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NASTO, INA. « CARATTERIZZAZIONE DELLE COMUNITA A CORALLO DI ACQUA FREDDA NEL ADRIATICO MERIDIONALE ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2017. http://hdl.handle.net/10281/180848.
Texte intégralRésumé :
INTRODUZIONE GENERALE
Le comunità di coralli di acqua fredda sono estremamente importanti per l'ecosistema bentonico. Essendo stato dichiarato un importante ecosistema sia per il valore ecologico che per quello economico, la proposta di questa tesi è quella di descrivere le comunità di coralli d'acqua fredda nell'Adriatico sud. Le attività di ricerca si sono concentrate su quattro diversi argomenti elencati di seguito.
La fauna bentonica di Sessile associata al corallo sub-fossile dell'acqua fredda dall'Albania
Questo studio presenta una descrizione preliminare della fauna associata al quadro corallo subfossile in due siti recentemente trovati in Albania. La Macrofauna è stata registrata durante due indagini di pesca sperimentali condotte nel marzo 2015 e nel maggio 2016 in due zone profonde della costa albanese, tra la profondità di 190 e 230 m. Sono stati analizzati campioni di coralli subfossili di Lophelia pertusa e Dendrophyllia cornigera per identificare la fauna associata. Sono state identificate 82 specie, 2 Foraminifera, 22 Porifera, 6 Cnidaria, 25 Mollusca, 14 Annelida, 1 Arthropoda, 11 Bryozoa, 1 Echinodermata, di cui 75 specie che sono nuovi record per la fauna albanese. Tutte le specie identificate sono state precedentemente riportate nelle aree coralline di Santa Maria di Leuca e Bari Canyon. Questo studio ha aggiornato la conoscenza della biodiversità del profondo mare Adriatico sudorientale, nonché della fauna marina albanese in particolare. Nuove informazioni ottenute per le specie di acque profonde confermano l'importante contributo del quadro di corallo dell'acqua fredda nella biodiversità del segnale acustico.
Variazioni morfologiche spatiotemporali del Mediterraneo Lophelia pertusa.
Per valutare se la variazione morfologica di L. pertusa segue un modello specifico basato su variabili ambientali (o altre), questo studio combina due differenti approcci morfometrici: la morfologia lineare lineare classica e l'utilizzo di punti di riferimento delle coordinate tridimensionali (landmarks). Gli obiettivi principali di questo studio sono quello di verificare l'esistenza di gruppi morfologici distinti all'interno della specie cosmopolita L. pertusa nel Mediterraneo e di individuare eventuali relazioni tra gruppi morfologici (sia nei coralli moderni che nei coralli fossili) e (paleo) delle condizioni oceanografiche.
Applicazioni della tomografia computazionale a raggi X nello studio della morfologia della L. Pertusa.
Lo scopo di questo lavoro è stato quello di confrontare 4 colonie di Lophelia pertusa corallo sub-fossile, provenienti dal Mediterraneo e dall'Atlantico orientale. I sottogruppi sono riferimenti importanti che testimoniano le condizioni ambientali del paleo-ambientale, pertanto il loro studio morfologico è un tema importante per l'ecologia. Lo scopo di questo è stato quello di indagare se esistono differenze veramente morfologiche tra queste quattro colonie Lophelia, sia nella morfologia dei coralli e nella loro organizzazione spaziale. La tomografia computerizzata dei campioni ci ha permesso di misurare alcune variabili scelte secondo le caratteristiche della specie.
Datazione la morte dei coralli sclerattiniani profondi del mare sud-orientale
Questa parte del mio studio riguarda la precisa datazione U / T di coralli morti provenienti provenienti da acque albanesi. Gli Smples furono ottenuti dall'Albania dalla crociera oceanografica CNR CoCoMap13 nel Mare Adriatico del sud-est e da una Lophelia pertusa colonia catturata durante le indagini di pesca sperimentali a nord della baia di Vlora. Lo scopo è di datare la presenza di CWC nelle acque profonde albanesi, valutando anche il tempo per l'insediamento e la scomparsa del CWC nel AdriATICOThe present study regarding the Albanian CWC and associated biota consists of specific research activities focused on the four main topics listed below. Sessile benthic fauna associated with sub-fossil Cold Water Coral from off Albania This section presents a preliminary description of the fauna associated with sub-fossil coral framework in two sites recently found in off Albania. Macrofauna was recorded during two experimental fishing surveys conducted in March 2015 and May 2016 in two deep areas of the Albanian coast, between the depth of 190 to 230 m. Sub-fossil coral samples of L. pertusa and D. cornigera were analyzed to identify the associated fauna. A total of 82 species were identified, 2 Foraminifera, 22 Porifera, 6 Cnidaria, 25 Mollusca, 14 Annelida, 1 Arthropoda, 11 Bryozoa, 1 Echinodermata, including 75 species that are new records for the Albanian fauna. Morphological variations of Mediterranean Lophelia pertusa The main aims of this study are to test the existence of distinct morphological groups within the quasi-cosmopolitan species L. pertusa in the Mediterranean and to identify, if any, relationships between morphological groups (both in modern and fossil corals) and (paleo) oceanographic conditions. Applications of X-ray Computed Tomography in the morphometric study of the Adriatic Lophelia pertusa The aim of this analysis was to investigate whether there are really morphological differences between these four Lophelia colonies, both in the morphology of the corallites and in their spatial organization. Computed tomography made possible to measure some variables chosen according to the species's characteristics. Dating the Albanian Adriatic cold water corals This part of my study deals on the the precise U/Th dating of dead corals specimens sourced coming from Albanian waters. Smples were obtained off Albania by the oceanographic CNR CoCoMap13 cruise in the southeastern Adriatic Sea and one Lophelia pertusa colony caught during experimental fishing surveys in north of the Vlora Bay. The purpose is to time in the presence of CWC in Albanian deep waters, assessing also the tempo for CWC settlement and demise in the southern Adriatic Sea.
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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.
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Miranda, Miguel Loiola. « Tolerância de mussismilia braziliensis (anthozoa : scleractinia) à sedimentação ». Universidade Federal da Bahia, Instituto de Biologia, 2012. http://repositorio.ufba.br/ri/handle/ri/19567.
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Atualmente, o aumento da sedimentação e do aporte de matéria orgânica são apontados como principais agentes causadores da devastação dos recifes de corais. Portanto este trabalho teve como objetivo investigar, em laboratório, os efeitos do aumento da sedimentação, associada ou não com matéria orgânica, sobre a fotossíntese, avaliada a partir da eficiência fotobiológica das zooxantelas associadas, e o estado físico do tecido, avaliado a partir de um índice quantitativo de susceptibilidade, de Mussismilia braziliensis, uma espécie de coral endêmico da Bahia e principal construtor do maior complexo recifal do Atlântico Sul. A susceptibilidade das colônias expostas ao sedimento sem matéria orgânica foi comparada com a susceptibilidade das colônias expostas ao sedimento com matéria orgânica. Os resultados encontrados possibilitaram a comparação com ecossistemas recifais mais estudados e também serão úteis para o manejo dos recifes contra impactos humanos. Os experimentos foram conduzidos em aquários do laboratório de Recifes de Corais e Mudanças Globais (RECOR). Para isso foram coletadas 19 colônias de M. braziliensis em um recife do arco costeiro de Abrolhos e sedimento lamoso no canal do rio Caravelas. No laboratório o sedimento foi preparado (lavado e secado) e separado em dois tratamentos, sendo um formado por sedimento com matéria orgânica e outro com sedimento sem matéria orgânica. O sistema experimental consistiu de 19 cubas de vidro de 4 litros, contendo água salina sintética a 36 psu, acondicionadas em aquários de 60 litros, com água doce circulante a 26°C, iluminados durante 12 horas diárias. Em cada cuba foi colocada uma colônia de M. braziliensis. Em sete cubas foram adicionadas concentrações de sedimento livre de matéria orgânica, equivalentes a 0, 15, 50, 150, 250, 350 e 450 mg.cm-2.dia-1. Nas 12 cubas restantes foram adicionadas concentrações de sedimento combinado com matéria orgânica equivalentes a 0, 15, 50, 100, 150, 200, 250, 300, 350, 400, 450 e 500 mg.cm-2.dia-1. Diariamente a água das cubas foi agitada por dois minutos para simular eventos de ressuspensão e deposição de sedimento. Para as colônias expostas ao sedimento sem matéria orgânica foi realizada uma análise de regressão linear simples entre a taxa de sedimentação e a susceptibilidade física das colônias, avaliada após 45 dias de exposição, a partir de um índice quantitativo de susceptibilidade à sedimentação. Para as colônias expostas ao sedimento associado com matéria orgânica, foram realizadas duas análises de regressão linear simples relacionando a taxa de sedimentação com a eficiência fotoquímica, estimada a partir do fluorômetro Diving-PAM, após 72 horas de exposição, e com o índice de susceptibilidade, após 120 horas de exposição. Após 120 horas de exposição foi comparada, através de um teste de Mann-Whitney, a susceptibilidade das colônias expostas ao sedimento sem matéria orgânica com a susceptibilidade de colônias expostas ao sedimento associado com matéria orgânica. Os testes de regressão mostraram uma relação positiva significativa entre a taxa de sedimentação e o índice de susceptibilidade das colônias de M. braziliensis expostas ao sedimento com e sem matéria orgânica associada. Para os dois conjuntos de colônias, entretanto, danos físicos severos foram encontrados apenas em colônias expostas a taxas superiores a 200 mg.cm-2.dia-1, que visaram simular impactos extremos como tempestades e dragagens. Diferente do esperado, o aumento da sedimentação não provocou a redução da eficiência fotobiológica das colônias expostas ao sedimento combinado com matéria orgânica. Os resultados encontrados são indicativos de tolerância à sedimentação e também da capacidade de fotoaclimatação dos corais de águas brasileiras, submetidos naturalmente a ambientes turvos. As colônias expostas ao sedimento associado com matéria orgânica apresentaram uma maior susceptibilidade à sedimentação, um resultado preocupante tendo em vista o aumento atual da poluição marinha como consequência do desenvolvimento costeiro e do mau uso da terra.
