic matter and abiotic parameters (temperature, salinity, dissolved oxygen, chlorophyll a and turbidity) recorded with a probe type CTD. Univariate, bivariate and multivariate analyzes were performed to describe and compare differences between the test and the results obtained. The environmental parameters did not show a gradient over the sample points, only a few specific changes near the discharge of effluents. There was high salinity in the study area, low levels of organic matter, sand predominance and dissolved oxygen above the minimum value of contamination in aquatic environments. 33 taxa were identified in a total of 151 individuals of benthic macrofauna, with annelids represented in 70% of samples highlighting the polychaete Aricidea , followed by Scoloplus, Heteromastus and Prionospio. No pattern was also observed for the environmental and biotic parameters. The deposit-feeders predominated in sample points followed in smaller numbers of suspension-feeders and carnivores. In the present study it was found that even if the dumping of waste has contributed to change some environmental parameters close to the launch point, community resident macrofauna did not appear influenced by the load of organic matter introduced, and therefore not clearly modifying the structure of this community. But in the long term this interference can enhance the effect of organic enrichment leading to an imbalance in the structure of local communities. / O lançamento dos efluentes domésticos, com ou sem tratamento prévio, em ambientes aquáticos, altera as condições ideais para a sobrevivência dos organismos e afeta a saúde humana, sendo a forma mais comum de poluição em áreas costeiras. O presente trabalho avalia a variação da estrutura da comunidade macrobêntica em uma área sob influência de efluentes domésticos tratados lançados no estuário do rio Ariquindá, litoral sul de Pernambuco. Foram escolhidos 10 pontos amostrais triplicados, sendo cinco a montante e cinco a jusante do ponto de lançamento. Para cada lado, os pontos foram distribuídos de acordo com a distância, em metros, do ponto de lançamento sendo eles, P0, P50, P100, P200 e P350, totalizando 30 amostras, coletadas com um cilindro de 10 cm de raio por 20 cm de comprimento, e peneiradas em malha de 0,3 mm de abertura. Os táxons encontrados foram identificados até o menor nível possível e os grupos tróficos a que pertence cada táxon determinado. Foram analisados dados de granulometria, matéria orgânica e parâmetros da água (temperatura, salinidade, oxigênio dissolvido, clorofila e a turbidez) registrados com Sonda tipo CTD. Análises uni, bi e multivariadas foram realizadas para descrever e comparar resultados obtidos. Os parâmetros ambientais não apresentaram gradiente ao longo dos pontos amostrais, apenas algumas alterações pontuais próximo a descarga de efluentes. Foram registrados valores de salinidade elevados na área de estudo, baixos valores de matéria orgânica, predominância de areia e teor de oxigênio dissolvido superior ao valor mínimo de contaminação em ambientes aquáticos. Foram identificados 33 táxons em um total de 151 indivíduos da macrofauna bêntica, estando os anelídeos representados em 70% das amostras com destaque para os poliquetas dos gêneros Aricidea, seguido de Scoloplus, Heteromastus e Prionospio. Nenhum padrão foi observado para os parâmetros ambientais e bióticos. Os depositívoros predominaram nos pontos amostrais seguidos em menor número dos suspensívoros e carnívoros. No presente estudo foi constatado que mesmo que o despejo dos efluentes tenha contribuído para alterar alguns parâmetros ambientais próximo ao ponto de lançamento, a comunidade da macrofauna residente não se apresentou influenciada por essa carga de matéria orgânica introduzida, e portanto não modificando claramente a estrutura dessa comunidade. Porém, a longo prazo essa interferência pode acentuar o efeito desse enriquecimento orgânico levando a um desequilíbrio na estrutura das comunidades locais.