Dissertations / Theses on the topic 'Corals'
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Robison, Jennifer D. "The photophysiology of symbiotic dinoflagellates (Symbiodinium) under varying light and thermal conditions and the implications for coral bleaching." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 8.14 Mb., 97 p, 2006. http://proquest.umi.com/pqdlink?did=1163244091&Fmt=7&clientId=8331&RQT=309&VName=PQD.
Full textSantora, Karen A. "Abundance and diversity of culturable bacteria from healthy and suspect white plague type II-infected corals in the Flower Garden Banks National Marine Sanctuary." Fairfax, VA : George Mason University, 2008. http://hdl.handle.net/1920/3074.
Full textVita: p. 103. Thesis director: Robert B. Jonas. Submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Science and Policy. Title from PDF t.p. (viewed July 3, 2008). Includes bibliographical references (p. 96-102). Also issued in print.
Billinghurst, Zoe. "Genetic variation within the coral Symbiodinium symbiosis of Bermudian reef corals." Thesis, University of York, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286055.
Full textChartrand, Kathryn M. "Distribution, photobiology, salinity tolerance and population structure of Siderastrea radians and its symbionts in Florida Bay, Florida USA." View electronic thesis, 2008. http://dl.uncw.edu/etd/2008-1/r1/chartrandk/kathrynchartrand.pdf.
Full textMõtus, Mari-Ann. "Silurian (llandovery-wenlock) tabulate corals of Baltoscandia : taxonomy, palaeoecology, distribution /." Tartu: Tartu University Press, 2005. http://dspace.utlib.ee/dspace/bitstream/10062/1292/5/m6tus.pdf.
Full textWittenberg, Mark. "Effects of eutrophication on juvenile scleractinian corals." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60552.
Full textFuchs, Eran 1963. "Fluorescence in reef corals." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/8966.
Full textIncludes bibliographical references (p. 248-251).
Fluorescence can be a powerful tool for probing biological systems. Prior measurements from Caribbean corals identified five fluorescing pigments in reef corals. In this thesis I study coral fluorescence spectra. I wanted to learn if fluorescence could be useful for large scale mapping and monitoring of the reef as a part of an effort to stop the recently reported global decline in coral reefs condition. 3D excitation I emission spectra, average wavelength locations and shape variability studies of each of the pigments is presented. I also present an in situ corrununity study of the species Montastraea cavernosa and investigate the variability of fluorescence emission among colonies of one species at one location. Coral's fluorescence emission spectrum can result from the excitation of one or more fluorescing pigments. A mathematical algorithm was developed to separate coral fluorescence spectra into individual components. The un-mixing algorithm was combined with a prediction model whose purpose was to predict the response that will be produced by any excitation light source given knowledge of the response produced by a different light source. Energy coupling between two of the pigments was discovered. An empirical coupling efficiency factor was defined and calculated to account for this energy transfer. The energy coupling between these pigments may have important consequences in future investigation of coral's evolution. A new experimental method to separate the reflectance and fluorescence spectral components of fluorescing corals was developed for in vivo and in situ data. Two experimental methods are proposed to measure and calculate a newly defined quantity, "practical fluorescence efficiency". This efficiency factor is essential for correct prediction of coral spectra under different illumination conditions. This part of my work will benefit optical models that calculate light interaction with the bottom of the ocean in shallow waters. Lastly I present a prototype Fluorescence Imaging Laser Line Scanner system and discuss its potential use as a remote sensing system for reef mapping and monitoring. Recommendations are made to better tune the system to the fluorescence characteristics of reef corals.
by Eran Fuchs.
Ph.D.
Ceh, Janja. "Coral-associated microbial communities in reef-building corals of Ningaloo Reef Western Australia." Thesis, Ceh, Janja (2011) Coral-associated microbial communities in reef-building corals of Ningaloo Reef Western Australia. PhD thesis, Murdoch University, 2011. https://researchrepository.murdoch.edu.au/id/eprint/8480/.