The increase in sedimentation and organic matter are pointed out as the major agents responsible for impacting corals around the world. In Brazil, where reefs generally occur in markedly turbid environments and productive, the direct effects of sediment and organic matter elevation are poorly known. Thus, in a laboratory experiment, the effect of sedimentation associated with or free of organic matter over photosynthesis and tissue physical state of Mussismilia braziliensis were compared. Seven colonies of M. braziliensis were exposed to a sedimentation gradient (0 to 450 mg.cm-2 .day-1 ) free of organic matter. After 45 days of exposure, the physical health of corals was estimated, evaluated on the basis of a susceptibility index of sedimentation, developed in this work. Twelve colonies of M. braziliensis were exposed to a gradient of sedimentation (0 to 500 mg.cm-2.day- 1) with approximately 10% organic matter. After 72 hours dark adapted maximum photochemical efficiency was measured using a Diving-PAM (Walz, Germany) fluorometer, and after 120 hours, coral tissue state based on the susceptibility was evaluated. The comparison of the susceptibility index of colonies submitted to sediment with organic matter with the index of the colonies submitted to sediment free of organic matter resulted in a significant and positive relationship with sedimentation rate. However, no significant effect of sedimentation and organic matter was observed on photochemical efficiency of M. braziliensis zooxanthellae. This study showed that the Brazilian coral M. braziliensis is tolerant to sedimentation, and capable of producing energy via photosynthesis even in environments impacted by intense sedimentation and increasing organic matter. On the other hand, these results suggest that the increase of sedimentation interfere negatively in M. braziliensis tissue health and represents a greater menace to corals when sediment is associated with organic matter.
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Muramatsu, Daniela. « Quantificação da gametogênese através de análises histológicas para estimar a reprodução sexuada de Madracis decactis Lyman, 1859 (Cnidaria, Anthozoa, Scleractinia) do litoral sul do Estado do Rio de Janeiro ». Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-16102007-132551/.
Texte intégralRésumé :
Uma das espécies de coral pétreo zooxantelado com mais ampla distribuição no litoral brasileiro é Madracis decactis Lyman, 1859. M. decactis forma colônias incrustantes nodulares que podem atingir até 30 cm de diâmetro. O estudo da gametogênese foi realizado através de coletas bimensais na Baía de Ilha Grande, RJ durante 21 meses (agosto/2004-maio/2006), totalizando 10 coletas (12 colônias/coleta) (Licença IBAMA no. 201/2004). Foram realizados cortes histológicos de 7 µm, e de 10 até 16 pólipos por colônia foram analisados, totalizando mais de 1800 pólipos. A análise dos pólipos indicou que M. decactis é hermafrodita, com gametas localizados no mesmo lóculo gástrico, porém em mesentérios diferentes. A gametogênese durou cerca de sete meses. A ovogênese iniciou-se ao redor de outubro, enquanto que a espermatogênese teve inicio no final de fevereiro, ambas terminando em sincronia no final do mês de maio. O exame dos pólipos férteis indicou a presença dos estágios I, II e III de desenvolvimento para a ovogênese e dos estágios I, II, III e IV para a espermatogênese. Não foram encontrados embriões ou plânulas nos cortes histológicos, indicando talvez que estes estágios permaneçam pouco tempo no interior do pólipo. O pico da atividade reprodutiva ocorre entre os meses de fevereiro e abril com todas as colônias férteis contendo ovócitos principalmente no estágio III de maturação. A provável época de liberação de plânulas ocorre entre os meses de abril e maio, sob influencia das condições ambientais como a temperatura da água do mar, a irradiação solar e a pluviosidade. O presente trabalho forneceu informações básicas a respeito da biologia reprodutiva de Madracis decactis presente em Ilha Grande, sendo uma contribuição para outros estudos mais específicos na área de manejo e conservação de ambientes marinhos.One of the most wide distributed coral species along the Brazilian cost is Madracis decactis Lyman, 1859. M. decactis growths as nodular incrusting colonies that can reach up to 30 cm in diameter. In order to study the gametogenesis cycle, bimonthly collections were done at Ilha Grande Bay, Rio de Janeiro, during 21 months (August/2004- May/2006), totaling 10 collections (12 colonies/collection) (License no. 201/2004). Histological sections of 7 µm thick were done to analyze 10 to 16 polyps per colony (more than 1800 polyps in total). The analysis indicated that M. decactis is hermaphroditic, with male and female gametes developing at the same gastric loculi, but in different mesenteries. The gametogenesis lasted about 7 months, the oogenesis starts at October , while spermtogenesis starts at the end of February, both reaching the maturity in synchrony at the end of May. The exam of fertile polyps indicated the presence of stages I, II and III for oogenesis and I, II, III and IV for spermatogenesis. No embryo or planula were observed in the histological sections, indicating that maybe these stages stay for a short period inside the polyp cavity. The peak of reproductive activity was between February and April when all the polyps were fertile containing manly stage III oocytes. The releasing of planulae may happen between April and May, under the influence of environmental conditions as sea water temperature, solar insolation and rainy season. The present study has provided basic information about the reproductive biology of Madracis decactis from Ilha Grande Bay, and it may be a contribution to further studies about management and conservation of marine environments.
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Wagner, Lauren M. « Population genetic structure of the temperate Scleractinian coral, Oculina arbuscula, in coastal Georgia ». Click here to access thesis, 2006. http://www.georgiasouthern.edu/etd/archive/spring2006/lauren%5Fm%5Fwagner/wagner%5Flauren%5Fm%5F200601%5Fms.pdf.
Texte intégralRésumé :
Thesis (M.S.)--Georgia Southern University, 2006."A thesis submitted to the Graduate Faculty of Georgia Southern University in partial fulfillment of the requirements for the degree Master of Science" ETD. Includes bibliographical references (p. 52-57) and appendices.
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Maier, Cornelia. « Exploring stable isotopic variation in scleractinian coral tissue and skeleton proxies for climate, ecological plasticity and coral functioning / ». [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2004. http://dare.uva.nl/document/73795.
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Grace, Sean Patrick. « Ecomorphology of the temperate scleractinian astrangia poculata : coral-macroalgal interactions in Narragansett Bay / ». View online ; access limited to URI, 2004. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3145417.
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Cassara, Jason Anthony. « Patterns of variation within the Montastraea "annularis" species complex : results from 2-D and 3-D geometric morphometrics ». Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/786.
Texte intégralRésumé :
Geometric morphometrics are a useful tool for studying morphological variation in scleractinian corals, extant and extinct. In the case of modern specimens, three-dimensional features of the calical surface can be measured. These features are rarely preserved in fossil corals, however, necessitating measurement of 2-D landmarks in transverse thin-sections of corallites. Unfortunately, 2-D and 3-D methods often yield differing answers to questions about interspecific, intraspecific and intracolonial variation. This issue is addressed in the present study by directly comparing results of 2-D and 3-D geometric morphometric analyses of identical colonies of extant members of the Montastraea "annularis" species complex.
Ten colonies of each extant species in the complex (M. annularis s.s., M. faveolata and M. franksi), identified in the field during collection and verified by molecular data, were selected for analysis. Slabs of colony surfaces and transverse thin-sections from ~1 cm below the surface were cut from tops and edges of each colony. Six corallites from each slab were measured in 3-D using a Reflex microscope, and six measured in 2-D on digital images of each transverse thin-section. Both datasets were explored using geometric morphometric methods and analyzed statistically to address questions related to measurement error, intracolonial variation in corallite morphology between tops and edges of colonies, and interspecific morphological differences. The shape data were superimposed using Procrustes generalized least squares, and examined using principal components and canonical variates analyses. Shape differences implied by axes obtained from PCA and CVA were depicted as deformations using the thin-plate spline, to identify which morphological features are correlated with axes of greatest total variance (PCA) and greatest between-group variance (CVA). Goodall's F-test was used to detect significant morphological differences among species and colony positions. All of the data used in these analyses are available in the supplementary file that accompanies this thesis (see Appendix C for a description of the contents of this file).
Measurement error analyses show significant differences among variances associated with replicate measurements of 2-D and 3-D landmarks. In many cases the variance is asymmetrical, and for 2D data especially, this asymmetry coincides with orientation of anatomical features. Significant shape differences between corallites from tops and edges of colonies of M. annularis and M. faveolata are found when 3-D data are used. These intracolonial differences are due in large part to height and shape of the septal margin. As a result, 2-D data are unable to find significant differences within colonies.
