The rocky intertidal zone, experiencing fully marine and fully terrestrial conditions, has become increasingly investigated as a model ecosystem for studying the future implications of climate change. The barnacle, Balanus glandula, a common rocky intertidal inhabitant, plays an important role as a key prey item for many organisms. Low tide can be particularly challenging for barnacles as they are marine organisms subjected to the abiotic conditions of a terrestrial environment. The most stressful of these are increased temperature and decreased oxygen availability. This study aimed to investigate how low tide impacts the energy budget, specifically the digestion, of B. glandula. Barnacles are unable to feed at low tide however, if they were able to digest at low tide, they could maximize their energy intake by emptying their stomach to prepare to feed at the next high tide. However, digestion is a metabolically costly activity, which could make it less energetically favorable to digest when there’s less oxygen available. To test for an effect of low tide on digestion, barnacles were fed, and the time to first fecal production measured as a ‘baseline’. This was repeated, but barnacles were exposed to either a 16ºC or 35 ºC low tide immediately after being fed. The change in digestion time was calculated by comparing these two times for each barnacle. It was found that regardless of temperature, barnacles delayed their digestion by about 50-60 minutes after exposure to a one hour low tide. To determine the energetic cost of digestion, the rate of oxygen consumption was compared between starved and digesting barnacles. I was unable to detect any evidence of elevated metabolic activity during digestion. Additional testing is needed to confirm these results as the barnacles may have not fed during the trial, thus had no food to digest. While it appears that increasing temperatures associated with climate change will have little impact on the digestion of barnacles at low tide, if climate change alters the duration of low tide, there could be an energetic impact to barnacles due to the slowing of their metabolism as indicated by the delay in their digestion.

Like all intertidal species, the barnacle Balanus glandula must cope with temperature and desiccation stress during daily low tide exposure. The increase in temperature at low tide leads to both increased metabolic rate and the potential for increased ATP demand. With its additional inhibition of oxygen intake, low tide thus has an energetic cost that is often reflected in an increase in oxygen consumption following resubmersion. As anthropogenically induced global climate change increases air and water temperatures, its cost might increase. B. glandula individuals were exposed to 4‑hour low tides with maximal temperatures of 18, 30, 35, and 38°C, and their oxygen consumption rates and behaviors were recorded for 4 hours upon resubmersion. It was found that aerial respiration could be measured, though aerial rates were only a fraction of aquatic rates. It was further found that relative aquatic oxygen consumption rates were not elevated following low tide for any temperatures. However, B. glandula individuals exposed to 35 and 38°C low tides remained active a significantly greater portion of time through the first and second hours of recovery, respectively. This indicates that a low tide stress effect is evident in B. glandula, but that it manifests not as an increase in the respiration rate when active, but rather as an increase in the overall activity time. Thus, with increasing global temperatures B. glandula will likely have increased energy needs. This might lead to range relocations, a drive to find new energy sources, and/or reallocations of energy budgets.

