Dissertations / Theses on the topic 'Marine chemical ecology'
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Jenkins, Kelly Matthew. "Chemical investigations of marine filamentous and zoosporic fungi and studies in marine microbial chemical ecology /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9907830.
Full textPaul, Nicholas Andrew School of Biological Earth & Environmental Sciences UNSW. "The ecology of chemical defence in a filamentous marine red alga." Awarded by:University of New South Wales. School of Biological, Earth and Environmental Sciences, 2006. http://handle.unsw.edu.au/1959.4/24304.
Full textGray, Christopher Anthony. "The role of a symbiotic bryozoan in the chemical ecology of a marine benthic predator-prey interaction." Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1005444.
Full text李崇志 and Sung-chi Lee. "Chemical ecology of algae and the cyanobacterium kyrtuthrix maculans on Hong Kong rocky shores." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31241955.
Full textLee, Sung-chi. "Chemical ecology of algae and the cyanobacterium kyrtuthrix maculans on Hong Kong rocky shores." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23316688.
Full textHicks, Melissa Kathryn. "Chemical cues affecting susceptibility of gorgonian corals to fungal infection." Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-11272005-165350/.
Full textRuchonnet, Diane Astrid. "The chemical ecology and antibacterial activity of the brown alga Halidrys siliquosa and other Scottish seaweeds." Thesis, University of Aberdeen, 2007. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=186834.
Full textD'Souza, Nicole. "A marine chemical ecology study of the sea hare, Bursatella leachii in South Africa." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1002952.
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Figuerola, Balañá Blanca. "Biodiversity and Chemical ecology in Antarctic bryozoans = Biodiversitat i ecologia química de briozous antàrtics." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/129165.
Full textAquesta tesi cobreix dos aspectes importants i poc coneguts dels briozous antàrtics: la biodiversitat i l'ecologia química. L'anàlisi comparatiu de diversitat realitzat aquí (Capítol 1 i 2) entre l'Antàrtida i altres zones geogràficament properes recolzen la hipòtesi de la separació seqüencial de Gondwana. Es discuteix que l'elevat nombre d'espècies de la regió de la Patagònia argentina (PA) compartides amb l'Antàrtida qüestiona el grau real d'aïllament de l'Antàrtida en briozous queilostòmats. Els nostres estudis (Capítols 1 i 2) són també una de les primeres caracteritzacions de les comunitats de briozous, principalment del talús, de la regió de la PA, i de l' Oceà Austral, especialment el Mar de Weddell. Els nostres resultats remarquen la importància dels estudis taxonòmics en aquestes regions escassament explorades, incloent un gran nombre de nous gèneres i espècies, i noves cites. Entre les noves espècies trobades en el nostre estudi, es descriu un briozou del gènere Reteporella caracteritzat per una rara aviculària esfèrica i gegant, portant-nos a reconsiderar quines són les possibles funcions de l'aviculària (Capítol 3). Com les comunitats estudiades de briozous, per sota de les zones afectades per pertorbacions locals (erosió per icebergs), estan subjectes principalment a factors biòtics com la competència i la depredació, l'evolució ha afavorit el desenvolupament de mecanismes químics de protecció (Capítols 4 i 5). Els nostres estudis són dels primers en ecologia química de briozous antàrtics. Els nostres resultats demostren la importància de diversos mecanismes d'ecologia química contra la competència i la depredació en briozous antàrtics. La majoria de les espècies de briozous mostraven activitat citotòxica i/o repel•lent contra l'eriçó de mar Sterechinus neumayeri i l'amfípode Cheirimedon femoratus, respectivament (Capítol 4). En el capítol 5, totes les espècies de briozous estudiats mostraven activitat de repel•lència alimentària contra almenys un dels dos depredadors abundants considerats, l'estrella de mar Odontaster validus i l'amfípode Cheirimedon femoratus. La tendència general en el nostre estudi indica la possessió d'una combinació de mecanismes físics i químics en la majoria de les espècies, fet que suggereix estratègies complementàries.
Wai, Ho Yin. "Effects of deployment of artificial reefs on the marine benthic environment, with special reference to sediment physico-chemical characteristics /." access full-text access abstract and table of contents, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?mphil-bch-b23750856f.pdf.