Both datasets find significant interspecific differences, but different anatomical features are found to be responsible. Important interspecific differences for 2-D data are relative thickness of the corallite wall and lengths of septa and costae. When 3-D data are used, results are most influenced by height of primary and secondary septa above the calical surface, as well as length of septa from the corallite wall toward the columella. Patterns of relative morphological similarity among species also differ between datasets. 2-D data show closest similarity between M. annularis and M. faveolata, while M. faveolata and M. franksi are most similar when 3-D data are used. The former result is consistent with previous 2-D analyses, while the latter conclusion is without precedent. Neither is consistent with relationships inferred using molecular data.
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Neulinger, Sven Christopher [Verfasser]. « Bacterial microflora of the cold-water coral Lophelia pertusa (Scleractinia, Caryophylliidae) = Bakterielle Mikroflora der Kaltwasser-Koralle Lophelia pertusa (Scleractinia, Caryophylliidae) / Sven Christopher Neulinger ». Kiel : Universitätsbibliothek Kiel, 2008. http://d-nb.info/1019670932/34.
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Wittenberg, 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.
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This study investigates effects of eutrophication on settlement, abundance, mortality and community structure of soleractinian corals on fringing reefs on the west coast of Barbados, W.I. Juvenile abundance was lower, but juvenile size larger, on eutrophic than less eutrophic reefs. The lower abundance results at least in part from a higher juvenile mortality on eutrophic reefs. Algae were more abundant and grazers (Diadema antillarum and herbivorous fish) less abundant on eutrophic reefs. Juvenile community structure on all reefs, and adult community structure on eutrophic reefs, was dominated by type 1 corals (high recruitment, high natural mortality). Type 2 corals (low recruitment, low natural mortality) were common in adult communities on less eutrophic reefs. Settlement of coral recruits on artificial substrates was lower on more eutrophic reefs.
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Tibbits, Matthew Alan. « Scleractinian micromorphology : taxonomic value vs. phenotypic plasticity ». Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2155.
Texte intégralRésumé :
Reef-building corals (Order: Scleractinia) are undergoing rapid taxonomic revision after molecular systematics disputed the relationships at all taxonomic levels within traditional classification. New morphological characters are being used to produce evolutionary relationships supported by molecular phylogenetics. While these characters are providing more congruent taxonomic relationships, their variation has not been fully explored. Additionally, phenotypic plasticity (changes in morphology resulting from environmental factors influencing the expressed phenotype despite a shared genotype) is prevalent amongst Scleractinia. In order to better understand the nature of these characters and explore their variation, I created a series of aquaria-based experiments designed to test the stability of these new morphological characters in response to differing environmental conditions. Light intensity and temperature were chosen as the environmental factors varied in these experiments on the basis of being a known trigger for environmentally-driven plasticity and their importance in calcification rate. In addition to aquaria-based phenotypic plasticity experiments I also examined a group (Family: Euphylliidae) within Scleractinia that had been divided by molecular phylogeny into two disparate groups. My research focused on morphological features viewed at magnifications observable by scanning electron microscopy (SEM) called micromorphology. Although variation in the skeletal micromorphology is observable, the new morphological characters that are used in taxonomy display only small amounts of variation caused by changing environmental conditions and were found to be stable for use in taxonomic studies. Additionally, I found a few micromorphological features distinguishing the two groups previously assigned to Euphylliidae including the shape of the septal margins and the fine-scale skeletal texture.
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Dodds, Lyndsey A. « The ecophysiology of the cold-water coral Lophelia pertusa (Scleractinia) ». Thesis, University of the Highlands and Islands, 2007. https://pure.uhi.ac.uk/portal/en/studentthesis/the-ecophysiology-of-the-coldwater-coral-lophelia-pertusa-scleractinia(2ed27e7e-1011-4162-bdc1-a06321a69364).html.
Texte intégralRésumé :
Lophelia pertusa is the world’s most common and widespread framework-forming cold-water coral. It forms deep-water coral reefs and carbonate mounts supporting diverse animal communities on the continental shelf and on seamounts. Cold-water corals are found throughout most of the world’s oceans at depths of around 200 to 1000 meters. Unlike their tropical counterparts, cold-water corals do not contain symbiotic algae. These recently discovered ecosystems have been damaged by deep-sea fishing and are threatened by climate change. Despite this, very little is known about the ecophysiology of L. pertusa and its likely response to environmental changes. The aims of this research were to investigate the physiology of L. pertusa and relate this to its environment. In particular, this research focused on the respiratory physiology, growth and lipid signature of L. pertusa. This is the first study to investigate the physiology of L. pertusa and relate it to aspects of its natural environment, including temperature and oxygen availability. Results suggest that L. pertusa has slow physiological rates that vary geographically and may be dependent on food sources. Lipid analysis suggested a strong link to surface production and preferential feeding on copepods. It appears that L. pertusa is sensitive to small temperature changes and is at least partially limited in distribution by oxygen levels. This environment is likely to be threatened by changes in seawater temperature, ocean acidification, alteration of food webs and water masses as well as destructive fishing impacts. The results of this research provide vital information that will underpin future research and allow us to predict the effects of anthropogenic impacts on L. pertusa.
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Neves, Elizabeth Gerardo. « Comportamento reprodutivo de Mussismilia hispida (Verril, 1902) (Cnidaria, Anthozoa, Scleractinia) ». Universidade Federal do Rio de Janeiro, 1998. http://hdl.handle.net/11422/4000.
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Através de análises histológicas foi verificado o padrão reprodutivo de Mussismilia hispida, espécie zooxantelada de coral, endêmica na costa brasileira. Fragmentos provenientes de 2 colônias fixas, as quais foram marcadas no campo para que pudessem ser repetidamente amostradas, e de 1O colônias escolhidas ao acaso foram mensalmente obtidos no periodo de abril/89 a março/90, na Praia da Tartaruga, Búzios, Rio de Janeiro. Os resultados mostraram que M. hispida é uma espécie hermafrodita sequencial, cujo modo de reprodução envolve a liberação de gametas para fertilização e desenvolvimento externos. Células femininas surgiram antes das masculinas e foram inicialmente observadas em abril/89. O tamanho dos ovócitos de Estágio 1, parcialmente imersos na camada mesogleal, variou de 13,04μm a 19,56μm. Entre fevereiro/90 e março/90, ovócitos alcançaram o máximo de amadurecimento e estavam aptos para fertilização. O maior ovócito...
Through histological analysis the reproductive pattern of Mussismilia hispida, a zooxanthellate coral species endemic to the Brazilian coast was verified. Fragments from 2 tagged colonies, which were marked in the field in order to be repeatedly sampled, and 10 others haphazardly chosen were collected monthly, from April/89 to March/90, at Praia da Tartaruga, Buzios, Rio de Janeiro. The results showed that M. hispida is a sequential hermaphroditic species with a broadcast-spawning mode of reproduction, and external fertilization and development. Female cells developed prior to male cells, and were first observed in April/89. Size of Stage I oocytes partially immersed into mesogleal layer ranged from 13,04μm to 19,56μm. Between February/90 and March/90, oocytes reached maximum ripeness and were ready for fertilization. The largest Stage III oocyte...
14
Te, Franklyn Tan. « The Effects of Dursban® Insecticide on Pocillopora damicomis (Cnidaria : Scleractinia) ». Thesis, University of Hawaii, Honolulu, 1992. http://hdl.handle.net/10125/18146.
Texte intégralRésumé :
The effects of Dursban®, a chlorpyrifos-based pesticide, on reef-building
corals was investigated. Short-term (96 hours) static bioassays with renewal of
toxicant every 24 hours were conducted with Pocillopora damicomis colonies.
Two sets of experiments were conducted. The first examined the toxicity of the
commercial pesticide mixture made up of filtered seawater (0.45 µm) and the
manufacturer's recommended dose for the treatment of lawns and gardens
(0.91 mI/l). The second determined the toxicity of effluent seawater obtained
from a soil column 24 hours after it was treated with Dursban® mixture (0.91 mi/l)
at the manufacturer's recommended level of coverage (1.53 ml/12.6 cm2). In both
experiments, coral branches were exposed to logarithmic dilutions of the toxicant
mixture for up to four days. The 96 hour median lethal concentration (96 h LC50)
for the pesticide mixture was found to be 1.2 x 10-7% of the original solution while
the soil effluent mixture had a 96 hour LC50 of 7.0 x 10-8% of the effluent solution.
Gas chromatographic analysis of the pesticide stock solution showed that the
chlorpyrifos levels remained relatively stable for the duration of the experiment.
Pesticide levels were monitored in the experimental test water at each dilution
level prior to exposure of corals to determine actual pesticide concentration
although several of the lower dilutions yielded concentrations below the
analytical detection limit of 2 µg/l.
Data gathered from the bioassay tests revealed high sensitivity of the coral
Pocillopora damicomis to the two toxicant preparations. The soil effluent water
was appreciably more toxic to the coral than the straight pesticide mixture. This
was thought to reflect formation of more toxic breakdown products derived from
chlorpyrifos after application to the soil column. Other factors, like the
interactive effects between the chemical binders and dispersants within the
commercial formulation and the soil may have contributed to the increase in
toxicity of the soil effluent solution. Effluent water from pesticide-treated areas
may be more toxic to corals than previously suspected.
15
Rhodes, Kristopher J. S. « Evolution Of shape morphologic variation of the genus Undaria (Scleractinia, Agariciidae) ». Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/586.
