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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Temporal and Spatial Analysis of Killer Whale Sightings in the Galapagos Marine Reserve, Ecuador

Smith, Kerri 2012 May 1900 (has links)
A study was conducted using data compiled from two sources to test the hypothesis that killer whales display seasonal variability in their occurrence in the Galapagos Marine Reserve (GMR), Ecuador. Three questions arise from this hypothesis: 1) do killer whale sightings display temporal variability; 2) are sightings spatially associated with resources; and 3) if sightings are spatially associated with resources, does the spatial association change temporally? I combined and evaluated two sets of GMR killer whale sighting data (n=154) spanning a twenty-year time frame collected via opportunistic sightings by an observer network and shipboard line-transect surveys. I tested for a (a) correlation between the total annual sightings and bi-annual seasonality (upwelling versus non-upwelling); (b) correlation between the total annual sightings and the Multivariate El Nino Southern Oscillation Index (MEI); (c) correlation between sightings, the MEI, and seasonality; (d) spatial association between sightings and resources; and (e) spatial change in sightings with seasonality. Sightings were roughly equally distributed between non-upwelling (56%) and upwelling seasons (July-December). No direct correlation was found between sightings and the MEI. Sightings occurred more often than expected by chance during the peak upwelling months of August-November when the MEI was within one standard deviation of the average (binomial z=2.91, p<0.05). Sightings were spatially associated with areas of high chlorophyll a values (binomial z=4.46, p&lt;0.05), pinniped rookeries (binomial z=6.03, p&lt;0.05), and areas with high combined resource value (binomial z=5.36, p&lt;0.05). The spatial distribution of sightings did not shift with seasonality, with the exception that sightings occurred less often than expected in areas of low combined resource value during the upwelling period (binomial z=-3.17, p&lt;0.05). Though variability in observer effort should be considered when evaluating these data, these results do not suggest a strong pattern of seasonal occupancy or that killer whales are responsive to El Nino Southern Oscillation events. Further research is needed to determine if killer whales in the GMR comprise a single resident population, multiple resident and transient populations, or if killer whales observed in the GMR are part of a population inhabiting the eastern tropical Pacific region, which visit the area at various times.
2

Petrogénesis de xenolitos en un ambiente de Hot-Spot: el Caso de la Isla Floreana, Archipiélago de Galápagos, Ecuador

Carreño Núñez, Francisco Javier January 2016 (has links)
Geólogo / La isla Floreana es una de las pocas fuentes de xenolitos de rocas ultramáficas en el sistema de islas volcánicas que forman el punto caliente del archipiélago de Galápagos. En este estudio se presenta un análisis petrogenético de cinco xenolitos de rocas ultramáficas representativos de los que se encuentran en dicha isla. Estos incluyen tres wehrlitas, una dunita y una hazburgita. El estudio comprende un análisis petrográfico detallado de las texturas de los minerales silicatados y sulfuros asociados, así como, datos cuantitativos de su composición química de elementos mayores y trazas. Asimismo, se presentan y discuten los primeros datos de concentraciones de metales nobles (elementos del grupo del platino y oro) en sulfuros de la litosfera bajo el archipiélago de las islas Galápagos. Los granos individuales de sulfuros fueron analizados in situ mediante ablación laser acoplada a fuente inductiva de plasma con arsenal multicolector (LA-ICP-MS). En base a su mineralogía, petrografía y química mineral, los xenolitos de rocas ultramáficas estudiados se clasificaron en: (1) grupo Al-augita, evidenciando composiciones similares a los cristales presentes en las lavas de la isla; y (2) grupo Cr-diópsido correspondientes a peridotitas con una química típica de punto caliente oceánico. Se estimaron sus condiciones P-T, obteniendo temperaturas entre 800 y 1100°C y presiones entre 3 y 12 kbar. Se interpreta que todas las muestras estudiadas se formaron en la litosfera de Floreana, pero a diferentes profundidades, encontrando tres xenolitos corticales o pertenecientes a la transición manto-corteza, un xenolito mantélico y un xenolito asociado a un reservorio magmático profundo. Los sulfuros identificados en las rocas estudiadas pertenecen al sistema composicional Fe-Ni-Cu-Co, cuyas temperaturas de equilibrio se estiman entre 900 y 1100 °C, consistente con las temperaturas calculadas en silicatos. Estos sulfuros contienen bajas concentraciones de metales nobles, lo cual fue atribuido a metasomatismo. En las wehrlitas protogranulares los patrones de metales nobles sugieren que los sulfuros precipitaron desde fluidos metasomáticos, mientras que en la wehrlita poikilitica los sulfuros tendrían un origen relacionado con fluidos residuales enriquecidos en elementos calcófilos, destacando la presencia de un grano enriquecido en Au.
3