Full text"Submitted to Department of Biology and Chemistry in partial fulfillment of the requirements for the degree of Master of Philosophy." Includes bibliographical references (leaves 144-191)
Wojnar, Joanna M. "Isolation of new secondary metabolites from New Zealand marine invertebrates : a thesis submitted to the Victoria University of Wellington in fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry /." ResearchArchive@Victoria e-Thesis, 2008. http://hdl.handle.net/10063/630.
Full textTaboada, Moreno Sergio. "Antarctic marine benthic invertebrates: chemical ecology, bioactivity and biodiversity / Invertebrados bentónicos marinos de la Antártida: ecología química, bioactividad y biodiversidad." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/83921.
Full textThe Thesis entitled “Antarctic marine benthic invertebrates: chemical ecology, bioactivity and biodiversity" covers different aspects related to Antarctic marine benthic invertebrates. This is a multidisciplinar thesis comprising several scientific papers making the following contributions: (i) on the one hand it revises the described Antarctic marine natural products derived from animals and algae up to May 2007. In this revision, special emphasis is given to the role that these natural products play in their ecosystem; (ii) this thesis also provides data from feeding repellent experiments using lipophilic extracts from benthic invertebrates from two poorly known areas (eastern Weddell Sea and Bouvet Island). These experiments, carried out using sympatric predators, showed that more than half of the invertebrates tested possess chemical defenses against possible predators. In some of the cases, these defenses seem to be located in the most exposed/vulnerable parts of the organisms; (iii) one of the papers included in this thesis confirms that marine benthic invertebrates from Antarctic and sub-Antarctic waters have an interesting antitumoral potential. This work is the largest carried out in the area with very promising results for phyla such as Chordata, Porifera, and Cnidaria, among others; (iv) finally, this thesis comprises the description of 4 new species of annelid polychaetes from the Antarctic waters. These organisms belong to the families Cirratulidae (1 species from the genus Cirratulus), Dorvilleidae (2 species from the genus Ophryotrocha) and Siboglinidae (1 species from the genus Osedax), which were described from whale bones experimentally deployed in Deception Island (South Shetland Islands). These findings confirm the importance that whale bones may have in the Antarctic shallow-waters context.
Case, Rebecca Biotechnology & Biomolecular Sciences Faculty of Science UNSW. "Molecular- and culturebased approaches to unraveling the chemical cross-talk between Delisea pulchra and Ruegeria strain R11." Awarded by:University of New South Wales. School of Biotechnology and Biomolecular Sciences, 2006. http://handle.unsw.edu.au/1959.4/30394.
Full textSieg, Robert Drew. "Chemically-mediated interactions in salt marshes: mechanisms that plant communities use to deter closely associated herbivores and pathogens." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47590.
Full textJohansson, Björn G. "Chemical Communication and Mate Choice : Investigations into the Meaning of a Fruit Fly Pheromone." Doctoral thesis, Uppsala University, Department of Ecology and Evolution, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4840.
Full textChemical signals are the most widely used form of sexual communication throughout the living world. However, there is in general little knowledge about what these signals actually communicate. The role of chemical signals, i.e. pheromones, in sexual behaviour has traditionally been seen as restricted to mate attraction and species recognition. This thesis reviews the evidence for pheromones as indicators of mate quality, and then investigates three important factors for mate quality signals – individual variation, heritability and cost – by using the male pheromone of the lekking fruit fly Drosophila grimshawi as a model.
The experiments presented indicate that the pheromone of D. grimshawi has multiple functions, and that these functions vary with social context. Thus, with regard to females, the pheromone seems to act mainly as a species/mate recognition signal, since females show little preference for the amount of pheromone deposited by a male. Moreover, males invest less in pheromone production when subjected to females as compared to when subjected to rival males. However, the pheromone seems to be costly in production since males that invest much in pheromone deposition has a shorter lifespan. This suggests a function for the pheromone in male-male interactions. Males can distinguish their own pheromone depositions from those of a strange male, and also discriminate between pheromone depositions from one and two strange males. This might give them the ability to assess the size of a lek and the competitive capacities of rivals, information that should be useful when optimizing sexual behaviour.
In conclusion, the pheromone seems to act as an honest mate/competitor quality signal in some social contexts, and as a non-costly species/mate recognition signal in other. In addition, I show for the first time that a chemical signal has differential fitness costs, and that an insect is able to distinguish between individual odour signatures.
