Giant clams (Tridacninae subfamily) are prominent members of Indo-Pacific corals reefs, including the Red Sea, where they play multiple roles and are of distinct ecological significance for these communities. Tridacninae stand out among other bivalves as one of the few molluscan groups that live in a symbiosis with dinoflagellate Symbiodiniaceae. This relationship is comparable to the symbiosis of corals and their associated algae, where the symbionts provide a substantial amount of the respiratory carbon demand of the host through their photosynthetic activity. Their photosymbiosis restricts the distribution of the Tridacninae holobiont (i.e. giant clam host, symbiotic algae and associated bacteria) to the sunlit, shallow waters of the euphotic zone, where organisms receive sufficient incident light to maintain their high rates of primary production and calcification. However, giant clams in these shallow reefs are simultaneously exposed to potentially high and damaging levels of solar (UV) radiation. This thesis includes research on the Red Sea Tridacna spp. holobiont from an ecosystem to microscale level. It assess the abundance and distribution of Red Sea giant clams, including their associated symbiotic microalgae and bacterial microbiome. Further, it describes the strong light-dependency of calcification and primary production of Red Sea Tridacna maxima clams and reports on the effective photo-protective mechanisms that have been evolved by these clams to thrive in shallow reefs, despite levels of high solar irradiance. Tridacninae developed effective behavioral mechanisms for photo-protection, by which the clam is able to flexibly adjust its shell gaping behavior to incident light levels within a narrow time frame. On a microscale, Tridacninae use advanced photonic structures (iridocytes) within their tissues to mitigate the potential negative effects of high solar UV radiation, and to promote the photosynthesis of their symbiotic algae. Understanding the role of the Tridacna spp. holobiont for Red Sea coral reefs, its contributions to overall productivity, and its abundances in the region may serve as a baseline for further studies on this charismatic invertebrate. It may also contribute to the conservation efforts from local to regional scales, and eventually aid the protection of Tridacninae in the Red Sea and elsewhere.

No description available.

The objective of this project was to examine the effects of various storage temperatures and times on the microbiological quality, safety, and viability of hard shelled quahog clams. Samples were stored at four different incubation temperatures (3.3, 7.2, 10.0, and 12.S0C) for a period of three weeks, following their harvest from growing waters during the summer when the water temperatures were ~ SO°F, and during the winter when water temperatures were ~ 40°F. With regards to safety, clams were analyzed for two naturally-occurring pathogens, Vihrio parahaemolyticus and Vihrio vulnificus. Aerobic plate counts (APCs), coliforms, and fecal coliforms were determined to define the level of quality. During the summer, mesophilic APCs containing 2% NaCI ranged from 104 to 108 CFU/g, and during the winter, mesophilic APCs with salt ranged from < 100 ESPC to 104 CFU/g. Comparatively, during the summer, mesophilic APCs containing no added NaCI ranged from < 100 ESPC to 105 CFU/g, and during the winter, APCs without salt ranged from < 100 ESPC to 102 CFU/g. Coliform and fecal coliform counts ranged from < 0.3 to 61.1 MPN/g and < 0.3 to 24.4 MPN/g, respectively. During the summer, V. parahaemolyticus was isolated from 56% of the samples, with the highest concentration, 24,000 MPN/g, occurring on day 12 at 12.8°C. / Master of Science