Cows in the Galápagos Islands: a study of cattle production at the Hacienda El Progreso

Riou-Green, Miranda 30 April 2018 (has links)
This thesis explores the zooarchaeology of cattle management and production at the 19th-century Hacienda El Progreso, on San Cristóbal Island, Galápagos, Ecuador. Many cattle products were exported, including salted meat, leather, and fat. In order to examine cattle commodification, comparative literature was reviewed, and the sequential steps that were undertaken to turn cattle into a product were assessed. The results were then compared to the faunal analysis of the Carpintero assemblage from Hacienda El Progreso using the chaîne opératoire framework in order to examine the possibility of interpreting the sequential production of cattle commodification from zooarchaeological specimens. Historical cattle from Hacienda El Progreso were a likely small bodied Criollo variety. While there was evidence of cattle management and production, there was limited opportunity to identify the hacienda’s operational sequence of cattle production for export as the Carpintero assemblage likely represented locally consumed animals. / Graduate
4

Tropical Pacific climate variability over the last 6000 years as recorded in Bainbridge Crater Lake, Galápagos

Thompson, Diane M., Conroy, Jessica L., Collins, Aaron, Hlohowskyj, Stephan R., Overpeck, Jonathan T., Riedinger-Whitmore, Melanie, Cole, Julia E., Bush, Mark B., Whitney, H., Corley, Timothy L., Kannan, Miriam Steinitz 08 1900 (has links)
Finely laminated sediments within Bainbridge Crater Lake, Galapagos, provide a record of El Nino-Southern Oscillation (ENSO) events over the Holocene. Despite the importance of this sediment record, hypotheses for how climate variability is preserved in the lake sediments have not been tested. Here we present results of long-term monitoring of the local climate and limnology and a revised interpretation of the sediment record. Brown-green, organic-rich, siliciclastic laminae reflect warm, wet conditions typical of El Nino events, whereas carbonate and gypsum precipitate during cool, dry La Nina events and persistent dry periods, respectively. Applying this new interpretation, we find that ENSO events of both phases were generally less frequent during the mid-Holocene (similar to 6100-4000 calendar years B.P.) relative to the last similar to 1500 calendar years. Abundant carbonate laminations between 3500 and 3000 calendar years B.P. imply that conditions in the Galapagos region were cool and dry during this period when the tropical Pacific E-W sea surface temperature (SST) gradient likely strengthened. The frequency of El Nino and La Nina events then intensified dramatically around 1750-2000 calendar years B.P., consistent with a weaker SST gradient and an increased frequency of ENSO events in other regional records. This strong interannual variability persisted until similar to 700 calendar years B.P., when ENSO-related variability at the lake decreased as the SST gradient strengthened. Persistent, dry conditions then dominated between 300 and 50 calendar years B.P. (A.D. 1650-1900, +/- similar to 100 years), whereas wetter conditions and frequent El Nino events dominated in the most recent century. Plain Language Summary Sediments accumulating at the bottom of Bainbridge Crater Lake have provided a record of Galapagos climate and the frequency of El Nino events over the past similar to 6000 years. Motivated by the importance of this lake for our understanding of climate in the tropical Pacific Ocean, we have been monitoring the link between climate, lake conditions, and the physical and chemical properties of the lake sediments since 2009. Based on this long-term monitoring, we find that the Bainbridge sediment record preserves both El Nino and La Nina events. This makes Bainbridge a particularly valuable archive of past climate, as most sediment-based records typically preserve only one or the other key phase of tropical Pacific climate.
5