Lam, Ka Sin. "The chemical nature of diatom-derived settlement cue(s) of the marine polychaete hydroides elegans (Haswell) /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?AMCE%202003%20LAM.
Full textFries, Jacqueline Lee. "Chemical Investigation of Antarctic Marine Organisms & Their Role in Modern Drug Discovery." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6084.
Full textKrug, Patrick Joseph. "Chemical and larval ecology of opisthobranch molluscs : variable development modes and settlement cues for larvae of Alderia modesta /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9907826.
Full textLane, Amy L. "Marine natural products as antimicrobial chemical defenses and sources of potential drugs." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26556.
Full textCommittee Chair: Kubanek, Julia; Committee Member: Fernandez, Facundo M.; Committee Member: Harvey, Stephen C.; Committee Member: Hay, Mark E.; Committee Member: Hud, Nicholas V. Part of the SMARTech Electronic Thesis and Dissertation Collection.
True, Aaron Conway. "Ecological engines: Finescale hydrodynamic and chemical cues, zooplankton behavior, and implications for nearshore marine ecosystems." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54019.
Full textJin, Tao. "Complex interactions among amino acids, biofilms and settling larvae of the polychaete hydroides elegans /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202005%20JIN.
Full textClark, Kathryn. "Marine chemical ecology: the search for sequestered and bioactive compounds in the sea hares «dolabrifera dolabrifera» and «stylocheilus striatus» and in their preferred food, the cyanobacterium, «lyngbya majuscula»." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19264.
Full textDes opisthobranches (anaspidea) dont une espèce nommé Dolabrifera dolabrifera a été étudié au Parc National Coiba, une île au Panama. Cette étude de chimie écologique marine est la première pour cette espèce. Dans sa glande digestive, on a retrouvé 5a,8a-épidioxycholest-6-en-3ß-ol. Ce composé possède des nouvelles activités contre le parasite de leishmanioses (Leishmania donovani). Lors d'une expérience d'alimentation D. dolabrifera a préféré la cyanobactérie Lyngbya majuscula, plutôt qu'une algue verte Chaetomorpha, une algue rouge Spyridia et une cyanobactérie Symploca. L'expérience suivante d'alimentation D. dolabrifera a mangé L. majuscula plutôt qu'une algue verte Cladophora. Deux peptides nouveaux étaient isolés de la L. majuscula, les deux actives en malaria (Plasmodium falciparum). Aussi un peptide actif en leishmanioses (L. donovani) et l'autre en malaria (P. falciparum). Ces composés étaient séquestrés dans un opisthobranche appelé Stylocheilus striatus. Ce travail suggère des études en chimie écologie chez les opisthobranches et les cyanobactéries qui peuvent amener à des composés ayant des activités contre les parasités tropicales.
Long, Jeremy Dillon. "Plasticity of Consumer-prey Interactions in the Sea: Chemical Signaling, Consumer Learning, and Ecological Consequences." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-11182004-164652/unrestricted/long%5Fjeremy%5Fd%5F200412%5Fphd.pdf.
Full textHay, Mark, Committee Chair ; Dusenbery, David, Committee Member ; Kubanek, Julia, Committee Member ; Paffenhofer, Gustav-Adolf, Committee Member ; Yen, Jeannette, Committee Member. Includes bibliographical references.
Martín, Martín Rafael Pablo. "Benthic marine algae from South Shetland Islands (Antarctica): biodiversity and evolutionary patterns." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673828.
Full textLounder, Cecelia. "Recruitment dynamics and otolith chemical signatures of juvenile gray snapper, Lutjanus griseus, among West Florida estuarine and coastal marine ecosystems." [Pensacola, Fla.] : University of West Florida, 2009. http://purl.fcla.edu/fcla/etd/WFE0000156.
Full textDesbois, Andrew P. "Antibacterial free fatty acids from the marine diatom, Phaeodactylum tricornutum." Thesis, St Andrews, 2008. http://hdl.handle.net/10023/568.
Full textParker, John D. "Plant-herbivore interactions : consequences for the structure of freshwater communities and exotic plant invasions." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/9460.
Full textNúñez, Pons Laura. "Ecología química en el bentos marino de la Antártida: productos naturales y defensa química en esponjas hexactinélidas, corales blandos y ascidias coloniales." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/104105.