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-14T14:41:09Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Ana Paula MC Valença.pdf: 2664032 bytes, checksum: 5b5c31bf5f29946a540d84d29e519535 (MD5) / Made available in DSpace on 2016-07-14T14:41:09Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Ana Paula MC Valença.pdf: 2664032 bytes, checksum: 5b5c31bf5f29946a540d84d29e519535 (MD5) Previous issue date: 2015-02-23 / FACEPE / A presente tese avaliou os possíveis impactos gerados pelos tapetes de alga na macrofauna estuarina. Em uma planície estuarina lamosa, situada no Complexo Estuarino do Canal de Santa Cruz, litoral norte de Pernambuco, foi registrada a ocorrência de tapetes de algas filamentosas em diferentes períodos (Setembro-2012, Setembro a Dezembro-2013 e Maio a Junho-2014). Através de estudos observacionais e manipulativos in situ foram testados: (I) o efeito do tapete algal na biogeoquímica sedimentar e na fauna, considerando a presença da alga e o seu estágio fisiológico; (II) a recolonização e a recuperação da macrofauna em sedimentos com remoção algal considerando os efeitos da compactação sedimentar gerada pelo tapete e do tamanho da área algal removida; a existência de efeitos (III) de barreira e (IV) de sazonalidade gerados pelo tapete algal e analisados sob a ótica da recolonização inicial. O estágio fisiológico da alga foi importante para a biogeoquímica sedimentar, enquanto que a presença do tapete algal se caracterizou como uma importante fonte de distúrbio para a fauna bêntica. A recolonização pela macrofauna nos sedimentos com remoção algal ocorreu de forma discreta e dependente da compactação sedimentar e do tamanho da área removida apenas para os parâmetros univariados. Além disso, não foi observada a recuperação das áreas experimentais até ao final do estudo (95 dias). A recolonização inicial (30 dias) não foi afetada pela presença do tapete algal circunvizinho às áreas experimentais. Embora tenha sido observado que a sazonalidade influencia no sedimento e na fauna, a análise da comunidade indicou uma tendência à convergência entre os tratamentos de remoção (AR) e sedimento natural (NA) independente da mesma. Além disso, foi observada uma relação entre o regime pluviométrico e o desenvolvimento do tapete algal. As consequências ecológicas do tapete algal, analisadas sob a recolonização a curto (30 dias) e médio prazo (95 dias), mostraram ser pouco previsíveis e extremamente influenciadas pela heterogeneidade ambiental. Além disso, a recuperação da comunidade em uma área afetada pelo desenvolvimento de tapete algal pode não apresentar a sequência sucessional observada em outros experimentos de colonização. Embora os estudos tenham sido conduzidos em um único local (na mesma planície estuarina), os resultados permitem uma melhor compreensão dos efeitos dos tapetes de algas na macrofauna bêntica estuarina. / This thesis assessed the possible impacts of algal mats on estuarine macrofauna. In an estuarine mudflat placed on Santa Cruz Channel Estuarine Complex, in the north coast of Pernambuco, the occurrence of filamentous mat-forming algae was registered at different periods (September-2012, September to December-2013 and May to June-2014). Observational and manipulative studies were conducted in situ and tested: (I) the effect of algal mats on sediment biogeochemistry and fauna, considering the presence of the algae and the physiological stage; (II) the recolonization and recovery of macrofauna in algal removal sediments relating to sediment compaction and the extension of algal removed (i.e. spatial scale); the existence of (III) boundaries and (IV) seasonal effects generated by the algal mat and analyzed using macrofauna recolonization data. The physiological stage affected significantly the sediment biogeochemistry and the presence of the algae was an important source of disturbance to benthic fauna. The recolonization of algal removal sediments varied regarding sediment compaction and spatial scale, but this was discrete and restricted to univariate measures. Besides, no recovery of any removal treatment was observed at the end of the experiment (95 days). Initial recolonization (30 days) was not affected by the surrounding algal mat found in the algal removal treatments. Although seasonal effects influence on sediment and fauna data, the analysis of benthic community showed a tendency of convergence between NA and AR treatments regardless of season. Moreover, it was possible to observe a relationship between rainfall seasonality and algal mat development. Ecological consequences of algal mats, analyzed through faunal recolonization within short- (30 days) and medium- (95 days) terms, showed to be less predictable and strongly influenced by environmental heterogeneity. Besides, community recovery in an area affected by algal coverage does not always include the successional sequence observed in other colonization experiments. Although the series of experiments have been conducted under one location (the same estuarine mudflat), the results provided strong insights on the effects of algal mats on tropical benthic macrofauna.