Texte intégralRésumé :
In this study, the corallite shapes of three species of the scleractinian genus Undaria from the Yague group, Dominican Republic, were examined through a period of time stretching from 6.4 mya to 3.4 mya, a total of 3.0 ma. Corallite shape was measured using 3 dimensional landmarks and manipulated using the well established procedures of geometric morphometrics. Differences in shape and size through time were examined using a variety of tools, including canonical variates analysis, principal components analysis, least squares regression, partial least squares regression, and a variety of evolutionary model fits. Evolutionary model fits were used to test three models against the shape and size variables: general random walk, which models a directional change through time; unbiased random walk, which models random change through time; and stasis, which models stability through time. Stasis is the most common parameter through time, supported in 9 of 15 (60%) of cases, while the unbiased random walk was supported 6 of 15 times. While there was a significant change in one species associated with environmental variables, those variables were also correlated with time and no causal relationship can be reached.
16
Maier, Elke. « Life history of the Scleractinian Coral Seriatopora hystrix ». Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-149063.
Texte intégral
17
White, Melody J. « Patterns of Scleractinian Health in Broward County, Florida ». NSUWorks, 2006. http://nsuworks.nova.edu/occ_stuetd/268.
Texte intégralRésumé :
This study was survey of disease distribution and abundance relating to coral diseases present in Broward County. Data of the 1330 scleractinian coral individuals found, 88 showed signs of disease. 19 coral species, 3 diseases and bleaching were represented. Diseases affected 9 of the species. Bleaching was the most common disease noted in this survey, followed by dark spot, red band, and yellow band.
Disease distribution appears to be scattered on the reef system. No apparent patterns were found when grouped by reef or corridor locations. MDS cluster analysis revealed a clumping of disease, but this was not correlated with location. Sites with more disease susceptible species tended to be clumped together.
Species diversity may play a role in the amount of disease present. Lower species diversity may cause an area to me more susceptible to disease. The more species located within an area, the less affect a disease affecting a subset of species would have.
18
Stafford-Smith, Mary Gillian. « The effect of sediments on Australian scleractinian corals ». Thesis, University of York, 1990. http://etheses.whiterose.ac.uk/4244/.
Texte intégral
19
Waller, 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.
Texte intégral
20
Yeung, Wai-shan Christine, et 楊慧珊. « Reproduction and growth of scleractinian corals in Hong Kong ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45164071.
Texte intégral
21
Rubin, Ewelina. « Scleractinian Coral Recruitment to Reefs Physically Damaged by Ship Groundings ». NSUWorks, 2009. http://nsuworks.nova.edu/occ_stuetd/227.
Texte intégralRésumé :
Southeast Florida reefs are impacted by a number of stress factors, among which ship groundings are one of the most physically damaging. In particular, portion of Florida reef tract located near Port Everglades in Broward County has been severely damaged by ship groundings. In 2004, extensive physical damage of more than 30,000 m2 was caused by the groundings of two large cargo ships, the MV Eastwind and MV Federal Pescadores. The present study was designed to examine differences in the recruitment patterns of scleractinian corals and pioneering benthic communities settling to these physically impacted sites compared to undamaged reef sites. Coral recruitment and non-coral benthic settlers were measured on unglazed terracotta tiles deployed for a period of one year from February 2007 to February 2008 at five different locations: three control sites (including a high coral cover site) and the two ship grounding sites. Colony morphology and two genetic markers: mitochondrial cytochrome oxidase subunit I and cytochrome b were used to identify the coral recruits. A whole genome amplification kit (REPLI-g, Qiagen) was used to obtain sufficient amounts of DNA from small coral spat. The image analysis software Coral Point Count with the Excel extension was used to quantify the percent cover of major benthic invertebrate and algal functional groups. Results revealed very low diversity of coral recruits and low recruitment rates (0.5-2.7 recruits m-2 yr-1), suggesting a low potential for recovery of the damaged areas. Other non-coral benthic groups, including turf algae, barnacles, sponges, tunicates and bryzoans, were found to proliferate and occupy almost the entire tile substrate, suggesting possible coral recruitment inhibition by space preemption or coral recruit mortality by overgrowth. Turf algae which comprised up to 50% of the total cover were the most dominant group settling to the tiles. This dominance of algae on the tiles reflects a similar pattern of algal dominance present on the reef system along the Florida coast.
22
Wan, Manna, et 溫雯娜. « The status of scleractinian corals in Hong Kong and theirconservation ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31255127.
Texte intégral
23
Crane, Kevin. « Reproductive biology of scleractinian corals at Rottnest Island, Western Australia ». Thesis, Crane, Kevin (1999) Reproductive biology of scleractinian corals at Rottnest Island, Western Australia. Honours thesis, Murdoch University, 1999. https://researchrepository.murdoch.edu.au/id/eprint/40886/.
Texte intégralRésumé :
The reproductive biology of selected scleractinian coral species was studied at Rottnest Island. At least 11 of the 25 coral species recorded at Rottnest Island were found to be reproductively active despite most species being at the southern limit of their latitudinal distribution.
In contrast to other tropical reefs in Western Australia and the Great Barrier Reef, spawning at Rottnest Island was not synchronous between coral species. Corals at Rottnest Island spawned during late summer I early autumn (January - May) after both full and new moon periods. This breakdown in synchrony probably occurs because these species are living at the latitudinal limits of their distribution.
Spawning was also not synchronous within four species with spawning occurring over one or more months. This provides further evidence that gamete release is generally not restricted to one short, discreet period.
Spawning occurred in the same general time frame as other corals from north western Australia, despite differences in seasonal temperature patterns. This provides further evidence that temperature does not operate as a simple direct proximate cue, to synchronise the various stages of gametogenesis.
A strong correlation between spawning and neap tides was not observed. Microtidal conditions at Rottnest Island may have not exerted enough selective pressure to shift spawning away from the inherited lunar rhythm.
Only a low level of coral recruitment (mean=l.44 recruits per tile pair) was detected in 1998 and these were exclusively from the Pocilloporidae. No recruitment of broadcast spawning corals occurred in 1998. If this were the norm for Rottnest Island, then these populations would have a reduced capacity to recover from damage.
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Barbeitos, Marcos Soares. « Variação de formas de crescimento de Montastraea cavernosa (Linnaeus, 1767) (Cnidaria, Anthozoa, Scleractinia) : uma abordagem modular ». Universidade Federal do Rio de Janeiro, 2000. http://hdl.handle.net/11422/3570.
Texte intégralRésumé :
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CAPES
Animais clonais crescem por acréscimo de unidades funcionais (zoóides) as quais formam a colônia. A abordagem modular consiste em descrever a forma das colônias do ponto de vista do arranjo e tamanho dos módulos. A abordagem modular foi usada aqui para quantificar variações na forma de crescimento do coral Montastraea cavernosa a partir da mensuração do arranjo e áreas dos pólipos na face interna do tecido colonial. Foram coletadas 46 amostras no Parcel das Paredes (BA) e João Pessoa (PB). Os resultados mostraram que área dos pólipos é parcialmente explicada por fatores ligados ao espaçamento entre eles. Estes fatores variam com a forma da colônia e com a faixa de tamanho de pólipos considerada. Foi proposto um modelo conceitual hipotético para a relação entre a forma de crescimento colonial, o tamanho e a organização dos pólipos. São discutidas possíveis razões evolutivas para o modelo proposto e implicações deste para estudos morfométricos da espécie.
Clonal animals grow through addition of functional units (zooids), whose assemblage constitutes a colony. The modular approach consists in describing colony form from the arrangement and size of modules. The modular approach was used here to access variations in growth forms of the coral Montastraea cavernosa using the arrangement and the size of polyps in the inner face of the colonial of 46 samples collected in Parcel das Paredes (BA) and João Pessoa (PB). Results showed that area of the polyps is partially explained by factors related to the spacing among them. These factors vary with the form of the colony and with the range of polyp sizes being analyzed. A hypothetical conceptual model for the relationship among colonial growth forms, polyp sizes and organization is proposed. Possible evolutionary reasons for such a model are discussed as well as possible implications to morphometric studies of this species.
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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.
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26
Prantoni, Selena. « Variazione della capacità riproduttiva del corallo Leptopsammia pruvoti (Scleractinia, Dendrophylliidae) lungo un gradiente latitudinale di temperatura ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3154/.
