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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Epifaunal assemblage of a newly established oyster reef with two substrates

Dow, Ian M 01 June 2008 (has links)
An artificial oyster reef constructed in Boca Ciega Bay, off of the War Veteran's Memorial Park, St. Petersburg, Florida, in 2005, was used to compare a mined shell material to the typical oyster shell substrate used in artificial reef projects as an alternative substrate and cultch material. Half of the reef's veneer was the fresh oyster shell and the other half was mined material. Experimental trays were deployed on top of the sediment along the leeward reef base and sampled quarterly to test the hypothesis that fresh shell is the preferential cultch material of the Eastern Oyster, Crassostrea virginica, promoting more oyster and epifaunal community development than the mined material. Monthly field observations along the reef face monitored the oyster community development on both substrates. The unanticipated influence of the reef's presence on the local current flows resulted in significant sediment loading on the reef. The sediment inundated and smothered the experimental trays over the course of the study, thereby converting the trays from hard substrate to soft bottom habitats. Any influence the different substrates might have had on community development was overwhelmed by sediment burial. Monthly field observations revealed positive oyster community development on both substrates. Live oyster abundance was significantly dissimilar between June and December 2006 on the fresh shell compared to the mined material (R = 0.241, p = 0.001). Epifaunal abundance showed even greater dissimilarity over the same time period (R = 0.474, p< [or] = 0.001). Greater abundances of large oysters were found on the fresh shell substrate due to an instability and deterioration of the larger pieces of mined material. A low replicate sample size of n = 3 leaves results from between month and between quarter sampling analyses open to interpretation. Though no definitive conclusions were drawn, the data from the community analyses provides useful information on the species inhabiting and utilizing oyster reefs in the Tampa Bay area.
12

A study on the Construction and Ecological succession of two Small Artificial Reefs on the Swedish West Coast

Forsberg, Malin, Järlind, Joakim January 2014 (has links)
Artificial reefs are being built in most parts of the world for a wide variety of purposes. Divingtourism is a common motivator for the construction of many reefs, particularly in the tropics,although the most widely used purpose is to improve or reconstruct hard bottom habitats andincrease the yield from fisheries. There are two main reasons for why aquatic life is attracted toartificial reefs. They provide excellent protection by often being hollow or filled with crevicesand cavities and increasing opportunities for improved foraging through accumulating biomassand extending the foraging range of an organism by acting like stepping stones. Sweden is acoastal country with few artificial reefs. In this study, two reefs were constructed in the sea offthe coast of Halmstad, Sweden to test small scale artificial reef production, marine organismcolonisation of the reefs during the first year, and to increase the local marine life diversity.Many marine organisms that would not normally occur in the sites where the reefs wereconstructed were observed, such as Symphodus melops and Anguilla anguilla. The reefs alsoprovided a new “clean slate” substrate for the settling of sessile organisms such as Urticina felinaor partially sessile organisms (i.e. during a certain stage of their life-cycle) such as some speciesof Cnidaria polyps. The tested method to construct these reefs was relatively cost effective for itspurpose. However a few minor but vital improvements, such as better binding materials, areneeded. Local marine life in the area has become more diverse during the experiment and thatalone is enough reason to motivate construction of similar reefs along the Swedish coast. / Artificiella rev anläggs runt om i världen med en mängd olika syften. Det är vanligt att dykturism används som anledning för att bygga artificiella rev, speciellt i tropikerna. Restaurering av hårdbottenrev och mål att öka kommersiella fiskebestånd är dock de största motiveringarna. Det finns två huvudsakliga orsaker till varför akvatiskt liv attraheras av konstgjorda rev. De erbjuder utmärkt skydd i form av håligheter och sprickor, samt att de ökar möjligheterna för födosök genom att ackumulera biomassa och fungera som ”stepping stones”, det vill säga utöka födosökningsområdet. Sverige är ett kustland med få artificiella rev. Två rev anlades i Laholmsbukten, Kattegatt, just utanför Tjuvahålan i Halmstad med syftet att undersöka effektiviteten och nyttan av småskaliga rev, att studera marina organismers kolonisering av reven och att öka den lokala biodiversiteten. Många marina organismer som inte borde förkommit i området där reven anlagts tidigare observerades. Ett par exempel är Symphodus melops) och (Anguilla anguilla). Reven fungerade även som rena underlag för sessila organismer att fästa på. Djur som till exempel havsros (Urticina felina) och Cnidariapolyper noterades. Metoden för att konstruera reven visade sig vara kostnadseffektiv i förhållande till syftet, men några viktiga steg, bland annat fästmaterialet, behöver förbättras. Den lokala artmångfalden ökade efter anläggningen av reven och borde vara nog motivering för att fortsätta bygga liknande rev längs den svenska kusten.
13