Full textHicks, Melissa Kathryn. "Chemical cues affecting susceptibility of gorgonian corals to fungal infection." Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-11272005-165350/.
Full textClark, Tracy Helen. "The ecology of indigenous and transplanted corals in the Cape d'Aguilar Marine Reserve, Hong Kong." Thesis, Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19036759.
Full textRandall, Carly J. "Elevated temperature effects on larval development, survivorship, and settlement of the elkhorn coral, Acropora palmata." View electronic thesis (PDF), 2009. http://dl.uncw.edu/etd/2009-1/r1/randallc/carlyrandall.pdf.
Full textKluter, Anke. "Pigmentation as a strategy for reducing solar damage in reef-building corals /." [St. Lucia, Qld.], 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17333.pdf.
Full textJohnson, Meaghan. "Staghorn Coral, Acropora cervicornis, Restoration in South Florida: Growth and Survivorship of Outplanted Nursery Corals." NSUWorks, 2015. http://nsuworks.nova.edu/occ_stuetd/384.
Full textWilliams, Branwen. "Biogeochemistry of Soft Corals and Black Corals, and Implications for Paleoceanography in the Western Tropical Pacific." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244743730.
Full textCollinson, Peter Ronald James. "The ecology of a peripheral, subtropical coral community in Hong Kong." Thesis, Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19667425.
Full textFitzhardinge, Rachel C. "The Ecology of Juvenile Hawaiian Corals." Thesis, University of Hawai'i, Honolulu, 1993. http://hdl.handle.net/10125/15320.
Full textThesis (Ph. D.)--University of Hawaii at Manoa, 1993. Includes bibliographical references (leaves 240-252)
Daniels, Camille Arian. "Microbial Landscapes of Corals and Ctenophores." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3061.
Full textGALLI, GIOVANNI. "Modelling Mediterranean corals and coralligenous habitats." Doctoral thesis, Università degli Studi di Trieste, 2016. http://hdl.handle.net/11368/2908051.
Full textGómez, Cabrera María del Carmen. "Some aspects of the physiology and ecology of the Acropora longicyathus multi-cladal symbiosis /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18706.pdf.
Full textOssolinski, Justin Emerson. "Carbon budget analysis of the branching coral Madracis mirabilis." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 96 p, 2007. http://proquest.umi.com/pqdweb?did=1338884351&sid=14&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full textWilliams, Lindsey C. "The U.S. Atlantic commercial fishing industry and cold water coral conservation history, current trends and next steps /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 115 p, 2009. http://proquest.umi.com/pqdweb?did=1824796041&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full textGeorge, Adrienne. "Cataloguing Diseases and Pests in Captive Corals." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3115.
Full textGuppy, Reia. "Surface microbial communities of reef-building corals." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430697.
Full textAdkins, Jess F. (Jess Firey). "Deep-sea corals : a new oceanic archive." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/44503.
Full textGilmour, James Paton. "Combining methods of analysis to understand the demography of corals : an example for populations of the mushroom coral Fungia fungites exposed to contrasting regimes of disturbance." University of Western Australia. School of Animal Biology, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0092.
Full textWood, Sally. "Modelling present and future dispersal of coral larvae : implications for the response of corals to climate change." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682361.