Texte intégralRésumé :
La temperatura influenza molti dei processi fisiologici degli organismi marini e, considerato che la riproduzione dei coralli sembrerebbe essere sensibile agli stress, è necessario comprendere come questa possa reagire ai cambiamenti climatici globali per riuscire a prevedere le future risposte delle popolazioni. Leptopsammia pruvoti (Scleractinia, Dendrophylliidae) è un corallo solitario non zooxantellato presente in Mediterraneo e lungo le coste Atlantiche dal Portogallo alla Gran Bretagna meridionale, dalla superficie fino a 70 metri di profondità.. È un organismo gonocorico con fecondazione interna. In questo lavoro di tesi sono stati analizzati gli aspetti della gametogenesi di L. pruvoti a diverse latitudini per ottenere risultati preliminari riguardanti le possibili correlazioni tra attività riproduttiva e parametri ambientali (temperatura e irradianza). Tale studio si colloca all’interno del progetto europeo sul riscaldamento globale e biologia dei coralli FP7–IDEAS-ERC “Corals and Global Warming: The Mediterranean versus the Red Sea” (CoralWarm). I risultati presentati in questo lavoro sono relativi a cinque popolazioni di L. pruvoti (Genova, Calafuria, Palinuro, Scilla e Pantelleria) disposte lungo un gradiente latitudinale di temperatura e irradianza nel versante occidentale della penisola italiana. I campioni sono stati raccolti mediante campionamenti mensili effettuati tramite immersioni subacquee. Su ogni campione sono state effettuate misurazioni biometriche e analisi cito-istometriche. Nelle popolazioni analizzate i parametri riproduttivi (fecondità, abbondanza, indice gonadico, dimensione) sono stati messi in relazione con la temperatura di fondo (DT, °C) e l’irradianza solare (W/m2) peculiari di ogni sito. L. pruvoti ha mostrato una sessualità gonocorica in tutti i siti considerati. In tutte le popolazioni, la presenza di due stock di ovociti e la distribuzione degli stadi di maturazione degli spermiari durante le fasi di attività riproduttiva, nell’arco dell’anno, hanno permesso di definire un periodo di reclutamento e uno di maturità gonadica, suggerendo che tali eventi siano influenzati dai cambiamenti stagionali della temperatura dell’acqua e del fotoperiodo. Nel periodo di reclutamento, la fecondità presentava una debole correlazione positiva con i parametri ambientali considerati. Al momento della maturità gonadica gli ovociti erano di dimensioni maggiori e meno numerosi rispetto al periodo precedente, nelle popolazioni con una maggiore temperatura e irradianza. Una possibile interpretazione potrebbe essere l’esistenza di un processo di fusione degli ovociti nel periodo di maturità gonadica che sembrerebbe più marcato nelle popolazioni più calde e maggiormente irradiate. La spermatogenesi, diversamente, non ha delineato finora un pattern chiaramente interpretabile. Con i dati attualmente in nostro possesso, non possiamo tuttavia escludere che le differenze riscontrate nelle dimensioni di ovociti e spermiari lungo il gradiente latitudinale considerato siano dovute a un lieve sfasamento nel raggiungimento della maturità gonadica, pur mantenendo la medesima stagionalità nel ciclo riproduttivo delle diverse popolazioni. Ulteriori studi saranno necessari per poter meglio comprendere i complessi meccanismi che regolano e controllano i processi riproduttivi al variare dei parametri ambientali. In questo modo sarà possibile considerare i risulti ottenuti nel contesto dei cambiamenti climatici globali.
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Cordie, David Russell. « Scleractinia soft tissue systematics : use of histological characters in coral taxonomy and phylogenetic reconstruction ». Thesis, University of Iowa, 2015. https://ir.uiowa.edu/etd/1574.
Texte intégralRésumé :
Coral reefs are some of the most diverse ecosystems in the world and provide economic value as well as biodiversity stability. Yet, these ecosystems are threatened from human degradation and climate change. Phylogenetic reconstructions can help identify which species have a potential to undergo greater amounts of change in the near future and also aids in determining evolutionary distinctiveness, which are critical components of conservation management. However, traditional Scleractinia morphological characters have been shown to have limited taxonomic use. Therefore, this study attempts to discover soft tissue characters to produce more robust phylogenies. Eight coral species from the Indo-Pacific families Merulinidae and Lobophylliidae were mail ordered and prepared for histological analysis under light microscopy. A character matrix was analyzed and the results were compared to phylogenies based on skeletal and molecular data. A total of seven MPTs of length 35, C.I. 0.60 and R.I. 0.58 were found. In addition, a detailed description of the histology is included. The topology of MPTs was inconsistent, but several were broadly similar to previous phylogenies based on molecular and skeletal data. Still, using only a small number of characters, the results do promise that histological characters in conjunction with skeletal characters could better delineate species and their evolutionary history. Future results could aid in making conservation decisions based on improved phylogenies.
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Calderon, Emiliano Nicolas. « Identificação dos coralitos de pólipos fundadores de corais recifais do Brasil (Cnidaria, Anthozoa, Scleractinia) ». Universidade Federal do Rio de Janeiro, 2003. http://hdl.handle.net/11422/3034.
Texte intégralRésumé :
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CAPES
FAPERJ
Para se estudar a história de vida de um organismo é fundamental que se possa identificá-lo ao longo de seu ciclo de vida. Em relação aos corais, um fator complicador é a dificuldade de sua identificação nos seus estágios iniciais. A taxonomia dos corais está fundamentada em caracteres presentes nos adultos. O objetivo deste trabalho é descrever os juvenis de corais recifais brasileiros e analisar criticamente as características esqueléticas de importância taxonômica em suas diferentes fases de desenvolvimento. Foram analisadas placas de recrutamento colocadas no Banco de Abrolhos, Recifes Itacolomis e Arraial do Cabo. Foram identificados oito táxons com até um ano de idade de família e espécie. Os resultados indicaram que a identificação depende do desenvolvimento do coralo, da morfogênese dos caracteres e dos caracteres que definem cada táxon. É viável classificar os juvenis, apesar desta atividade se mostrar muito trabalhosa, exigindo considerável conhecimento e treino de identificação. Estas identificações são importantes em estudos de história de vida, de padrões de recrutamento e avaliações de manutenção e crescimento das populações de corais recifais. Estas são uma ferramenta fundamental na otimização de manejo, conservação e recuperação dos recifes de coral.
To study an organism's life history, it is important to identify them throughout their life cycle. ln corals, a complicating factor is the difficulty of identification at their initial stages. The taxonomy of corais is based on skeletal structures present in the adults. The purpose of this study was to describe the juveniles of Brazilian reef corals and critically analyze the taxonomic important skeletal characteristics at different developmental stages. Recruitment plates from Banco de Abrolhos, Itacolomis Reefs and Arraial do Cabo, were examined. Eight taxa, up to one year of age, were identified from family to species. Results show that recruitment identification depends on the corallum, its skeletogenesis, and the structures that define each taxa. This study demonstrates that it is possible to classify juvenile corals, although the process of identification can be demanding, requiring an extensive knowledge of the structures involved in the identification. Juvenile identification is important for life history and recruitment studies, as well as, the estimation of growth and maintenance of coral populations. The identification of recruits is an important tool for the optimization of management, conservation, and recovery of reef corals.
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Fadiga, Troy Robert. « Cladistic analysis of Meandrinidae and Oculinidae (Anthozoa : Scleractinia) with comments on not applicable characters ». Thesis, University of Iowa, 2011. https://ir.uiowa.edu/etd/1136.
Texte intégralRésumé :
A morphological phylogenetic analysis of the coral families Oculinidae and Meandrinidae suggest multiple transitions between colonial and solitary forms. Many morphological characters are logically dependent on a taxon being colonial. The treatment of not applicable characters has remained unresolved, with traditional treatments of not applicable characters having well known flaws. A new method for treating not applicable characters, the Not Applicable Corrected Tree Length (NACTL) method, is presented. The NACTL method retrieves a different phylogenetic signal than traditional approaches, but is more consistent with molecular phylogenetic analyses.
30
Naumann, Malik. « Biogeochemical consequences of organic matter release by reef-building scleractinian corals ». Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-131831.
Texte intégral
31
Zievis, Craig John. « Enhanced Growth of the Scleractinian Coral Porites rus through Elevated Alkalinity ». Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/ZievisCJ2005.pdf.
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Gustafson, Steven K. « Assessment of Image Analysis as a Measure of Scleractinian Coral Growth ». Scholar Commons, 2006. http://scholarcommons.usf.edu/etd/3768.
Texte intégralRésumé :
Image analysis was used to measure basal areas of selected colonies of Montastraea annularis and Porites astreoides, following the colonies over a three-year period from 2002 to 2004. Existing digital images of permanently-marked quadrats in the Caye Caulker Marine Reserve, Belize, were selected based on image quality and availability of images of selected quadrats for all three years. Annual growth rates were calculated from the basal-area measurements. Mean growth rates (radial skeletal extension) for M. annularis and P. astreoides were 0.02 cm yr-1 and -0.20 cm yr-1, respectively. Basal area measurements demonstrated a large degree of variability. Increases were approximately balanced by declines giving the impression of stasis. By removing negative values and correcting by 25% to allow for comparison with vertical growth rates, mean values increased to ~0.5 cm yr-1 for M. annularis and ~0.8 cm yr-1 for P. astreoides.
Basal area as a growth measure was compared to methods used in earlier studies. A new growth index based on basal area and perimeter was proposed and modeled. This growth index can be useful for reporting growth measured from basal areas and comparable other methods. The index also measures negative growth, or mortality, which conventional methods cannot do.
33
Wan, Manna. « The status of scleractinian corals in Hong Kong and their conservation / ». Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B23424849.
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34
McCorry, Denise. « Hong Kong's scleractinian coral communities : status, threats and proposals for management / ». Thesis, Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B25155131.
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35
Airi, Valentina <1979>. « Reproduction of Mediterranean zooxanthellate and azooxanthellate scleractinian corals along environmental gradients ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6425/1/PhDThesis_Airi.pdf.