Marketing de lugares: estudo de impactos do recife artificial multifuncional / Place marketing: impacts study of the multipurporse artificial reef

Marco Antonio de Moraes Ocke 24 August 2015 (has links)
Marketing de lugares se caracteriza como uma ferramenta para a gestão das trocas que ocorrem no âmbito territorial possibilitando o fortalecimento da competitividade e da imagem de uma determinada localidade através da geração e entrega de valor a seus diferentes mercados e da atração de investimentos que assegurem seu desenvolvimento no longo prazo. Neste cenário, esta pesquisa apresenta como objeto de estudo o recife artificial multifuncional, estrutura implantada em ambiente marinho com a finalidade de promover a proteção costeira, aprimorar as condições de surfe e criar novos habitats marinhos. Sob a perspectiva de marketing, o potencial benefício deste programa de ação está ancorado no desenvolvimento do lugar e na entrega de valor aos seus públicos a partir da manutenção da infraestrutura local de forma sustentável, da oferta de lazer aos usuários, do aumento do número de visitantes e do incremento da rede de serviços. Neste contexto, o objetivo da tese é a investigação dos impactos resultantes da implantação do recife artificial multifuncional e da relação entre as bases conceituais do marketing de lugares com suas implicações práticas a fim de incentivar o avanço desta linha de pesquisa, principalmente no Brasil, onde o conhecimento da área se encontra em estágio embrionário. Para tanto, a pesquisa qualitativa exploratória aqui presente se divide em duas partes. A primeira apresenta a revisão teórica abordando o conceito de marketing de lugares e três grandes blocos do marketing para fundamentar o raciocínio: produto, segmentação e posicionamento. A segunda parte desenvolve o estudo de caso da cidade de Gold Coast na Austrália contando com coleta de dados por meio de análise documental e entrevista. Os resultados observados na pesquisa indicam que a implantação do recife artificial multifuncional trouxe uma significativa contribuição para o desenvolvimento de longo prazo da localidade analisada e que grande parte das implicações práticas do marketing de lugares observadas no caso encontra-se alinhada à teoria revisitada. O estudo permite ainda sugerir recomendações para localidades que planejam implantar o recife artificial multifuncional em seus programas de ação. / Place marketing is characterized as a tool for the management of exchanges that take place in the territorial scope thus strengthening competitiveness and image of a particular place by generating and delivering value to its different markets and attracting investments to ensure its development in the long term. In this scenario, this research presents as the object of study the multipurpose artificial reef, a structure implemented in the marine environment in order to promote coastal protection, improve surfing conditions and create new marine habitats. From a marketing perspective, the potential benefit of this action program is anchored in place development and value delivering to its stakeholders, through the maintenance of local infrastructure in a sustainable way, the leisure offer to users, increasing the number of visitors and the enhance in services network. In this sense, the objective of the thesis deals with the investigation of impacts resulting from the implementation of multipurpose artificial reef and the relationship between the conceptual bases of place marketing with its practical implications in order to encourage the advancement of this field of research, especially in Brazil, where knowledge of the area is in the embryonic stage. To that end, the exploratory qualitative research hereby is divided into two parts. The first presents a theoretical review addressing place marketing concept and three major marketing blocks to support the reasoning: product, targeting and positioning. The second part develops the case study of Gold Coast City in Australia relying on data collection through documents analysis and interview. The results from this research indicate that the implementation of the multipurpose artificial reef brought a significant contribution to the long term development of the place in analysis and much of the practical implications of place marketing observed in the case are in line with theory revisited. The study also allows suggesting recommendations for places planning to deploy multipurpose artificial reef in their action programs.
14

A Comparison of Infaunal Community Structure Between Pre- and Post Construction Sampling of Artificial FDOT Rock- Pile Reefs in Broward County, Florida