Submitted by Caroline Falcao (caroline.rfalcao@ufpe.br) on 2017-05-22T17:05:47Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Lacerda2014 (versão BC).pdf: 15671958 bytes, checksum: bd96e677f6b27688458828455de7708d (MD5) / Made available in DSpace on 2017-05-22T17:05:47Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Lacerda2014 (versão BC).pdf: 15671958 bytes, checksum: bd96e677f6b27688458828455de7708d (MD5) Previous issue date: 2014 / As zonas costeiras são consideradas áreas de transição entre os domínios continental e marinho, apresentando alta complexidade e dinamismo. Representando aproximadamente 10% das áreas emersas habitáveis, abrigam atualmente cerca de dois terços da população mundial proporcionando inúmeros serviços econômico-sociais a sociedade humana, que em constante expansão sobrecarrega cada vez mais esses ambientes que exercem papéis ecológicos fundamentais na manutenção da biodiversidade (e produtividade) local e de ecossistemas adjacentes (terrestre e marinho). Dentre os diferentes ecossistemas costeiros, os sistemas estuarinos são bastante conhecidos por estarem presentes em praticamente toda a costa brasileira, assim como por apresentarem grande importância ecológica, econômica e social. Na costa nordeste do Brasil muitos ecossistemas estuarinos ainda encontram-se pouco ou até mesmo não estudados, deixando uma lacuna nos estudos ecológicos referentes a esses ecossistemas que além de grande dinamismo também apresentam muitas particularidades, principalmente ao longo dessa região (NE) onde a plataforma continental é mais estreita. Dessa forma, durante o período de doze meses o habitat praia estabelecido na porção externa do estuário do Rio Goiana foi amplamente estudado, tendo como objetivo principal, avaliar o potencial desse ambiente como berçário para as assembleias de peixes. Um total de três desenhos amostrais foram elaborados e executados nas praias adjacentes a foz do Rio Goiana. A partir do esforço amostral, aspectos relacionados à composição e dinâmica da comunidade de fauna, assim como, características morfodinâmicas e ambientais, foram descritos pela primeira vez nesse habitat, que atualmente encontra-se sob a condição de Reserva Extrativista (RESEX Acaú-Goiana). Foi identificado que as praias adjacentes ao estuário ocorrem junto a um extenso terraço de baixa-mar, cortado pelo canal principal do rio ao longo da margem sul do estuário. Por se tratar de um ambiente dominado pela maré, diferentes ciclos ambientais como o ciclo lunar e circadiano, apresentaram grande influencia nos padrões das variáveis ambientais (salinidade, temperatura da agua, oxigênio dissolvido e profundidade), assim como, no uso do habitat pelas diferentes espécies da fauna. A diferença no regime de chuvas ao longo do ciclo sazonal mostrou-se determinante na composição da comunidade biótica das praias, dominadas por espécies estuarinas durante a estação chuvosa, e abrigando um maior número de espécies costeiras durante a estação seca. Esse ciclo sazonal do habitat, estimulado pelas oscilações de variáveis ambientais como salinidade e temperatura, permite que o habitat contemple um maior número de espécies, e aumenta a eficiência do fluxo de energia entre a porção interna do estuário e habitats costeiros adjacentes. A porção externa do estuário do Rio Goiana proporciona um extenso habitat de aguas rasas, ideal para o desenvolvimento inicial de varias espécies de peixes e crustáceos. É nesse habitat, que o berçário de espécies chave para a subsistência de famílias tradicionais como, Mugil spp. e Callinectes danae ocorre. O grande acúmulo de matéria orgânica, típico de terraços de maré, associado às baixas profundidades e transparência, promovem proteção e recursos alimentares para inúmeras espécies em desenvolvimento inicial, se apresentando assim, como uma importante alternativa de berçário para as assembleias de peixes e crustáceos. As praias estudadas podem exercer um importante papel na manutenção da biodiversidade do ecossistema estuarino e adjacente. As informações levantadas no presente estudo são inéditas, podendo servir de auxilio aos órgãos competentes, em seus planos de manejo de ecossistemas costeiros em unidades de conservação. / Coastal areas are considered transition zones between continental and marine environments, with high complexity and dynamism. Representing approximately 10% of the habitable emerged areas, currently home to about two-thirds of the world population providing numerous services (economic and social) to human society, which in constantly expanding, overwhelms these environments which performing key ecological roles in the maintenance of local biodiversity (and productivity ) and in the adjacent ecosystems (terrestrial and marine). Among the different coastal ecosystems, estuarine systems are well known to be present in practically the entire Brazilian coast, as well as presenting ecological, economic and social services. On the northeast coast of Brazil many estuarine ecosystems are still little or even not studied, leaving a gap in ecological estuarine studies, especially over this region (NE), where the continental shelf is narrower providing many particularities to this ecosystems. So, during the twelve-month period, the beach habitat established in the outer portion of the estuary Goiana was widely studied, with the main purpose of evaluating the