Dissertations / Theses on the topic 'Marine invertebrates – North Sea'
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Orav-Kotta, Helen. "Habitat choice and feeding activity of benthic suspension feeders and mesograzers in the northern Baltic Sea /." Tartu, Estonia : Tartu University Press, 2004. http://dspace.utlib.ee/dspace/bitstream/10062/489/5/Kotta.pdf.
Full textWest, Fraser James Craig. "Interactions between marine benthic invertebrates and sediments in intertidal and deep sea environments." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395057.
Full textBrink, Laura Ann. "Cross-shelf transport of planktonic larvae of inner shelf benthic invertebrates." Thesis, Thesis (M.S.)--University of Oregon, 1996, 1997. http://hdl.handle.net/1794/10073.
Full textMair, Angus. "Investigation into a prominent 38 kHz scattering layer in the North Sea /." St Andrews, 2008. http://hdl.handle.net/10023/490.
Full textPrzeslawski, Rachel. "Sunburnt sea snails the role of ultravoilet radiation in the development of encapsulated embryos from temperate rocky shores /." Access electronically, 2005. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060221.093951/index.html.
Full textAllsop, Timothy. "Early compaction history of marine siliciclastic sediments." Thesis, Durham University, 1994. http://etheses.dur.ac.uk/5675/.
Full textArnberg, Maj. "Combined effects of ocean acidification, ocean warming and oil spill on aspects of development of marine invertebrates." Thesis, University of Plymouth, 2016. http://hdl.handle.net/10026.1/5287.
Full textIngram, Caroline S. "Ostracod palaeoecology and biogeochemistry of marine and estuarine interglacial deposits in North West Europe." Thesis, Bangor University, 1999. https://research.bangor.ac.uk/portal/en/theses/ostracod-palaeoecology-and-biogeochemistry-of-marine-and-estuarine-interglacial-deposits-in-north-west-europe(4cd7fd25-815b-4e1d-aebb-cada60a3d9b4).html.
Full textGypens, Nathalie. "Modélisation des efflorescences algales et des cycles du C, N, P et Si dans l'écosystème eutrophisé de la mer du Nord." Doctoral thesis, Universite Libre de Bruxelles, 2006. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210778.
Full textLe modèle validé a ensuite été utilisé pour étudier le fonctionnement de l’écosystème et les cycles biogéochimiques associés. Plus précisément, les bilans de carbone et de nutriments réalisés sur base des flux biologiques modélisés ont montré que l’écosystème de la BCZ, dominé par les efflorescences de Phaeocystis, se caractérise par une faible efficience trophique, une faible capacité de rétention/élimination des apports de nutriments d’origine anthropique et une faible capacité d’absorption du CO2 atmosphérique. Des scénarios annulant tour à tour l’activité biologique et les apports de carbone par les rivières ont permis de déterminer les rôles respectifs de la température, des processus biologiques et des apports de nutriments et de carbone par les rivières dans l’évolution saisonnière de la pCO2 des eaux de surface.
L’effet combiné des apports anthropiques de nutriments et des conditions météorologiques locales (débit, vent, température) a été étudié sur base d’une simulation effectuée pour la période contemporaine (1989-2003) en utilisant les forçages réels mesurés. La comparaison visuelle des simulations et des observations montre que, si le modèle est parfaitement capable de reproduire les successions phytoplanctoniques, il est par contre moins performant en ce qui concerne la reproduction des signaux extrêmes. Il apparaît donc que l’échelle de temps (mensuelle) utilisée pour décrire la variabilité des forçages est trop longue et ne permet pas de capter les variations hydrologiques à court terme résultant du vent et de la marée.
De manière à mieux comprendre le lien entre les activités humaines sur le bassin versant et l’eutrophisation des zones côtières, le modèle MIRO a été couplé aux sorties du modèle de rivière RIVERSTRAHLER appliqué à la Seine et à l’Escaut sur une période de 50 ans (1950-1998). Les résultats obtenus montrent que l’importance des efflorescences de diatomées est conditionnée par les apports de PO4, alors que l’importance des Phaeocystis est directement liée à l’importance des apports de NO3. Un bilan établi pour la BCZ montre que plus de 50% des apports annuels de N et 60% des apports annuels de P proviennent des eaux Atlantiques et pointe l‘importance des apports de la Seine pour l’enrichissement de la BCZ.