Texte intégralRésumé :
Despite extensive studies focus mainly on sexual reproductive characteristics in tropical scleractinian species, there is limited knowledge on temperate regions. The Mediterranean is a biodiversity hotspot under intense pressure from anthropogenic impacts. Climatic models further predict that the Mediterranean basin will be one of the most impacted regions by the ongoing warming trend. This makes it a potential model of more global patterns to occur in the world’s marine biota, and a natural focus of interest for research on climate. The present research contributed to increase data on reproductive modes and sexuality of temperate scleractinian corals, highlighting their developmental plasticity, showing different forms of propagation and different responses to environmental change. For the first time, sexuality and reproductive mode in Caryophyllia inornata were determined. An unusual embryogenesis without a clear seasonal pattern was observed, suggesting the possibility of an asexual origin. Sexual reproduction of Astroides calycularis was governed by annual changes in seawater temperature, as observed for other Mediterranean dendrophylliids. Defining the reproductive biology of these species is the starting point for studying their potential response to variations of environmental parameters, on a global climate change context. The results on the influence of temperature on reproductive output of the zooxanthellate (symbiosis with unicellular algae) Balanophyllia europaea and the non-zooxanthellate Leptopsammia pruvoti suggest that the latter may be quite tolerant to temperature increase, since the zooxanthellate species resulted less efficient at warm temperatures. A possible explanation could be related to their different trophic system. In B. europaea thermal tolerance is primarily governed by the symbiotic algae, making it more sensitive to temperature changes. On the contrary, the absence of symbionts in L. pruvoti might make it more resistant to temperature. In a progressively warming Mediterranean, the efficiency on scleractinian reproduction could be influenced in different ways, reflecting their extraordinary adaptability.
36
Airi, Valentina <1979>. « Reproduction of Mediterranean zooxanthellate and azooxanthellate scleractinian corals along environmental gradients ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6425/.
Texte intégralRésumé :
Despite extensive studies focus mainly on sexual reproductive characteristics in tropical scleractinian species, there is limited knowledge on temperate regions. The Mediterranean is a biodiversity hotspot under intense pressure from anthropogenic impacts. Climatic models further predict that the Mediterranean basin will be one of the most impacted regions by the ongoing warming trend. This makes it a potential model of more global patterns to occur in the world’s marine biota, and a natural focus of interest for research on climate. The present research contributed to increase data on reproductive modes and sexuality of temperate scleractinian corals, highlighting their developmental plasticity, showing different forms of propagation and different responses to environmental change. For the first time, sexuality and reproductive mode in Caryophyllia inornata were determined. An unusual embryogenesis without a clear seasonal pattern was observed, suggesting the possibility of an asexual origin. Sexual reproduction of Astroides calycularis was governed by annual changes in seawater temperature, as observed for other Mediterranean dendrophylliids. Defining the reproductive biology of these species is the starting point for studying their potential response to variations of environmental parameters, on a global climate change context. The results on the influence of temperature on reproductive output of the zooxanthellate (symbiosis with unicellular algae) Balanophyllia europaea and the non-zooxanthellate Leptopsammia pruvoti suggest that the latter may be quite tolerant to temperature increase, since the zooxanthellate species resulted less efficient at warm temperatures. A possible explanation could be related to their different trophic system. In B. europaea thermal tolerance is primarily governed by the symbiotic algae, making it more sensitive to temperature changes. On the contrary, the absence of symbionts in L. pruvoti might make it more resistant to temperature. In a progressively warming Mediterranean, the efficiency on scleractinian reproduction could be influenced in different ways, reflecting their extraordinary adaptability.
37
Kitano, Yuko. « Molecular phylogeny of the genus Goniopora and taxonomic revision of the family Poritidae (Cnidaria : Scleractinia) ». 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188513.
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38
Hoke, S. Michael. « Gametogenesis and spawning of the elliptical star coral, Dichocoenia stokesi (Cnidaria : Scleractinia) in Southeast Florida ». NSUWorks, 2007. http://nsuworks.nova.edu/occ_stuetd/263.
Texte intégralRésumé :
Reproductive characters of the elliptical star coral Dichocoenia stokesi (Cnidaria: Scleractinia) were investigated based in histological examination of tissues collected in southeastern Florida between September 1999 and September 2000. The study population was predominantly gonochoric with a small incidence of hermaphroditism. Dichocoenia stokesi exhibits intermediate egg size (312.2 ± 40.4μm; mean ± SD) compared with other scleractinian species, suggesting a moderately lecithotrophic larval stage. Although spawning was not directly observed in this study, two separate spawning events per year are inferred from histological slide analyses; the first in late August or early September, and the second in early October. Sea water temperature was significantly positively correlated with female gonadal development in D. stokesi, whereas insolation was significantly inversely correlated with gonadal development. A recent epizootic of White Plague Type II in south Florida appears to be skewing local D. stokesi populations toward smaller - and potentially less fecund - colony sizes, although colony size and fecundity were not correlated in this study. The mean fecundity of the study population is estimated as 1138.1 eggs cm-2 yr-1.
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Casebolt, Sahale Nichole. « Phylogenetic analysis and quantitative assessment of micromorphology and microstructure in the coral family Mussidae (scleractinia) ». Thesis, University of Iowa, 2011. https://ir.uiowa.edu/etd/1208.
Texte intégralRésumé :
Coral morphology is highly homoplastic, and reconstructing coral phylogeny based on morphological characters has long been problematic. Coral skeletal micromorphology and skeletal microstructure may be less homoplastic than traditional skeletal macromorphology. Micromorphology includes characteristics of septal teeth and associated features, such as granules. Microstructure is the internal structure of septa, walls and dissepiments. These micro-features can be visualized using light and scanning electron microscopy, and transverse thin sections, respectively. Although coral micro-features have been of interest to coral workers for decades, few have attempted using micro features for phylogenetic analyses. A phylogenetic analysis of the coral family Mussidae using micro-features as characters found that, in this family, phylogenies based on a combination of macromorphology and micro-features are more consistent with molecular phylogenies than phylogenetic analyses based on traditional macromorphological characters alone. Further exploration of micro-features using a quantitative method to assess septal dentition also supports the potential utility of micro-features in coral taxonomy. An elliptic Fourier analysis of septal tooth curvature within the coral family Mussidae reveals that there is quantifiable inter-specific variation in septal tooth shape. Although differences in septal tooth shape have long been described qualitatively, a quantitative assessment of this particular micro-feature confirms the objectivity of septal tooth shape variation. This outline analysis represents an important step toward novel approaches to exploring coral micro-features.
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Ramos, Bárbara Segal. « Comunidades recifais do Arquipélago dos Abrolhos, BA, com ênfase em corais (Cnidaria : Scleractinia e Milleporidae) : aspectos metodológicos e comparações entre locais ». Universidade Federal do Rio de Janeiro, 1998. http://hdl.handle.net/11422/3615.
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A quantificação das comunidades coralíneas em três locais do Arquipélago dos Abrolhos, BA (Face Norte e Portinho, na Ilha de Santa Bárbara, e Ilha Siriba), foi realizada através de transectos de interseção de linha e de quadrados. Para as cinco espécies mais frequentes ou abundantes (Agaricia agaricites, Favia gravida, Mussismilia braziliensis, Porites branneri e Siderastrea stellata) foram avaliados os tamanhos e inclinações de colônias, distâncias entre ponto aleatório e colônias e entre colônias. Ao se comparar os resultados obtidos por quadrados e transectos, não se detectou diferença entre eles quanto à representação das comunidades ( contribuições de diferentes organismos para a cobertura da área). Entretanto, os transectos de interseção de linha detectaram um maior número de espécies, conferindo à amostra um maior poder de resolução do que o método de quadrados. Os organismos construtores dominantes em profundidades entre...
The quantification of coral communities in three areas in the Abrolhos Archipelago (northern and southern inshore areas in Santa Bárbara Island, and Siriba Island) was performed using quadrats and intercept line transect methods. Colony size and inclination, the distances from random points to the nearest colony and between nearest colonies of the same species were evaluated for the five most frequent or abundant coral species (Agaricia agaricites, Favia gravida, Mussismilia braziliensis, Porites branneri e Siderastrea stellata). No differences were detected in the representation of the community ( contributions of different organisms to coverage of an area) when the results of data from quadrats and transects were compared. However, intercept line transects detected more species, presenting higher resolution than quadrats. Dominant reef building organisms, between depths of...
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Iuffrida, Letizia. « Transcriptional profiles inferring thermal stress responses of scleractinian corals from Mediterranean Sea ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20374/.
Texte intégralRésumé :
Shallow-water corals of the Mediterranean Sea are facing a dramatic increase in water temperature due to climate change. In many cases, a shift toward environmental conditions outside the normal range of variability may cause suboptimal physiological performance, such as enhanced respiration, higher susceptibility to pathogens, bleaching, reduced calcification and tissue necrosis. However, not all corals are thought to be affected equally, because physiological performances and responses are the principal determinant of a species tolerance to environmental variability and may change the ability of corals to cope with changing conditions. In this study, transcriptional profiles of four genes involved in apoptosis (bax and bcl-2), redox regulation (sod) and energy metabolism (gapdh) have been analyzed in three common shallow-water Mediterranean scleractinian, namely Astroides calycularis, Balanophyllia europaea and Leptopsammia pruvoti. The main aim was to assess the contribution of these cytoprotective mechanisms to the physiological plasticity of the species, that possess different growth modes (solitary vs colonial) and trophic strategies (zooxanthellate vs azooxanthellate). Using quantitative real-time PCR, expression profiles after an acute heat-shock exposure (2h at 32°C + 0-24 h post-stress recovery) were assessed, and a potential timeline for the events occurring in the investigated species was disclosed. The overall transcriptional response to heat stress aligns with relative differences in stress susceptibility of the species and suggests a contribution of trophic strategy in the degree of coral resilience to stress. Understanding the overall molecular processes is demanding for corals inhabiting the Mediterranean (a biodiversity “hot spot”), in light of projected scenarios of anthropogenic global change.