potential of this environment as a nursery for fish assemblages. A total of three sampling designs were developed and implemented in the sandy beaches adjacent to Goiana River’s mouth. Aspects related to the composition and dynamics of the faunal community, as well as, morphodynamic and environmental features, were described for the first time in this area, a Marine Conservation Unit, of type Extractive Reserve (RESEX Acaú-Goiás). It was identified that the adjacent estuarine beaches occur along an extensive low tide terrace, crossed by the Goiana main channel along the southern shore. As a tide dominated environment, different environmental cycles, such as circadian and lunar cycle, had great influence on the patterns of environmental variables (salinity, water temperature, dissolved oxygen and depth), as well as in habitat use by different fauna species. The differences in rainfall regime along the seasonal cycle, proved decisive in the composition of the biotic community, dominated by estuarine species during the rainy season, and harboring a greater number of coastal species during the dry season. This seasonal cycle of the habitat, allows the sandy beaches to contemplate a larger number of species, and increases the efficiency of energy flow between the inner portion of the estuary and adjacent coastal habitats. The outer portion of Goiana River estuary provides an extensive shallow water habitat, ideal for the initial development of various species of fish and crustaceans. In this habitat, the nursery of key species for the livelihoods of traditional families as Mugil spp. and Callinectes danae occurs. The large accumulation of organic matter (wrack), typical of tidal terraces, associated to lowest depths and water transparency, promote protection and food resources for many species in early development, presenting as an important alternative nursery and feeding site for fish and crustaceans species. Thus, the sandy beach habitat plays an important role in the livelihood of the local community, as well as in maintaining the biodiversity of estuarine-coastal continuum. The information gathered in this study, should be taken into account by environmental agencies in their planning of coastal ecosystems.

Ces travaux de thèse concernent la morpho-dynamique d'une plage de poche sableuse, située en environnement macrotidal. L'étude est menée sur la plage de Porsmilin, une plage de type intermédiaire avec une terrasse de basse mer. Cette étude s’appuie sur des observations in situ acquises lors de campagnes de mesures, organisées au cours de cette thèse. Le principal objectif est de caractériser le rôle de la pente, dans l'équilibre dynamique existant entre les processus hydrodynamiques et la morphologie de la plage. La dynamique des niveaux d’eau, de la propagation des ondes infragravitaires et de la turbulence sont examinés et mis en regard des variations morphologiques de la plage, en particulier de la pente locale de la plage. Les niveaux d’eau sont globalement sous-estimés par les formulations empiriques proposées dans la littérature. Des formules adaptées au site de Porsmilin sont présentées. L’impact de la brisure de pente observée le long du profil de plage sur la dynamique de la plage, est étudié. La variabilité de la position de la brisure de pente est impliquée dans les processus d’accommodation à court terme de la plage. Cela se traduit par un retrait vers le haut de plage de la brisure de pente, permettant une dissipation plus efficace de l’énergie incidente par la terrasse de basse mer. En revanche, ce retrait peut conduire, à une concentration d’énergie importante en haut de plage, lors de conditions particulièrement énergétiques, associées à un marnage important. La position de la brisure de pente pourrait être un bon indicateur de l'état de vulnérabilité de la plage face à des évènements énergétiques, ce qui constitue une information primordiale dans le contexte actuel d’érosion généralisée des littoraux sableux. / This PhD work is focused on the morphodynamic of a pocket beach, located in a macrotidal environment. The beach type is intermediate, with a low tide terrace. The study is based on in situ observations, collected during field campaigns organized during the PhD. The objective is to characterize the beach slope impact on hydrodynamics processes and beach morphology. The water levels dynamic, infragravity waves propagation and turbulence generation in the swash zone, are examined and linked to the beach slope variability.The empirical formulations proposed in the literature show large under-estimations of water levels in the site. Empirical formulations adapted to the beach are proposed.The characteristic break slope presents along the cross-shore profile of low tide terrace beaches is studied. The variability of the break slope location is relevant to explain the short term accommodation of the beach. Under incident wave energy, the location of the beach slope moves shoreward, allowing higher wave dissipation by the low tide terrace. Nevertheless, the reflective part is reduced, which leads to a vulnerable state of the upper beach under strong forcing associated with high tide. The location of the beach slope is found to be a good indicator of the beach vulnerability under a given wave forcing. It provides valuable information in the globalized beach erosion context.