Toxicity of copper to larval <I>Mercenaria mercenaria</I> was evaluated with static non-renewal and continuous renewal methods that permitted daily observation of mortality, activity, development, and metamorphosis without subsampling. Clam larvae, 100 - 150 microns, were held for up to two weeks in small, 30 mm, sealed petri plates during static assays with excellent survival of control organisms, low evaporative losses, and relatively low between replicate variability. An eight day LC50 of 12 micrograms / liter for six day old organisms was determined as well as EC50s (active swimming). EC50s at 24 hours were as much as much as seven times lower than LC50s after 24 hours of exposure. Flow - through assays were conducted with a modified petri dish design. Two sections from opposing sides of a 30 mm petri dish were removed and covered with 35 micron polyester screening. This dish (organism dish) was placed in an outer catch dish that captured the effluent toxin as it passed through the screening and routed it to a catch bottle for water quality analysis. The toxicant feed line entered through the catch dish cover and slowly dripped toxin into the organism dish. Water quality in the flow - through assay remained excellent. Survival of control organisms in the flow - through assay was lower than in static assays, but metamorphosis was not delayed as had been observed in static assays. Data variability was low enough that statistical distinctions were made between the effects of copper on metamorphosis. A non-standard "M" shaped survival response was observed in all assays. The responses generating the "M" shaped response in the static petri assay were statistically different from each other. Activity, as judged by swimming, in organisms was not observed to follow the "M" shaped pattern. Instead, it decreased exponentially with increasing copper concentrations. Static experiments with unfed clams, observations of activity, and data from experiments in copper accumulation by algae led to a theory relating the unusual dose response to food consumption and its relationship to the effective dose of copper to which the larval clams were exposed. / Master of Science

Submitted by (edna.saturno@ufrpe.br) on 2017-02-22T12:12:45Z No. of bitstreams: 1 Sergio Rodrigues da Silva Neto.pdf: 392491 bytes, checksum: 393fcac7622ccd3d114c36fedb33575d (MD5) / Made available in DSpace on 2017-02-22T12:12:45Z (GMT). No. of bitstreams: 1 Sergio Rodrigues da Silva Neto.pdf: 392491 bytes, checksum: 393fcac7622ccd3d114c36fedb33575d (MD5) Previous issue date: 2011-07-28 / The species Anomalocardia brasiliana is a marine bivalve mollusk that has great economic and social importance to artisanal fisheries in the Brazilian coast. This study aimed to evaluate the distribution and abundance of Anomalocardia brasiliana in Mangue Seco beach, Pernambuco, Brazil, estimating and relating the characteristics of temperature, salinity and sediment grain size with the distribution and abundance of species. The study area comprises 90% sand, salt has up to 37 for the month of January and a minimum of 26 months to June, as the highest temperature was found in the month of December/2010 (37.6 ° C) and the lowest June/2010 month (24 ° C). The highest average value of individuals collected in Mangue Seco beach was 263.6 org. / M² for the month of December/2010 and lowest for the month was 127.38 with January/2011 org. / M², the values of average length found for the region over the study show that in the month of lowest density was the lowest average length of about 16.5 ± 5.7 mm, a fact that may be related to an increased stress on the stock due to increased demand for meat from A. brasiliana. / A espécie Anomalocardia brasiliana é um molusco bivalve marinho que apresenta grande importância econômica e social para pesca artesanal no litoral brasileiro. O presente estudo teve como objetivo avaliar a distribuição e abundância da Anomalocardia brasiliana na praia de Mangue Seco, Pernambuco, Brasil, estimando e relacionando as características de temperatura, salinidade e granulometria do sedimento com a distribuição e abundância da espécie. A área estudada é composta por 90% areia, possui salinidade máxima de 37 para o mês de janeiro e mínima de 26 para o mês de junho, já a temperatura mais elevada foi encontrada no mês de dezembro/2010 (37.6°C) e a menor no mês de junho/2010 (24°C). O maior valor médio de indivíduos coletados na praia de Mangue Seco foi de 263,6 org./m² para o mês de dezembro/2010 e o menor valor foi do mês de janeiro/2011 com 127,38 org./m², os valores de comprimento médio encontrados para a região ao longo do estudo demonstram que no mês de menores valores de densidade ocorreu a menor média de comprimento com cerca de 16.5±5.7 mm, fato este que pode ser relacionado a um maior esforço sobre o estoque devido ao aumento na procura da carne da A. brasiliana.

