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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.
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Santora, 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.
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Thesis (M.S.)--George Mason University, 2008.Vita: 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.
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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.
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Chartrand, 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.
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Mõtus, 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.
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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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Fuchs, Eran 1963. "Fluorescence in reef corals". Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/8966.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1999.Includes 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.
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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/.
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Coral reefs are at risk and human-induced environmental stressors in synergism with microorganisms have been shown to be the key players for their deterioration. Little is known about the dynamics of coral-microbial associations through different life stages of the coral holobiont and virtually nothing is known about coral-microbial partners in Western Australian coral reef systems. This project intended to investigate the presence, diversity, community structure and role of coral-associated microbes in Ningaloo Reef spawning and brooding corals. Different coral life stages were assessed.
To determine ‘normal ranges’ of coral-associated microbes, three coral species (Acropora tenuis, Pocillopora damicornis and Favites abdita) were tagged and examined over a period of one year, with sampling deployed every three months. One coral species was additionally sampled on Rottnest Island, 1200km south of Ningaloo Reef, to provide comparisons between coral-associated microbes in different geographical areas. The community structure of the coral-associated microorganisms was analysed by phylogenetic analysis of 16S rRNA gene clone libraries. Principal component analysis (PCA) revealed that samples grouped according to time and not species, indicating that coral-microbial associations may be a result of environmental drivers such as oceanographic characteristics, benthic community structure and temperature. Tissue samples from Rottnest Island corals revealed similarities in bacteria to the samples at Ningaloo Reef. This study highlights that coral-associated microbial communities are highly diverse; however, the complex interactions that determine the stability of these associations are not necessarily dependant on coral host specificity.
Reproduction plays a crucial role in the survival of species, therefore, data was acquired from three adult coral colonies, Acropora tenuis (broadcast spawner), Pocillopora damicornis (brooder) and Tubastrea faulkneri (ahermatypic), before and after coral mass spawning to determine if and through which drivers coral microbial communities changed through this event. A contemporary 454 sequencing approach was implemented and results revealed distinct bacterial shifts through coral mass spawning for all corals, independently of reproductive activity. Clear changes in bacterial assemblages were also detected for brooders after planulation. This infers that coral-associated microbial communities change through a coral mass spawning event and are likely driven by environmental factors and the respective bacterial community in the seawater, as well as by actual coral reproduction. Differences in coral-microbial communities reflected different life styles between brooding and spawning corals. Most α-Proteobacteria increased in abundance after spawning as well as after planulation, suggesting that specific bacteria are involved in coral reproduction irrespective of reproductive strategies; particularly bacteria affiliated with the Roseobacter clade followed this pattern.
The assessment of seawater collected from the broadcast spawning coral A. tenuis and P. damicornis after spawning and planulation, respectively revealed that adult corals, irrespective of their reproductive strategy release bacteria with their offspring which likely increases the fitness in the following processes involved in settlement and survival. Species affiliated with the genera Roseobacter and Alteromonas appear to play important roles in coral reproduction and early life history in corals.
Isolates from P. damicornis planulae were mainly affiliated with the genera Vibrio and Alteromonas and were found to be similar to bacteria released by the mother colony during planulation.
Finally the establishment of coral-microbial partnerships in coral larval stages and the potential role of these symbiotic relationships were studied. The early onset of bacterial associations in brooding and broadcast spawning corals was visualized, exploring bacterial presence and their location in the coral organism, determining when and how bacteria enter coral tissues and their cycling of nutrients towards the coral-symbiotic algal partners. Nano-scale Second Ion Mass Spectrometry (SIMS) was applied to detect, image and map the uptake and translocation of 15N from bacteria into coral larvae on a sub-cellular level. The study also combined Fluorescent In Situ Hybridisation (FISH) to co-localize the labelled substrate with bacteria and Transmission Electron Microscopy (TEM) to allow for ultra-structural resolution images to provide high resolution images. This study for the first time demonstrated the beneficial role of specific bacteria in translocating nitrogen into the coral holobiont, which is particularly important in the nutrient-poor environments corals live in.
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Hicks, 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/.
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Clark, 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.
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Randall, 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.
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Kluter, 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.
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Johnson, 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.