Full textLos habitantes del bentos antártico combaten la depredación, la competencia y el recubrimiento desarrollando mecanismos como la defensa química. Ésta estrategia está particularmente extendida entre organismos sésiles y organismos de cuerpo blando. Las defensas repelentes contra depredadores han de considerarse junto con la calidad nutricional, pues las dietas muy energéticas enmascaran la repelencia. La producción de metabolitos secundarios defensivos es costosa. Por ello, la Teoría de Defensa Optimizada (ODT) prevé que han de localizarse en las regiones corporales más valiosas o expuestas. En las comunidades antárticas los principales depredadores son las estrellas de mar y se postula la concentración de defensas en áreas superficiales en las presas. Pero también influyen las poblaciones de anfípodos asociados a los biosustratos, obteniendo en ellos refugio y fuente de alimentación. Esta tesis se centra en las defensas químicas de tres grupos relevantes del bentos antártico relativamente poco estudiados: esponjas hexactinélidas, corales blandos y ascidias coloniales. Se seleccionaron dos depredadores simpátricos, la estrella Odontaster validus y, por primera vez, fue utilizado el anfípodo Cheirimedon femoratus. Diseñamos un nuevo protocolo con numerosas ventajas metodológicas además de un gran potencial discriminatorio, y observamos que en 31 especies hubo mayor repelencia hacia el anfípodo que hacia la estrella, sobretodo en algas y esponjas, que podrían representar potenciales huéspedes-presa. A partir de aquí estudiamos muestras de los tres grupos seleccionados. En hexactinélidas, las defensas químicas son más débiles y derivadas del metabolismo primario, pero compensadas con un bajo valor nutricional. Algunos glucoesfingolípidos, podrían tener valor quimiotaxonómico como marcadores de la familia Rossellidae. En corales blandos existen metabolitos de defensa primarios y secundarios operando sinérgicamente, y probablemente forman parte del mucus superficial. En ascidias coloniales, los metabolitos defensivos son secundarios y muy potentes; además, en algunas especies éstos tienden a acumularse en tejidos internos, presumiblemente para producir larvas protegidas químicamente. Las ascidias mostraron poca actividad antibacteriana, pero algunos corales exhibieron respuestas inhibitorias. Esta Tesis proporciona la estructura, distribución y posible origen de los metabolitos responsables de las actividades defensivas en tres grupos relevantes de invertebrados antárticos.
Rasher, Douglas B. "Chemically mediated competition, herbivory, and the structure of coral reefs." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/49019.
Full textCohen, Staci Padove. "Functional identification and initial characterization of a fish co-receptor involved in aversive signaling." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29677.
Full textCommittee Chair: McCarty, Nael A.; Committee Co-Chair: Kubanek, Julia; Committee Member: Derby, Charles; Committee Member: Goodisman, Michael; Committee Member: Pardue, Machelle; Committee Member: Weissburg, Marc. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Pavaux, Anne-Sophie. "Ecologie chimique du dinoflagellé toxique Ostreopsis cf. ovata en Méditerranée Nord Occidentale." Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS292.
Full textToxic microalgae are known to produce a large panel of secondary metabolites whose effect on the environment remains so far poorly understood. To better understand this ecological problematic, this thesis aimed to decipher the chemical ecology of the benthic, toxic dinoflagellate Ostreopsis cf. ovata in the Northern Occidental Mediterranean Sea. First, we realized a monitoring of O. cf. ovata abundances on biotic substrates (macroalgae) and in the water column to confirme the tychoplanctonic lifestyle of O. cf. ovata, meaning that this dinoflagellate alternatively switches between benthic and planktonic phase within a single day. Because of these daily changes, it thus impacts both benthic and planktonic ecosystems. In order to study the interactions between O. cf. ovata and its environment during both benthic and planktonic phases, we evaluated its impact on survival, growth, and metabolome of various biologic models, including competitors (diatoms), several direct (benthic and planktonic copepods) and indirect (sea urchins) predators during in situ and laboratory assays. Both in situ and laboratory monitoring could not reveal any effect of O. cf. ovata on the physiology and behavior of sea urchins, suggesting that the invertebrate mass mortality episodes that have been previously documented rather result of the hypoxia linked to O. cf ovata blooms. By contrast, our results showed that O. cf. ovata inhibits the growth of competitor diatoms, while the later in return inhibits photosynthetic efficiency and growth of O. cf. ovata. Finally, our results exhibited species-related effects on copepods, with most importantly reprotoxic effects on benthic species. To further analyze toxic effects of O. cf. ovata strains during blooms in a faster, easier and steadier way, we then adapted to this dinoflagellate an Artemia fransciscana based toxicity assay. Finally, this work was complemented by a metabolomic approach, which allowed us to identify the nature of the secondary metabolites produced by O. cf. ovata. Among these metabolites, toxins are likely to take part in the biological interactions mentioned above. In addition, our results further suggested that other metabolites of unknown nature also contribute to the chemical ecology of this species. In sum, our work demonstrates that O. cf. ovata is a valuable biological model to study chemical ecology of toxic marine microalgae, because of its frequent blooms, its tychoplanctonic lifestyle as well as the great diversity of secondary metabolites it produces
Ivanisevic, Julijana. "Metabolisme secondaire des éponges Homoscleromorpha : diversité et fluctuation de son expression en fonction des facteurs biotiques et abiotiques." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22034.