Integrated hydrogeological study of San Cristobal Island (Galapagos) / Etude hydrogéologique intégrée de l'île San Cristobal (Galapagos)

Dominguez, Christian 09 May 2016 (has links)
La compréhension du cycle de l'eau d'une région où les ressources en eau sont limitées est fondamentale pour assurer une gestion durable de celles-ci, c'est le cas de Galápagos. Cette thèse présente la première étude intégrée du fonctionnement hydrogéologique des aquifères perché de l'île San Cristóbal. Pour ce faire, une approche pluridisciplinaire, fondée sur la mise en place d'un site expérimental sur le bassin versant de Cerro Gato (CG), a été conduite. Pour quantifier les entrées d'eau dans le système hydrologique une approche canopée-transfert hydrique du sol a été utilise. La recharge est principalement affectée par l'altitude en raison de l'effet orographique sur les gradients de pluie et d'évapotranspiration. Néanmoins, à haute altitude, la différence est principalement associée à la couverture végétale en raison de l'apport additionnel fourni par l'interception du brouillard sous la forêt. Une analyse hydrologique montre que les pertes des bassins versants situés à haute-altitude deviennent les entrées d'eau souterraine des bassins versants situés à moyenne altitude (comme CG). Les données du méthode électromagnétique héliportée SkyTEM permettent définir l'extension du bassin hydrogéologique de CG qui est plus grande que le bassin hydrologique. Des approches précédemment décrites, découlent un modèle conceptuel des sources de CG. Ainsi, les eaux souterraines de ces sources sont issues d'un aquifère perché qui s'est formé à la faveur d'une fine couche peu perméable. Ce modèle est testé par simulations numériques qui montrent cette plausibilité. Cette thèse fournit les fondements scientifiques d'une gestion durable des ressources en eau. / The understanding of the hydrogeological functioning in regions such as San Cristobal Island (Galapagos), where water is limited, is fundamental for a suitable management of its resources. This work is the first study of this type on high-level aquifers in San Cristobal using a multi-disciplinary approach, based in the implementation of an experimental site and modeling strategies. For this purpose, a hydrological network was installed in Cerro Gato (CG) and surrounding watersheds. Inputs to the watershed are estimated using the joint modeling of a canopy and soil water transfer. Recharge rates are mainly affected by altitude in mid-elevation watersheds, whereas land cover is the main controlling factor at high-elevation watersheds because of the additional input of fog interception in forests. A hydrological analysis shows that losses from the high-elevation basins become groundwater inputs in the mid-elevation basins, while others have inputs from watersheds at the same altitude, such as CG. The detailed geometry of its hydrogeological watershed is obtained from the dataset of a high resolution AEM SkyTEM survey, which confirms the assumption that its hydrogeological watershed is bigger than its hydrological one. Results from these approaches allow proposing a hydrogeological conceptual model for the springs of CG, where the groundwater flow of springs is fed by a perched aquifer suspended by a low permeability thin layer. This model is tested with numerical simulations, which confirm the plausibility of the existence of a perched aquifer. This thesis provides scientific basis for an effective water management strategy.
6

Anisotropie et atténuation sismique en domaine océanique: application aux panaches mantelliques de la Polynésie française et des Galápagos