Différents scénarios de réduction des apports de nutriments provenant des rivières ont été réalisés afin de cibler le ou les nutriments à diminuer prioritairement pour réduire les efflorescences de Phaeocystis. Les résultats montrent que, dans les conditions actuelles, seule une réduction des apports de NO3 prédit une diminution des efflorescences de Phaeocystis. De plus, pour avoir un abattement significatif de ces efflorescences, il est nécessaire d’agir de manière conjointe sur les apports de la Seine et de l’Escaut.
En vue de l’implémentation du code MIRO dans un modèle 3D hydrodynamique et pour tenir compte de la variabilité spatiale des sédiments dans la zone étudiée, une paramétrisation des flux de nutriments à l’interface eau-sédiment a été recherchée sur base des résultats obtenus avec un modèle diagénétique analytique décrivant la dégradation de la matière organique et les cycles de l’azote et du phosphore dans les sédiments.
Doctorat en sciences, Spécialisation biologie animale
info:eu-repo/semantics/nonPublished
Schneider, von Deimling Jens [Verfasser]. "Hydroacoustic and geochemical traces of marine gas seepage in the North Sea / Jens Schneider von Deimling." Kiel : Universitätsbibliothek Kiel, 2010. http://d-nb.info/1019951257/34.
Full textRoncari, Chiara. "Evaluation of microplastic content in faecal sample from hospitalized loggerhead sea turtles (Caretta caretta) of the North Adriatic Sea." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20386/.
Full textTonino, Marco <1982>. "Transboundary governance of marine protected areas : a comparison of the North Adriatic and Wadden Sea case studies." Doctoral thesis, Università Ca' Foscari Venezia, 2014. http://hdl.handle.net/10579/4672.
Full textWeissbach, Astrid, Urban Tillmann, and Catherine Legrand. "Allelopathic potential of the dinoflagellate Alexandrium tamarense on marine microbial communities." Linnéuniversitetet, Institutionen för naturvetenskap, NV, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-7332.
Full textAllelopathy among phytoplankton - a structuring force among phytoplankton
Ilyina, Tatjana P. "The fate of persistent organic pollutants in the North Sea : multiple year model simulations of [gamma]-HCH, [alpha]-HCH and PCB 153 /." Berlin [u.a.] : Springer, 2007. http://www.loc.gov/catdir/toc/fy0710/2006939205.html.
Full textFERRANTI, MARIA PAOLA. "Implementation of controlled reproduction techniques on marine invertebrates: gastropod molluscs of Patella genus Sperimentazione di tecniche di riproduzione controllata di invertebrati marini: Molluschi gasteropodi, Genere Patella." Doctoral thesis, Università degli studi di Genova, 2021. http://hdl.handle.net/11567/1047349.
Full textThe PhD project was mainly focused on the implementation of controlled reproduction techniques in the Patella genus. The species considered were P. caerulea and more particularly P. ferruginea, a protected and endangered species, whose repopulation is the subject of the European ReLife project (LIFE15 NAT/IT/000771). Being P. ferruginea a protected species, we initially preferred to test the non-lethal induction treatments on a cogeneric species, P. caerulea, common and abundant along the Italian coasts. The various treatments tested have provided excellent results, and the “bubbling” treatment was the best, both in terms of time of response to stimulation of the specimens and of replicability and ease of use. The results obtained made it possible to draw up a non-lethal spawning protocol, and to carry out artificial fertilization with subsequent larval development and settlement of the juveniles (Ferranti et al., 2018). In addition, monitoring was carried out along the Ligurian coast, which allowed reporting the presence of P. ferruginea, considered extinct along these coasts (Espinosa et al., 2014). P. ferruginea distribution, along the Ligurian coasts, is extremely scarce and fragmented; in fact the species has been found as isolated specimens or small groups, such as in the Cinque Terre MPA. However, these findings permitted to expand the mapping of the presence of P. ferruginea along the Mediterranean coasts (Ferranti et al., 2019). Furthermore, to better understand the reproductive cycle and the timing of P. ferruginea natural spawning at our latitudes, we placed specimens at sea for maturation in natural conditions, up to the beginning of the expected reproductive period. Specimens were later subjected to a biopsy of the gonad, both before being placed in the sea to determine sex (Guallart et al., 2013a), and at the beginning of the expected reproductive period to understand the stage of maturation. The