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This thesis provides a detailed analysis of the growth and survivorship of outplanted Acropora cervicornis corals from underwater nurseries within three regions of the Florida Reef Tract. Substantial loss of stony coral cover on Florida’s coral reefs, including the branching staghorn coral, Acropora cervicornis, has occurred for decades due to disturbances such as disease, temperature induced bleaching, hurricanes, sedimentation, and pollution. This rapid population decline contributed to A. cervicornis being listed as a threatened species under the U.S. Endangered Species Act in May 2006. To aid in the recovery of the species, coral fragments were grown in underwater nurseries and outplanted to selected sites located within unique cross-shelf zones in the Upper Florida Keys, Lower Keys, and Biscayne regions. This study evaluated the regional and zonal variation in growth and survivorship of known genotypes of outplanted A. cervicornis corals to better inform future large-scale restoration projects. The zone in which corals of A. cervicornis were outplanted to had a more significant effect on growth than the coral genotype. The forereef zone within the Upper and Lower Keys regions and the mid-channel zone in the Biscayne region had significantly higher mean growth rates. When comparing growth rates of genotypes that performed best, high growth, in the Lower Keys nursery, these same genotypes did not perform the best at any of the outplant sites. Survivorship was not significantly different in any of the regions. Based on these results, future coral outplantings focused in the forereef and mid-channel zones would maximize growth. Choosing coral genotypes based on their high growth rates in the nursery does not ensure the same high growth rates when outplanted.
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Williams, 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.
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Collinson, 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.
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Fitzhardinge, Rachel C. "The Ecology of Juvenile Hawaiian Corals". Thesis, University of Hawai'i, Honolulu, 1993. http://hdl.handle.net/10125/15320.
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I studied coral recruitment, growth and community
development in Kaneohe Bay, Oahu, Hawaii. In one
experiment, I investigated coral recruitment at 7 sites, in
3 consecutive years. Coral community development was
followed for up to 3 y. Hollow concrete blocks were used
as experimental substrata. The smallest recruits which I
detected were 1 mm in diameter.
variability in recruitment was observed both between
sites and between surfaces of the blocks. Temporal
variability in recruitment patterns between years was also
recorded. After 3 mo immersion, Pocillopora damicornis, a
brooding species, was-the most abundant coral. Another
brooding species, Cyphastrea ocellina, and the ahermatype,
Culicia cf. tenella were also detected. Two spawning.
species, Montipora verrucosa and Porites compressa were not
detected until after 6 mo immersion. Over 3 y, the
relative abundance of Pocillopora damicornis declined at
most sites and the relative abundance of Porites compressa
increased. Montipora verrucosa recruits remained uncommon.
The distribution of hermatypic corals on the blocks
also changed with time. Initially recruits were most
abundant on interior top surfaces after 3 y, they were most
common on outer surfaces of the blocks.
Inter- and intraspecific differences in growth were
recorded. pocillopora damicornis attained the largest colony sizes. Growth rates varied considerably between
sites. Successful recruitment was highest after 3 y
immersion, at sites where corals grew most rapidly.
In the second set of experiments, I measured invisible
recruitment sensu wallace (1983) and investigated the
effects of urchin and fish grazing on coral recruitment.
Montipora verrucosa was the most common recruit after 3 mo
immersion. Fish and urchin grazing significantly affected
the abundance of M. verrucosa but not that of Porites
compressa or Pocillopora damicornis.
After 3 mo immersion, the maximum size attained by P.
damicornis was greater than P. compressa or M. verrucosa
which had similar colony diameters and number of polyps.
However, during the next 5 mo P. compressa grew more
rapidly than M. verrucosa. The different growth rates of
these species explains why P. compressa increased, and M.
verrucosa decreased in relative abundance.
Interspecific differences in larval size at
settlement, the time taken to deposit a skeleton, and postsettlement
growth strategies, all influence recruitment
success.Thesis (Ph. D.)--University of Hawaii at Manoa, 1993. Includes bibliographical references (leaves 240-252)
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Daniels, Camille Arian. "Microbial Landscapes of Corals and Ctenophores". Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3061.