A distribuiÃÃo dos organismos em relaÃÃo ao seu habitat à de importÃncia central para a ecologia. A natureza dessa distribuiÃÃo fornece visÃo inicial sobre os tipos de processos ecolÃgicos que regulam as assemblÃias e populaÃÃes. O presente trabalho tem como objetivo caracterizar e comparar a estrutura da macrofauna bentÃnica, correlacionando-a com as condiÃÃes ambientais de bancos arenolamosos nos estuÃrios dos rios Pacoti e Pirangi, CearÃ. Em fevereiro de 2005, foram coletadas 45 amostras em cada estuÃrio e preservadas em formol, lavadas em Ãgua corrente, coradas com rosa bengala, triadas com o auxÃlio de microscÃpio eletrÃnico e os organismos identificados ao menor nÃvel taxonÃmico possÃvel. Os parÃmetros temperatura, matÃria orgÃnica, CaCO3, cascalho, areia e finos apresentaram diferenÃas significativas (p<0,05) entre os dois estuÃrios. No Pacoti, a espÃcie Laeonereis culveri (Annelida: Polychaeta) apresentou maior densidade (10422,98 ind/m2) e, no Pirangi, Tagelus plebeius (Mollusca: Bivalvia) com 910,35 ind/m2. A anÃlise apontou forte correlaÃÃo negativa entre a abundÃncia mÃdia com a matÃria orgÃnica e argila no estuÃrio do Pirangi e uma forte correlaÃÃo positiva entre a riqueza com mÃdia do grÃo, matÃria orgÃnica, silte e correlaÃÃo negativa com a areia no estuÃrio do rio Pacoti. A abundÃncia mÃdia foi mais elevada no Pacoti, porÃm riqueza, equitabilidade e diversidade foram mais elevadas no rio Pirangi. No rio Pacoti, a anÃlise de agrupamento revelou um banco areno-lamoso altamente homogÃneo, com elevado grau de similaridade entre os pontos. Jà o Pirangi mostrou-se mais heterogÃneo com menor grau de similaridade. A anÃlise do BIOENV discriminou seleÃÃo do grÃo, carbonato de cÃlcio e teor de matÃria orgÃnica como os fatores abiÃticos que melhor explicaram a estrutura da macrofauna bentÃnica do banco areno-lamoso do rio Pacoti e a porcentagem de cascalho e de finos no banco areno-lamoso do rio Pirangi. / The distribution of organisms regarding their habitat plays an important role in ecological studies. The nature of this distribution provides an initial view on the types of ecological processes regulating the assemblages and the populations. The present study aims to characterize and to compare the benthic macroinfauna community structure, correlating it with the environmental conditions at the muddysand flats at the Pacoti and the Pirangi estuaries. In February 2005, 45 samples were collected in each estuary, sample were preserved in formol, passed through a 0,3mm mesh, dyed with rose, sorted and the organisms identified. The amount of shingle, sand, silt, and clay presented significant differences (p<0,05) between the two estuaries. At Pacoti estuary, Laeonereis culveri presented the highest density (10,423 ind/m2) and, at Pirangi estuary, Tagelus plebeius was the dominant species with a density of 910.35 ind/m2. Analysis pointed out a strong negative correlation between the average abundance and the organic matter, and between the average abundance and clay at the Pirangi estuary. At the Pacoti estuary, a strong positive correlation was observed out between the richness and several parameters such as the mean grain size, organic matter, and silt. A negative correlation between the richness and the amount of sand was also evidenced at the same estuary. The average abundance was higher at Pacoti, whereas richness, equitability, and diversity were higher at Pirangi. At the Pacoti estuary, the cluster analysis revealed a highly homogeneous muddy-sand flat, with strong similarity among samples. On the other hand, Pirangi was more heterogeneous with a lower similarity degree. The BIOENV analysis discriminated grain selection, CaCO3, and the amount of organic matter as the abiotic factors that best explain the structure of benthic macroinfauna communitâs in the muddy-sand flat at Pacoti. At the Pirangi estuary, the relevant abiotic factors were the shingle and fine sediment percentage.

