Dissertations / Theses on the topic 'Continental slopes'
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Gales, Jenny Anne. "The geomorphology of Antarctic submarine slopes." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/the-geomorphology-of-antarctic-submarine-slopes(d117ad12-927b-44f1-bf67-d195e2fef51b).html.
Full textMcPhee, Erika E. "Internal-wave mixing along sloping boundaries : a mechanism for generating intermediate nepheloid layers /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/10972.
Full textUrlaub, Morelia. "The role of sedimentation rate on the stability of low gradient submarine continental slopes." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/359117/.
Full textVieira, Isabela Barboza. "Composição e distribuição dos foraminíferos do Talude Continental Superior ao longo da Costa de Sergipe, Brasil." Pós-Graduação em Geociências e Análise de Bacias, 2014. https://ri.ufs.br/handle/riufs/5389.
Full textNeste trabalho foram analisadas 18 amostras de sedimento provenientes do talude continental superior do Estado de Sergipe, coletadas em janeiro de 2007. Os objetivos do trabalho foram analisar a composição e o padrão de distribuição dos foraminíferos recentes ao longo do talude continental superior de Sergipe e correlacioná-los aos fatores abióticos, como granulometria, teor de matéria orgânica e carbonato de cálcio. Foram triadas 300 carapaças de foraminíferos de cada amostra, totalizando 5400 exemplares. As amostras de sedimento foram quarteadas, em seguida foram lavadas, pesadas (1g de sedimento) e triadas para análise dos foraminíferos. Foram identificados 4.504 exemplares de foraminíferos bentônicos e 896 exemplares de planctônicos, com um total de 167 táxons. Tanto os foraminíferos bentônicos quanto os planctônicos estiveram presentes em todas as amostras analisadas. Foram identificados 84 gêneros de foraminíferos bentônicos representados por 157 táxons. Os bentônicos que apresentaram maior frequência relativa foram Amphistegina sp, Cassidulina laevigata, Siphonina pulchra e Peneroplis carinatus. Em relação aos planctônicos foram identificados sete gêneros representados por 10 espécies. As espécies planctônicas com maior frequência foram Globigerinoides conglobatus, G. ruber, G. trilobus, Globorotalia menardii e Globigerina bulloides. Os 18 pontos de amostragem da área de estudo estão predominantemente localizados em ambientes bioclásticos, com exceção de dois pontos que estão localizados próximos ao canyon do rio São Francisco, que é um ambiente siliciclástico. Em relação ao índice de equitatividade, os táxons identificados em cada uma das amostras apresentam uma tendência à homogeneidade nas 18 amostras. Os resultados obtidos trazem o conhecimento inédito sobre a composição dos foraminíferos que ocorrem ao longo do talude continental superior da costa do Estado de Sergipe. Os dados são compatíveis aos encontrados por outros autores em diferentes regiões da costa do nordeste brasileiro. Foi possível revisar, a partir de diversas literaturas, algumas mudanças taxonômicas dos foraminíferos a nível genérico e específico.
Lee, Simon Edward. "Sedimentary processes recorded by continental slope morphology." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398697.
Full textWang, Xiaoming. "Interaction of an eddy with a continental slope." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12890.
Full textIncludes bibliographical references (leaves 213-216).
by Xiaoming Wang.
Ph.D.
Chatwin, Paul Gareth. "Nearbed flows and sediment movement on the continental slope." Thesis, University of Plymouth, 1996. http://hdl.handle.net/10026.1/2051.
Full textAlvarado, Bustos Ruben. "Mixing in the continental slope : study case Gulf of Cadiz." Thesis, University of Liverpool, 2011. http://livrepository.liverpool.ac.uk/3253/.
Full textGontikaki, Evangelia. "Carbon cycling in continental slope sediments : the role of benthic communities." Thesis, University of Aberdeen, 2010. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=128351.
Full textPantland, Nicolette Ariana. "3D numerical techniques for determining the foot of a continental slope." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49807.
Full textENGLISH ABSTRACT: The United Nations Convention on the Law of the Sea (UNCLOS) provides an opportunity for qualifying coastal signatory states to claim extended maritime estate. The opportunity to claim rests on the precept that in certain cases a continental shelf extends beyond the traditionally demarcated two hundred nautical mile (200M) Exclusive Economic Zone (EEZ) mark. In these cases a successful claim results in states having sovereign rights to the living and non-living resources of the seabed and subsoil, as well as the sedentary species, of the area claimed. Where the continental shelf extends beyond the 200M mark, the Foot of the Continental Slope (FoS) has to be determined as one of the qualifying criteria. Article 76 of UNCLOS de nes the FoS as ". . . the point of maximum change in the gradient at its base." Currently Caris Lots is the most widely used software which incorporates public domain data to determine the FoS as a step towards defining the offshore extent of an extended continental shelf. In this software, existing methods to compute the FoS are often subjective, typically involving an operator choosing the best perceived foot point during consideration of a two dimensional profile of the continental slope. These foot points are then joined by straight lines to form the foot line to be used in the desk top study (feasibility study). The purpose of this thesis is to establish a semi-automated and mathematically based three dimensional method for determination of the FoS using South African data as a case study. Firstly, a general background of UNCLOS is given (with emphasis on Article 76), including a brief discussion of the geological factors that influence the characteristics of a continental shelf and thus factors that could influence the determination of the FoS. Secondly, a mathematical method for determination of the surfaces of extremal curvature (on three dimensional data), originally proposed by Vanicek and Ou in 1994, is detailed and applied to two smooth, hypothetical sample surfaces. A discussion of the bathymetric data to be used for application introduces the factors to be taken into account when using extensive survey data as well as methods to process the raw data for use. The method is then applied to two sets of gridded bathymetric data of differing resolution for four separate regions around the South African coast. The ridges formed on the resulting surfaces of maximum curvature are then traced in order to obtain a foot line definition for each region and each resolution. The results obtained from application of the method are compared with example foot points provided by the subjective two dimensional method of computation within the Caris Lots software suite. A comparison of the results for the different resolutions of data is included to provide insight as to the effectiveness of the method with differing spatial coarseness of data. Finally, an indication of further work is provided in the conclusion to this thesis, in the form of a number of recommendations for possible adaptations of the mathematical and tracing methods, and improvements thereof.