Guerra, Joan Lorraine 10 December 2015 (has links)
Artificial reefs (ARs) are generally created with the intention of increasing local fish populations, biodiversity and corresponding habitat productivity, most often in support of commercial and recreational uses (e.g., diving and fishing). Numerous studies have investigated the communities that develop on artificial reefs. By contrast, far less research has focused on the surrounding infaunal communities, which represent critical trophic resources for many species that populate both natural and artificial reefs, and which may be affected both by AR deployment and the organisms that subsequently recruit to them. This study compared infaunal organism abundances at four sites between the inner and middle reefs off Broward County, Florida, before deployment of a series of Florida Department of Transportation (FDOT) AR boulders in 2009 (pre-construction) and four years later in 2013 (post-construction). Samples consisted of sediment collected in hand-held core tubes taken on open sediment adjacent to the proposed ARs and along transects at distances 3 m and 7 m from the ARs post-construction. Sample depths ranged from 12.1 to 14.6 m. Analyses were carried out on organisms retained on a >0.5 mm sieve and identified to the lowest practical taxonomic level. Data consisted of abundances rather than densities, because pre-construction samples did not record sediment volume per core. A total of 163 taxa were identified, of which only 50 were identified to genus and 64 to species. Polychaete families Spionidae, Sabellidae, Syllidae, and Hesionidae, and sipunculan superfamily Phascolosomatidea dominated pre-construction samples. Polychaetes also dominated post-construction samples, with high relative abundances of Sabellidae and Hesionidae, but with increased proportions of bivalves and amphipods. Statistical analyses (PRIMER, PERMANOVA, and SIMPER) determined whether infaunal composition, richness and, diversity differed among samples by year, site and distance from AR boulders. A slight but statistically insignificant difference in species diversity appeared between 3- and 7-m distances between years. However, composition, richness, and diversity of infauna did not differ either between pre-and post-construction samples or by sample distance from the adjacent AR boulders. The increase in homogeneity among samples post-construction may reflect recovery following the disturbance created by AR deployment, or a response to different benthic conditions generated by AR deployment. As other studies have suggested that AR fauna may influence surrounding infaunal communities to distances greater than 7 m, and that conditions may not stabilize around ARs for up to ten years following deployment, additional sampling is recommended to determine the longer-term effects of the FDOT ARs on infauna and benthic habitat (e.g., sediment composition, water movement) and assist in determining best practices for future AR deployments (e.g., composition, structure, location).
15

Does Landscape Context Affect Habitat Value? The Importance of Seascape Ecology in Back-reef Systems

Yeager, Lauren 22 February 2013 (has links)
Seascape ecology provides a useful framework from which to understand the processes governing spatial variability in ecological patterns. Seascape context, or the composition and pattern of habitat surrounding a focal patch, has the potential to impact resource availability, predator-prey interactions, and connectivity with other habitats. For my dissertation research, I combined a variety of approaches to examine how habitat quality for fishes is influenced by a diverse range of seascape factors in sub-tropical, back-reef ecosystems. In the first part of my dissertation, I examined how seascape context can affect reef fish communities on an experimental array of artificial reefs created in various seascape contexts in Abaco, Bahamas. I found that the amount of seagrass at large spatial scales was an important predictor of community assembly on these reefs. Additionally, seascape context had differing effects on various aspects of habitat quality for the most common reef species, White grunt Haemulon plumierii. The amount of seagrass at large spatial scales had positive effects on fish abundance and secondary production, but not on metrics of condition and growth. The second part of my dissertation focused on how foraging conditions for fish varied across a linear seascape gradient in the Loxahatchee River estuary in Florida, USA. Gray snapper, Lutjanus griseus, traded food quality for quantity along this estuarine gradient, maintaining similar growth rates and condition among sites. Additional work focused on identifying major energy flow pathways to two consumers in oyster-reef food webs in the Loxahatchee. Algal and microphytobenthos resource pools supported most of the production to these consumers, and body size for one of the consumers mediated food web linkages with surrounding mangrove habitats. All of these studies examined a different facet of the importance of seascape context in governing ecological processes occurring in focal habitats and underscore the role of connectivity among habitats in back-reef systems. The results suggest that management approaches consider the surrounding seascape when prioritizing areas for conservation or attempting to understand the impacts of seascape change on focal habitat patches. For this reason, spatially-based management approaches are recommended to most effectively manage back-reef systems.
16

A Comparison of Macroinfaunal Community Structure between Artificial Concrete Boulder Reefs and Adjacent Natural Reefs in Broward County, Florida