The focus of this study was to determine the effect of clam presence and behavior on the crossflow of the ambient horizontal flow and the effect of ambient horizontal flow characteristics influence the clam feeding behavior. Hence, there is a reciprocal relationship between organisms and the physical environment, and this study ultimately addressed the role of hydrodynamics in the predator-prey relationship between bivalve clams, Mercenaria mercenaria, and their predators, blue crabs and whelks. The study concludes that clams alter the chemical odorant source characteristics and control the transmission of the chemical signal through altering the crossflow. The first part of the study is a field experiment designed to quantify the effect of the presence and behavior of clams on the crossflow of the horizontal crossflow. The second part of this study is a two-part laboratory experiment designed to isolate the influence of environmental factors on clam behavior. One experiment quantifies the unsteadiness of the clam excurrent jet velocity time record according to environmental cues such as the horizontal crossflow velocity, the density of the clam patch, and the size of the clam. The second laboratory experiment quantifies the unsteadiness of the jet velocity values according to the presence of predator cues in the upstream flow. Clams are found, using an ADV system in the field, to alter the vertical distribution of velocity according to the sediment in which they are buried. Also, turbulence characteristics, such as Turbulent Kinetic Energy and Reynolds shear stress, are altered in the presence of clams according to the ambient horizontal crossflow velocity and treatment site. The laboratory flume PIV system captured vector plots for two-dimensional planes that bisect the clam excurrent siphons and clam jet velocity time records were extracted. A fractal analysis and a lacunarity analysis of the jet velocity time records found that clams alter their jet excurrent velocity unsteadiness according to the horizontal crossflow velocity. This behavioral change may contribute to the differences in the turbulence characteristics in the field experiment. Another result from the laboratory experiments is that the effect of clam patch density on the feeding activity was dependent on the size of the organism. This size/density dependent relationship suggests that predation by blue crabs dominates the system since larger clams are no longer susceptible to blue crab predation, whereas clams of all sizes are susceptible to whelk predation. Finally, clams increase the randomness of their excurrent jet velocity values when predator cues are located in the upstream flume flow. This suggests that the presence of predators elicits clam behavior that promotes the mixing and dilution of their chemical metabolites.

Salmon aquaculture is a controversial industry in British Columbia (BC). First Nations in BC have expressed concerns about possible contamination of traditionally harvested foods by waste from salmon farms. Trace elements are released from farms via waste feed and feces, as well as leaching from netpens and antifouling paints. In addition to elemental analysis, farm waste can also be traced using stable isotopes of nitrogen and carbon. Due to the use in salmon feed of protein and oil derived from pelagic marine fish, farm waste is typically enriched in heavier isotopes of nitrogen and carbon when compared to marine particulate organic matter. in partnership with First Nations from Ahousaht, BC, I investigated these effects by determining the concentrations of three metals and one metalloid in salmon feed, sediment and Manila clams Venerupis philippinarum from six sites in Clayoquot Sound, on the west coast of Vancouver Island, BC. Samples were collected from three sites near salmon farms and three reference sites in four different months spanning the traditional clam harvesting season. The results suggested that salmon feed continues to be a source of trace elements in the marine environment; however, salmon farms did not appear to be elevating concentrations in nearby clam tissue and sediment. Different environmental conditions between sites may have exerted a greater influence on elemental concentrations than farm-derived elements. Contrary to findings in earlier studies, the nitrogen signature of salmon feed was not enriched relative to marine particulate organic matter and was not a useful tracer of farm waste. This may have resulted from the reformulation of salmon feed to include greater quantities of protein and oil from terrestrial rather than marine sources. Due to the importance of Manila clams in First Nations' diets, the high density of salmon farms in the study area, the likelihood of ongoing feed reformulation, and the propensity for contaminants to accumulate over time, ongoing monitoring of sediment and bivalves in the area would be advisable.