AFRIKAANSE OPSOMMING: Die Verenigde Nasies se Konvensie oor die Wet van die See (UNCLOS) bied 'n geleentheid aan kwalifiserende state wat ondertekenaars van die Konvensie is om aanspraak te maak op uitgebreide maritieme gebied. Die geleentheid om op uitgebreide gebied aanspraak te maak berus op die veronderstelling dat 'n kontinentale tafel in sekere gevalle tot buite die tradisioneel afgebakende 200 seemyl eksklusiewe ekonomiese zone (EEZ) strek. In sulke gevalle het 'n suksesvolle aanspraak die gevolg dat die staat soewereine reg oor die lewende en nie-lewende bronne van die seevloer en ondergrond verkry, sowel as die inwonende spesies van die gebied buite die EEZ waarop aanspraak gemaak word. Die voet van die kontinentale tafel (FoS) moet vasgestel word as een van die bepalende kriteria vir afbakening van die aanspraak waar die kontinentale tafel tot buite die EEZ strek. Artikel 76 van UNCLOS defineer die FoS as ". . . die punt van maksimale verandering in die helling by sy basis." Die mees algemeen gebruikte rekenaar sagteware wat openbare domein data aanwend om die voet van die helling te bepaal, is tans "Caris Lots." Die metodes wat in die program gebruik word om die voet van die helling te bepaal, is dikwels subjektief en berus tipies op 'n operateur se keuse van die beste afgeskatte punt van die voet van die helling uit 'n oorweging van 'n twee dimensionele profiel van die kontinentale tafel. Die berekende voet-punte word dan deur middel van reguit lyne verbind om 'n hellingsvoetlyn te vorm. Hierdie voetlyn kan dan in die Suid-Afrikaanse lessenaarstudie (doenlikheidstudie) oor die bepaling van die voet van die kontinentale tafel gebruik word. Die doel van hierdie verhandeling is om 'n semi-outomatiese en wiskundig gebaseerde drie-dimensionele metode te beskryf vir die vasstelling van die FoS, deur as 'n gevallestudie van Suid-Afrikaanse data gebruik te maak. 'n Algemene agtergrond van UNCLOS, met beklemtoning van Artikel 76, word eerstens gegee. 'n Kort bespreking van die geologiese faktore wat die kontinentale tafel beïnvloed en wat gevolglik 'n invloed kan hê op die vasstelling van die voet van die helling, is ingesluit. Tweedens word 'n wiskundige metode, wat oorspronklik in 1994 deur Vanicek en Ou voorgestel is, vir bepaling van die oppervlaktes van maksimale kromming (gebaseer op drie-dimensionele data) in detail bespreek en 'n voorbeeld van 'n toepassing op twee gladde, denkbeeldige oppervaktes word beskryf. Die faktore wat in ag geneem moet word wanneer omvattende dieptemeting data gebruik word, en die metodes wat gebruik word om die rou data te verwerk, word ingelei deur 'n bespreking van die aard van die dieptemeting data wat gebruik is. Die metode word dan toegepas op twee stelle geruite dieptemeting data van verskillende resolusies vir vier afsonderlike streke om die Suid-Afrikaanse kus. Die riwwe wat op die resulterende oppervlaktes van maksimale kromming gevorm word, word dan nagetrek ten einde 'n lyndefinisie van die voet van die kontinentale tafel vir elke streek teen elke resolusie te bepaal. Die resultate verkry uit toepassings van die metode word vergelyk met hellingsvoetpunte soos bepaal deur die subjektiewe twee dimensionele berekeningsmetode in die "Caris Lots" rekenaar-program. 'n Vergelyking van die resultate vir die verskillende data resolusies word ingesluit om die doeltreffendheid van die metode met betrekking tot die hantering van verskillende ruimtelike data resolusies te ondersoek. 'n Aanduiding van verdere werk, bestaande uit 'n aantal aanbevelings vir moontlike aanpassings en verbeterings van die wiskundige en natrek metodes, word ten slotte in die gevolgtrekking van die verhandeling verskaf.
Kelner, Maëlle. "Analyse des processus de glissements gravitaires sous-marins par une approche géophysique, géotechnique et expérimentale : cas de la pente continentale de Nice." Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4113/document.
Full textSmall submarine landslides, when triggered near the coast represent a major coastal hazard due to erosion of the coastline and marine submersion. In October 1979, a submarine landslide generated a part of the airport platform of Nice (France) to collapse at sea and provoked a tsunami. Because the continental slope off this region is abrupt, close to the coast and subject to moderate seismic activity it is a natural laboratory to study small-scale submarine mass movements processes. This work is based on a multidisciplinary approach allowing a global study of landslide processes in the source area. It integrates data from marine geophysics, sedimentology, geotechnics and numerical modelling. For the first time morphology and architecture of the Var delta deposits are investigated using very high resolution data. It allows identification of numerous small-size gravitational processes signatures as well as their embedding at depth. In the case of the 1979 landslide previously unknown features are identified: 1) eastern and western scars, 2) in-situ blocks and lateral spreading’s traces, 3) in-depth sliding surface, 4) estimation of a total displaced volume, which is different from the evacuated sediment volume. The sedimentary cores are then used to discuss the proximal distribution of deposits, erosion and paleo-landslides records from the deposits overconsolidation. The landslide activity has been estimated over time in terms of return frequencies. The largest landslides (>106 m3) have return frequencies nearing 50 years; the medium-size landslides (105 > V > 106 m3) between 3 and 25 years; and the numerous small landslides (<105 m3) every 1-2 months to 5 years during the most active periods in the last 50 years. Landslides deposits recorded in the source area show return frequencies of 3-7 years during periods of greater activity over the last 400 years. The morphology’s evolution follows successive cycles of sliding/quiescence/reloading. In recent times, two main cycles can be observed (from 1967 to 1999 and from 1999 to 2011) during which triggering are clustered in 5-10 years. On a longer time scale, the turbidites clusters span 20-40 years and quiescence periods ~100 years. Finally, this study brings new constraints on preconditioning and triggering factors acting on the Var delta. The stability of the area seems to be strongly conditioned by the complexity of the topography, the sediments consolidation and the quantity of sediments brought by the Var river. The deposits architecture mainly constrains the depth of the instabilities. Among the external drivers known in the area the extension of the gas-rich zone as well as fluids plumes in the water column have been considered and mapped. Looking at other external drivers, the analysis shows that the magnitude of rainfall and floods, and the alluvial water level would be too low over the past 50 years to act as an isolated triggering factor. In order to destabilize slopes, these external drivers need to be tackled together or associated to earthquakes. Relationships between databases analyses, landslides activity and numerical tests suggest that regional seismicity and historical earthquakes are either too small or too distant from the source areas to generate sufficient peak ground acceleration (0.2 g) and to have an individual impact on the delta slopes
Mohd, Akhir Mohd Fadzil. "Physical processes along the southern continental shelf and slope of Western Australia." University of Western Australia. School of Environmental Systems Engineering, 2010. http://theses.library.uwa.edu.au/adt-WU2010.0118.
Full textSwift, Stephen Atherton. "Cenozoic geology of the continental slope and rise off western Nova Scotia." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/58016.
Full textMicrofiche copy available in Archives and Science
Includes bibliographies.
by Stephen Atherton Swift.
Ph.D.
Jafri, Rooh Ullah. "Acoustic stratigraphy, seafloor morphology andbottom current influence along theNW Svalbard continental slope." Thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-101275.