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As technology and engineering allow mankind to survey nature at finer scales, the importance of bacteria has been elucidated in their metabolic diversity, ability to transfer genetic information, involvement in biogeochemical cycling, and sheer abundance. With an individual domain of life unto themselves, this diverse group of microorganisms plays an integral role in facilitating life on land and in the oceans, and is second only to viruses in abundance on Earth. They carve niches in a wide range of environments, including those inhospitable to other life forms, and reside in concert or to the detriment of other microbes and/or hosts they inhabit. Solely culturing microorganisms has proven to
severely underestimate microbial numbers, capturing less than 1% of marine microbes. However, the advent of molecular methods has revealed the ubiquity, abundance, and diversity of bacteria. Higher organisms have evolved varying degrees of ecological relationships with bacteria, ranging from mutualism to parasitism. As the microbial
players are elucidated, determining the specificity and functional roles of these bacteria is a critical and exciting scientific question. The
microbiome of corals is an interesting model of complexity, with the animal host striving to maintain a delicate symbiosis, and using its microbiota to assist in nutrient cycling and protection. A contrasting example to the well-studied cnidarians are ctenophores, gelatinous organisms that are globally distributed in the world's oceans, yet the literature contains few studies on microbiota associated with this unique group of animals. Since ctenophores are one of the earliest diverging, extant multicellular animals, these unique organisms could prove to be a better model system than cnidarians.
The first project in this dissertation examined spatial structure of bacteria across wild, healthy colonies of the coral Montastraea annularis. Microscale heterogeneity of the bacterial community was observed in coral mucus samples collected tens of centimeters apart on the same coral colony, which has implications for sampling
strategies in microbiological studies, and impacts the application of the bacterial community as a proxy for determining coral condition in coral restoration projects. The second project looked at the linkages between coral bacterial community composition and zooxanthellae clade in Pocillopora damicornis, and results suggested that clade is not a major factor in influencing coral bacterial community composition. Sample location was also considered in the P. damicornis bacterial surveys and determined to be driving
community structure. The third project is the first study to describe bacteria associated with ctenophores (Mnemiopsis leidyi and Beroe ovata). The ctenophores contained bacterial communities that were distinct from the surrounding water column, and
temporal variability was exhibited by bacteria associated with the ctenophores. Exploring microbial landscapes in cnidarians and ctenophores to understand microbial roles in health and disease is the uniting theme of the three separate projects that will be discussed in this dissertation.
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GALLI, GIOVANNI. "Modelling Mediterranean corals and coralligenous habitats". Doctoral thesis, Università degli Studi di Trieste, 2016. http://hdl.handle.net/11368/2908051.
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The Mediterranean sea, just like the rest of the world seas, is facing a whole new variety of pressures related to human activities; vulnerable species and habitats are already being altered by such pressures. Among Mediterranean biocenoses, the coralligenous reefs, mid-water calcareous bioconstructions, are especially vulnerable.
For these reasons it is needed to build a solid knowledge about the relations that underlie climate and biological organisms. A convenient way to address these issues is trough numerical models becausse they allow for generality to emerge and are suitable tools for predictive purposes.
This thesis presents a collection of contributions focused on marine calcifiers from Mediterranean coralligenous habitats. Various aspects of ecology and phisiology are addressed at various scales in both time and space trough numerical applications.
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Gómez, 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.
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Ossolinski, 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.
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Williams, 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.
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George, Adrienne. "Cataloguing Diseases and Pests in Captive Corals". Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3115.