Full textConi, Ericka Oliveira Cavalcanti. "Abundância e vitalidade do coral solitário Scolymia SSP. no Brasil: comparação entre um sistema costeiro e um oceânico." Universidade Estadual da Paraíba, 2012. http://tede.bc.uepb.edu.br/tede/jspui/handle/tede/1707.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
Coral reefs are one of the most valuable ecosystems on Earth. However, they have suffered declines over the past four decades. The main factors responsible for the mass mortality of corals are bleaching and disease. In Brazil diseases in corals proliferated up since 2005, threatening to wipe out some of the major endemic species and reef builders. On a global scale, the proliferation of diseases and bleaching is related to the increase in the temperature of the sea surface, while the main factors at the local scale are adding nutrients and proliferation of macroalgae in coastal waters. Despite the recognition of the influence of these factors on the vitality of corals, there is little information about the relative contribution of these different threats. The effects of global impacts can be better understood from comparative studies of coastal areas and control areas isolated and distant from the coast (eg oceanic islands), since the latter suffer less or are free of local impacts. This work has as main objectives: 1) To study the spatial and temporal dynamics in abundance and vitality of coral lone Scolymia wellsi the largest South Atlantic reef complex (Abrolhos Bank, BA), as well as to evaluate the influence of environmental variables and disorders anthropic this region and 2) compare the abundance and vitality of Scolymia spp. between a coastal system (Abrolhos Bank) and an oceanic system (Archipelago of São Pedro and São Paulo archipelago). Due to its geographic isolation, the archipelago is less susceptible to human impacts. Therefore, the results obtained here allow an assessment of the relative influence of local and global impacts on the abundance and vitality (ie proportion of tissue alive and healthy versus diseased tissue and dead) of Scolymia spp. in Brazil.
Os recifes de corais são um dos ecossistemas mais valiosos da Terra. No entanto, eles vêm sofrendo declínios acentuados nas últimas quatro décadas. Os principais fatores responsáveis pela mortalidade em massa de corais são o branqueamento e as doenças. No Brasil as doenças em corais proliferaram-se a partir de 2005, ameaçando de extinção algumas das principais espécies endêmicas e construtoras de recifes. Em escala global, a proliferação de doenças e branqueamento está relacionada com o aumento na temperatura da água superficial do mar, enquanto que os principais fatores em escala local são a adição de nutrientes e proliferação de macroalgas em águas costeiras. Apesar do reconhecimento da influência destes fatores na vitalidade dos corais, existem poucas informações sobre a contribuição relativa destas diferentes ameaças. Os efeitos de impactos globais podem ser mais bem compreendidos a partir de estudos comparativos entre áreas costeiras e áreas-controle isoladas e afastadas da costa (e.g. ilhas oceânicas), uma vez que estas últimas sofrem menos ou são isentas de impactos locais. Esta dissertação tem como objetivos principais: 1) Estudar a dinâmica espacial e temporal na abundância e vitalidade do coral solitário Scolymia wellsi no maior complexo recifal do Atlântico Sul (Banco dos Abrolhos, BA), assim como avaliar a influência de variáveis ambientais e de distúrbios antrópicos nesta região e 2) Comparar a abundância e vitalidade de Scolymia spp. entre um sistema costeiro (Banco dos Abrolhos) e um sistema oceânico (Arquipélago de São Pedro e São Paulo, ASPSP). Devido a seu isolamento geográfico, o ASPSP é menos susceptível a impactos antrópicos. Portanto, os resultados obtidos aqui permitem uma avaliação da influência relativa dos impactos locais e globais na abundância e vitalidade (i.e. proporção de tecido vivo e saudável versus tecido doente e morto) de Scolymia spp. no Brasil.
Tomascik, Tomas. "The effects of eutrophication on the growth rates, reproductive potential and community structure of the inshore reef-building corals in Barbados, West Indies /." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74000.
Full textWithers, Karen J. T. "Empire building colonials : the implications of size in the hard coral Plesiastrea versipora." Phd thesis, School of Biological Sciences, 2000. http://hdl.handle.net/2123/9033.
Full textGibbs, David A. "Distance-dependent survival and distribution of juvenile corals: Janzen-Connell effects do not operate on two brooding Indo-Pacific corals." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52231.
Full textArnold, Suzanne N. "Spatial and Temporal Scales of Coral Recruitment and Key Ecological Processes." Fogler Library, University of Maine, 2011. http://www.library.umaine.edu/theses/pdf/ArnoldSN2011.pdf.