Full textScott, Nicole D. "The Geomorphology and Shallow Structure of the Northeastern New Jersey Continental Slope." W&M ScholarWorks, 1995. https://scholarworks.wm.edu/etd/1539617687.
Full textEberly, Lauren Elizabeth. "Internal Wave Generation Over Rough, Sloped Topography: An Experimental Study." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3437.
Full textVieira, Rui Pedro Silva. "Functioning and vulnerability of continental slope ecosystems : combining stable isotope and visual survey approaches." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/415531/.
Full textPayne, Danielle Sarah. "Shelf-to-slope sedimentation on the north Kaipara continental margin, northwestern North Island, New Zealand." The University of Waikato, 2008. http://hdl.handle.net/10289/2413.
Full textWang, Dong 1963. "Continental-slope sedimentation adjacent to an ice-margin, Labrador sea : depositional facies and glacial cycles." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56949.
Full textSix major glacial advances were identified in Mid- to Late-Wisconsinan (64-10 ka) slope sediments by 6 very dark hemipelagic units containing abundant sinistral-coiling, cold-water foraminifera. The associated ice-retreat phases are characterized by the occurrence of turbidites, debris-flow deposits, nepheloid-flow deposits, and ice-rafted debris (IRD).
Wellington, Claire Margaret. "The Composition of Continental Shelf and Slope Demersal Fish: The Effects of Depth and Latitude." Thesis, Curtin University, 2019. http://hdl.handle.net/20.500.11937/80409.
Full textNeto, JoÃo Capistrano de Abreu. "AnÃlise textural e geoquÃmica dos argilominerais do talude continental do oeste do CearÃ." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=8713.
Full textEsta pesquisa foi realizada no talude continental da regiÃo de Camocim, a 80 km do continente. Seu objetivo principal foi caracterizar o testemunho SIS-134, coletado a uma profundidade de 1350 m, quanto a textura, cor, composiÃÃo quÃmica e mineralogia, na busca de auxiliar na classificaÃÃo dos sedimentos das zonas submersas. Os estudos foram baseados em referencial bibliogrÃfico e utilizadas metodologias de anÃlise geoquÃmica e caracterizaÃÃo dos argilominerais por tÃcnicas de DRX e fluorescÃncia de raios-X. A geologia do talude continental faz parte da margem passiva, tendo sua evoluÃÃo ocorrida no perÃodo de rifteamento da bacia oceÃnica, sendo modelado pela atuaÃÃo do tectonismo, das variaÃÃes do nÃvel mÃdio do mar, da deposiÃÃo fluvial, das marÃ, correntes oceÃnicas, ondas, entre outros. Houve predominÃncia de sedimentos lamosos em todas as seÃÃes analisadas, com teores variando de 75,3% a 90,8%, sendo o menor valor encontrado na base do testemunho, indicando que a Ãrea compÃe um ambiente de baixa energia onde se depositam somente os sedimentos de granulometria mais fina. Os argilominerais encontrados correspondem aos grupos da esmectita, caulinita e ilita. Os valores de ilita foram de 42,36% no topo, 51,32% no meio e 60,9% na base do testemunho, o que pode indicar que no passado houve uma maior influÃncia da aÃÃo fluvial na sedimentaÃÃo deste ambiente. A esmectita obteve nas seÃÃes topo, meio e base, teores de 12,06%, 1,09% e 4,9% respectivamente. A caulinita se apresentou no testemunho com teores de 45,58%, 47,59% e 34,2% respectivos a topo, meio e base. Na composiÃÃo quÃmica do testemunho, foi verificada a predominÃncia de CaO3, seguido de SiO3, Al2O3, e Fe2O3, que reforÃa a influÃncia da sedimentaÃÃo continental do talude. O teor de CaO3 se apresentou elevado em quase todo o testemunho, sendo os maiores valores encontrados nas seÃÃes topo e meio com 95,2% e os menores valores foram encontrados na base do testemunho com 40,5% e 57,1%. O teor de matÃria orgÃnica variou de 7,03% a 36,21%, que se justifica pela baixa energia e lenta deposiÃÃo do ambiente. Os resultados geraram uma maior base nos estudos sobre o mar profundo e sua dinÃmica
This research was conducted on the continental slope of Camocim region, 80 km from the mainland. Its main objective was to characterize the core SIS-134, collected at a depth of 1350 m, about the texture, color, chemical composition and mineralogy, in search of help to classify the sediments of submerged areas. The studies were based on literature references and used methodologies for geochemical analysis and characterization of clay by XRD and X-ray fluorescence techniques. The geology of the continental slope is part of the passive margin, and its evolution occurred during the rifting of the ocean basin, being modeled by the action of plate tectonics, the variations of the mean sea level, fluvial deposition, the tides, ocean currents, waves, among others. There was a predominance of muddy sediments in all sections analyzed, with levels ranging from 75.3% to 90.8%, the lowest value found in the bottom of the core, indicating that the area comprises a low energy environment where is deposited only sediment of finer grain size. The clay minerals found correspond to groups of smectite, kaolinite and illite. Values were 42.36% illite the top, in the middle 51.32% and 60.9% on the basis of the core, which may indicate that in the past there was a strong influence of a river environment. The smectite in the sections got the top, middle and base levels of 12.06%, 1.09% and 4.9% respectively. The kaolinite is presented in the core at levels of 45.58%, 47.59% and 34.2% respective to the top, middle and base. In the chemical composition of the core, there was a predominance of CaO3, followed by SiO3, Al2O3, Fe2O3, and that reinforces the influence of the continental slope sedimentation. The content CaO3 appeared high in almost all the testimony, and the highest values found in the top and middle sections with 95.2% and the lowest values were found at the base of the core with 40.5% and 57.1%. The organic matter content, which ranged from 7.03% to 36.21% is explained by the slow deposition and low energy environment. The results generated a higher based on studies of the deep sea and its dynamics
Kiss, Andrew Elek, and Andrew Kiss@anu edu au. "Dynamics of laboratory models of the wind-driven ocean circulation." The Australian National University. Research School of Earth Sciences, 2001. http://thesis.anu.edu.au./public/adt-ANU20011018.115707.
Full textBerti, Debora. "Clay mineralogy and its effect on physical properties in the Gulf of Mexico northwestern continental slope." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/1624.
Full textTisch, Timothy Daniel. "Assessing the energetic interactions of subtidal flow on the continental slope in an Eastern boundary region." Diss., Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23821.