A l’échelle de l’Atlantique Nord-Est, la Manche se situe à un carrefour biogéographique entre les provinces boréale et lusitanienne. Ainsi, de nombreuses espèces y sont en limite d’aire de distribution. L’objectif de cette thèse est d’évaluer les effets du changement climatique récent sur la distribution de la macrofaune benthique subtidale, peu étudiée à ce jour, en se basant sur la comparaison de données collectées à l’échelle de la Manche lors une période froide (i.e. années 1960-70) et lors d’une période chaude (i.e. 2012 et 2014) dans les sédiments grossiers circalittoraux. L’étude de la structure des assemblages inféodés à cet habitat a mis en évidence deux grandes communautés benthiques : la communauté des sédiments grossiers sablo-graveleux et celle des cailloutis et graviers. L’analyse de l’évolution des températures de fond au cours des 30 dernières années a montré l’hétérogénéité spatiale du réchauffement, variant de 0,1 à 0,5°C par décennie d’ouest en est. Ce réchauffement ne se s’est pas traduit par d’importants déplacements de l’aire de distribution des espèces mais par une forte diminution du nombre d’occurrences des espèces d’eaux froides et une forte augmentation de celui des espèces d’eaux chaudes. Le développement de modèles de distribution d’espèces a permis de déterminer l’importance relative des facteurs climatiques et édaphiques dans la distribution des invertébrés benthiques en Manche et d’apprécier l’aptitude des espèces à ajuster leur distribution à la hausse de températures. L’ensemble de ces résultats suggère que le changement climatique en cours pourrait entraîner une diminution de la biodiversité benthique aux limites d’aires de distribution, en particulier si la connectivité entre populations limite l’arrivée de nouveaux individus. / In the North-East Atlantic, the English Channel constitutes a biogeographical transition zone between the Boreal and Lusitanian provinces. Thus, many species reach there their distribution range limits. The aim of this thesis is to assess the effects of recent climate change on the distribution of the subtidal benthic macrofauna, poorly studied to date, basing on the comparison of data collected during a cool period (i.e. 1960s-70s) and during a warm period (i.e. 2012 and 2014) in the circalittoral coarse sediments. Two large communities were highlighted in the study of the structure of the assemblages found in this habitat: the gravelly coarse sand community and the pebbles and gravels community. The analysis of the evolution of seabed temperature for the last 30 years showed the spatial heterogeneity of the warming, varying from 0.1 to 0.5°C per decade from West to East. This warming did not translate into large species distribution shifts but into a sharp decrease in the number of occurrences of cold-water species and a sharp increase in the number of occurrences of warm-water species. Development of species distribution models allowed to identify the relative importance of climatic and edaphic factors in the distribution of benthic invertebrates in the Channel and to assess the species’ ability to adjust their distribution to the rise in temperature. The whole results suggest that ongoing climate change could lead to a decrease in benthic biodiversity at range limits, especially where connection routes are lacking for new migrants.