Fontaine, Fabrice 31 January 2005 (has links) (PDF)
L'influence de la présence de liquide sur les propriétés sismiques des systèmes partiellement fondus, ici les chambres magmatiques des dorsales océaniques et les panaches mantelliques, est mal contrainte. Cette étude apporte de nouvelles observations sismologiques sur l'anisotropie sismique sous la Polynésie française et les Galápagos. Les mesures du déphasage des ondes SKS et l'analyse de la polarisation des ondes P en Polynésie française montrent la participation de deux contributions: asthénosphérique et lithosphérique. La présence de liquide dans le manteau supérieur sous l'archipel des Galápagos pourrait se traduire par une absence d'anisotropie au centre de l'archipel. Les mesures d'atténuation des ondes ScS multiples confirment l'existence d'une zone plus atténuée au niveau de la Polynésie française que dans le reste du Pacifique sud. En outre, des mesures d'atténuation ont été réalisées dans des gabbronorites partiellement fondues aux fréquences sismiques, entre 500 et 1200°C. Au-dessus de la température de fusion, l'atténuation augmente significativement avec une dépendance plus forte à la fréquence. Il est montré que le mécanisme d'atténuation associé à l'écoulement localisé de liquide pourrait se superposer à un mécanisme d'atténuation associé à une diffusion au niveau des joints de grains. D'autre part, de nouvelles mesures expérimentales de la viscosité de deux silicates basaltiques et d'un silicate andésitique ont été effectuées. Des lois expérimentales de fluage décrivant les variations de viscosité dans une large gamme de températures sont proposées, ainsi que les paramètres thermodynamiques des échantillons analysés.
7

Population Fluctuation of the Nodular Coral Psammocora stellata in the Galápagos Islands, Ecuador: An Indicator of Community Resilience and Implications for Future Management

Brown, Kathryn 13 April 2016 (has links)
Corals are experiencing a worldwide decline in abundance and diversity. Reasons for this include anthropogenic impacts and associated changes to environmental conditions, including global climate change. Increasing atmospheric CO2 levels lead to a coordinated increase in sea surface temperatures and decrease in oceanic pH. Warming events associated with El Niño-Southern Oscillation (ENSO) amplify the impacts of steadily increasing temperatures. For example, coral communities in the Galápagos Islands experienced mortality rates of up to 95-99% during severe ENSO warming in 1982-1983. Persisting through such extreme conditions imposes additional challenges to survival in already marginal environments for coral growth and development that occur in the eastern tropical Pacific. This study quantifies via photoquadrats population changes in mean live coral cover, density, and colony size over a 7-year period (2004-2011) in a small community of the nodular coral Psammocora stellata located at Xarifa Island in the Galápagos Islands. The physical characteristics of this shallow (1-3 m depth) habitat include shading by tall basalt cliffs and strong water flushing action that may contribute to the persistence of this species at this atypical locality through mitigation of anomalously warm and cold conditions. Coral cover is high for this region, and significantly increased from 39.7% in 2004 to 58.3% in 2011 (p=0.006, Tukey HSD), an overall increase of 47%. Fluctuations in coral cover were associated with anomalous temperatures (up to +3.5° and -4.6° C compared to daily means). Negative temperature anomalies in 2007 were associated with a non-significant decrease in coral cover (55.3% in 2007 to 49.5% in 2009), and coral cover rebounded in 2011 to 58.3%. From 2004 to 2011 colony density increased significantly, from 258±62 to 612±245 colonies m-2 (p2 (pin situ, documenting values that ranged from 16.8° - 28.9° C. The persistence of the Psammocora community through both strong and moderate ENSO events demonstrates the resistance and resilience of the species to these temperature anomalies. Adding to the understanding of this species and its interactions with the surrounding physical processes will aid in the development and improvement of management strategies.
8

Changes in Coral Community Composition at Devil's Crown, Galapagos Islands, Ecuador: A 7,700 Year Perspective