Full textBrito, Tania Aparecida Silva. "Taxonomic and ecological studies on Antarctic octocorals of the genus Thouarella (octocorallia: primnoidae)." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239681.
Full textUnderwood, Jim. "Routine and rare genetic connections in corals off northwest Australia and the implications for conservation." University of Western Australia. School of Animal Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0158.
Full textJoyce, Karen E. "A method for mapping live coral cover using remote sensing /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18618.pdf.
Full textPAPAZACHARIOU, VASILIKI. "Coral Fungia fungites- associated microbial communities and their shifts upon anthropogenic disturbances." Thesis, Uppsala universitet, Limnologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-377137.
Full textZayasu, Yuna. "The cospeciation between massive corals and gall crabs." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188516.
Full textMerks, Roeland Mattheus Hermanus. "Branching growth in stony corals a modelling approach /." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2003. http://dare.uva.nl/document/31821.
Full textJatkar, Amita. "Mucus layer properties and dynamics in reef corals." Thesis, University of Newcastle Upon Tyne, 2009. http://hdl.handle.net/10443/125.
Full textStafford-Smith, Mary Gillian. "The effect of sediments on Australian scleractinian corals." Thesis, University of York, 1990. http://etheses.whiterose.ac.uk/4244/.
Full textGaudian, Gudrun. "Taxonomic and ecological studies on Red Sea corals." Thesis, University of York, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329667.
Full textWaller, Rhian G. "The reproductive ecology of deep-water scleractinian corals." Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402225.
Full textWild, Fiona Jane. "The photophysics of luminescent banding in reef corals." Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/13232.
Full textRiegl, Bernhard. "Taxonomy and ecology of South African reef corals." Doctoral thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/9666.
Full textThis thesis provides a complete taxonomic review of South African hermatypic Scleractinian reef corals, a description of coral communities on northern Natal coral reefs, experiments isolating the influence of the most important abiotic factors forcing these communities and finally management suggestions for the marine reserves within which these reefs are situated, based on the results of the ecological investigation. The taxonomic part reviews the entire hermatypic scleractinian coral fauna of South Africa and Southern Mozambique, including also material from the Atoll Bassas da India in the Mozambique channel. The study of coral communities on Northern Natal coral reefs revealed major differences in the nature of the reefs and the community structure of the reef corals from typical coral reefs in the Inda-Pacific. The study lead to the assumption that wave-action and sedimentation are the most important abiotic factors influencing these coral communities. These hypotheses were experimentally tested in the field and in the laboratory, using indicator species for specific community types, as identified in the community study. Testing fragment survival of the hard coral Acropora austera confirmed the assumption that wave action is an important factor shaping coral communities by only allowing this species to dominate in depths greater than 18m. Four hard- and five soft coral species were used to quantify the effects of sedimentation on the coral communities. It was demonstrated that long-term sedimentation had greater influence on soft corals than on hard corals, leading to tissue necroses and local bleaching. These experiments confirmed the assumption that sedimentation is a major forcing factor on South African coral communities. The final part of thesis provides management options for the St. Lucia and Maputaland Marine Reserves focussing on conservation of the coral communities. The findings obtained in the ecological investigation allowed to identify which activities in the reserves have to be controlled in order to minimize damage to the coral communities by park visitors.
Idjadi, Joshua Aziz. "Aggregation promotes species coexistence among reef-building corals." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 96 p, 2008. http://proquest.umi.com/pqdweb?did=1609283431&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full textGeorgian, Sam Ellis. "ENVIRONMENTAL AND ENERGETIC CONSTRAINTS ON COLD-WATER CORALS." Diss., Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/382890.
Full textPh.D.