Full textSeventeen-month time series (May 1989 - October 1990) of current, temperature and conductivity were obtained from 100, 300 and 500 m depth at site P2, located on the 800 m isobaths off Point Sur, and one-year time series (May 1990 - May 1991) of the same variables at similar depths were obtained from site P3, approximately 25 km father offshore on the 1800 m isobath. Results show that no net growth or decay of eddy potential energy (EPE) occurred at wither mooring during their respective deployment periods. At mooring P2, baroclinic instabilities within the water column were signaled by downgradient horizontal eddy heat fluxes that converted mean potential energy (MPE) to EPE at both 225 and 425 m. The dominant balance at 225 m was between mean flow advection (source) and upward eddy heat fluxes (EPE to eddy kinetic energy, EKE), with additional losses coming from downstream advection by the eddy flow. At 425 m, the dominant balance was between downgradient eddy heat fluxes (source) and downstream advection by eddy flow (sink). Unlike 225 m, vertical eddy heat fluxes at 425 m were a weak source (EKE to EPE) while mean flow advection was negligible. At P3, the net balance involved only downward eddy heat fluxes (source) and downstream advection by eddy flow (sink), as mean advection and MPE-EPE conversions were negligible. Analysis of energetic events within the time series of terms in the EPE equation did not reveal any canonical or common pattern which would explain the temporal means described above, but suggest the flow in this region is highly variable. In fact, most events magnitudes of terms were anywhere from 1o to 200 times that of the associated temporal mean. Events at P2 involved both horizontal and vertical processes and had longer time scales (several days to weeks) compared to those at P3, which had much shorter time scales and appeared to involve vertical processes only.
Buck, P. J. "Sedimentology and micropalaeontology of gravity cores from the N.E. Atlantic continental slope south west of Ireland." Master's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/17655.
Full textEleven gravity cores from the continental margin off Eire and Land's End (SW England) were examined and found to document the major trends of the Late Pleistocene climate. Several stratigraphic indicators; - carbonate content, sediment texture, grain size, composition, nature of terrigenous components, ice-rafted debris and foraminiferal diversity were examined and show that the glacial history of the study area can be closely correlated with the palaeoclimatic evolution of the adjacent European shelf. Sediments deposited during Late Pleistocene glacial conditions show the following characteristics when compared to the surface sediments deposited under Holocene interglacial conditions: an increase in the quantity of ice-rafted debris and percentage of mica, and a notable increase in the degree of frosting and pitting of the quartz grains. Overall grain size was finer resulting in a silty sediment package. Sedimentologically the cores fall into two groups (1 and 2). The major difference being that Group 1 (located on the Pendragon Escarpment) received increased quantities of fine silts from a 'shelf spill-over' mechanism operating on the Fastnet and Western Approaches Basins, during glacial regressions. All sediment samples displayed polymodal characteristics reflecting the interaction of several different physical processes e.g. ice-rafting, contour currents etc. Striking variations in the populations of planktonic foraminifera were noted, alternating between Arctic and Sub-Arctic assemblages, reflecting the waxing and waning of glacial activity. The coccolith-carbonate minima correlate with the Arctic-fauna maxima and the ¹⁸O/¹⁶O maxima of the oxygen-isotope curves. Foraminiferal-test analysis (ratio of whole foraminifera fragmented foraminifera) revealed that no correlation existed with any of the other parameters analysed. However, the cores were severely affected by the presence of bottom currents which were strong enough to remove the fragmented tests. Parallellaminated contourites and evidence of erosion were noted in all cores. Ten cores penetrated sediments deposited during the last glacial maximum of 20,000 B.P - 18,000 B.P. near the 75cm depth mark (Core 1865 was too short to reach such sediments). However sediments reflecting the 11,000 B.P glacial readvance, detected at around the 25cm mark, were not as clearly represented. Bioturbation has smoothed the climatic record throughout the lengths of these cores and has also suppressed the high-frequency oscillations (<10³ B.P).
Wrenn, Jonothan. "DEPTH AND DEVELOPMENT OF THE SONIC SYSTEM IN DEEP-SEA MACROURID FISHES ON THE CONTINENTAL SLOPE." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4657.
Full textBeckler, Jordon Scott. "The biogeochemical source and role of soluble organic-Fe(III) complexes in continental margin sediments." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53016.
Full textHuppertz, Tammo Jan [Verfasser], Rüdiger [Akademischer Betreuer] Henrich, and David [Akademischer Betreuer] Piper. "Styles of continental margin sedimentation: comparing glaciated and non-glaciated slope systems using case studies on the southeast Canadian and northern Argentine and Uruguay continental slope / Tammo Jan Huppertz. Gutachter: Rüdiger Henrich ; David Piper. Betreuer: Rüdiger Henrich." Bremen : Staats- und Universitätsbibliothek Bremen, 2011. http://d-nb.info/1071898426/34.
Full textThomas, Ryan Douglas. "3-D multichannel seismic reflection study of variable-flux hydrocarbon seeps, continental slope, northern Gulf of Mexico." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1176.
Full textRuso, Simona. "Stratigraphic Architecture and Characterization of a Neoproterozoic Continental Slope System, Windermere Supergroup, East-Central British Columbia, Canada." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42660.
Full textAguilar, Tulia Isabel Martinez. "Distribuição espacial e sazonal de grupos do microzooplâncton na Bacia de Campos em cinco massas de água, da superfície ao batipelagial." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/21/21134/tde-26092013-171600/.
Full textThe composition and the distribution of numerical abundance and biomass of microzooplankton groups were sutudied in the Campos Basin located southeastern Brazil, between Victoria (20.5°S) and Frio Cape (24°S). Microzooplankton samples were collected with horizontal hauls using a Multinet (64 ?m) in five depth layers (surface up to 2300m bathypelagial zone) and in two seasonal periods: Period one (P1) May, April - 2009 and Period two (P2) August, September - 2009 (HABITATS CENPES / PETROBRAS). The total abundance ranged from 1 to 57 Org/m³ during the P1 and from 80 to 207 Org/m³ during the P2. Total biomass ranged from 2x10-5 to 2 mg/m³ during the P1, and from 6x10-6 to 5 mg/m³ during the P2. Most frequent taxonomic groups (> 50% relative frequency) in P1 were Radiolaria, Tintinnina, Foraminifera, Copepod nauplii, Cyclopoida, Calanoida, Gastropoda, Pteropoda, and Bivalvia. In P2, the most frequent taxonomic groups were Acantharia, Radiolaria, Tintinnina, Foraminifera, Copepod nauplii, Cyclopoida, Calanoida, Harpacticoida, Gastropoda, Bivalvia, and Polychaeta. Copepod nauplii dominated the surface samples, with 65% of relative abundance during both periods; Radiolaria, Tintinnina and Foraminifera dominated the deep water samples. There were differences in the abundance and biomass in response to environmental, spatial and seasonal variationsn the Tropical Water (TW-1 m) and in the South Central Atlantic Water (SCAW-250 m), These variations may related tothe rise of nutrient-rich deep waters of the SCAW to the euphotic zone, which leads to the increase of the productivity and the increase of the primary production in neritic areas, linking it to the frequent occurrence of cyclonic vortices associated with Brazil Current. In the deepest layers Antarctic Intermediate Water (AAIW-800 m), Upper Circumpolar Water (UCW-1200 m) and North Atlantic Deep Water (NADW-2300 m) it was noted a horizontal homogeneity of the microzooplankton associated with thermohaline stability. However, it is noteworthy that the high values of Radiolaria in deep water could be conditioned by the physical and chemical characteristics of the UCW. It was possible to conclude thatthe abundance and biomass of microzooplankton were higher in the surface layer and SCAW, f due to climatic fluctuations of temperature and salinity.. The temperature was the variable that most influenced the concentrations of organisms; in contrast, the low salinity fluctuations in the Campos Basin had no significant influence on the groups of microzooplankton. The data from AAIW, UCW, and NADW obtained in this work are fundamental for the understanding of the mesopelagical and bathypelagical zones in the Brazilian oceanic waters. Finally the FlowCAM used for semi-automatic analysis of samples was a useful tool for counting and obtaining information about the morphometric microzooplankton.