A Plataforma Oeste da Península Antártica (POPA) é uma região onde a produtividade primária na superfície do oceano apresenta padrões altamente sazonais e considerável variabilidade interanual. A dinâmica do gelo marinho é o principal fator condicionante da produtividade e, por consequência, dos fluxos de matéria orgânica da superfície para o leito marinho. A matéria orgânica particulada depositada, chamada de fitodetrito, forma densas camadas de alimento lábil disponível para os organismos bênticos. Essa relação estreita entre os processos da coluna de água e aqueles que ocorrem no bentos é chamada de acoplamento bento-pelágico. Com o objetivo de avaliar as respostas da macrofauna bêntica aos fluxos e deposição de alimento, foi realizada uma série temporal sazonal de amostragens (novembro/1999 a março/2001) na POPA em três estações de coleta perpendiculares à costa. Cerca de 25.000 indivíduos pertencentes a 22 táxons foram coletados em 15 amostras de box corer (0,25 m2 cada). Mesmo com alguma variação ao largo da plataforma (de 10.886 ind.m-2 (estação A) a 2.326 ind.m-2 (B)), atribuída a diferenças na topografia, a macrofauna apresentou pouca variabilidade em termos de composição e abundância ao longo do período estudado. Além disso, diferenças na composição e abundância entre estratos sedimentares também foram notáveis, sendo que 90% dos indivíduos foram encontrados entre 0 e 5 cm. Dentre as 185 espécies identificadas, Aurospio foodbancsia (Polychaeta, Spionidae), uma espécie típica de regiões de plataforma na Antártica, mas muito próxima da espécie de mar profundo A. dibranchiata, foi a espécie dominante em todos os períodos e estações (2.087 ind.m-2). Além de Polychaeta, outros grupos abundantes na POPA foram Bivalvia, Tanaidacea e Oligochaeta. Picos de abundância foram observados para algumas espécies, provavelmente associados a eventos sazonais de recrutamento, porém nem sempre associados à chegada do alimento ao fundo marinho da região. Os grupo funcionais de Polychaeta também não variaram ao longo do período estudado, o que indicou que animais depositívoros de superfície e subsuperfície se alimentam ao longo de todo o ano, aproveitando o alimento que permanece lábil e disponível, mesmo no inverno, quando o fluxo de matéria orgânica para o bentos é mínimo. Os resultados encontrados neste trabalho confirmam os resultados já encontrados dentro do projeto FOODBANCS, que a macrofauna da POPA age como um filtro, respondendo menos às flutuações sazonais. / The West Antarctic Peninsula shelf (WAP shelf) experiences a high seasonal and interannual variability in surface primary production. Sea ice dynamics is the principal factor controlling productivity and, therefore, the downward particulate organic matter (POM) fluxes. The deposited POM, also called phytodetritus, forms dense layers of available labile food for benthic organisms. This straight relationship between water column and benthic processes is called benthic-pelagic coupling. A seasonal time-series study was conducted between November 1999 through March 2001 in tree sites on WAP shelf, to determine this relationship, specially the benthic macrofauna (> 300 µm) response to the POM flux and its posterior deposition. From a total of 15 box-corer samples (0.25 m2 each), approximately 25,000 macrofaunal individuals were collected, belonging to 22 taxa. Even with some variation along the shelf, ranging from 10,886 ind.m-2 (site A) to 2,326 ind.m-2 (B), the abundance and composition of macrofauna showed only modest seasonal changes. Differences in these parameters were clear between the inner and outer shelves, probably owing to the topography, which was composed of a basin in the innermost region and a flat region, in the offshore area. Differences in abundance and composition between sediment layers were also notable, with 90% of all individuals belonging to the 0-5 cm layer. Among the 185 identified species, Aurospio foodbancsia (Polychaeta, Spionidae), a typical species of Antarctic shelf regions and closely related to the deep-sea species A. dibranchiata, was dominant in all seasons and sites (2,087 ind.m-2). Besides polychaetes, bivalves, tanaids and oligochaetes were also abundant in WAP shelf. Peaks in abundance were observed for some species and this is believed to be related to seasonal recruitment, however not always associated with the availability of food. Polychaete functional groups did not vary along seasons, indicating that surface and subsurface deposit feeders were subsisting on the labile POM along the year, even during the winter, when POM flux to the benthos is extremely low. The results are similar to those obtained in other FOODBANCS works, and indicate that the WAP shelf macrofauna act as a low-pass filter, muting the seasonal water column processes.