Full textSecondary metabolism plays a major ecological role in the interactions between the organisms and their environment. An integral study of the organisms’ biology and ecology and the variations of their metabolism is essential for understanding the role of secondary metabolites in the ecosystems. This kind of approach is rare in the marine environment. Small sponge clade Homoscleromorpha constitutes a real potential for the discovery of new species and potentially bioactive molecules. In addition, its dominance in some Mediterranean benthic communities makes it a good model in marine chemical ecology research. This work has started with a description of new species of Oscarella genus, O. balibaloi. This new species forms sometimes, with two other commun Oscarella species, O. tuberculata and O. lobularis, special facies within the coralligenous and semi-dark cave communities. All three Oscarella species are caraterized by a seasonal reproductive cycle with differences in the period of gametogenesis and larval emission as well as the variation in sensitivity facing the changes in thermal regime. Two major lysophospholipid compounds were isolated and caracterized for the first time in O. tuberculata and confirmed in O. lobularis. Their potential role as signal molecules in the reproduction process (embryogenesis and development) was proposed and should be confirmed by experimental studies. One new familly of glycosilated seterterpens (named balibalosides) was found in O. balibaloi. A pluriannual study of species metabolism was performed using three complementary approaches and enabled to test the models of resource allocation to secondary metabolite production. Variation patterns in the expression level of target metabolites, in the metabolic fingerprints and the bioactivities of sponge extracts reflected the significant influence of the reproductive cycle to the secondary metabolite production. Holisitic approaches (métabolomics and bioactivity) pointed out the important modification in the secondary metabolism variation pattern followed by the decrease in bioactivity during the costly period of reproduction (asexual reproduction, embryogenesis and larval development). These results highlight the trade-off in resource allocation between the primary (reproduction) and secondary metabolism and therefore support the Optimal Defense Theory. Metabolomic approach applied to the study of interspecific relations turned out as a good indicator of chemical diversity which allowed the classification of Mediterranean Homoscleromorpha sepcies. The obtained classification was congruent with recent molecular phylogeny results proposing the restauration of two ancient clades within Homoscleromorpha, the Plakinidae, a group of species possesing skeleton and the Oscarellidae, a group of species lacking skeleton. Approaches developed during my thesis opened a numerous perspectives in chemosystematics and marine chemical ecology. The use of metabolic fingerprints can be transposed to other questions in systematics, particularly to demonstrate the existance of cryptic species and to support phylogenetic hypothesis within other problematic clades. [...]
Hill, Jennifer Marie. "Predator biomass and habitat characteristics affect the magnitude of consumptive and non-consumptive effects (NCEs): experiments between blue crabs, mud crabs, and oyster prey." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41172.
Full textAYO-BALI, ABIODUN Emmauel. "Geochemical Analysis of the Environmental Phases of La Barra de Santiago Estuary, El Salvador." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1556804693894507.
Full textde, Nys Rocky. "Natural products chemistry and chemical ecology of tropical marine algae." Thesis, 1991. https://researchonline.jcu.edu.au/16979/1/01front.pdf.
Full textWalls, Justin T. "The chemical ecology of four bryozoan species from Tasmanian coastal waters." Thesis, 1993. https://eprints.utas.edu.au/22318/1/whole_WallsJustinT1993_thesis.pdf.