Cold-water corals act as critical foundation species in the deep sea by creating extensive three-dimensional habitat structures that support biodiversity hotspots. There is currently a paucity of data concerning the environmental requirements and physiology of cold-water corals, severely limiting our ability to predict how resilient they will be to future environmental change. Cold-water corals are expected to be particularly vulnerable to the effects of ocean acidification, the reduction in seawater pH and associated changes to the carbonate system caused by anthropogenic CO2 emissions. Here, the ecological niche and physiology of the cold-water coral Lophelia pertusa is explored to predict its sensitivity to ocean acidification. Species distribution models were generated in order to quantify L. pertusa’s niche in the Gulf of Mexico with regard to parameters including seafloor topography, the carbonate system, and the availability of hard substrate. A robust oceanographic assessment of the Gulf of Mexico was conducted in order to characterize the current environmental conditions at benthic sites, with a focus on establishing the baseline carbonate system in L. pertusa habitats. Finally, an experimental approach was used to test the physiological response of biogeographically separated L. pertusa populations from the Gulf of Mexico and the Norwegian coast to ocean acidification. Based on my findings, it appears that L. pertusa already persists near the edge of its viable niche space in some locations, and therefore may be highly vulnerable to environmental change. However, experimental results suggest that some populations may be surprisingly resilient to ocean acidification, yielding broad implications for the continued persistence of cold-water corals in future oceans.
Temple University--Theses
PIEROZZI, JUNIOR Ivan. "Influ?ncia de esponjas no processo de aglutina??o de rodolitos e forma??o de recifes consolidados." Universidade Federal Rural do Rio de Janeiro, 2015. https://tede.ufrrj.br/jspui/handle/jspui/1308.
Full textMade available in DSpace on 2016-10-18T18:36:37Z (GMT). No. of bitstreams: 1 2015 - Ivan Pierozzi Junior.pdf: 92591526 bytes, checksum: b6f151111ef71de5cd89f7d46f910fff (MD5) Previous issue date: 2015-11-27
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Rhodolith bed has aroused growing interest of the scientific community, not being different to the Fernando de Noronha Archipelago (FNA). FNA rhodolith banks occur at depths of 10 to 100m and are peculiar habitat that increases structural complexity, providing increased associated diversity compared to unconsolidated substrates. The interaction between rhodoliths and sponges is the focus of this study. On the banks of AFN sponges play an important role in the stabilization mechanism of rhodoliths, accounting for coalescing neighbour nodules, which may point to an early stage of an on going process of stabilization in the form of a consolidated reef. The presence of reef-building corals in the adjacent rocky shore can also be related to the rhodolith banks as polyp?s skeletons were found nucleating rhodoliths. This study identified which organisms were agglutinating rhodolith nodules at Cabe?o da Sapata (45m deep) and if is there any relationship between physical characteristics of the bank and the occurrence of agglutinated complex. It was also described the physical structure and the frequency of occurrence of agglutinated rhodolith. Sponges was the main group of sessile fauna found coalescing rhodoliths and this process points to a relationship between size of the nodules and the variation in size between the nodes. The importance of sponges to the rhodoliths beds and potentially to the process of consolidated reefs formation is reinforced by this study.
Os bancos de rodolitos tem despertado interesse cada vez maior da comunidade cient?fica, n?o sendo diferente para o Arquip?lago de Fernando de Noronha (AFN). No AFN os bancos de rodolitos ocorrem em profundidades de 10 a 100m e s?o habitat peculiares que aumentam a complexidade estrutural, propiciando um aumento da diversidade associada quando comparados com substratos n?o consolidados. A intera??o entre os rodolitos e por?feros ? o foco desse estudo. Nos bancos do AFN as esponjas desempenham um importante papel no mecanismo de estabiliza??o dos rodolitos, sendo respons?veis por aglutinar n?dulos pr?ximos, o que pode apontar para um estagio inicial de um processo permanente de estabiliza??o, na forma de um recife consolidado. A presen?a de recifes coral?neos no cost?o rochoso adjacente tamb?m podem ter rela??o com os bancos de rodolitos j? que esqueletos de p?lipos foram encontrados nucleando rodolitos. Neste estudo foram identificados quais organismos foram respons?veis pela aglutina??o de n?dulos do banco de rodolitos do Cabe?o da Sapata (45m de profundidade) e se existe rela??o entre caracter?sticas f?sicas do banco e a ocorr?ncia de aglutinados. Tamb?m foi descrita a estrutura f?sica e a frequ?ncia de ocorr?ncia de aglutinados de rodolitos. Por?fero foi o principal grupo da fauna s?ssil encontrado aglutinando rodolitos e esse processo aponta para uma rela??o entre tamanho dos n?dulos e a varia??o de tamanho entre os n?dulos. A import?ncia das esponjas nos bancos de rodolitos, e potencialmente no processo de forma??o de recifes consolidados, ? refor?ada pelo presente estudo,
Leal, Miguel Albuquerque da Costa. "Trophic plasticity in the cnidarian-dinoflagellate symbiosis." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13738.