Grinyó, Andreu Jordi. "Ecological study of benthic communities in the continental shelf and upper slope in the Menorca Channel (North Western Mediterranean)." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/403988.
Full textLes millores tecnològiques i la major disponibilitat de vehicles operats remotament i submains tripulats han incrementat l'accessibilitat a entorns profunds, revelant la presència associacions d'organismes bentòniques riques i diverses, dominades per suspensívors. Aquestes agregacions han estat altament impactades per la pesca al Mediterrani. És urgent incrementar el coneixement, sobre la distribució d'aquestes associacions i aspectes claus de la biologia i ecologia de les principals espècies que les constitueixen per tal d'establir mesures de conservació efectives. En aquesta tesi es caracteritzen les associacions bentòniques de la plataforma i talús continentals del Canal de Menorca a través d'una aproximació multidisciplinària a diferents nivells ecològics. S'han identificat sis associacions bentòniques diferents, que es diferencien principalment pel tipus de substrat i el rang batimètric. En els substrats durs s'hi ha trobat fons d'esponges i coralls, en els fons tous s'hi han trobat camps de crinoïdeus i braquiòpodes. Al marge continental s'hi concentren la diversitat més elevada, probablement resultant de l'heterogeneïtat ambiental i l'hidrodinamisme d'aquest entorn. Al Canal de Menorca les gorgònies són un dels organismes bioenginyers més importants i diversos, formant denses agregacions sobre amplies zones. Les agregacions de gorgònies a la plataforma i part superior del talús eren principalment monoespecífiques, mentre que les del marge continental eren multiespecífiques. Les colònies petites eren les més abundants al llarg de tot el rang batimètric. Tot i així, en entorns profunds les colònies mitjanes i grans incrementaven la seva abundància. El bon estat de les associacions bentòniques i les poblacions de gorgònies probablement resulta de la baixa pressió del ròssec, que es concentra a major fondària. Paramuricea macrospina és la gorgònia més abundant del Canal de Menorca. Al llarg de la seva distribució batimètrica es varen observar tres variants cromàtiques diferents. Dues es varen trobar a la plataforma i una tercera es trobà al marge continental. Per tal d'esbrinar si les diferents variants eren unitats taxonòmiques diferents s'han estudiat la forma colonial, la variabilitat de tamany i formes dels esclerits així com la variabilitat en marcadors mitocondrials. Es va detectar molt poca variabilitat en la morfologia colonial de les tres variants, suggerint que és un caràcter conservatiu. El tamany i la morfologia dels esclerits diferia significativament entre les tres variants, suggerint que estan influenciats per factors ambientals i genètics. No es varen trobar diferències entre els tres marcadors mitocondrials. S'ha avaluat el cicle reproductor, l'acúmul energètic i les necessitats metabòlics de P. macrospina. El cicle reproductiu d'aquesta espècia està retardat respecte les espècies de gorgònia mediterrànies somes. Aquesta situació podria sorgir de l'augment tardà de la temperatura de l'aigua a la plataforma continental mediterrània. El fet que P. macrospina sigui una internal brooder contrasta amb que Paramuricea clavata sigui una surface brooder. El contingut lipídic de P. macrospina és més baix però més constant que el d'espècies somes mediterrànies. D'altra banda la composició de la d13C i la d15N gairebé nos presentaven fluctuacions estacionals. Suggerint que la disponibilitat d'aliment a la plataforma és més baixa però més constant que en entorns somers. Al marge sud del Canal de Menorca hi trobem el Canyó de Menorca. Tot i l'elevada oligotròfia del mar Balear, les associacions d'organismes bentònics a la capçalera del canyó i proximitats són d'una elevada riquesa. S'ha avaluat el flux de partícules durant dos anys consecutius al canyó. Els fluxos recollits eren comparativament inferiors que els registrats en d'altres canyons mediterranis, reflectint la manca d'aportacions continentals. Els processos, de resuspensió i diferents paràmetres hidrodinàmics, semblen controlar el TMF.
De, Beukelaer Sophie Magdalena. "Remote sensing analysis of natural oil and gas seeps on the continental slope of the northern Gulf of Mexico." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/1164.
Full textWolak, Jeannette Marie. "Sedimentology and stratigraphy of a deepwater transient fan on the continental slope: the Late Miocene Isongo Formation, equatorial West Africa." Diss., Montana State University, 2011. http://etd.lib.montana.edu/etd/2011/wolak/WolakJ0511.pdf.
Full textVillar-Muñoz, Lucia [Verfasser], Jan [Akademischer Betreuer] Behrmann, and Sebastian [Gutachter] Krastel-Gudegast. "Gas hydrate in sediments on the Southern Chile continental slope / Lucia Villar-Muñoz ; Gutachter: Sebastian Krastel-Gudegast ; Betreuer: Jan Behrmann." Kiel : Universitätsbibliothek Kiel, 2019. http://d-nb.info/1202630014/34.
Full textVillar-Muñoz, Lucia [Verfasser], Jan Hinrich [Akademischer Betreuer] Behrmann, and Sebastian [Gutachter] Krastel-Gudegast. "Gas hydrate in sediments on the Southern Chile continental slope / Lucia Villar-Muñoz ; Gutachter: Sebastian Krastel-Gudegast ; Betreuer: Jan Behrmann." Kiel : Universitätsbibliothek Kiel, 2019. http://nbn-resolving.de/urn:nbn:de:gbv:8-mods-2019-00004-9.
Full textRau, Amanda Jane. "A late quaternary history of Agulhas-Benguela interactions from two sediment cores on the western continental slope of South Africa." Doctoral thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/9554.
Full textChanges in circulation and productivity in the southeastern South Atlantic Ocean over the last 850 kyr are investigated through the multiproxy study of two giant piston cores, MD962080 and MD962084, retrieved from the Agulhas Bank and Olifants River continental slopes of South Africa. The stable oxygen isotope record of the benthic foraminifer, Cibicidoides wuellerstorfi, and the planktonic taxon, Globorotalia inflata, provide the stratigraphic framework from which the age models were created. The results indicate that biotic responses to surface hydrological changes in the study area are complex and involve both high- and low-frequency variations.