Full textKoya, C. N. Haneefa. "Studies on ecology, chemical constituents and culture of marine macroalgae of Minicoy Island, Lakshadweep." Thesis, 2000. http://eprints.cmfri.org.in/7110/1/TH-86_Han.pdf.
Full textFerioli, Laurie Jean. "In situ chemical characterization of cold seep fluid in Monterey Bay, California." 1997. http://catalog.hathitrust.org/api/volumes/oclc/38743635.html.
Full textBausch, Alexandra Renee. "Interactive effects of ocean acidification with other environmental drivers on marine plankton." Thesis, 2018. https://doi.org/10.7916/D81278PZ.
Full textGhandourah, Mohammed Ali H. "Marine natural products and brown macroalga cystophora moniliformis chemistry." Thesis, 2012. http://hdl.handle.net/1959.13/1032382.
Full textChemists have isolated and identified many diverse natural products from both terrestrial and marine organisms. The fascinating structural peculiarities and unusual molecular arrangements of many marine compounds have made the field of marine natural products particularly attractive. In the marine natural products group at The University of Newcastle our research is focussed on the identification of new compounds and, in addition, investigation of chemotaxonomy and ecological chemistry. Much of our work is involved with the marine brown algae of the genus Cystophora which consists of about 20 species endemic to Australasian waters, from the western coast of Australia around to the southeast to Newcastle, including Tasmanian and New Zealand waters. The marine brown algae that was the focus of this research is Cystophora moniliformis, which has a wide distribution across southern Australia. Sixteen secondary metabolites were isolated from C. moniliformis. Fifteen had been previously identified (18, 19, 21, 23-32, 34 and 37). Compound 42 is a new linear terpenoid belonging to the same farnesylacetone family as the other metabolites and possess an unusual quaternary aldehyde functionality. [Figures could not be replicated]. The secondary metabolites of algae potentially have roles such as in allelopathic interactions or as herbivore feeding deterrents. Geranylacetone, a metabolite isolated from a South Australian collection of C. moniliformis was found to act as a feeding deterrent towards the sea urchin Tripneustes gratilla. The concentration of secondary metabolites in the marine ecosystem may be affected by herbivore interactions and seasonal variations. We were interested in seeing whether secondary metabolite production varied in response to the presence of herbivores (and/or the level of herbivory), however, before commencing this study we had to establish the baseline variability of secondary metabolite concentrations throughout the year. Algae were sampled monthly for just over one year and crude extracts examined by gas chromatography - mass spectrometry. We have been able to show that the concentration of the major secondary metabolites generally vary regularly with the seasons, but superimposed on this, there are smaller scale variations, which have significant implications on how the metabolites interact with each other, due to their order of biosynthesis and in response to environmental factors and events. The secondary metabolites could be divided into three groups, those that showed maximum production close to the time of maximum algal metabolic production in late summer, a second that peaked much later, in winter, and the third group which contains "the others" - compounds that peaked somewhere in between the first two groups or showed unique fluctuations in their compound concentration profile. It appears that the biosynthesis of the first group may be quite sensitive to water temperature, whereas the second group are less so. The possible implications of the significance of a compound belonging to the third group is discussed. In one case, the compound may be misplaced (and should be in the second group), perhaps due to limitations in the analysis, while others may be compounds that have responded to environmental or ecological events not measured in this study. Water temperature appears to show the closest association with metabolite production, especially compounds falling in the first group of secondary metabolites and primary metabolism in general. What was especially interesting is that it appears that sudden precipitation events can affect metabolite production by causing changes in water temperature. We conclude that to gain a proper understanding of the details of marine ecosystems and the factors that affect them, purely observational studies of an ecosystem should include as many environmental, chemical and biological variables as possible, so that cause and effect is not mis-attributed as it may be in more limited studies. These can subsequently be confirmed by the sue of well designed and executed manipulative experiments which will allow unambiguous assignment of 'cause and effect'.
Putz, Annika [Verfasser]. "Secondary metabolites from marine sponges, with focus on the chemical ecology and biochemical characterisation of the stress induced biotransformation of Aplysina alkaloids = Sekundärmetabolite mariner Schwämme, mit Schwerpunkt auf der chemischen Ökologie und biochemischen Charakterisierung der stressinduzierten Biotransformation von Aplysina-Alkaloiden / vorgelegt von Annika Putz." 2009. http://d-nb.info/994615175/34.
Full text