observation of the material obtained through biopsy made it possible to determine that the specimens had reached gonadal maturation and that one of them had performed sex change, an event known in the literature, but observed here for the first time at the north-western Mediterranean latitude (Ferranti et al., 2021). This implies that the species can complete its reproductive cycle along the Ligurian coasts. Always in view of a better understanding of the timing of gonad maturation, we applied the Magnetic Resonance Imaging (MRI) techniques on limpets. MRI, through a non-invasive approach, allowed to observe the thickness of the gonad and also to understand whether or not a specimen had released gametes, in order to eventually apply stimulation techniques to spawning only at the right time, reducing stress on specimens. The results indicated that MRI can be very useful as an additional tool, both in evaluating the sexual maturity of P. ferruginea and in minimizing the number of induction trials for each specimen, and consequently the stress (Guallart et al., 2020). Even more relevant is having provided evidence, for the first time, that spawning can be induced in P. ferruginea and demonstrated the feasibility of obtaining juveniles, under controlled conditions through low-invasive methods. These results allowed drawing up a preliminary protocol on the induction of spawning of P. ferruginea, which allows for the spontaneous release of gametes, without sacrificing the broodstock of a protected species. Furthermore, this allowed us to carry out an artificial fertilization that led to larval development, settlement, metamorphosis and growth of a pretty large number of P. ferruginea juveniles (Ferranti et al., in prep.). Consequently, knowing that the species is present along the Ligurian coast, that it manages to reach maturity even at these latitudes, and that it is possible to reproduce P. ferruginea under controlled conditions until it reaches the juvenile stage, we provide evidence of the feasibility of P. ferruginea restocking and reintroduction in the natural environment, recovering this species in this area, as expected from the ReLife project. Moreover, the reintroduction made from specimens obtained through aquaculture techniques, without substantially affecting donor populations, is also in accordance with the Spanish strategy for the conservation of the species (MMAMRM, 2008), and generally, repopulation actions through controlled reproduction, could allow in the future to repopulate other coastal areas, where populations of P. ferruginea are disappeared and/or in regression, for the recovery of the species at a global level.
Gebühr, Christina [Verfasser]. "Investigations on the ecology of the marine centric diatom Paralia sulcata at Helgoland Roads, North Sea, Germany / Christina Gebühr." Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2012. http://d-nb.info/1037011295/34.
Full textGuerin, Andrew James. "Marine communities of North Sea offshore platforms, and the use of stable isotopes to explore artificial reef food webs." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/168947/.
Full textHolgate, Nicholas. "Geological characterisation of shallow marine-to-deltaic sandstone reservoir targets, Krossfjord and Fensfjord formations, Troll Field, Norwegian North Sea." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/32135.
Full textNorris, Joel R. "Interannual variability in cloudiness, sea surface temperature, and atmospheric circulation over the midlatitude North Pacific during summer." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/10050.
Full textDanis, Bruno. "Bioaccumulation and effects of polychlorinated biphenyls (PCBs) in the sea star Asterias rubens L." Doctoral thesis, Universite Libre de Bruxelles, 2004. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211171.
Full textUbiquist, abundant and generally recognized as a good bioindicator species, the common NE Atlantic sea star Asterias rubens (L.) is an ecosystem-structuring species in the North Sea and was chosen as an experimental model. The present study focused on the characterization of PCB bioaccumulation in A. rubens exposed through different routes (seawater, food, sediments) and on subsequent biological responses, at immune and sucellular levels. The considered responses were respectively (i) the production of reactive oxyggen species (ROS) by sea stars amoebocytes, which constitutes the main line of defence of echinoderms against pathogenic challenges and (ii) the induction of a cytochrome P450 immunopositive protein (CYP1A IPP) which, in vertebrates, is involved in PCB detoxification.