Ai, Fei [Verfasser], Achim [Akademischer Betreuer] Kopf, and Tobias [Akademischer Betreuer] Mörz. "Slope stability along active and passive continental margins: a geotechnical approach / Fei Ai. Gutachter: Achim Kopf ; Tobias Mörz. Betreuer: Achim Kopf." Bremen : Staats- und Universitätsbibliothek Bremen, 2013. http://d-nb.info/1072077620/34.
Full textPolanco, Fernández Andrea [Verfasser]. "Dynamics of the continental slope demersal fish community in the Colombian Caribbean : deep-sea research in the Caribbean / Andrea Polanco Fernández." Gießen : Universitätsbibliothek, 2016. http://d-nb.info/1118289889/34.
Full textMartins, Mariana da Fontoura. "Estrutura populacional e biologia reprodutiva da raia-elétrica-cega, Benthobatis kreffti (Chondrichthyes, Narcinidae) no talude continental do estado de São Paulo /." Rio Claro, 2017. http://hdl.handle.net/11449/181307.
Full textResumo: A raia elétrica cega Benthobatis kreffti é endêmica do Altântico Sul Ociedental e apresenta distribuição restrita desde o sul até o sudeste Brasileiros, ocorrendo em profundidades entre 400 e 600 m. Apesar de seu extremo endemismo, sua biologia é virtualmente desconhecida, especialmente no que diz respeito à porção norte de sua distribuição. O objetivo deste trabalho foi estudar a estrutura populacional e biologia reprodutiva desta espécie, no talude continental do estado de São Paulo. Os indivíduos foram capturados em julho e agosto de 2003 e dezembro de 2007 no cruzeiro científico Soloncy Moura, o qual operou em 492-501 m de profundidade entre os municípios de Santos e Cananéia. Quanto à composição de captura, B. kreffti foi o condricte mais capturado, seguido por Gurgesiella dorsalifera. Os demais foram Hydrolagus matallanasi, Dipturus sp. e Torpedo, sp. Quanto à estrutura em tamanho, fêmeas diferem de machos por apresentarem maiores comprimentos (máximo de 299 mm em fêmeas e 256 mm em machos). A razão sexual total foi diferente de 1:1, bem como para indivíduos adultos. Nos outros estágios de maturidade considerados (imaturo e em desenvolvimento), não houve diferença significativa. A relação comprimento-peso e o tamanho onde 50% da população encontra-se maduro (LT50) também foram diferentes entre os sexos, em favor das fêmeas. Fêmeas apresentaram LT50 de 191 mm enquanto machos maturam em 176 mm. A fecundidade uterina foi de três embriões por fêmea, com embriões nascendo en... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The blind electric ray Benthobatis kreffti is endemic to the South West Atlantic and has a restricted distribution, from south and southeast Brazil, occurring in 400-600 m depth. Despite its endemism, its biology is virtually unknown, especially concerning the north extreme of its distribution. For this reason, the aim of this work was to study the population structure and reproductive biology of B. kreffti off São Paulo State continental slope. Individuals were captured in July and August of 2003 and December 2007 during the scientific cruise Soloncy Moura, operating in 492-501 m depth between Santos and Cananéia municipalities. Benthobatis kreffti was the most captured chondrichthyan, followed by Gurgesiella dorsalifera. Other chondrichthyan captured were: Hydrolagus matallanasi, Dipturus sp and Torpedo sp.. Concerning size structure, females were larger than males (females: 299 mm; males: 256 mm total length). Total sex ratio was different from 1:1, as well as for adult individuals. At other maturity stages considered (immature and developing), no differences were observed. The length-weight relationship and size at 50 % maturity (LT50) were also different between sexes, biased toward females. Female´s LT50 was 191 mm, while in males, LT50 was 176 mm total length. Uterine fecundity was three embryos/ female, with size at birth estimated in 90-100 mm total length (about1/3 of the total length recorded for this species).
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Ammons, Archie Wood. "Macrofaunal community structure on the gulf of mexico continental slope: the role of disturbance and habitat heterogeneity at local and regional scales." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5947.
Full textSacchetti, Fabio. "Late Quaternary sedimentation associated with the British-Irish Ice Sheet on the NW Irish continental slope: a marine geological and geophysical investigation." Thesis, University of Manchester, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.646396.
Full textAli, Heba. "THE EFFECT OF DEPTH ON DEVELOPMENT AND SEXUAL DIMORPHISM OF THE SONIC SYSTEM IN DEEP SEA NEOBYTHITINE FISHES: THE UPPER CONTINENTAL SLOPE." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4095.
Full textOzgul, Ercin. "Geochemical assessment of gaseous hydrocarbons mixing of bacterial and thermogenic methane in the deep subsurface petroleum system, Gulf of Mexico continental slope /." Texas A&M University, 2002. http://hdl.handle.net/1969/223.
Full textBillington, Tyler. "Sedimentologic and Petrographic Evidence of Flow Confinement In a Passive Continental Margin Slope Channel Complex, Isaac Formation, Windermere Supergroup, British Columbia, Canada." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39727.
Full textYamamoto, Naira Tieme. "Padrão de distribuição vertical dos foraminíferos bentônicos vivos no talude continental do setor norte da Bacia de Campos, margem sudeste brasileira: resposta da fauna ao aporte de matéria orgânica." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/21/21136/tde-10042015-140154/.
Full textSediment samples were collected in the upper and middle slope of Campos Basin to evaluate the quantity and quality of organic matter (OM) available in the environment. From geochemical, sedimentological (grain size, ratio and silt/clay), and microfaunistic data was possible to identify differences in the contribution of OM in slope. The upper slope had higher organic carbon content (TOC) and lipids, high density values, low values of diversity, richness, evenness, ALD10, and vertical profile with higher densities, predominance of epifaunal and/or shallow infaunal species, indicating higher primary productivity environment with greater influence on the pulse of phytodetritus, due to the influence of the Vitória Eddy carrying nutrients to the deep sea. The average slope had lower TOC values, lipids and density, higher values of diversity, richness, evenness, ALD10, predominant agglutinated species, indicating conditions with lower input of labile nutrients. Microfaunistic data obtained cannot be applied by the TROX model to the upper and middle slope of Campos Basin as an evaluator of trophic conditions due to non-inclusion of factors such as availability of labile OM, and bioturbation that influence the vertical distribution of living benthic foraminifera in the upper and middle slope of Campos Basin.
Santín, Muriel Andreu. "Exploration and discovery of sponge assemblages on the continental shelf and slope of the Catalano-Balearic Sea by means of non-invasive techniques." Doctoral thesis, Universitat Politècnica de Catalunya, 2022. http://hdl.handle.net/10803/673567.