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Stony corals (Order Scleractinia) are susceptible to a variety of diseases, which can occur from abiotic or biotic factors, or a combination of both. Public aquaria provide opportunities to study coral disease. Because coral mucus is the first line of defense against disease, the Biolog EcoplateTM is a useful tool to detect differences in microbial assemblages in the surface mucopolysaccharide (mucus) layer when comparing healthy and diseased corals. Histological examination is essential to document structural changes in coral tissue in response to diseases. This study identifies and characterizes diseases in captive corals through visual recognition, characterization of carbon utilization by microbial assemblages in coral mucus samples, and histological examination. In March 2010, surveys were sent to public aquaria throughout the United States that house corals. If the survey was returned indicating that the aquarium had diseased coral specimens present, sample kits were sent to the aquarium to acquire photographs, mucus samples for microbial carbon utilization analysis, and tissue samples for histological examination. Eighteen aquaria participated in the survey and 25 sets of samples were provided. The gross lesions from diseased samples fit into six categories: discoloration associated with darkening of the tissue or with color loss (bleaching), growth anomalies, and tissue loss associated with pests, with brown jelly, or with no obvious cause. Seven categories of possible contributing factors were reported: addition of inadequately quarantined corals to the tank, damage during transport, change of location, manual stress, and variations in light, salinity, or temperature. Introduction of inadequately quarantined specimens was the most common possible contributing factor to pest introduction. Significant differences in carbon source utilization were found between tank-water samples and mucus from both healthy and diseased areas of sampled corals. Although mucus samples from healthy and diseased samples did not differ in carbon source utilization overall, D-mannitol was used by 52% of microbial assemblages from mucus from diseased areas compared with only 17% of microbial assemblages from healthy mucus samples. Histologically, the most commonly observed features across all samples were healthy zooxanthellae, endolithic organisms, and nematocysts, all of which are normal features that can be influenced by stress factors. Brown granular material and ciliates were found associated with some anomalies, primarily the three categories of tissue loss. The presence of dense aggregates of zooxanthellate-engorged ciliates in corals afflicted with brown jelly was highly similar to histological observations of brown band syndrome, previously described from natural coral reefs.
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Guppy, 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.
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Adkins, Jess F. (Jess Firey). "Deep-sea corals : a new oceanic archive". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/44503.
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Gilmour, 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.
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[Truncated abstract] Most ecological research investigates the demography of organisms, which can be summarised by their population dynamics and structure. Population dynamics are the rates of birth, growth, reproduction and survival of individuals, which determine the number of individuals in different stage classes, or, the population structure. Understanding the demography of organisms is particularly difficult, and requires the application of different methods of investigation. A number of methods of investigation are required because each can only investigate particular aspects of population demography, and is subject to problems of inaccuracy and bias. Thus, population demography is best understood by simultaneously collecting complimentary data using different methods of analysis to quantify how and why the dynamics and structure of populations change with their environment. The need for complimentary methods of investigation to understand population demography is even greater for organisms that have complex life histories, such as corals. The life histories of corals are particularly complex because they display a variety of modes of sexual and asexual reproduction, and their rates of growth, reproduction and survival are strongly influenced by the size of the individual, which can change rapidly. Additionally, the rates of sexual recruitment to populations of corals are notoriously variable in space and time. Thus, corals are an ideal model to investigate the usefulness of combining methods of analysis to better understand the demography of organisms. In this thesis I demonstrate that combining data from a number of methods of analysis provides a much better understanding of the demography of populations of the mushroom coral Fungia fungites that were exposed to contrasting regimes of disturbance. I used methods of analysis that produce unique and complimentary results, in the form of genetic, size-structure, life history and experimental data. Genetic data confirmed that I was correctly identifying life history stages of polyps, indicated the extent to which a stock-recruitment relationship existed between the sexual recruits and the adult polyps at each population, and provided an estimate of the relative contribution of asexual recruitment to population maintenance. Changes in the size-structures of populations were quantified to determine the effects of different regimes of disturbance, and these changes in population structure were explained by quantifying the life history traits of polyps and their rates of transition through their life cycle. An experimental manipulation was conducted to specifically quantify the effects of sedimentation on the rates of survival and asexual recruitment of polyps, because sedimentation was an important disturbance whose effects were confounded by additional variables. Together, the set of complimentary data provided a good understanding of population demography in the context of varying levels of exposure to certain disturbances, and enabled the best possible predictions about the future of each population under a variety of conditions
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Wood, 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.