Experimental exposures carried out have shown that A. rubens efficiently accumulates PCBs. Exposure concentrations were always adjusted to match those encountered in the field. PCB concentrations reached in sea stars during the experiments matched the values reported in field studies ;therefore our experimental protocol was found to accurately simulate actual field situations. Uptake kinetics were related to the planar conformation of the considered congeners :non-coplanar PCB uptake was described using saturation models, whereas coplanar PCBs (c-PCBs) were bioaccumulated according to bell-shaped kinetics. Non-coplanar congeners generally reached saturation concentrations whithin a few days or a few weeks, which means that sea stars can be used to pinpoint PCB contamination shortly after occurrence. On the other hand, c-PCB concentrations reached a peak followed by a sudden drop, indicating the probable occurrence of c-PCB-targeted metabolization processes in sea stars. Our experimental studies also demonstrated that seawater was by far the most efficient route for PCB uptake in sea stars and that even if PCB levels in seawater are extremely low compared to sediment-associated concentrations, seawater constitutes a non-negligible route for PCB uptake in marine invertebrates. Among the different body compartments, bodywall displayed the highest bioaccumulative potency and can therefore be considered as particularly interesting for field biomonitoring applications. Rectal caeca, which play a central role in digestion and excretion processes in sea stars, have also rised particular interest as results suggest these organs could be involved in the elimination of PCB 77 degradation products.
The field work carried out during the present study showed that PCB concentrations measured in A. rubens tissues reflect environmental levels of certain congeners. As it was the case in experimental conditions, A. rubens differentially accumulated PCB congeners according to their planarity. Strong relationships were found between concentrations measured in sediments and those determined in sea stars body wall for certain non-coplanar congeners (e.g. 118 and 138), thus allowing to consider A. rubens as a suitable bioindicator species for medium-chlorinated PCB congeners. On the other hand, sea stars appeared to be able to regulate -to a certain extent- their content in coplanar PCBs. This implies that (i) A. rubens cannot be strictly considered as an indicator organism for c-PCBs and (ii) c-PCBs probably affect essential aspects of sea star biology, potentially leading to deleterious effects.
The present study addressed effects of PCB exposure on A. rubens biology, in both experimental and field conditions. In experimental conditions, PCBs were found to significantly alter ROS production by sea stars amoebocytes. This alteration also occurred in a congener-specific way :c-PCBs were found to significantly affect, and probably impair sea stars immune system, whereas non-coplanar congeners had no effect. In the field, the PCB contribution to immunotoxicity could not be determined because none of our studies considered ROS production along with c-PCB concentration measurements. However, the levels of ROS production by sea stars amoebocytes measured in field and experimental conditions were found to potentially lead to altered immunity, and therefore to impair sea stars defence against pathogenic agents.
A specially designed ELISA was used to measure CYP1A IPP in experimental and field conditions. Experimental work has shown that the induction of this protein was related to PCB exposure in a congener-specific fashion :c-PCBs alone were found to strongly induce the production of CYP1A IPP according to a dose-dependent relationship. These results have highlighted many similarities between the dioxin-like responsiveness of CYP1A IPP induction in sea stars and that occurring in vertebrates. This strongly suggests similarities in the toxicity-triggering mechanism of dioxins and c-PCBs. In the field, CYP1A IPP induction was found to be significantly related to PCB levels determined in bottom sediments. It can thus be considered as a valuable biomarker. Further research is however needed to better characterize the influence of physico-chemical and physiological parameters on CYP1A induction to refine the interpretation of the information gathered via this biomarker.
Results obtained in our study have lead to questionning international regulations applying to PCB biomonitoring in the marine environment. For instance, we strongly suggest that the selection of congeners to be systematically considered should be revised to include c-PCBs. Indeed, in our experiments PCB toxicity was almost always attributable to the sole c-congeners. Historically, determination of c-PCB concentrations was extremely difficult due to analytical limitations ;however, nowadays, these problems have been overcome and do no more justify their exclusion from monitoring studies.
Although A. rubens appeared to be quite resistant to PCB contamination, levels measured in sea stars from the southern North Sea can possibly affect their immune and endocrine systems in a subtle way, but with relatively low risk for this species at the short-term. However, this does not mean that other species in this region undergo similarly low risks, or that sea star-structured ecosystems may not become affected in the long-term
Doctorat en sciences, Spécialisation biologie animale
info:eu-repo/semantics/nonPublished
Chiti, Bernardo. "Holocene fluvial and marine influences and settlement interactions in the lower Ribble Valley, Lancashire, U.K." Thesis, University of Stirling, 2004. http://hdl.handle.net/1893/1805.