A Plataforma Oeste da Península Antártica (POPA) é uma região onde a produtividade primária na superfície do oceano apresenta padrões altamente sazonais e considerável variabilidade interanual. A dinâmica do gelo marinho é o principal fator condicionante da produtividade e, por consequência, dos fluxos de matéria orgânica da superfície para o leito marinho. A matéria orgânica particulada depositada, chamada de fitodetrito, forma densas camadas de alimento lábil disponível para os organismos bênticos. Essa relação estreita entre os processos da coluna de água e aqueles que ocorrem no bentos é chamada de acoplamento bento-pelágico. Com o objetivo de avaliar as respostas da macrofauna bêntica aos fluxos e deposição de alimento, foi realizada uma série temporal sazonal de amostragens (novembro/1999 a março/2001) na POPA em três estações de coleta perpendiculares à costa. Cerca de 25.000 indivíduos pertencentes a 22 táxons foram coletados em 15 amostras de box corer (0,25 m2 cada). Mesmo com alguma variação ao largo da plataforma (de 10.886 ind.m-2 (estação A) a 2.326 ind.m-2 (B)), atribuída a diferenças na topografia, a macrofauna apresentou pouca variabilidade em termos de composição e abundância ao longo do período estudado. Além disso, diferenças na composição e abundância entre estratos sedimentares também foram notáveis, sendo que 90% dos indivíduos foram encontrados entre 0 e 5 cm. Dentre as 185 espécies identificadas, Aurospio foodbancsia (Polychaeta, Spionidae), uma espécie típica de regiões de plataforma na Antártica, mas muito próxima da espécie de mar profundo A. dibranchiata, foi a espécie dominante em todos os períodos e estações (2.087 ind.m-2). Além de Polychaeta, outros grupos abundantes na POPA foram Bivalvia, Tanaidacea e Oligochaeta. Picos de abundância foram observados para algumas espécies, provavelmente associados a eventos sazonais de recrutamento, porém nem sempre associados à chegada do alimento ao fundo marinho da região. Os grupo funcionais de Polychaeta também não variaram ao longo do período estudado, o que indicou que animais depositívoros de superfície e subsuperfície se alimentam ao longo de todo o ano, aproveitando o alimento que permanece lábil e disponível, mesmo no inverno, quando o fluxo de matéria orgânica para o bentos é mínimo. Os resultados encontrados neste trabalho confirmam os resultados já encontrados dentro do projeto FOODBANCS, que a macrofauna da POPA age como um filtro, respondendo menos às flutuações sazonais. / The West Antarctic Peninsula shelf (WAP shelf) experiences a high seasonal and interannual variability in surface primary production. Sea ice dynamics is the principal factor controlling productivity and, therefore, the downward particulate organic matter (POM) fluxes. The deposited POM, also called phytodetritus, forms dense layers of available labile food for benthic organisms. This straight relationship between water column and benthic processes is called benthic-pelagic coupling. A seasonal time-series study was conducted between November 1999 through March 2001 in tree sites on WAP shelf, to determine this relationship, specially the benthic macrofauna (> 300 µm) response to the POM flux and its posterior deposition. From a total of 15 box-corer samples (0.25 m2 each), approximately 25,000 macrofaunal individuals were collected, belonging to 22 taxa. Even with some variation along the shelf, ranging from 10,886 ind.m-2 (site A) to 2,326 ind.m-2 (B), the abundance and composition of macrofauna showed only modest seasonal changes. Differences in these parameters were clear between the inner and outer shelves, probably owing to the topography, which was composed of a basin in the innermost region and a flat region, in the offshore area. Differences in abundance and composition between sediment layers were also notable, with 90% of all individuals belonging to the 0-5 cm layer. Among the 185 identified species, Aurospio foodbancsia (Polychaeta, Spionidae), a typical species of Antarctic shelf regions and closely related to the deep-sea species A. dibranchiata, was dominant in all seasons and sites (2,087 ind.m-2). Besides polychaetes, bivalves, tanaids and oligochaetes were also abundant in WAP shelf. Peaks in abundance were observed for some species and this is believed to be related to seasonal recruitment, however not always associated with the availability of food. Polychaete functional groups did not vary along seasons, indicating that surface and subsurface deposit feeders were subsisting on the labile POM along the year, even during the winter, when POM flux to the benthos is extremely low. The results are similar to those obtained in other FOODBANCS works, and indicate that the WAP shelf macrofauna act as a low-pass filter, muting the seasonal water column processes.