Metallo, Amber C 20 November 2015 (has links)
Relatively little is known about either the biological (i.e., predation) or physical (i.e., current, sedimentation) effects that artificial reefs may have on surrounding benthic infaunal communities. Following deployment of artificial reefs (concrete boulders) between the first and second reefs off Fort Lauderdale, Florida, on 30 October 2009, sediment cores were taken at 4 distances along three replicate 10-m transects on 13 and 26 September 2013, and 24 and 25 May 2014 at each of four artificial reef sites and four of their adjacent natural reef sites using SCUBA. Infauna (>0.5mm) were extracted from the sediment and identified to the lowest possible taxonomic level. Statistical analysis (PRIMER, PERMANOVA, SIMPER) focused on four main variables: type of reef, year, site, and distance. Type of reef, year, and site was significantly different between samples, while distance did not affect density. There is a clear separation of communities between the artificial and natural reefs. From 2013 to 2014, a slight shift occurred between communities suggesting the artificial reef community composition became slightly more similar to the natural reef. All four artifical reef sites were more taxonomically distinct at the phylum and class level then the natural reef, which had higher diversity, higher species richness and more low-density taxa. This two year study provides insight on infauna communities four and five years out from deployment, but follow up monitoring in 3-5 years could shed light on whether these patterns of shift to more similar assemblages between reefs will continue as the artificial reef matures. Environmental data collection including longer time-series datasets, longer transects, and physical and geological data could provide more knowledge of how the artificial reef infaunal communities are changing over time.
17

The environmental, social and economic impacts of an artificial surf reef : the UK experience

Rendle, Emma Jane January 2016 (has links)
The study presented in this thesis discusses the topic of ASRs through the use of a specific case study constructed at Boscombe, UK. With the main aim to provide an impartial and independent study into the environmental, social and economic impacts of an ASR. The research presented is therefore multidisciplinary in nature, the separate components utilise key techniques from the geophysical, numerical modelling and socio-economic disciplines are combined to present a significant contribution to the knowledge and understanding of ASRs. Whilst previous studies have focused on one of these disciplines, there are no independent detailed studies of a constructed ASR utilising an multidisciplinary approach. The ASR concept and structures are still in their development infancy, the subject has received cursory independent review in the literature. There have been few successful projects, those that have survived structurally in the ocean are not being used primarily for surfing. The Boscombe ASR is an example of high overspend, poor management and construction, loss of geotextile SFC and users deem the project a failure. The consequences of not correctly planning, managing and overseeing the construction has resulted in a poorly viewed project of limited success. All stages of this project could have benefited from thoughtful planning, thereby avoiding this outcome. If lessons are to be learnt from this project then the planning and management are key areas of the process that need addressing. Ensuring that any future ASR projects are securely integrated with the coastal zone management plan will provide sustainability and success. The DPSIR framework approach can be used to highlight and address the causes of problems in the project. This framework enables the various disciplines to be discussed in relation to each other; links can be identified between the environmental, social and economic impacts of the ASR construction. Strict protocols will increase the success of any ASR project. The final crest height of the Boscombe ASR was 0.5 m higher than the final design height, this is a fundamental design flaw that should not be occurring in modern coastal engineering practice. It is suggested that guidelines are written based on this research for the design and construction process of an ASR. The recommendations and guidelines for ASR monitoring are provided by this research. The emphasis for future projects should lie in the final design and in monitoring, baseline field data should be collected to understand the environmental state change and socio-economic impacts. Planning and government proposals should be accompanied by extensive stakeholder engagement ensuring transparency for the project and ownership within the coastal community. The exclusion of stakeholders at key decision points created distrust and misunderstanding towards the Boscombe ASR project. Avoiding unrealistic expectations within the surfing community and wider coastal community was discussed throughout this research, and by others in the literature. This research agrees with these statements, the issue of poor surfability would be improved by a greater area to manipulate the bathymetry. However this would come at a greatly increased cost in geotextile SFCs, which the current construction method is certainly not capable of delivering successfully. It would be recommended in this case that an alternative construction material was used that is resilient to the marine environment and readily adaptable given poor performance. Further testing of materials, both geotextile SFCs and alternatives, are required for the successful advancement of ASR technology.
18

Exploring the Potential for Artificial Reefs in Coral Reef Restoration: Responses and Interactions of Associated Biota to Varying Experimental Treatments in the Mexican Caribbean