This project deals with the concepts of care, contentedness and self-reflection in light of the ecological plights that face our planet and the way that my artistic practice reflects this. It achieves this by focusing on marine forms of plastic pollution along Cape Town’s coastline as well as on the water resources during Cape Town’s water crisis that started in 2017. To unite these areas of interest, the conceptual platform and the visual associations of “a low tide” were used to navigate material and practical considerations of my chosen alternative photographic media and how they can best address such interests. / Art and Music / M.V.A.

La thèse aborde une question originale et d'actualité: l'extension artificielle des côtes. Afin de mieux comprendre ce phénomène dans son actualité, la thèse attache une importance à la description de la pratique des États en fournissant les informations aussi précises, aussi actuelles et aussi concrètes que possible. C'est à partir de cette pratique que la thèse répond à la question de savoir comment les règles de droit répondent aux exigences de la pratique. En ce qui concerne la pratique des États, la thèse explique, dans une première partie, que l'extension artificielle des côtes est destinée, tantôt, à protéger les côtes contre l'élévation du niveau de la mer, tantôt à gagner des terres pour diverses fins: habitat humain, agricoles, développement des ports et de leurs infrastructures pour les besoins des navires modernes et du commerce international. Mais parallèlement, cette extension entraîne des effets négatifs pour l'écosystème côtier (chapitre I). Des travaux de ce genre ont été menés, ou vont l'être, en Europe (Pays-Bas, Allemagne, Belgique, France, R.-U., etc), aux États-Unis, en Asie (Bahreïn, Malaisie, Hong Kong, Singapour, Japon), en Australie, et sur certains archipels du Pacifique (chapitre II). La seconde partie de la thèse examine le droit applicable au phénomène d'extension artificielle des côtes. Sont ainsi passées en revue: les règles relatives à la navigation (chapitre III), les règles relatives aux lignes de base (chapitre IV), les règles relatives aux hauts-fonds découvrants (chapitre V), les règles relatives aux îles et aux rochers (chapitre VI) et enfin les règles relatives à la protection de l'environnement marin (chapitre VII).

La thèse aborde une question originale et d'actualité: l'extension artificielle des côtes. Afin de mieux comprendre ce phénomène dans son actualité, la thèse attache une importance à la description de la pratique des États en fournissant les informations aussi précises, aussi actuelles et aussi concrètes que possible. C'est à partir de cette pratique que la thèse répond à la question de savoir comment les règles de droit répondent aux exigences de la pratique.<p><p>En ce qui concerne la pratique des États, la thèse explique, dans une première partie, que l'extension artificielle des côtes est destinée, tantôt, à protéger les côtes contre l'élévation du niveau de la mer, tantôt à gagner des terres pour diverses fins: habitat humain, agricoles, développement des ports et de leurs infrastructures pour les besoins des navires modernes et du commerce international. Mais parallèlement, cette extension entraîne des effets négatifs pour l'écosystème côtier (chapitre I). Des travaux de ce genre ont été menés, ou vont l'être, en Europe (Pays-Bas, Allemagne, Belgique, France, R.-U. etc), aux États-Unis, en Asie (Bahreïn, Malaisie, Hong Kong, Singapour, Japon), en Australie, et sur certains archipels du Pacifique (chapitre II).<p><p>La seconde partie de la thèse examine le droit applicable au phénomène d'extension artificielle des côtes. Sont ainsi passées en revue: les règles relatives à la navigation (chapitre III), les règles relatives aux lignes de base (chapitre IV), les règles relatives aux hauts-fonds découvrants (chapitre V), les règles relatives aux îles et aux rochers (chapitre VI) et enfin les règles relatives à la protection de l'environnement marin (chapitre VII).<p> / Doctorat en droit / info:eu-repo/semantics/nonPublished