The aim of this diploma thesis was exploration, interpretation and proposing of the preventive care of photographic fund from the state castle Grabštejn. The theoretical part is generally dedicated to the funds and collections administered by the National Heritage Institute, their destiny after the 2nd World War and the historical context which caused movements of these funds. A separate chapter is also devoted to the methods of exploration of the funds and collections. The second part of this thesis focuses on the history of the Grabštejn castle and its last owners - the Clam-Gallas family, with whom the preserved photographs are associated, and on the transport of the funds in the postwar period. The thesis follows the main journey of the photographic fund and related archival materials from the Grabštejn state castle to the collecting sites, museums and archives. Therefore the survey also took place in the National Museum Archives, the National Archives, the Institute of Art History of the Czech Academy of Sciences and the State Regional Archives in Litoměřice. The fundamental part of the survey was carried out in the castle Grabštejn. There were also studied the specific climate conditions for the photographs, which differ in the castle from the classical museum and archival depositories. Measuring of humidity and temperature was evaluated at the end of the thesis and recommendations for the preventive care were suggested.

The original aim of the research project was to investigate the mechanism of power capture from sea waves and to optimise the performance of a vee-shaped floating Wave Energy Converter, the Floating Clam, patented by Francis Farley. His patent was based on the use of a pressurised bag (or ‘reservoir’) to hold the hinged Clam sides apart, so that, as they moved under the action of sea waves, air would be pumped into and out of a further air reservoir via a turbine/generator set, in order to extract power from the system. Such “Clam Action” would result in the lengthening of the resonant period in heave. The flexibility of the air bag supporting the Clam sides was an important design parameter. This was expected to lead to a reduction in the mass (and hence cost) of the Clam as compared with a rigid body. However, the present research has led to the conclusion that the Clam is most effective when constrained in heave and an alternative power take-off is proposed. The theoretical investigations made use of WAMIT, an industry-standard software tool that provides an analysis based on potential flow theory where fluid viscosity is ignored. The WAMIT option of Generalised Modes has been used to model the Clam action. The hydrodynamic coefficients, calculated by WAMIT, have been curve-fitted so that the correct values are available for any chosen wave period. Two bespoke mathematical models have been developed in this work: a frequency domain model, that uses the hydrodynamic coefficients calculated by WAMIT, and a time domain model, linked to the frequency domain model in such a way as to automatically use the same hydrodynamic and hydrostatic data. In addition to modelling regular waves, the time domain model contains an approximate, but most effective method to simulate the behaviour of the Clam in irregular waves, which could be of use in future control system studies. A comprehensive series of wave tank trials has been completed, and vital to their success has been the modification of the wave tank model to achieve very low values of power take-off stiffness through the use of constant force springs, with negligible mechanical friction in the hinge mechanism. Furthermore, the wave tank model has demonstrated its robustness and thus its suitability for use in further test programmes. The thesis concludes with design suggestions for a full-scale device that employs a pulley/counterbalance arrangement to provide a direct connection to turbine/generator sets, giving an efficient drive with low stiffness and inherently very low friction losses. At the current stage of research, the mean annual power capture is estimated as 157.5 kW, wave to wire in a far from energetic 18 kw/m mean annual wave climate, but with scope for improvement, including through control system development.