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Massé, Anaïs. « Association between the microboring chlorophyte of the genus Ostreobium and scleractinian corals ». Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS584.
Texte intégralRésumé :
Les coraux scléractiniaires sont associés à de nombreux microorganismes, dont les microperforants colonisant activement leur squelette carbonaté et qui sont encore peu connus. L’objectif de la thèse était d’étudier l’interaction entre l’algue microperforante Ostreobium et l’hôte corallien Pocillopora acuta, espèce branchue à croissance rapide. Les résultats montrent que la colonisation par Ostreobium se fait dès les stades précoces de vie du corail, depuis le substrat de fixation. Cette colonisation, plus ou moins importante selon le type de substrat, n’affecte pas la croissance des juvéniles coralliens. L’isolement de souches d’Ostreobium sous formes libres et bioérodantes, appartenant aux clades dominants chez P. acuta, a permis de déterminer leurs profils chimiques (pigments, acides gras) et leurs signatures isotopiques (δ13C, δ15N). Les résultats montrent des différences majeures entre les deux formes, liées à leur habitat. Les Ostreobium bioérodants sont notamment capables d’assimiler une partie du C et N libérés lors de la dissolution du carbonate. Ce résultat permet de mieux appréhender le rôle d’Ostreobium dans le cycle récifal des carbonates. Pour tester l’hypothèse de transfert actif de photo-assimilats des Ostreobium vers le corail, des chambres d'incubation ont été conçues et testées, de même qu’une méthode d’imagerie quantitative de traceurs isotopiques (13C-bicarbonate, 15N-nitrate) à la sonde ionique NanoSIMS, afin de visualiser les sites d’acquisition du C et N à l'échelle des filaments d’Ostreobium. Ces résultats ouvrent de nouvelles perspectives pour explorer le possible rôle d’ectosymbionte d’Ostreobium chez les coraux scléractiniairesReef-building scleractinian corals are associated with many microorganisms including microborers which actively colonize their carbonate skeletons and are little known. The aim of the thesis was to study the interaction between the microboring alga Ostreobium and the coral host Pocillopora acuta, a fast-growing branching species. Results show that Ostreobium colonization occurs in coral early life stages, from the settlement substrates. This colonization, more or less abundant depending on the type of settlement substrate, does not affect the growth of coral juveniles. The isolation of Ostreobium strains under free-living and bioeroding forms, belonging to dominant clades in P. acuta, allowed to determine their chemical profiles (pigments, fatty acids) and their isotopic signatures (δ13C, δ15N). Results show major differences between both Ostreobium forms, related to their habitat. Bioeroding Ostreobium are especially able to assimilate a part of C and N released during the carbonate dissolution. This result will help to have a better view of the Ostreobium role in the carbonate reef cycle. To test the active transfer hypothesis of photoassimilates from Ostreobium to the coral host, incubation chambers were designed and tested, likewise for the quantitative imaging method of isotopic tracers (13C-bicarbonate, 15N-nitrate) with the NanoSIMS ion microprobe, in order to visualize carbon and nitrogen acquisition sites at the microscale of individual Ostreobium algal filaments. These results path the way to explore the possible ectosymbiont role of Ostreobium in scleractinian corals
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Albright, Rebecca. « Effects of Ocean Acidification on Early Life History Stages of Caribbean Scleractinian Corals ». Scholarly Repository, 2011. http://scholarlyrepository.miami.edu/oa_dissertations/574.
Texte intégralRésumé :
Ocean acidification (OA) refers to the increase in acidity (decrease in pH) of the ocean’s surface waters resulting from oceanic uptake of atmospheric carbon dioxide (CO2). Mounting experimental evidence suggests that OA threatens numerous marine organisms, including reef-building corals; however, few studies have focused on the effects on early life history stages. Coral recruitment is critical to the persistence and resilience of coral reefs and is regulated by several early life processes, including: larval availability (gamete production, fertilization, etc.), larval settlement, post-settlement growth, and survival. Environmental factors that disrupt these early life processes can result in compromised or failed recruitment and profoundly affect future population dynamics. To evaluate the effects of OA on the sexual recruitment of corals, sexual reproduction (including fertilization and sperm swimming speeds) and several critical early life history stages (including larval metabolism, larval settlement, and post-settlement growth) were tested in common Caribbean coral species. Three pCO2 levels were used: ambient seawater (380 µatm) and two pCO2 scenarios that are projected to occur by the middle (560 µatm) and end (800 µatm) of the century as determined by the Intergovermental Panel on Climate Change. Results show that fertilization success, larval metabolic rates, larval settlement rates, and post-settlement growth rates are all compromised with increasing pCO2. This dissertation demonstrates that OA has the potential to negatively impact sexual reproduction and multiple early life history processes of several common Caribbean coral species and may contribute to substantial declines in sexual recruitment that are felt at the community and/or ecosystem scale.
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Te, Franklyn Tan. « Responses of Hawaiian Scleractinian Corals to Different Levels of Terrestrial and Carbonate Sediment ». Thesis, University of Hawai'i, Honolulu, 2001. http://hdl.handle.net/10125/15323.
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Goals of this investigation were: 1) Differentiate between the effects of
turbidity and sedimentation on corals. 2) Differentiate the effects of carbonate
and terrigenous sediments on coral growth and metabolism. 3) Develop a
predictive model relating increased sediment loading to the photosynthetic rate,
growth and survival of corals. 4) Evaluate the validity of the widely cited "10 mg
cut-off point" and determine the levels of turbidity and sedimentation that are
tolerated by corals. Earlier studies suggest that coral reefs decline when sediment loading levels exceed a sediment trapping rate of 10 mg cm-2 d-1 or a
turbidity of 10 mg I-1.
An integrated experimental design linked field and laboratory experiments.
In the field, corals were transplanted to sites with varying levels of sedimentation.
Turbidity, as linked to reduced light availability, had a significant affect on coral
growth and metabolism in laboratory experiments but not coral growth or survival
in field experiments. Turbidity in the field was highly variable and influenced
greatly by wind velocity and rainfall.
Terrigenous (or land-derived) sediments influenced light extinction more
than carbonate (reef-derived) sediments. In laboratory experiments turbidity was
more important than sediment trapping rate in affecting the photosynthetic ability
and growth rates of corals.
The predictive model stated that the lower the light level (as caused by
increased turbidity) the lower the photosynthetic production of corals. The model
was supported by results of laboratory experiments where conditions were precisely controlled and monitored. Under field conditions, the predictive model
did not hold due to extreme natural variability in sediment loading and variation in
a wide range of other environmental factors encountered at the experimental
sites.
Corals tolerated turbidity exceeding 120 mg I-1 and sediment trapping
rates in excess of 11 mg cm2 d-1. Sediment loading is correlated with other
environmental factors such as nutrient loading and reduced salinity. Composition
of sediment varies widely between different locations. The "10 mg cutoff may
prove to be useful in setting limits to vigorous coral reef development, although
individual corals or coral assemblages may be able to survive and grow at levels
exceeding this value.Thesis (Ph. D.)--University of Hawaii at Manoa, 2001. Includes bibliographical references (leaves 235-264).
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Brahmi, Chloé. « Study of scleractinian coral biomineralization using ⁸⁶Sr-labeling and NanoSIMS ion-microprobe imaging ». Paris, Muséum national d'histoire naturelle, 2012. http://www.theses.fr/2012MNHN0042.
Texte intégralRésumé :
Les coraux Scléractiniaires produisent un exosquelette en carbonate de calcium (aragonite). Leurs processus de biominéralisation ont été étudiés chez trois espèces présentant différents taux de croissance et vivant ou non en symbiose avec les zooxanthelles. Une hétérogénéité de composition du tissu et du squelette a été mise en évidence, à différentes échelles, via des techniques d’observations et de micro-analyses, à haute résolution spatiale. Un thème central a été le développement et l’application d’une méthode de marquage de biocarbonates marins basée sur un enrichissement avec un isotope stable d’un élément trace, naturellement présent dans l’eau de mer (86Sr). Le biocarbonate formé, présentant des enrichissements isotopiques correspondants, est ensuite imagé à la NanoSIMS afin de visualiser, à l’échelle submicrométrique, les zones formées durant le marquage. Cette technique permet ainsi de résoudre les détails ultrastructuraux et accéder à la dynamique de croissance squelettiqueScleractinian corals build an aragonitic calcium carbonate exoskeleton. Their biomineralization processes have been studied in three different scleractinian species with or without zooxanthellae and with different growth rates. Heterogeneity of the tissue and the skeletal compositions was revealed at different length scales, using complementary observations and micro-analytical techniques at high spatial resolution. A central theme was the development and application of a method to label marine biocarbonates through a concentration-enrichment of a minor stable isotope of a trace element that is a natural component of seawater (86Sr), resulting in the formation of biocarbonate with corresponding isotopic enrichments. This biocarbonate was subsequently imaged with a NanoSIMS ion microprobe to visualize the locations of the isotopic marker on submicrometric length scales, permitting resolution of all ultra-structural details and access to the skeletal growth dynamics
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Travaglione, Natalie. « Influence of turbidity on trophic plasticity in scleractinian corals in the Dampier Archipelago ». Thesis, Travaglione, Natalie (2022) Influence of turbidity on trophic plasticity in scleractinian corals in the Dampier Archipelago. Honours thesis, Murdoch University, 2022. https://researchrepository.murdoch.edu.au/id/eprint/65505/.