Full textCoral reefs are of utmost ecological and economical importance but are currently in global decline due to climate change and anthropogenic disturbances. Corals, as well as other cnidarian species, live in symbiosis with photosynthetic dinoflagellates of the genus Symbiodinium. This relationship provides the cnidarian host with alternative metabolic pathways, as the symbionts translocate photosynthetic carbon to the animal. Besides this autotrophic nutrition mode, symbiotic cnidarians also take up organic matter from the environment (heterotrophy). The nutritional balance between auto- and heterotrophy is critical for the functioning, fitness and resilience of the cnidariandinoflagellate symbiosis. New methodological approaches were developed to better understand the role of auto- and heterotrophy in the ecophysiology of cnidarians associated with Symbiodinium, and the ecological implications of this trophic plasticity. Specifically, the new approaches were developed to assess photophysiology, biomass production of the model organism Aiptasia sp. and molecular tools to investigate heterotrophy in the cnidarian-dinoflagellate symbiosis. Using these approaches, we were able to non-invasively assess the photophysiological spatial heterogeneity of symbiotic cnidarians and identify spatial patterns between chlorophyll fluorescence and relative content of chlorophyll a and green-fluorescent proteins. Optimal culture conditions to maximize the biomass production of Aiptasia pallida were identified, as well as their implications on the fatty acid composition of the anemones. Molecular trophic markers were used to determine prey digestion times in symbiotic cnidarians, which vary between 1-3 days depending on prey species, predator species and the feeding history of the predator. This method was also used to demonstrate that microalgae is a potential food source for symbiotic corals. By using a stable isotope approach to assess the trophic ecology of the facultative symbiotic Oculina arbuscula in situ, it was possible to demonstrate the importance of pico- and nanoplanktonic organisms, particularly autotrophic, in the nutrition of symbiotic corals. Finally, we showed the effects of functional diversity of Symbiodinium on the nutritional plasticity of the cnidarian-dinoflagellate symbiosis. Symbiont identity defines this plasticity through its individual metabolic requirements, capacity to fix carbon, quantity of translocated carbon and the host’s capacity to feed and digest prey.