Kilfoyle, Audie Kirk 30 March 2017 (has links)
Coral reefs are being negatively impacted by various causes worldwide, and direct intervention is often warranted following disturbance to restore or replace lost ecosystem structure and function. An experimental coral reef restoration study involving standardized artificial reef modules (ReefballsTM) was conducted in Mexico’s Yucatan Peninsula in the towns of Puerto Morelos and Akumal. The purpose was to explore the use of artificial structure for restoration and mitigation applications in a highly diverse and dynamic Caribbean coral reef environment by applying and evaluating the performance of select experimental treatments hypothesized to accelerate development of the associated biota. The first treatment consisted of invertebrate enhancing artificial substrate padding material, which provided structurally complex refuge space for mobile epifaunal/infaunal invertebrates and other benthic organisms. The second treatment consisted of coral transplants, intended to provide additional structural complexity and kick-start development of stony coral populations. The third treatment consisted of settlement plates which were intended to provide data on coral recruitment and survival rates. Multiple hypotheses relating to the interactions between experimental treatments and the resulting macroalgal, non-coral invertebrate, stony coral, and coral reef fish assemblages were examined, and comparisons were made between natural and artificial substrates. In Puerto Morelos there were 40 modules; 10 controls and 10 of each of 3 treatments: substrate pads, coral transplants, and settlement plates. In Akumal there were 12 modules; 6 controls and 3 of each of 2 treatments: substrate pads and settlement plates. Following module deployment, 6 biannual monitoring trips were made over the course of three years to assess the development of the biota, with a final 7th trip made six years post-deployment. Divers conducted non-destructive visual surveys to evaluate total abundance, species richness, size class distribution, and assemblage structure of coral reef fishes. Other monitoring work included coral recruit surveys, mobile epifaunal invertebrate collections from substrate pads, and digital imaging of coral transplants, natural reef reference corals, and benthic quadrat areas. Hurricane Dean compromised the Akumal study site during the first year of the study, but Puerto Morelos was unaffected. There the modules developed biotic assemblages that differed from what was found on the natural reef, and the data suggests that the substrate pads may have had an effect on the development of faunal assemblages. Lobophora variegata macroaglae and Desmapsamma anchorata sponge were the major contributors to benthic community composition, and both had significantly greater coverage on the substrate pads treatment modules. Lobophora grew rapidly and peaked within the first year, while sponges increased steadily throughout the first three years of the study, surpassing the coverage of macroalgae before the end of the second year, much to the detriment of coral transplants and many coral recruits. By the end of the study, over 75% of the transplants were overgrown by D. anchorata, and density of new coral recruits on the Pads treatment modules was lower than the other treatments and controls. Coral recruitment was dominated by Porites astreoides on all treatments and controls, and the number of corals increased steadily throughout the study. The controls had consistently greater numbers of corals than the treatments, as well as lower percent coverage of macroalgae and sponges. Total abundance and species richness of reef fishes was generally unaffected by the treatments. However, at the family and species level, several differences were detected, particularly for the substrate pads treatment and to a lesser extent for the coral transplants treatment. For future restoration or mitigation efforts utilizing similar or identical treatments to artificial substrates, this study suggests that, in the absence of routine maintenance, greater success may be achieved after waiting several years post-deployment for the initial wave of unchecked growth by benthic organisms (i.e., macroalgae and sponges) to reach a balance point before a large investment of resources is devoted to coral transplanting. Further recommendations include routine monthly or quarterly on-site maintenance to enhance transplant survival, as well as a longer monitoring window to assess community development in response to experimental treatments. The results of this study suggest that the experimental treatments did indeed have an effect on the biota, but whether or not the effect was beneficial largely depends upon perspective. The Pads treatment in particular had the greatest effect on both reef fish and benthic community development, however, it was not beneficial for stony coral recruitment. Additional research is needed to fully understand the long-term performance and effects of the padding material on biotic assemblage development for future restoration or mitigation projects.
19

Offshore wind farms - ecological effects of noise and habitat alteration on fish

Andersson, Mathias H. January 2011 (has links)
There are large gaps in our understanding how fish populations are affected by the anthropogenic noise and the alteration of habitat caused by the construction and operation of offshore wind farms. These issues are of great importance as the construction of offshore wind farms will increase all over the world in the near future. This thesis studies these effects with a focus on fish. The wind turbine foundations function as artificial reefs and are colonized by invertebrates, algae and fish. The epibenthic assemblages are influenced by factors such as hydrographical parameters, time of submergence, distance to natural hard bottom, material and texture (PAPER I, II). Once an epibenthic assemblage has been developed, fish utilize it for different ecosystem services such as food, shelter, and spawning and nursery area. Benthic and semi-pelagic species show a stronger response to the introduced foundation than pelagic species, as it is the bottom habitat that has mainly been altered (PAPER I, II). Pelagic species could be positively affected by the increased food availability - but it takes time and the effect is local. Construction noise like pile driving creates high levels of sound pressure and acoustic particle motion in the water and seabed. This noise induces behavioural reactions in cod (Gadus morhua) and sole (Solea solea). These reactions could occur up to tens of kilometres distance from the source (PAPER III). During power production, the wind turbines generate a broadband noise with a few dominating tones (PAPER IV, V), which are detectable by sound pressure sensitive fish at a distance of several kilometres even though intense shipping occurs in the area. Motion sensitive species will only detect the turbine noise at around a ten meter distance. Sound levels are only high enough to possibly cause a behavioural reaction within meters from a turbine (PAPER IV, V). / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3, 4 and 5: Manuscripts.

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