Full textKeeble, Kathryn. "Common drivers and indicators of large-scale changes in the community structure and function of three UK marine ecosystems : the Irish Sea, North Sea and Western English Channel." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.577148.
Full textFortuna, Caterina Maria. "Ecology and conservation of bottlenose dolphins (Tursiops truncatus) in the north-eastern Adriatic Sea." Thesis, St Andrews, 2007. http://hdl.handle.net/10023/157.
Full textNooner, Scott L. "Gravity changes associated with underground injections of CO₂ at the Sleipner storage reservoir in the North Sea, and other marine geodetic studies /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3171110.
Full textSimmons, Kayelyn Regina. "Evidence of the Enemy Release Hypothesis: Parasites of the Lionfish Complex (Pterios volitans and P. miles) in the Western North Atlantic, Gulf of Mexico, and Caribbean Sea." NSUWorks, 2014. http://nsuworks.nova.edu/occ_stuetd/2.
Full textKumblad, Linda. "Radionuclides in the Baltic Sea : Ecosystem models and experiments on transport and fate." Doctoral thesis, Stockholm : Institutionen för systemekologi, Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-175.
Full textWilson, Sarah Jane. "High resolution comparative palynostratigraphy and palaeoecology of oligocene sequences in the terrestrial basins of the Western British Isles and the marine North Sea basin." Thesis, University of Sheffield, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527316.
Full textRay, Kacy Lyn. "Factors affecting Wilson's Plover (Charadrius wilsonia) demography and habitat use at Onslow Beach, Marine Corps Base Camp Lejeune, North Carolina." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/30996.
Full textMaster of Science
Dixon, Henry David John. "Effect of black swan foraging on seagrass and benthic invertebrates in western Golden Bay : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Ecology, Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1214.
Full textMcArthur, Adam D. "Temporal and spatial relationships of syn-rift, deep-marine hangingwall stratigraphy : examples from the Upper Jurassic of the Inner Moray Firth and the Central North Sea." Thesis, University of Aberdeen, 2012. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=191932.
Full textWise, Matthew Geoffrey. "Iceberg-keel ploughmarks on the seafloor of Antarctic continental shelves and the North Falkland Basin : implications for palaeo-glaciology." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/276147.
Full textRiebel, Philippe N. "Acute effects of petroleum hydrocarbons on the arctic littoral mysid, mysis oculata (Fabricius)." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61781.
Full textCox, Tom, Tom Maris, Karline Soetart, Daniel Conley, Damme Stefan van, Patrick Meire, Jack J. Middelburg, Matthijs Vos, and Eric Struyf. "A macro-tidal freshwater ecosystem recovering from hypereutrophication : the Schelde lease study." Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2010/4518/.
Full textAstoreca, Rosa. "Study and application of the Inherent Optical Properties of coastal waters from the Phaeocystis-dominated Sounthern Bight of the North Sea." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210646.
Full textThe area is characterised by a high spatio-temporal variability of IOPs due to the high dynamics of the area in terms of currents, salinity gradients and biological production. During spring the presence of P. globosa modulates the IOPs across all the area, the particle absorption is significantly higher than summer and there is no significant coast-offshore variability for phytoplankton and CDOM.
The design of chl a retrieval algorithms assumes negligible absorption of NAP and CDOM in the near infrared (NIR) and the use of a fixed value of specific phytoplankton absorption. It is shown that neglecting the NAP and CDOM absorption in the NIR will have a significant overestimation impact in retrieval of chl a. On the other hand, the specific phytoplankton absorption was found to be highly variable (0.015 „b 0.011 m2 mg chl a-1). Both results will affect directly the retrieved chl a. The spatial variability of CDOM was significant varying between 0.20-1.31 m-1 in the marine area and between 1.81-4.29 m-1 in the Scheldt estuary. CDOM was found to be related to salinity with conservative mixing within the Scheldt estuary and during some seasons in the BCZ, however deviations from conservative mixing suggest other inputs to the CDOM pool. Analyses of the spectral slope of the CDOM absorption curve revealed two main CDOM pools in the area, an allochthonous one delivered by the Scheldt estuary and an autochthonous one associated with the phytoplankton spring bloom decomposition. Algorithms for CDOM retrieval will be affected if the variability in the relation between CDOM and salinity is not taken into account.