Made available in DSpace on 2015-03-12T11:48:01Z (GMT). No. of bitstreams: 1 MarinaGV_TESE.pdf: 3115364 bytes, checksum: 35f6859ed189e76dc56e8be8b28a3c16 (MD5) Previous issue date: 2013-12-16 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This study aimed to characterize, for the first time, the benthic invertebrates that inhabit the region of soft bottoms adjacent to the APARC reefs in order to situate them as an important component of infralittoral coastal areas of Northeast Brazil. Soft bottoms areas of APARC corresponds to infralittoral zones vegetated by seagrass Halodule wrightii and unvegetated infralittoral zones, both subjected to substantial hydrodynamic stress. Through scuba diving, biological and sedimentary samples of both habitats were analyzed, with a cylindrical sampler. We identified 6160 individuals belonging to 16 groups and 224 species. The most abundant macrofaunal group was Polychaeta (43%), followed by Mollusca (25%) and Crustacea (14%), what was expected for these environments. In the first chapter, regarding vegetated areas, we tested three hypotheses: the existence of differences in the faunal structure associated with H. wrightii banks submitted to different hydrodynamic conditions; the occurrence of minor temporal variations on the associated macrofauna of banks protected from hydrodynamic stress; and if the diversity of macrofauna is affected by both benthophagous predators and H. wrightii biomass. It was observed that macrofauna associated at the Exposed bank showed differences in structure when comparing the Protected bank, the granulometry of the sediments, that co-varies with the hydrodynamism, was the cause of these variations. The results also pointed to a lower temporal variation in the macrofaunal structure on the Protected bank and a negative relation between macrofaunal and benthophagous fish abundance. At the Exposed bank, a greater faunal diversity was observed, probably due to the higher seagrass biomass. The second chapter compares the vegetated and non-vegetated areas in order to test the hypothesis that due to greater seasonal stability in tropical environments, seagrass structure would act to distinguish the vegetated and non-vegetated areas macrofauna, over time. It was also expected that depositivores were the most representative invertebrates on non-vegetated environments, on the assumption that the seagrass bank would work as a source of debris to adjacent areas, enriching them. Considering all sampling periods, the total macrofauna abundance and diversity were higher in vegetated areas, when compared to non-vegetated ones. Seasonally, the structural complexity provided by Halodule differentiated more clearly the fauna from vegetated and non-vegetated areas, but only at the climatic extremes, i.e. Dry season (extreme climatic stability, with low hydronamism variation) and Rainy season (great hydrodynamism variation and probably vegetated bank burial). Furthermore, the high organic matter levels measured in the sandy banks coincided with an outstanding trophic importance of deposit feeders, proving the debris-carrying hypothesis. The last chapter focused on the non-vegetated areas, where we tested that the hypothesis infaunal halo in tropical reefs depending on local granulometry. In this context, we also tested the hypothesis that benthophagous fish predation would have an effect on the low abundance of macrofaunal groups due to the high hydrographic stress, thus allowing other predatory groups to have greater importance in these environments. Proving the hypothesis, no spatial variation, both on abundance families neither on community structure, occur along distance of the edge reefs. However, we found that complex combinations of physical factors (grain size and organic matter levels originated from local hydronamic conditions) covary with the distance from the reefs and has stronger influence on macrofauna than considered biological factors, such as predation by benthophagous fishes. Based on the main results, this study shows that unconsolidated areas around APARC reefs are noteworthy from an ecological and conservational point of view, as evidenced by the biota-environment and organismal relations, never before described for these areas / Objetivou-se caracterizar, pela primeira vez, os invertebrados bent?nicos que habitam a regi?o de fundos moles adjacentes aos recifes da ?rea de Prote??o Ambiental dos Recifes de Corais (APARC), a fim de situ?