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Corals, sessile as adults, disperse by releasing a pelagic larval stage into the water, which drifts with the ocean currents over potentially thousands of kilometres between reef habitats. Determining patterns of dispersal is an important but difficult task for reef conservation science; coral larvae are impossible to track directly in the marine environment. Biophysical models provide an essential tool to explore the patterns and drivers of dispersal. However, they have previously been utilised at regional scales, excluding the potential for long-distance transport events of particular importance to coral biogeography. In light of recent computational advances, I develop the first high-resolution global model of coral larval dispersal. The model provides critical evidence regarding the influence of dispersal on coral biogeography, highlighting vulnerable isolated areas as well as important sources and stepping stones for dispersal. For example, eastern Pacific reefs emerge as some of the most isolated globally. Contrary to hypotheses of increased dispersal into this region during El Nino events, I find only westward dispersal out of the eastern Pacific over a 10 year period, including the extreme 1997-98 El Nino. The Galapagos Islands act as the sole source for dispersal across the 6000 km separating eastern from central Pacific reefs. The model is the first to incorporate the effects of environmental factors (temperature and ocean pH) on larval physiology, predicted to result in alterations to patterns of dispersal with climate change. I find that dispersal patterns are especially sensitive to the effect of temperature on larval mortality, although the response varies geographically. Increases in temperatures predicted for 2060 reduce long-distance dispersal and increase local retention in the model, potentially reducing the scale over which /management efforts will be effective. Future work will aim to incorporate various other factors likely to influence future dispersal, informing management of reefs under climate change.
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Coni, 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.
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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.
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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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Withers, 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.
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Gibbs, 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.
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The Janzen-Connell hypothesis proposes that species-specific enemies promote species coexistence through distance- and density-dependent survival of offspring near conspecific adults. I tested this hypothesis experimentally by transplanting juvenile-sized fragments of two species of brooding corals varying distances from conspecific adults, and observationally by assessing the spatial distribution of those two species in the field. Small fragments (as proxies for ?6 month old juveniles) of Pocillopora damicornis and Seriatopora hystrix were transplanted 3, 12, 24 and 182 cm upstream and downstream (relative to the prevailing current) of conspecific adults and their survivorship and condition (bitten off, overgrown by algae, or bleached) checked every 1-2 d. I also characterized the spatial distribution of P. damicornis and S. hystrix within replicated plots on three Fijian reef flats and measured densities of small colonies within 2 m of larger colonies of each species.
Contrary to the Janzen-Connell hypothesis, juvenile-sized transplants exhibited no differences in survivorship as a function of distance from adult P. damicornis or S. hystrix and P. damicornis and S. hystrix were aggregated rather than overdispersed on natural reefs. Survival unaffected by distance from focal colonies as well as certain recruitment processes could generate the observed aggregation. I did observe predation of P. damicornis that was spatially patchy and temporally persistent due to feeding by the territorial triggerfish Balistapus undulatus. This patchy predation did not occur for S. hystrix. Thus, I found no support for the Janzen-Connell hypothesis, but did document hot-spots of species-specific corallivory that could create variable selective regimes on an otherwise more uniform environment, and help maintain the high diversity of corals typical of Indo-Pacific reefs.
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Arnold, 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.
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Brito, 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.
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Underwood, 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.
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[Truncated abstract] The extent to which marine populations are connected by larval dispersal is crucial to their distribution, maintenance and diversity. Thus, for the effective conservation of threatened systems such as coral reefs, understanding patterns of connectivity is essential. However, the biophysical mechanisms that retain or disperse larvae within and among populations are poorly understood. Though the open ocean environment provides the opportunity for long-distance dispersal, if this potential is only rarely realised, recruits produced from afar are unlikely to contribute to the local-scale demography of populations over ecological time frames, but will limit broad-scale genetic diversification over evolutionary time. This thesis explores the extent of genetic and demographic connectivity of two species of reef-building corals over a range of spatial scales among the discontinuous reef systems of northwest Australia. ... Putative source and sink dynamics were not random, but were associated with levels of disturbance and recovery from a recent and catastrophic coral bleaching. When S. hystrix samples from another two offshore systems were included in the analysis, large differences among systems showed that gene flow over hundreds of kilometres is rare over microevolutionary time scales that account for connections over multiple generations. Levels of subdivision over the same spatial scales were markedly lower in the acroporid coral, Acropora tenuis, than in S. hystrix. These results are congruent with expectations based on reproductive mode; in contrast to S. hystrix, which releases brooded larvae that are competent to settle immediately, A. tenuis broadcasts its gametes, and after external fertilisation, the larvae need to develop for several days before they are competent to settle. Despite the differences in levels of broad-scale subdivision, in both species significant differentiation was detected between reefs within systems (>10 km), and between sites within some reefs (< 10 km). These results indicate not only that dispersal between reefs and even some reef patches is restricted, but also that hydrodynamics influence retention of brooded and spawned larvae in similar ways. Further analysis of A. tenuis populations from two coastal systems detected significant differences in genetic diversity among the four major systems of northwest Australia. Additionally, genetic divergence between the coastal and offshore zones was greater than expected by the geographic separation of systems, indicating that connectivity between these zones via transport of A. tenuis larvae on oceanic currents occurs rarely even over microevolutionary time scales. This study has two primary implications for conservation. First, since coastal and offshore reefs of northwest Australia appear to be discrete genetic entities, they have independent evolutionary potential to adapt to local conditions and environmental change. Second, systems, reefs and some reef patches of northwest Australia are demographically independent units. Therefore, designs of coral reserve networks should consider routine dispersal distances of kilometres to a few tens of kilometres.