The optical characterisation of diatoms and P. globosa from the BCZ in pure cultures revealed that the main differences in the phytoplankton absorption spectra were found at 467 and 500 nm corresponding to the absorption of the pigments chlorophyll c3 (chl c3) characteristic of P. globosa and fucoxanthin, respectively. Accordingly, both the absorption at 467 nm and the ratio 500/467 nm were successfully used to discriminate the two taxa in cultures and field samples. This latter indicator was not preserved in the reflectance signal due to degradation of the signal when passing from absorption to reflectance, and thus could not be used for algorithm development. The spectral feature at 467 nm was later used as the basis for the development of a flag-type algorithm to detect chl c3 using either absorption or water-leaving reflectance data. Also, the correlation between the algorithm¡¦s retrieved chl c3 and P. globosa cell number allowed the quantification of the bloom. The main findings of this thesis highlight the importance of the IOPs characterisation for the improvement and development of ocean colour retrieval algorithms in these highly complex waters.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Leary, Arianne Ella. "Effects of the Deepwater Horizon Oil Spill on Deep Sea Fishes." UNF Digital Commons, 2015. http://digitalcommons.unf.edu/etd/566.
Full textMeynier, Laureline. "Feeding ecology of the New Zealand sea lion (Phocarctos hookeri) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor Philosophy in Zoology at Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/901.
Full textMoulins, Aurélie. "To the integrated approach and to the management of pelagic biodiversity inside a marine protected area : case of the cetacean populations in the Pelagos sanctuary (north-western Mediterranean sea)." Lyon 1, 2008. http://www.theses.fr/2008LYO10027.
Full textVirgili, Auriane. "Modelling distributions of rare marine species : the deep-diving cetaceans." Thesis, La Rochelle, 2018. http://www.theses.fr/2018LAROS003/document.
Full textDeep-diving cetaceans, sperm- and beaked whales Physeteridae, Kogiidae and Ziphiidae, are rare marine species. Due to their low densities, wide distribution ranges and limited presence at the water surface, visual surveys usually result in low sighting rates. This paucity of data challenges the modelling of their habitat, prerequisite for their conservation. Models have to cope with a great number of zeros that weakens the ability to make sound ecological inferences. Consequently, this thesis aimed at finding a methodology suitable for datasets with a large number of zeros, determining how environmental variables influence deep-diver distributions and predicting areas preferentially used by these species. By testing the predictive performance of various habitat models fitted to decreasing numbers of sightings, I selected the most suitable model and determined that at least 50 sightings were needed to provide reliable predictions. However, individual surveys can rarely provide sufficient deep-diver sightings thus I merged many visual survey datasets to produce the first basin-wide deep-diver density maps in the North Atlantic Ocean and the Mediterranean Sea. Highest densities were predicted in waters from 1500-4000 m deep and close to thermal fronts ; hotspots were predicted along the continental slopes, particularly in the western North Atlantic Ocean. In addition, a model transferability analysis highlighted that habitat drivers selected by the models varied between contrasted large ecosystems. Finally, I discussed challenges related to statistical modelling applied to rare species and the management applications of this thesis
Alappat, Linto [Verfasser]. "Application of OSL dating on coastal sediments : case studies from shallow marine sediments of Southern North Sea, Germany, and coastal sub-surface and surface sediments from south India / Linto Alappat." Berlin : Freie Universität Berlin, 2011. http://d-nb.info/1025938771/34.
Full textRomán, Moreno Sara. "Ecology and biodiversity of the deep-sea meiobenthos from the Blanes Canyon and its adjacent slope (NW Mediterranean) = Ecología y biodiversidad del meiobentos profundo del Cañón de Blanes y su talud adyacente (NO Mediterráneo)." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/456986.