Full textLas comunidades de esponjas dominan multitud de entornos de fondo duros, siendo uno de los organismos estructurales dominantes en varias áreas del mundo. Aunque la fauna de esponjas mediterráneas se encuentra entre las más estudiadas del mundo, la información disponible actualmente es mínima para las esponjas que se encuentran en las zonas más profundas del mediterráneo en comparación con sus aguas más someras, y la mayoría de los datos disponibles han sido obtenidos mediante métodos de muestreo indirectos o de capturas accidentales por pesquerías de fondo. Aprovechando el metraje y material recogido durante los proyectos Life + INDEMARES, ABIDES y ABRIC, la presente tesis pretende arrojar luz, mediante métodos no invasivos, sobre las comunidades de esponjas que se dan en dos áreas destacadas del Mar Catalano-Balear (mar Mediterráneo noroccidental): el Sitio de Interés Comunitario (SCI) del Canal de Menorca (archipiélago balear), que se convertirá en un futuro Área Marina Protegida (AMP), y las comunidades de corales de agua fría recientemente descubiertas en el cañón de Blanes. En cuanto al SIC del Canal de Menorca, esta tesis caracterizó, mediante análisis cuantitativos de video-transectos, las principales comunidades de esponjas de la zona, con especial énfasis en la distribución geográfica, batimétrica y estructural de las especies formadoras de hábitat más relevantes. El análisis cuantitativo de 85 video-transectos (una distancia lineal total de 75 km), junto con el análisis de especímenes para confirmar la identificación de especies, permitió discriminar seis comunidades principales, que correspondían principalmente a diferencias en el tipo de sustrato y profundidad. Las mayores densidades y abundancias de esponjas se concentraron en áreas de alto hidrodinamismo, a saber, las zonas rocosas frente a la costa del Cabo Formentor y la cabecera del Cañón de Menorca. También se observó un patrón claro de zonificación en profundidad, que va desde la plataforma continental interior hasta el talud superior. Al mismo tiempo, la plataforma continental albergaba la presencia de diversas morfologías, pero las formas más grandes ocurrieron en el borde de la plataforma y el talud. A su vez, la mayoría de las especies estudiadas estaban dominadas por individuos de tamaño pequeño a mediano, lo que sugiere eventos de reclutamiento a pulsos. En cuanto a las comunidades de esponjas identificadas, en la plataforma continental interior dominaban axinélidos semiesciáfilos que se localizaban sobre afloramientos rocosos. A su vez, los lechos de maërl en la plataforma continental interior estaban dominados por Haliclona (Reniera) mediterranea, mientras que la esponja córnea Aplysina cavernicola y varios haliclonidos dominaban principalmente los lechos de maërl y los sustratos rocosos de la plataforma exterior. Los sedimentos blandos en el borde de la plataforma albergaban una comunidad monoespecífica de Thenea muricata, mientras que los sustratos rocosos del borde de la plataforma se caracterizaron por una mezcla de esponjas incrustantes, columnares y en forma de abanico. Finalmente, la vertiente superior del talud continental estaba dominada por Hamacantha (Vomerula) falcula y la hexactinélida Tetrodictyum reiswigi. Así pues, esta tesis pone en valor la presencia de densas poblaciones de esponjas en el Canal de Menorca y proporciona la base científica para su futuro seguimiento una vez que se declare el área como AMP, pudiendo servir a su vez los datos generados como referencia para otras comunidades de esponjas que se encuentren en la región atlántico-mediterránea. En cuanto al cañón de Blanes, la presente tesis proporciona los primeros datos sobre la fauna de esponjas asociada a las comunidades de corales de agua fría (‘CWC provinces’, del inglés cold water corals) recientemente descubiertas en el área, al tiempo que revisa el conocimiento actual de la fauna de esponjas que habita en todas las ‘CWC provinces’ del Mediterráneo. En referencia a las especies encontradas en al área de estudio, algunas se citan por vez primera en el Mediterráneo o han sido redescubiertas, siendo dos de ellas, Hamacantha (Hamacantha) hortae y Hamigera bibiloni, nuevas para la ciencia. A nivel Mediterráneo, las comunidades de corales de agua fría parecen ser puntos calientes o ‘hotspots’ de biodiversidad de poríferos. Sin embargo, los valores de diversidad actuales en cada ‘CWC province’ representan más bien una pequeña fracción de su fauna espongiológica real, que muy posiblemente este infrarrepresentada en la actualidad. Además, se refuta la existencia de una fauna de esponjas endémica que habite exclusivamente en las comunidades de corales de agua fría. No obstante, la fauna de poríferos que habita en las comunidades de corales de agua fría del Mediterráneo parece ser diferente de la de otras regiones atlánticas. Con el conocimiento actual, la fauna de esponjas de las ‘CWC provinces’ mediterráneas se agrupa en tres clusters diferenciables (Mar de Alborán, Mediterráneo Occidental y Oriental), que parecen estar determinados por la circulación de las masas de agua en la cuenca, especialmente la ‘Levantine Intermediate Water’ y la ‘Atlantic Water’, y siguiendo un patrón occidental-oriental desde el Estrecho de Gibraltar hasta el mar Adriático. Finalmente, las esponjas que viven en las ‘CWC provinces’ del Mediterráneo todavía están poco exploradas, pero parecen ser buenas candidatas para estudios biogeográficos.