-los como importante componente das zonas infralitorais costeiras do Nordeste do Brasil. As ?reas de fundos moles, ou n?o consolidadas, da APARC compreendem regi?es de infralitoral, vegetadas pela angiosperma marinha Halodule wrightii, e regi?es de infralitoral n?o vegetadas, ambas submetidas a um considerado estresse hidrodin?mico. Atrav?s de mergulho aut?nomo, foram analisadas amostras biol?gicas e sedimentares de ambos os habitats, com aux?lio de amostrador cil?ndrico de PVC. Foram identificados 6160 indiv?duos, distribu?dos em 16 grandes grupos e 224 esp?cies, sendo que o grupo macrofaunal mais abundante foi Polychaeta (43%), seguido de Mollusca (25%) e Crustacea (14%), resultado j? esperado para ambientes n?o consolidados infralitorais. No primeiro cap?tulo, relacionado ?s ?reas vegetadas, foram testadas tr?s hip?teses: a exist?ncia de diferen?as na estrutura??o da fauna associada a bancos de H. wrightii, submetidos a diferentes condi??es hidrodin?micas; a ocorr?ncia de menores varia??es temporais sobre a macrofauna associada aos ambientes mais protegidos do estresse hidrodin?mico; e se a diversidade da macrofauna ? afetada, tanto pelos predadores bent?fagos como pela biomassa da pr?pria H. wrightii. Foi verificado que a macrofauna associada do banco Exposto apresentou diferen?as na estrutura??o quando comparado ao banco Protegido, sendo a granulometria dos bancos, a qual varia conjuntamente com o hidrodinamismo, a respons?vel por estas varia??es. Os resultados tamb?m apontaram para uma menor varia??o temporal na estrutura da macrofauna no banco Protegido e uma rela??o negativa entre a abund?ncia macrofaunal e peixes bent?fagos. J? no banco Exposto, foi encontrada uma maior diversidade faunal, provavelmente em fun??o da maior biomassa de gram?nea. O segundo cap?tulo aborda uma compara??o entre ?reas vegetadas e n?o vegetadas, pretendendo testar a hip?tese de que, em fun??o de uma maior estabilidade sazonal nos ambientes tropicais, a estrutura da faner?gama atuaria na distin??o da macrofauna associada entre ?reas vegetadas e n?o vegetadas, ao longo do tempo. Tamb?m se esperava que os deposit?voros fossem os invertebrados mais representativos nos ambientes n?o vegetados, partindo da premissa de que o banco de faner?gama funcionaria como fonte de detritos para ?reas adjacentes, enriquecendo-as. Todavia, sazonalmente, a complexidade estrutural proporcionada por Halodule discriminou, com mais evid?ncia, a fauna de ?reas vegetadas de n?o vegetadas somente nas extremidades clim?ticas, isto ?, no per?odo Seco (extrema estabilidade clim?tica, com pouca varia??o no hidrodinamismo) e no per?odo Chuvoso (grande varia??o do hidrodinamismo e prov?vel soterramento do banco vegetado). Al?m disso, os elevados teores de mat?ria org?nica medidos nos bancos arenosos coincidiram com uma destacada import?ncia tr?fica dos deposit?voros, comprovando a hip?tese de carreamento de detritos. O ?ltimo cap?tulo focou nas ?reas n?o vegetadas, em que se testou a hip?tese de que a varia??o da estrutura da macrofauna perto e longe ocorre em decorr?ncia da granulometria. Neste contexto tamb?m foram testadas a hip?tese de que a preda??o por peixes bent?fagos teria um baixo efeito na abund?ncia dos grupos da macrofauna em fun??o do alto estresse hidrogr?fico, abrindo, assim, espa?o para outros grupos de predadores bent?fagos terem uma maior import?ncia nestes ambientes. Comprovando as hip?teses levantadas, n?o foi verif icada varia??o espacial significativa entre as dist?ncias da borda dos recifes, tanto na abund?ncia das principais fam?lias identificadas como na estrutura geral das comunidades bent?nicas. Entretanto, verificou-se que uma complexa combina??o de fatores f?sicos (tamanho do gr?o e teor de mat?ria org?nica derivadas das condi??es hidrodin?micas locais) variam conjuntamente com a dist?ncia e influencia mais a macrofauna do que os fatores biol?gicos considerados, como a preda??o por peixes bent?fagos. Com base nos principais resultados encontrados, este trabalho mostrou que as ?reas de fundos n?o consolidados do entorno dos recifes da APARC merecem destaque do ponto de vista ecol?gico e de conserva??o, pois evidenciou-se importantes rela??es da biota com o ambiente e da biota com outros organismos n?o descritas antes para estas ?reas