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Joyce, 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.
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PAPAZACHARIOU, 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.
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One of the main focus of coral reef ecology has been to shed light on the importance of all microbial members of coral holobiont and how their interactions contribute to the coral’s resilience. However, knowledge is lacking about the composition of microbial communities inhabiting the surface mucus layer of corals including Fungia fungites, a species that lives under stressful conditions close to fish farms in Vietnam. I investigated the prokaryotic communities that are thriving in Fungia fungites surface mucus layer (SML) in the wild and how they were affected upon antibiotics and nitrogen stress using 16S rRNA gene-based techniques. Firstly, I observed a significant alteration in the composition of microbial communities due to antibiotics effect, with exposed communities featuring lower richness and α-diversity in contrast to the controls. Further, mucosal microbial communities were found to be mostly dominated by Proteobacteria (especially of the classes of Alphaproteobacteria and Gammaproteobacteria) and less by Bacteroidetes (Flavobacteriia). Results from this study suggest a developed antibiotic resistance of Alteromonadales and Campylobacterales indicated by their increased abundance upon antibiotics effect. Moving forward, future studies should focus on exploring also the contribution of non-prokaryotic microbial members of Fungia fungites holobiont and how antibiotic resistance can potentially influence coral’s health. The results support that Fungia fungites SML microbial communities are strongly affected by antibiotics exposure and call for future research to focus on the function of these microbial communities and how they can contribute to the coral’s resilience.
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Zayasu, Yuna. "The cospeciation between massive corals and gall crabs". 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188516.
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Merks, 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.
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Jatkar, Amita. "Mucus layer properties and dynamics in reef corals". Thesis, University of Newcastle Upon Tyne, 2009. http://hdl.handle.net/10443/125.
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Mucus functions as the first line of defence against infections, amongst other roles. The protective role of mucus depends upon gel-forming properties of mucin molecules that are encoded by the MUC genes. Failure of this protective barrier has been associated with changes in structure, function and physical properties of mucins in human diseases (cancer, IBD and cystic fibrosis) and has been proposed as a prognostic tool for early diagnosis of these diseases. The study of coral mucus is in its infancy and early investigations on coral mucus gave incomplete and variable chemical composition data. The dynamic nature of the coral surface mucus layer (SML) in limiting pathogens remains unexplored. The present study attempts to detect coral muc genes by tracing the evolution of muc genes from cnidarians to mammals using bioinformatics tools, examines the coral mucin molecule and investigates the response of epidermal and surface mucus to the changing environmental conditions. The presence of a continuous SML at least 145 μm thick on the coral epithelium has been demonstrated for the first time. Rheological studies confirmed the presence of high molecular weight, polymeric glycoprotein similar to mammalian mucin. The study has also developed molecular tools (primers) based on bioinformatics information and has detected tandem repeats rich in serine, threonine and proline and C-terminal Cysteine Knot regions homologous to those of human gel forming mucins. A variation in the epidermal mucus content as well as SML was noticed in between the species as a response to bleaching (loss of zooxanthellae and complete white appearance of coral tissue) and changing environmental conditions (tidal cycle). Thus, study of mucus indicates the health of corals and plays an important role in survival of coral during diseases and environmental stressful conditions.