Full textLos cañones submarinos son una de las principales estructuras geomorfológicas del margen continental y un recurso de heterogeneidad del fondo marino. Su abrupta topografía influye en el régimen hidrodinámico local, interrumpiendo y amplificando las corrientes e incrementando los flujos de partículas. Juegan un papel importante en el transporte entre plataforma y océano profundo atrapando, acumulando y canalizando sedimentos y materia orgánica con importantes consecuencias para la diversidad, funcionamiento y dinámica del bentos. La meiofauna es un componente importante del bentos. Dado su pequeño tamaño, está íntimamente relacionada con el sedimento y sus posibles alteraciones (p. ej., alteración de las tasas de sedimentación, resuspensión). Esta Tesis se centra en el Cañón de Blanes (NO Mediterráneo), lugar de importante actividad pesquera. Partiendo de muestras recogidas en primavera y otoño de 2012 y 2013, el principal objetivo ha sido incrementar el conocimiento y las pautas y tendencias de las comunidades de meiofauna (densidad, biomasa, diversidad y estructura) del Cañón de Blanes, así como de su talud adyacente con especial énfasis en los nematodos. Las elevados tasas de sedimentación detectados en el cañón (hasta los 1,750 m), sugieren un efecto indirecto de la pesca de arrastre, que estaría afectando a la meiofauna, sugiriendo la parcial antropogenización de los ambientes profundos del cañón. La variabilidad temporal observada obedece a: entradas estacionales de materia orgánica (derivadas de la producción primaria), procesos de formación de aguas profunda y heterogeneidad topográfica, combinados con entradas recurrentes no estacionales de materia orgánica. Sin embargo, la variabilidad a pequeña escala (cm) causa un mayor efecto en la estructura y diversidad de la comunidad de nematodos, principalmente debido a la disminución en diversidad a lo largo del perfil vertical del sedimento. El Cañón de Blanes muestra mayor variabilidad en el sedimento y disponibilidad de materia orgánica que el talud adyacente, así como una mayor variabilidad en la composición y estructura de las comunidades meiofaunales. Nuestros resultados apoyan la relevancia del papel de los cañones submarinos en la distribución de la fauna bentónica, así como su consideración como hot spots de densidad, biomasa y diversidad.
Hammill, Allison L. "Effects of Localized NAO, ONI (ENSO) and AMO Events on Reproductive Patterns in Loggerhead (Caretta caretta) Sea Turtles in Broward County, FL, USA." NSUWorks, 2013. http://nsuworks.nova.edu/occ_stuetd/135.
Full textDonaldson, Laura Patricia Constance. "The distribution of fatty acids and presence of environmental contaminants in the blubber of the New Zealand sea lion (Phocarctos hookeri) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Palmerston North, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/887.
Full textAndrié, Chantal. "Utilisation des traceurs helium-3 et tritium en oceanographie." Paris 6, 1987. http://www.theses.fr/1987PA066241.
Full textOrbi, Abdellatif. "Circulation de marée dans le Golfe normand-breton." Brest, 1986. http://www.theses.fr/1986BRES2024.
Full textBitar, Ghazi. "Etude de peuplements benthiques littoraux des côtes atlantiques et méditérranéennes du Maroc : impact de la pollution, comparaisons biogéographiques." Aix-Marseille 2, 1987. http://www.theses.fr/1987AIX22005.
Full textGenco, Marie-Laure. "Les marées dans l'Océan atlantique : modélisation et bilan énergétique." Grenoble 1, 1993. http://www.theses.fr/1993GRE10009.
Full textPika, Jana. "New cytotoxic natural products from North-Eastern Pacific marine invertebrates." Thesis, 1993. http://hdl.handle.net/2429/1975.
Full textHurlbut, Catherine Jane. "Variations in larval density and settlement in space and time : important determinants of recruitment in sessile marine invertebrates?" Thesis, 1990. http://hdl.handle.net/10125/10315.
Full textLino, Sílvia Patrícia Pena. "Bioprospecting deep-sea marine animal lipids from Azores for therapeutic applications." Doctoral thesis, 2015. http://hdl.handle.net/10400.3/4073.