Hendrickson, Katharine Jane 11 December 2014 (has links)
Coral mortality caused by El Niño–Southern Oscillation (ENSO) activity and its related disturbances has been researched throughout the Eastern Pacific. In the past three decades, disturbances related to the El Niño–Southern Oscillation (ENSO) have been shown to influence coral growth in the Eastern Pacific. In the Galápagos Islands, Ecuador, more than 97% of corals experienced mortality after the severe 1982-1983 ENSO episode. However, two of the most dominant coral species found in a coral community adjacent to Devil’s Crown; Psammocora stellata and Diaseris distorta survived this severe ENSO event. By reconstructing sediment cores of the coral community, this study assessed how the coral assemblage has changed over the past 7,700 years of the Holocene epoch. The historical reconstructions were then related to existing records of Holocene ENSO variability in order to determine if changes in the relative abundance of coral species were related to ENSO activity and disturbances. We observed high variability in the relative abundances of P. stellata and D. distorta in the cores, including an increase in the abundance of D. distorta at approximately 2,200 yBP. Between the two species, opposite abundance trends were observed and supported by Detrended Correspondence Analysis (DCA) and Non-metric Multidimensional Scaling (NMDS) ordination analysis. Overall, the high variance in coral composition at the site throughout the Holocene documents repeated disturbance events in this region.
9

La tortue, le requin et le jaguar. : L'aménagement du territoire et la gouvernance des ressources naturelles dans les aires protégées, par les instruments de politique. Les cas des Galápagos et du Yasuní en Equateur. / The turtle, the shark and the jaguar. Land use planning and governance of common pool resources in protected areas analysed via policy tools. The case of the Galapagos islands and the Yasuni in Ecuador. / La tortuga, el tiburón y el jaguar. Ordenamiento territorial y gobernanza de recursos naturales comunes en áreas protegidas, a través los instrumentos de política pública. El caso de las islas Galápagos y el Parque Yasuní en Ecuador.

Ciccozzi, Elena 09 December 2015 (has links)
Espaces emblématiques des dynamiques complexes entre l’homme et l’écosystème dans des aires protégées abritant des ressources naturelles commune, les îles Galápagos et le Yasuní en Équateur partagent une histoire de dégradation environnementale, conflits socio-environnementaux et chaos territorial. La présence de biens communs, source d’une rente économique liée à la biodiversité et aux hydrocarbures (Yasuní) attire depuis un demi-siècle les intérêts des industriels du pétrole et du tourisme qui ont systématiquement exercé un poids déterminant sur les décisions en matière d’aménagement et de gestion de ces espaces, influant également sur leur gouvernance. Cette réalité joue à l’encontre de politiques d’aménagement territorial pour les deux espaces, Réserves de la Biosphère de l’UNESCO, depuis des décennies. Les Galápagos et le Yasuní témoignent en même temps de la manière dont les gouvernements équatoriens ont eu recours à une « instrumentation » des politiques pour décider le sort des deux aires protégées. Cette thèse montre comment un problème structurel – l’absence d’une politique d’aménagement territorial – a facilité la mobilisation d’instruments de politique pour administrer les deux réserves naturelles. L’histoire du Yasuní est un exemple éloquent de cette pratique d’instrumentation de politiques. La création du parc en 1979, puis les modifications de ses limites et le découpage de la Réserve de la Biosphère Yasuní, dont le parc est le noyau, ont été tous réalisés par des instruments de politiques. De même, aux Galápagos la puissance publique a opéré ses choix en matière d’accès aux espaces protégés et d’utilisation de leurs ressources, en privilégiant les instruments de politique. La loi spéciale des Galápagos (LOREG) a de facto gouverné l’archipel depuis son entrée en vigueur en 1998. Dans les deux cas, l’absence d’une politique d’aménagement territorial a permis l’adoption de décisions top-down sur l’administration des deux espaces.La «révolution citoyenne» du président Correa, en dépit d’une profonde refonte institutionnelle et d’un nouveau paradigme de développement – le Buen Vivir, ou Sumak Kawsay – ne saura changer la manière d’aménager les espaces des deux aires protégées. La planification est élevée à politique d’État qui prime sur toute autre politique, mais dans cette vision l’aménagement du territoire devient un instrument au service de la planification étatique.Ce travail, conduit dans une perspective interdisciplinaire en utilisant une grille de lecture encore peu explorée (les instruments de politique publique) veut aussi contribuer à de nouvelles pistes de réflexion sur l’action publique en matière d’aménagement du territoire ainsi que sur la gouvernance d’aires protégées riches en ressources naturelles communes. / Archetypes of the complex interactions between humans and ecosystems in protected areas rich in Common Pool Resources (CPR), the Galapagos Islands and the Yasuní in Ecuador share a history of environment degradation, socio-environmental conflicts and chaotic land development. The abundance of CPR, source of a lucrative rent from biodiversity and crude (in the Yasuní case) have attracted the interests of oil and tourism businesses over the last fifty years. These industries have consistently steered public decisions over the creation, spatial organisation and administration of these natural reserves, additionally affecting their governance, a reality which has hindered the implementation of land-use planning policies for these areas which are two UNESCO MAB Reserves. The Galapagos and Yasuní protected areas are also a powerful example of the peculiar way whereby Ecuador governments over the last five decades have “instrumented” policy making, preferring the use of policy tools to public policies to decide on the two areas’ fate. This thesis shows how a structural problem such as the absence of a land use planning policy, has thrust the practice of policy tools adoption, instead of policy making, to manage the two protected areas. The “revolución ciudadana” led by president Correa succeeded in re-founding State institutions and launching a new development paradigm (Sumak Kawsay or Buen Vivir) however, it did not advance on land-use management related issues particularly regarding the two areas. Correa has placed national planning at the heart of public policy making it the state policy – backed by a powerful bureaucratic structure – but in this process, land use planning is considered as an instrument in support of national planning. This research, carried out under an interdisciplinary perspective, using policy tools as analytical key, wishes to contribute new insights and methods of analysis on public land use planning and management, as well as governance of common pool resources in protected areas.
10