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Stafford-Smith, Mary Gillian. "The effect of sediments on Australian scleractinian corals". Thesis, University of York, 1990. http://etheses.whiterose.ac.uk/4244/.
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Gaudian, 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.
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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.
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Wild, Fiona Jane. "The photophysics of luminescent banding in reef corals". Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/13232.
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Under ultraviolet light, massive coral skeletons reveal a series of luminescent bands that can be categorised as "bright" (yellow/green) and "dull" (blue). This work elucidates the photophysical processes that are responsible for the appearance of bright and dull bands. Samples from Papua New Guinea (subject to terrestrial inundation) and Oman (not subject to terrestrial inundation) have been investigated and compared. It has been shown that luminescent banding can be recorded directly from the surface of the coral, without the need for extraction of the component luminophores. Using 3D EEM spectroscopy, the luminescence properties of the bright and dull bands have been reproducibility characterised. Using optical fibre beam delivery, spatial resolution of the banding pattern has been achieved. The variations in intensity of luminescence along the coral core have been recorded with excellent reproducibility. The bright and dull bands observed in all samples contain similar groups of luminophores. The relative intensity of luminescence from each group varies between bands and between samples from different locations. Samples from locations with no terrestrial input exhibit similar luminescence characteristics as those that are regularly inundated with terrestrial run-off. This suggests that luminescent banding is not due solely to the incorporation of terrestrial matter into the coral skeleton. Studies have suggested that the banding pattern is also related to structural variations in the skeleton. It has been established that corals exhibit phosphorescence. The difference is phosphorescence intensity between bright and dull bands is substantially greater than the difference in total luminescence intensity. Hence, phosphorescence is an important indicator of the banding pattern and may prove to be a more valuable tool than luminescence in unravelling the environmental records stored in coral skeletons.
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Riegl, Bernhard. "Taxonomy and ecology of South African reef corals". Doctoral thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/9666.
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Bibliography: p. 492-494.This 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.
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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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Georgian, 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.
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BiologyPh.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
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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.
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CAPES
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,
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Leal, Miguel Albuquerque da Costa. "Trophic plasticity in the cnidarian-dinoflagellate symbiosis". Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13738.
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Doutoramento em BiologiaCoral 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.
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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.
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Montseny, 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.
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Cold-water coral (CWC) habitats dwell on continental shelves, slopes, canyons, seamounts, and ridge systems around the world’s oceans, from 50 m to depths up to 4000 m. CWC species provide heterogeneous habitats supporting a myriad of associated fauna and form highly diverse CWC reefs and CWC gardens. Main threats, currently impacting CWC ecosystems come from anthropogenic stressors, such as fishing activities, oil and gas exploitation and the incipient mining activity. Likewise, climate change, causing changes in the water column, is also affecting these ecosystems. Life-history traits of CWC species (long lifespans, slow growth and limited recruitment) make them very vulnerable to current and potential threats. Given their limited recovery capacity, interest to preserve and restore CWC ecosystem is steadily growing. The creation of Marine Protected Areas and active ecological restoration actions are nowadays the best management tools to conserve native ecosystems and represents an opportunity to revert the anthropogenic damage that has already taken place. Through passive (natural regeneration after the cessation of stressors) and active (human interacts with biotic and/or abiotic ecosystem features) approaches, restoration activities seek to accelerate the recovery of ecosystem structure and functioning relative to a reference model. Contrarily to terrestrial and shallow-water marine ecosystems, ecological restoration in intermediate (50 – 200 m) and deep marine (> 200 m) environments has received lesser attention. To date, only few restoration actions at local scales have been carried out at those depths, mainly due to technical and economic limitations which questions its wide application. Scaling-up restoration actions and make them affordable are the main present challenges for CWC restoration. In this sense, in order to move forward towards the conservation of intermediate and deep-sea ecosystems, the general aim of the present thesis is to assess the impact of fishing activity on CWC gardens as well as to explore the feasibility of novel active ecological restoration techniques.