Les comunitats d'esponges dominen en multitud d'entorns marins de fons durs, essent considerats com un dels organismes estructurals principals de dites comunitats en diverses àrees del món. Encara que la fauna d'esponges mediterrànies es troba entre les més ben estudiades del món, la informació disponible actualment és mínima per a les esponges que es troben en les zones més profundes del mediterrani en comparació amb les seves aigües més someres, i la majoria de les dades disponibles fins a avui en dia han estat obtingudes mitjançant mètodes de mostreig indirectes o bé de captures accidentals per pesqueres de fons. Aprofitant el metratge i material recollit durant els projectes Life + INDEMARES, ABIDES i ABRIC, la present tesi pretén aportar llum, mitjançant mètodes no invasius, sobre les comunitats d'esponges que es donen en dues àrees destacades de la Mar Catalano-Balear (mar Mediterrani nord-occidental): el Lloc d'Importància Comunitària (LIC) del Canal de Menorca (arxipèlag balear), que ha d’esdevenir en un futur pròxim una Àrea Marina Protegida (AMP), i les comunitats de coralls d'aigua freda recentment descobertes en el Rec de Blanes. En quant al LIC del Canal de Menorca, aquesta tesi va caracteritzar, mitjançant anàlisis quantitatiu de vídeo-transsectes, les principals comunitats d'esponges de la zona, amb especial èmfasi en la distribució geogràfica, batimètrica i estructural de les espècies formadores d'hàbitat més rellevants. L'anàlisi quantitatiu de 85 vídeo-transsectes (una distància lineal total de 75 km), juntament amb l'anàlisi d'espècimens per a confirmar la identificació d'espècies, va permetre discriminar sis comunitats principals, que reflectien principalment diferències en la composició del substrat i la profunditat. Les majors densitats i abundàncies d'esponges es van concentrar en àrees d'alt hidrodinamisme, a saber, les zones rocoses enfront de la costa del Cap Formentor i la capçalera del Rec de Menorca. També es va observar un patró clar de zonificació en profunditat, que va des de la plataforma continental interior fins al talús superior. Al mateix temps, la plataforma continental albergava la presència d’una major diversitat de morfologies, però les formes més grans o exuberants es concentraven en el límit de la plataforma i el talús continental. Al seu torn, l’estructura de talles de la majoria de les espècies estudiades estava dominada per individus de grandària petita i/o mitjana, la qual cosa suggereix esdeveniments de reclutament a polsos. En quant a les comunitats d'esponges identificades, en la plataforma continental interior dominaven els axinèl·lids semiesciàfils que es localitzaven sobre afloraments rocosos de la plataforma continental interior. Al seu torn, els llits de maërl de la plataforma continental interior estaven dominats per Haliclona (Reniera) mediterranea, mentre que l'esponja còrnia Aplysina cavernicola i varies ‘Haliclona’ dominaven principalment els llits de maërl i els substrats rocosos de la plataforma exterior. Alhora, els sediments tous en la vora de la plataforma albergaven una comunitat monoespecífica de Thenea muricata, mentre que els substrats rocosos de la vora de la plataforma es van caracteritzar per una mescla d'esponges incrustants, columnars i en forma de ventall. Finalment, el vessant superior del talús continental estava dominada per Hamacantha (Vomerula) falcula i la hexactinèl·lid Tetrodictyum reiswigi. Així doncs, aquesta tesi posa en valor la presència de denses poblacions d'esponges en el Canal de Menorca i proporciona la base científica per al seu futur seguiment una vegada que es declari l'àrea com AMP, podent servir al seu torn les dades generades com a referència per a altres comunitats d'esponges que es trobin a la regió atlàntomediterrània. Referent al Rec de Blanes, la present tesi proporciona les primeres dades sobre la fauna d'esponges associada a les comunitats de corals d'aigua freda (‘CWC provinces’, de l'anglès cold-water corals) recentment descobertes en l'àrea, al mateix temps que revisa el coneixement actual de la fauna d'esponges que habita en totes les ‘CWC provinces’ del Mediterrani. En referència a les espècies trobades en a l'àrea d'estudi, algunes se citen per primera vegada en el Mediterrani, sent dues d'elles, Hamacantha (Hamacantha) hortae i Hamigera bibiloni, noves per a la ciència. A nivell Mediterrani, les comunitats de corals d'aigua freda semblen ser punts calents o ‘hotspots’ de biodiversitat de porífers. No obstant això, els valors de diversitat actuals en cada ‘CWC province’ representen més aviat una petita fracció de la seva fauna espongiològica real, que molt possiblement resulta infrarepresentada en l'actualitat. A més a més, es refuta l'existència d'una fauna d'esponges endèmica que habiti exclusivament en les comunitats de corals d'aigua freda. No obstant això, la fauna de porífers que habita en les comunitats de corals d'aigua freda del Mediterrani sembla ser diferent de la d'altres regions atlàntiques. Amb el coneixement actual, la fauna d'esponges de les ‘CWC provinces’ mediterrànies s'agrupa en tres clústers diferenciables (Mar d'Alborán, Mediterrani Occidental i Mediterrani Oriental), que semblen estar determinats per la circulació de les masses d'aigua en la conca, especialment la ‘Levantine Intermediate Water’ i la ‘Atlantic Water’, i seguint un patró oest-est des de l'Estret de Gibraltar fins al Adriàtic. Finalment, les esponges que viuen en les ‘CWC provinces’ del Mediterrani encara tot i estar poc explorades, semblen ser bones candidates per a estudis biogeogràfics.
Ciències del mar
Quéméneur, Philippe. "Caractérisation géotechnique en zone d"offshore" profond et analyse régionale de la stabilité des pentes : application à quelques secteurs de la pente continentale du golfe de Guinée." Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL073N.
Full textLlopart, Serra Jaume. "Storfjorden Trough Mouth Fan (Western Barents Sea): slope failures in polar continental margins; significance of stress changes and fluid migration induced by glacial cycles." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/401559.
Full textL’evolució de dos ventalls glacials, Storfjorden i Kveithola, s’ha investigat fent servir dades geofísiques i mostres de sediment. D’aquesta manera s’ha pogut establir de forma detallada la seva estratigrafia. A partir de l’anàlisi estratigràfic i dades de literatura s’ha pogut establir que el gel va ocupar la plataforma continental com a mínim en tres ocasions durant els últims ~200 ka: 19.5 a 22.5 ka, 61 a 65 ka i 135 to 167 ka. A més la bona cobertura i resolució de les dades geofísiques ha permès de refinar el model d’evolució dels ventalls glacials. Les diferències més important respecte a treballs previs corresponen a que la formació de xaragalls no dóna només en els deglacials, sinó també en els interglacial degut a les aigües denses de plataforma, i també l’ocurrència de esllavissades durant la deglaciació del marge. En aquest estudi queda palès el control climàtic en la tassa de sedimentació, els sediments dipositats i els avanços i retrocessos de gel. Aquestes variacions influeixen en el patrons de fluid del subsòl i el desenvolupament de sobrepressions en els sediments. Aquesta hipòtesi ha estat investigada utilitzant models d’elements finits (BASIN i Plaxis) a partir de les dades geofísiques i assajos geotècnics. La modelització dels darrers 2.7 Ma mostra que l’inici dels períodes glacials, fa aproximadament 1.5 Ma, va promoure la formació bandes de baixa permeabilitat (tills) a la plataforma. La càrrega de gel a la plataforma durant els màxims glacials, va provocar una ràpida consolidació dels sediments subjacents i l’expulsió de l’aigua intersticial, incrementant així el flux de fluids cap al talús superior. Alhora, aquest flux focalitzat cap als sediments més permeables del talús (plumites) va incrementar dràsticament les sobrepressions. Les sobrepressions màximes van tenir lloc durant l’últim màxim glacial i els següents mil·lennis. Degut a aquestes sobrepressions, el factor de seguretat del talús es va reduir a la meitat, arribant a valors de 1.2 al final de l’últim màxim glacial. Tot i els que aquest valors són baixos, els terratrèmols provocats pel rebot glacio-eustàtic han de ser considerats com a desencadenants finals de les esllavissades identificades a la zona.
Badewien, Tanja Verfasser], Jürgen [Akademischer Betreuer] [Rullkötter, and Hans-Jürgen [Akademischer Betreuer] Brumsack. "Origin and characteristics of plant signals in surface and subrecent sediments of the southwest African continental slope / Tanja Badewien. Betreuer: Jürgen Rullkötter ; Hans-Jürgen Brumsack." Oldenburg : BIS der Universität Oldenburg, 2015. http://d-nb.info/1072500639/34.
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