Full textA região dos Açores apresenta uma grande diversidade de comunidades faunísticas em ecossistemas marinhos de profundidade, com numa grande variedade de "hotspots" no fundo do mar, tais como montes submarinos, encostas das ilhas e fontes hidrotermais. No entanto, apesar desta enorme biodiversidade, os seus invertebrados marinhos de profundidade nunca foram bio prospectados enquanto produtos naturais marinhos funcionais. Esta tese teve como objectivo fazê-lo. Foram extraídos lípidos de dezanove espécies animais, num total de trinta e seis extractos brutos, subsequentemente testados in vitro como antibacterianos, antimaláricos e anticancerígenos. Da diversidade de animais de profundidade que incluiu corais, esponjas, ouriços e invertebrados das fontes hidrotermais, os resultados revelaram que os extractos apresentam actividade para todos os ensaios biológicos testados, com as esponjas a apresentarem-se como os animais mais úteis como fonte de compostos naturais marinhos anticancerígenos e os corais de água fria, como antimaláricos. Foi usada uma estratégia de fracionamento guiado pela bioactividade, nos extractos dos animais mais activos: as mega-esponjas Petrosia sp. E Leiodermatium sp.. Os esteróis (Petrosterol, Sitosterol e 23, 24-Dihydrocalysterol) foram identificados nas fracções de Petrosia sp. Mais anticancerígenas mas devido a perca de actividade durante a separação dos compostos, não foi possível confirmá-los como principais anticancerígenos presentes. O estudo com a esponja Leiodermatium sp. resultou no isolamento de uma mistura complexa de compostos, demonstrando um potente efeito anticancerígeno (IC75=0,08 μg/ml). Os compostos foram identificados como pertencentes a uma mesma família de macrólidos e foram denominados "azorelides". Foi possível isolar os compostos azorelide A e azorelide B mas a esteroquímica absoluta de ambas as moléculas não foi determinada devido às suas escassas quantidades (1,1 mg de azorelide A/kg e 0,47 mg de azorelide B/kg de esponja Leiodermatium seca).
ABSTRACT: Azores region presents a great diversity of deep-sea ecosystems with faunal communities in a variety of benthic hotspots, as seamounts, islands slopes and hydrothermal vents. Despite its high biodiversity, these deep-sea invertebrates were never bio prospected in regard to their natural products. This thesis aims to do so. Lipids were extracted from nineteen animal species and a total of thirty-six crude extracts were tested in vitro as potential antibacterial, antimalarial and anticancer activities. From a deep-sea diversity of corals, sponges, seaurchins and hydrothermal vents invertebrates, results showed that extracts were active for all tested bioassays, with sponges presenting the best outcomes as anticancer and corals as antimalarial natural product sources. A bioactivity-guided fractionation strategy was used in the most active animal extracts: the mega sponges Petrosia sp. and Leiodermatium. Sterols (Petrosterol, Sitosterol and 23, 24- Dihydrocalysterol) were identified in the most active anticancer fraction from Petrosia sp. but, due to activity lost during compounds isolation, it was not possible to confirm these as the main anticancer compounds present. Study with Leiodermatium sponge extracts lead to isolation of a complex mixture of compounds, showing potent anticancer activities (IC75=0.08 μg/ml). Compounds were identified as belonging to the same macrolide family and were named "azorelides". It was possible to isolate azorelide A and azorelide B, but their absolute stereochemistry was not achieved due to amount scarcity (1.1 mg of azorelide A/kg and 0.47 mg of azorelide B/kg of dry Leiodermatium sponge).
Several projects financed part of laboratory consumables and chemicals products used during this research, namely PTDC/QUI-QUI/119116/2010-"Ocean Treasures", PTDC/MAR/111749/2009-DeepFun; PEst-C/EQB/LA0006/2013, Pest-OE/BIA/UI0457/2011-CREM, FP7/2007-2013 n° PCOFUND-GA-2009-246542 and LA 9-2013-2014-PEST OE/EEI/LA0009/2013, financed by FCT, Ministério da Educação e Ciência, Portugal and FEDER.
McClellan, Catherine Marie. "Behavior, Ecology, and Conservation of Sea Turtles in the North Atlantic Ocean." Diss., 2009. http://hdl.handle.net/10161/1128.
Full textSea turtles have experienced dramatic population declines during the last century as a consequence of direct harvest, by-catch in fisheries, and habitat loss. Despite almost 50 years of partial international protection, several populations of sea turtles are still at imminent risk of extinction. Our knowledge of their complex life histories is still far from complete; these knowledge gaps hinder our ability to provide scientific advice regarding their conservation and management. It is the very complexity of their life histories, which allows them to exploit widely separated habitats during development, often over the course of decades, which makes them inherently difficult to study. I used satellite telemetry (n=60) to investigate the movements and habitat use patterns of juvenile loggerhead (
Dissertation