Variable Recovery of the Massive Coral, Porites Lobata, in Response to El Nino-Southern Oscillation Events at Devil's Crown, Galapagos, Ecuador

Paul, Nicole Christine 21 December 2012 (has links)
Porites lobata is an important reef building coral in the tropical eastern Pacific and the dominant Porites species in the Galápagos archipelago. Following the 1982-83 El Niño-Southern Oscillation the Galápagos Islands experienced 97-99% coral mortality, leaving many areas throughout the archipelago denuded of corals. Because very few long term assessments have been conducted on the growth and resilience of P. lobata to natural disturbances in the Galápagos Islands (Glynn et al., 2001; Glynn et al., 2009), benthic surveys were performed on a uniquely dense aggregation of P. lobata colonies at Devil’s Crown, Floreana Island between 1993 and 2011. Annual changes in live tissue area were calculated for the majority of the population (n=17) using Coral Point Count with Excel extensions (CPCe 3.6) software to determine growth and recovery trends for this aggregation. Total live tissue area (n=10) increased from 1993 to 2011, however due to high interannual variability this increase was not significant. Within this overall pattern, a general trend of decline was observed in live tissue cover from 1993 to 2000, with increases in tissue area observed from 2000 to 2011. Severe bleaching (85-100%) was observed during the 1998 survey, followed by 42% tissue loss (n=10), coinciding with sea water warming associated with the very strong 1997-1998 El Niño-Southern Oscillation event. Subsequent regrowth of coral tissue was observed during the 2001 survey with continued recovery through 2009. Multiple comparison testing revealed a significant difference between the impacted state (1999) and the recovered state (2009), (p = 0.002, Dunn’s method, n=17), suggesting this aggregation required a period of ten years to recover from this disturbance. During this recovery period the moderately strong 2007-2008 La Niña, with accompanying stressful low temperatures, occurred but did not interrupt tissue regrowth. Warmer than average sea surface temperatures occurred during the warm months from 2008 to 2011, during which time a cool period occurred from 2010 to 2011. While the magnitude and duration of temperature anomalies during warming were not as great as those observed during the 1997-98 ENSO, low temperatures observed during the cool period were similar to those experienced throughout the 2007-08 La Niña. During this time total live tissue cover was reduced by 19% (n=10); however it is unknown whether this was due to warming or the following cool period. Based on results from the 1997-98 El Niño and 2007-08 La Niña, this reduction in live tissue was most likely caused by elevated sea surface temperatures. Data on the growth and resilience of P. lobata populations at Devil’s Crown will be used for conservation and management of this important resource.

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