All the work performed during this thesis has been carried out at the Cap de Creus marine area (North-Western Mediterranean Sea), specifically at the continental shelf (60 – 130 m), where gorgonians, sponges, and sea pen species form CWC gardens supporting a variety of mobile associated fauna. The target species is the yellow gorgonian Eunicella cavolini (Koch, 1887) which dominate in the area forming density patches. In the first chapter, the impact of artisanal fishing was quantified to evaluate the threat of this activity on CWC gardens and to provide essential information to mitigate such impact. The rest of chapters (2, 3 and 4) evaluated, for the first time, the viability to actively restore degraded E. cavolini populations. Specifically, in the second chapter, gorgonians obtained from bycatch (accidentally caught of non-target species) of local artisanal fishers, were transplanted to artificial structures deployed on the continental shelf (805 m). This pilot study demonstrated, for the first time, the high survival of E. cavolini transplants. Following, and going one step forward, in the third chapter, field experiments and modeling approaches
were combined to develop and technically validate an innovative large-scale and cost- effective restoration method for CWC gardens. Successful results evidenced the feasibility of recovering bycatch E. cavolini and returning them to their natural habitat with this novel method so-called “badminton method”. Finally, in the fourth and last chapter, a large- scale restoration action of E. cavolini populations was carried out in collaboration with local artisanal fishers during two consecutive fishing seasons by applying the technique previously developed. A large number of gorgonians (460 colonies) were successfully reintroduced and survived at the end of the action (2 years) at 80-100 m depth. The results suggested an initial establishment of a new gorgonian population, which will potentially evolve toward a comparable natural population in terms of size and spatial structure, if natural recruitment also occurs. Moreover, an economic evaluation was performed, also confirming the cost efficiency of this method aimed at enhancing the recovery of impacted CWC gardens.
The lack of knowledge of some key ecological processes of CWC ecosystems as well as the technical limitations hinder a complete evaluation of restoration efforts performed. However, this thesis represents a promising improvement for the conservation and recovery of CWCs that could be extended to other areas and regions.Els 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.
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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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This study examined the occurrence of Lophelia pertusa on North Sea oil infrastructure and its environmental sensitivity to oil and gas activities. Underwater videos from industry platform surveys were examined to identify L. pertusa, detail its occurrence at two sites (Heather and North Alwyn A (NAA)), and to look for evidence of exposure to drilling muds and cuttings (discharges). In addition, live corals were exposed to 4-h sedimentation events of increasing rates and polyp behaviour analysed. Sediment removal mechanisms were also examined. Finally, skeletal characteristics and trace metal concentrations were measured in skeletons sampled from platform sites exposed to drilling discharges and control sites. The results showed a newly established sub-population of L. pertusa in the northern North Sea. L. pertusa was identified on 14 platforms and 947 colonies were recorded on Heather and NAA between 59 to 132 m depth coinciding with the presence of year round Atlantic water. Original recruits were likely from the northeast Atlantic and are now annually self-recruiting to the platforms. Additional video from Tern in 1993, 1994, 1998, and 2002 provided the first in situ colony growth rate (26 ± 5 mm yr-1) for L. pertusa. Visual evidence of contamination from drilling discharges was limited to colonies close to drilling discharge points where partial and complete colonies were dead. Polyp behaviour was negatively affected only at the highest sedimentation rates (12-19 mg cm-2 min-1), which are likely to be significantly higher than in situ rates, and polyps cleared sediment with ciliary currents and ingestion, which may be an indiscriminate feeding response. Corals exposed to discharges had shorter and narrower corallites compared to controls but other causal factors merit consideration such as genetics and hydrography. Further results showed that polyps bud annually and reach their maximum height in their first year, while the theca thickens at a constant rate, thus implying that the innermost growth band likely represents the first year of growth. Relatively depleted δ13C and δ18O along the inner growth band, which indicates fast calcification, supported this result. Copper and barium in coral skeletons including visible detrital inclusions were significantly higher in exposed versus control colonies. Chromium and barium along the growth axis, avoiding detrital inclusions, showed one exposed polyp from a colony living two meters above the cuttings pile on North West Hutton (NWH) with higher barium compared to control colonies. Short-lived barium spikes were observed in two polyps from a control colony sampled from North Cormorant. It is hypothesised that the NWH coral may have been exposed to dissolved barium released during cuttings resuspension, while barium spikes in the control colony may result from natural fluctuations in seawater barium, thus advocating that L. pertusa can act as an archive of the marine environment.