Texte intégralRésumé :
Tropical scleractinian coral communities and coral reef biodiversity are in a state of decline due to cumulative global and anthropogenic stressors. However, some coral communities are able to survive, and indeed thrive, in stressful environments. The mechanisms that these corals employ to survive in challenging conditions are poorly understood. This study aimed to assess the influence of turbidity on the degree of trophic plasticity expressed by three genera of scleractinian corals (Acropora spp., Porites spp. and Platygyra spp.) and to investigate the temporal variations in the stable δ13C and δ15N isotopes of these three genera in the Dampier Archipelago, Western Australia. This study utilised stable isotope δ13C and δ15N analysis of whole and fractioned (separate host tissue and endosymbiont) corals in conjunction with modern Bayesian isotopic niche analysis to deliver several lines of evidence and provide a representation of the spatio-temporal variability of coral trophic plasticity. This study found that, (i) coral genera exhibited different levels of reliance on heterotrophy under different levels of turbidity, with both Platygyra spp. and Acropora spp. utilising mixotrophic (i.e. both autotrophic and heterotrophic) feeding strategies, whilst Porites spp. was more reliant on heterotrophic resources. (ii) In turbid environments all coral genera increased their reliance on heterotrophy, with clear evidence of a lack of resource sharing between symbiotic partners. (iii) Temporal environmental variability influenced the δ13C and δ15N signatures of corals, whereby signatures were δ13C enriched and δ15N depleted in the wet season (December – April), and the inverse occurred in the dry season (May – November). These results may reflect supressed photosynthetic rates in response to increased turbidity in the wet season. This study provides evidence that some scleractinian corals can adjust their feeding strategies in response to variable turbidity levels. As nearshore coral reefs are expected to become more turbid due to future climate change and anthropogenic activities, the knowledge from this study will allow for improved environmental impact assessment and predictive modelling for future coral reef conservation.
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Caparelli, Alice Castor. « Esforço reprodutivo de Mussismilia braziliensis (Verrill, 1868) (Cnidaria, Scleractinia, Mussidae) no complexo recifal dos Abrolhos, BA, Brasil ». Universidade Federal do Rio de Janeiro, 2004. http://hdl.handle.net/11422/3050.
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Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2017-10-18T22:31:26Z
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Mussismilia braziliensis é endêmica da Bahia, sendo uma das principais espécies formadoras de recife da região. Dez fragmentos de colônias foram coletados em três áreas do Complexo Recifal dos Abrolhos, as quais se encontram a diferentes distâncias da costa. O esforço reprodutivo foi estimado pela fecundidade (número de ovócitos por: pólipo, cm 2, mesentérios e colônias). Foi desenvolvido um novo método de coloração para observação dos ovócitos nos pólipos dissecados. Não foi observada diferença significativa na acurácia da fecundidade por gônada obtida pela dissecção e a histologia. A fecundidade média encontrada por pólipo foi 338,7 (73,5 d.p.) e o número máximo de ovócitos observado foi 987. A fecundidade por pólipo apresentou correlação significativa com sua área, volume, altura e o número de mesentérios férteis do pólipo. A porcentagem de mesentérios férteis por pólipo foi similar entre os locais. Entretanto, a fecundidade por mesentério variou entre colônias e locais. Os dados mostraram que a fecundidade é um parâmetro variável. A área mais próxima da costa (Pedra de Leste) apresentou a maior fecundidade média por pólipo e cm 2 (410 [159,29 d.p.] e 233,47 [219,44 d.p.], respectivamente). Essa área apresenta a maior contribuição de siliciclásticos nos sedimentos depositados nos recifes, e também tem a maior cobertura de Palythoa caribaeorum. Sugerimos que M. braziliensis aumenta a chance de sobrevivência da espécie em ambientes com mais distúrbios ao investir maior energia na produção de gametas. O trabalho fornece dados que podem ser usados como uma ferramenta caso haja impactos ambientais na área.
Mussismilia braziliensis is endemic to Bahia State. lt plays an important role as one of the major reef builders in the area. Ten fragments of colonies were collected at three sites in the Abrolhos Reef Complex, located at different distances from the coast. Reproductive effort was estimated through fecundity (number of eggs per: polyp, cm 2, mesenteries and colony). A new staining method was used to ease identifying and counting eggs in the dissected polyps. The accuracy of the fecundity per gonad obtained through dissection was compared with histological analyses, and showed no significant difference. Mean fecundity per polyp was 338,7 (73,5 s.d.) and the higher number of eggs per polyp was 987. Fecundity per polyp increases as its area, volume, height and number of fertile mesenteries increases. Percentages of fertile mesenteries per polyp were similar among sites. However, the fecundity per mesenteries varied among colonies and sites. Our data showed that the fecundity is variable. The area closest to the coast (Pedra de Leste) presents the highest mean fecundity per polyp and cm 2 (410 [159,29 s.d.] and 233,47 [219,44 s.d.], respectively). This area presents the highest contribution of siliciclastics to the sediment depositing on the reefs and has also the highest cover of Palythoa caribaeorum. We suggested that M braziliensis invest a lot of energy in egg production to increases its chance of survival of the species in more disturb habitats. The study shows data that can be used as a tool if environment threat occur in the area.
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Fontana, Roberto. « Ciclo riproduttivo annuale del corallo solitario Caryophyllia inornata (Scleractinia, Caryophylliidae) caratterizzato da un inusuale modello di embriogenesi ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/6672/.
Texte intégralRésumé :
La varietà dei processi riproduttivi dei coralli riflette la loro straordinaria abilità rigenerativa. Le scleractinie sono un noto esempio di animali clonali, che possono esibire una strategia mista di riproduzione sessuale e asessuale per mantenere la loro popolazione. Questo studio descrive per la prima volta il ciclo riproduttivo annuale e l’embriogenesi del corallo temperato Caryophyllia inornata. I campioni sono stati raccolti mediante immersioni subacquee dal relitto di un aereo, a largo delle coste dell’Isola d’Elba. Sono state eseguite analisi citometriche per definire lo sviluppo annuale delle cellule germinali e l’embriogenesi. Caryophyllia inornata è risultata gonocorica con una sex ratio di 1:3.3 a favore dei maschi. I polipi erano sessualmente maturi a 7 mm di lunghezza. Lo sviluppo degli embrioni è stato osservato in maschi, femmine ed individui sessualmente inattivi. Gli spermiari richiedevano circa 10 mesi di maturazione, mentre l’ovogenesi sembrava essere più rapida. I polipi femmina sono stati trovati solo da Febbraio a Luglio. Il tasso di sviluppo gonadico aumentava sensibilmente da Marzo a Maggio e la fecondazione avveniva tra Maggio e Luglio, quando le cellule germinali all’interno dei polipi iniziavano a scomparire. La gametogenesi ha mostrato una forte influenza stagionale mentre gli embrioni sono stati trovati durante tutto l’anno nei maschi e negli individui sessualmente inattivi, non presentando un andamento ben definito. Questo modello di embriogenesi è poco comune ed è stato osservato solo in quattro scleractinie tropicali (Pocillopora damicornis, Tubastrea Diaphana, T. coccinea e Oulastrea crispata) in cui avviene una produzione interna di embrioni per via agamica. La natura precisa di questo processo è ancora sconosciuta.
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Liu, Chia-Yen, et 劉佳妍. « Sexual reproduction of the scleractinian coral, Platygyra verweyi (Scleractinia ; Merulinidae) exposed to different thermal environments ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/74535044927905159049.
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碩士國立臺灣大學
海洋研究所
101
Coral reefs worldwide suffer from increasing anthropogenic and climatic disturbances. Response of corals with different life-histories strategies may provide valuable insights on which species may occur in future communities. Particularly, reproduction is usually considered as a key factor for the maintenance of coral population. In this study, we compare the reproduction of corals in two contrasting thermal environments: Wanlitung, and the Outlet of the Nuclear Power Plant (NPP Outlet), located at Kenting - Southern Taiwan. Fifteen colonies of massive coral Platygyra verweyi was tagged respectively at each site. Colonies were sampled from March 2012 to May 2013 and their histological statements were examined. Temperature recorder showed average temperature and daily temperature variation at NPP Outlet (27.9 ± 1.5 °C, 2.1 ± 1.0 °C, respectively ) were higher than Wanlitung (27.1 ± 1.6 °C, 1.1 ± 0.4 °C, respectively, Paired t-test, p <0.001). Results confirmed that P. verweyi is simultaneous hermaphrodite with a single annual reproductive cycle at both sites. However, mature egg diameter of P. verweyi at the Outlet (270 ± 34 μm, n = 300) was larger than at Wanlitung (225 ± 31 μm, n = 300). Number of matured eggs in P. verweyi was lower in samples from Outlet (72 ± 32 polyp-1, n = 45) compared to Wanlitung (137 ± 61 polyp-1, n = 45). No linear regression relationship was found between colony size and egg size or number between two sites. Overall, this study shows that reproductive responses in corals inhabited in the contrast environments implicated differ remarkably. The change in reproduction represents that P. verweyi may have alternative reproductive strategies for egg size, fecundity, and gamete development at the NPP Outlet and Wanlitung, due to adaptation or acclimatization of life history characteristics in different thermal environments.
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Nu-Wei, Vivian Wei. « Interspecies relationships in Acropora (Cnidaria : Scleractinia) ». 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-3001200721012000.
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