Os recifes de coral são ecossistemas de elevada importância ecológica e económica. Contudo, encontram-se em declínio global devido ao efeito das alterações climáticas e outras perturbações de origem antropogénica. Os corais, tal como outros cnidários, vivem em simbiose com dinoflagelados fotossintéticos do género Symbiodinium. Esta associação permite ao hospedeiro dispor de vias metabólicas alternativas, uma vez que os simbiontes fixam carbono fotossinteticamente e translocam-no para o hospedeiro. Para além deste modo de nutrição autotrófico, estes cnidários também se alimentam de matéria orgânica disponível no meio ambiente (heterotrofia). O balanço nutricional entre auto- e heterotrofia é fundamental para o funcionamento, capacidade adaptativa e resiliência da simbiose entre cnidários e dinoflagelados. No presente trabalho foram utilizadas novas abordagens metodológicas para investigar a importância da auto- e heterotrofia na ecofisiologia de cnidários em simbiose com Symbiodinium e as implicações ecológicas desta plasticidade trófica. Os métodos aqui desenvolvidos estão relacionados com a fotofisiologia, produção de biomassa do organismo modelo Aiptasia pallida e métodos moleculares para investigar heterotrofia na simbiose entre cnidários e dinoflagelados. Foram utilizados métodos não invasivos para avaliar padrões espaciais fotofisiológicos em cnidários associados com Symbiodinium e explorar a relação entre a fluorescência da clorofila e a abundância relativa de clorofila a e proteínas verdes fluorescentes. As condições de cultivo que maximizam a produção de Aiptasia sp. foram identificadas, bem como as respetivas implicações na sua composição em ácidos gordos. A utilização de marcadores tróficos moleculares permitiu identificar que o tempo de digestão em cnidários associados com Symbiodinium varia entre 1 e 3 dias e que depende da espécie de predador e de presa, bem como do historial trófico do predador. O mesmo método molecular permitiu concluir que as microalgas são uma presa potencialmente importante para a nutrição de corais simbióticos. Adicionalmente, os resultados obtidos através da utilização de isótopos estáveis in situ, para avaliar a ecologia trófica do coral simbiótico facultativo Oculina arbuscula, confirmaram a importância que os organismos pico- e nanoplanctónicos, principalmente autotróficos, podem representar para a nutrição de corais simbióticos. Por fim, o efeito da diversidade funcional de Symbiodinium na plasticidade trófica da simbiose entre cnidários e dinoflagelados foi investigado. Concluiu-se que a identidade do simbionte define esta plasticidade através dos seus requisitos metabólicos individuais, capacidade para fixar carbono, quantidade de carbono translocado e a capacidade de ingestão e digestão de presas do cnidário hospedeiro.
Williams, Amanda C. "Mapping land use change as an indicator for live coral cover at Boracay Island Philippines." View electronic thesis (PDF), 2009. http://dl.uncw.edu/etd/2009-1/r3/williamsa/amandawilliams.pdf.
Full textMontseny, Cuscó Maria. "Ecological restoration of cold-water corals on the Mediterranean continental shelf." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/672257.
Full textEls coralls d’aigua freda habiten en les plataformes continentals, talussos, canyons, muntanyes submarines i dorsals oceàniques d’arreu del món, des de 50 a 4000 metres de profunditat. Les espècies de coralls d’aigua freda creen hàbitats heterogenis que donen suport a una infinitat de fauna associada i formen esculls i boscos de coralls altament diversos. Les principals amenaces que actualment impacten aquests ecosistemes de coralls d’aigua freda son d’origen antròpic, com ara l’activitat pesquera, l’explotació de petroli i gas i l’incipient explotació minera. Així mateix, el canvi climàtic, el qual provoca canvis en la columna d’aigua, també està afectant aquests ecosistemes. Les característiques vitals dels coralls d’aigua freda (longevitat, creixement lent i reclutament limitat) els fan molt vulnerables a les amaces tan actuals com futures. Atesa la seva limitada capacitat de recuperació, l’interès per preservar i restaurar els ecosistemes de coralls d’aigua freda està en constant creixement. La creació d’àrees marines protegides i les accions restauració ecològica activa són avui en dia les millors eines de gestió per conservar ecosistemes autòctons i representen una oportunitat per revertir els