Made available in DSpace on 2015-04-01T12:17:41Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3689736 bytes, checksum: 727f212a3d43cfe51e158ce0f1485daf (MD5) Previous issue date: 2013-07-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In last years there has been a huge concern about environment. This present study aims to study the viability of using mollusk shell powder, as particulate reinforcement in polymer composites of High Density Polyethylene (HDPE), in order to this research contributes potentially to mitigate the environmental impact caused by increase of shell waste associated with mollusk commercial activities on the coast of Paraiba State. To this end, a study on influence of mollusk shell additions (for concentrations of 2, 5 and 8% in weight and for granulometries with both 200 and 325 meshes) in changing the mechanical, morphological, and thermal properties of pure HDPE is done. In addition, a titanate coupling agent was used to treat surfaces of mollusk shell powder of the composite having 5% in weight of shell. All composites were processed in a single-screw extruder with a mixing component (Madock) and specimens are molded by injection. It was performed a chemical characterization of the shell powder by X-ray fluorescence in order to identify its constituents and it was found 97.95% calcium oxide, which is the main constituent of calcium carbonate. In addition, it was performed a MFI analysis and thermal, morphological, and mechanical characterization for all composites as well as for pure HDPE. The MFI analysis of the composites showed only slight changed, therefore the mollusk shell did not influence definitely on rheological behavior of the pure HDPE.The cristalinity degree of the pure UHWPE increased when mollusk shell powder was increased. The composition of 5% in weight with granulometry of 325 mesh produced the highest increase of cristalinity degree of non-treated powders, almost 29%, whereas 38% cristalinity degree was obtained when a 200-mesh composition of 5% in weight was treated with the titanate coupling agent. This behavior suggest a probable effect of particles as nucleating agent. Fracture surfaces show there is both low bonding among the phases and particle agglomerates, mainly in 8% composite for both granulometries. The addition of shell powder changed tensile mechanical properties of pure HDPE, where in major cases its stiffness was increased excepted for 5% compositions. Both the impact strength and bending mechanical properties of the pure HDPE were increased when the thinner shell powders were additioned. Hence shell powder is a potential particle reinforcement for use in HDPE composites. / Nos últimos anos existe uma preocupação muito grande com meio ambiente. O presente estudo tem como objetivo estudar a viabilidade do uso de pó de conchas de moluscos, como carga particulada em compósitos poliméricos de polietileno de alta densidade, (PEAD) a fim de que essa pesquisa contribua potencialmente para amenizar o impacto ambiental causado pelo aumento da produção dessas conchas, associadas com as atividades comerciais de moluscos, ao longo de toda a costa do estado da Paraíba. Com este objetivo foi realizado um estudo sobre a influência da concha, nas concentrações de 2, 5, 8% em massa, nas granulometrias de 200 e 325 mesh, sobre as propriedades mecânicas, morfológica e térmica do PEAD puro. Neste estudo, um agente de acoplamento titanato também foi utilizado para tratar as superfícies das partículas do pó da concha do compósito contendo uma concentração de 5 % de concha. Os compósitos foram processados em uma extrusora mono rosca com um componente de mistura(Madock) e os corpos de prova foram moldados por injeção. Foi realizado uma caracterização química no pó da concha por fluorescência de Raio X para verificar seus constituintes, e encontrando 97,95% de oxido de cálcio constituinte principal do carbonato de cálcio. Também foi realizada análise de MFI, caracterização térmica, morfológica e mecânica para todos os compósitos e para o PEAD puro. O MFI dos compósitos teve pequena alteração, logo a carga não influenciou o comportamento reológico do PEAD. O grau de cristalinidade do PEAD puro aumentou à medida que o teor de pó de concha foi aumentado, sendo que a composição de 5% em massa, na granulometria de 325 mesh foi a que apresentou maior aumento, quase 29% com relação ao puro, já o compósito com 5% em massa de pó de concha(200 mesh) tratado com agente de acoplamento titanato teve um aumento de quase 38%. Esse comportamento indica um provável efeito nucleante dessas partículas. A superfície de Fratura mostrou que existe pouca adesão entre as fases presentes e que existem aglomerados das partículas, principalmente com a composição de 8% nas duas granulometrias. A adição da concha alterou as propriedades mecânicas sob tração do PEAD puro, de um modo geral, sua rigidez foi aumentada, exceto os compósitos contendo 5% em massa, que diminuíram o módulo de elasticidade do PEAD puro. A resistência ao impacto e as propriedades mecânicas sob flexão do PEAD puro foram aumentadas com a adição do pó de concha, com a granulometria mais fina. O pó da concha é um reforço particulado potencial para o uso em compósitos de PEAD.