danys antròpics que ja han tingut lloc. A través d’enfocaments passius (regeneració natural després del cessament del impacte) i actius (l’ésser humà interacciona amb les característiques biòtiques i/o abiòtiques de l’ecosistema), les activitats de restauració busquen accelerar la recuperació de l’estructura i funcionament dels ecosistemes en funció a un model de referència. Contràriament als ecosistemes terrestres i d’aigües someres, la restauració ecològica enfocada a ambients marins intermedis (50–200 m) i profunds (> 200 m) ha rebut menor atenció. Fins ara, a aquestes profunditats només s’han dut a terme algunes poques accions de restauració a escala local, principalment a causa de limitacions tècniques i econòmiques que qüestionen la seva àmplia aplicació. Els principals reptes actuals per la restauració de coralls d’aigua freda són incrementar l’escala espacial de les accions de restauració i fer-les econòmicament més assequibles. En aquest sentit, per avançar en la conservació dels ecosistemes de fons intermedis i profunds, l’objectiu general de la present tesi és avaluar l’impacte de l’activitat pesquera sobre els boscos de coralls d’aigua freda i explorar la viabilitat de innovadores tècniques de restauració activa. Tot el treball realitzat en aquesta tesi s’ha dut a terme a la zona marina del Cap de Creus (Nord-Oest del mar Mediterrani), contretament a la plataforma continental (60 – 130 m) on espècies de gorgònies, esponges i plomalls formen boscos de coralls d’aigua freda donant suport a una gran varietat de fauna mòbil associada. L’espècie objectiu és la gorgònia groga Eunicella cavolini (Koch, 1887) la qual domina a la zona formant denses agregacions. En el primer capítol, es va quantificar el impacte de la pesca artesanal per avaluar l’amenaça d’aquesta activitat sobre els boscos de coralls d’aigua freda i proporcionar informació essencial per mitigar aquest impacte. La resta de capítols (2, 3 i 4) van avaluar, per primera vegada, viabilitat de restaurar activament les poblacions degradades de E.cavolini. Especificament, en el segon capítol és van trasplantar les gorgònies capturades accidentalment pels pescadors artesanals de la zona, a estructures artificials fondejades a la plataforma continental (85 m). Aquest estudi pilot va demostrar per primera vegada l’alta supervivència dels transplantaments d’E.cavolini. Seguidament, i anant un pas més enllà, al tercer capítol es van combinar experiments de camp i modelització per desenvolupar i validar tècnicament una nova tècnica de restauració per als boscos de coralls d’aigua freda, a gran escala i econòmicament assequible. Els exitosos resultats van evidenciar la viabilitat de recuperar les colònies de E.cavolini capturades accidentalment i retornar-les al seu hàbitat natural amb aquesta innovadora tècnica , anomenada “el mètode bàdminton”. Finalment, al quart i últim capítol, es va dur a terme una acció de restauració de les poblacions de E.cavolini a gran escala, amb la col·laboració de pescadors artesanals de la zona i al llarg de dues temporades de pesca consecutives aplicant la tècnica desenvolupada anteriorment. Un gran nombre de gorgònies (460 colònies) van ser re-introduïdes amb èxit i van sobreviure al final de l’acció (2 anys) a 80-100 m de profunditat. Els resultats van suggerir l'establiment inicial d'una nova població gorgònies, que potencialment evolucionarà cap a una població natural comparable en termes d’estructura de talles i estructura espacial, sempre i quan es produeix també un reclutament natural. D'altra banda, es va fer una avaluació econòmica, que va confirmar la rendibilitat d'aquest mètode dirigit a millorar la recuperació dels boscos de coralls d’aigua freda impactats. El desconeixement d'alguns processos ecològics claus en els ecosistemes de coralls d’aigua freda, així com les limitacions tècniques, dificulten una avaluació completa dels esforços de restauració realitzats. Tanmateix, aquesta tesi suposa una millora prometedora per a la conservació i recuperació dels coralls d’aigua feda, que es podria estendre a altres zones i regions.
Gass, Susan Elizabeth. "The environmental sensitivity of cold-water corals, Lophelia pertusa." Thesis, Open University, 2006. https://pure.uhi.ac.uk/portal/en/studentthesis/the-environmental-sensitivity-of-coldwater-corals-lophelia-pertusa(dc5259d3-80eb-4f6d-9c89-5f4c8152ca5d).html.
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