Dissertations / Theses on the topic 'Ocean Change'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Ocean Change.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Byrne, Michael P. "Land-ocean contrasts under climate change." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/97332.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 155-163).
Observations and climate models show a pronounced land-ocean contrast in the responses of surface temperature and the hydrological cycle to global warming: Land temperatures increase more than ocean temperatures, low-level relative humidity increases over ocean but decreases over land, and the water cycle has a muted response over land in comparison to ocean regions at similar latitudes. A comprehensive physical understanding of these land-ocean contrasts has not been established, despite the robustness of the features and their importance for the regional and societal impacts of climate change. Here we investigate land-ocean contrasts in temperature, relative humidity, and precipitation minus evaporation (P - E) under climate change using both idealized and full-complexity models. As in previous studies, we find enhanced surface warming over land relative to the ocean at almost all latitudes. In the tropics and subtropics, the warming contrast is explained using a convective quasi-equilibrium (CQE) theory which assumes equal changes in equivalent potential temperature over land and ocean. As the CQE theory highlights, the warming contrast depends strongly on changes in relative humidity, particularly over land. The decreases in land relative humidity under warming can be understood using a conceptual model of moisture transport between the land and ocean boundary layers and the free troposphere. Changes in P - E over ocean are closely tied to the local surface-air temperature changes via a simple thermodynamic scaling; the so-called "rich-get-richer" mechanism. Over land, however, we show that the response has a smaller magnitude and deviates substantially from the thermodynamic scaling. We examine the reasons for this land-ocean contrast in the response of P - E by analyzing the atmospheric moisture budget. Horizontal gradients of surface temperature and relative humidity changes are found to be important over land, with changes in atmospheric circulation playing a secondary role outside the tropics. An extended thermodynamic scaling is introduced and is shown to capture the multimodel-mean response of P - E over land, and the physical mechanisms behind the extended scaling are discussed.
by Michael P. Byrne.
Ph. D. in Climate Physics and Chemistry
Tedesco, Matthew P. "Strategic change management in ship design and construction." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9851.
Full textLlort, Jordi Joan. "Bloom phenology, mechanisms and future change in the Southern Ocean." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066064.
Full textPrimary production (PP) in the Southern Ocean (SO) plays a crucial role on atmospheric carbon uptake. PP in this ocean is highly iron-limited and presents a marked seasonal cycle. Such a seasonal cycle has a strong productive phase in late winter, called bloom, which distribution and intensity is highly variable. My PhD focus on two specific aspects of the PP in the SO: first, the mechanisms that drive such a bloom and its dynamics and, second, the elements able to control the bloom intensity at present and in the future. The first aspect (bloom phenology and mechanisms) was addressed by setting up a mechanistic approach based on a novel model configuration: a complex biogeochemical model (PISCES) forced by a 1D idealised physical framework. This methodology allowed me to conciliate the different bloom formation theories and to identify the SO bloom specificities. Moreover, I proposed how to use different bloom detection criteria to properly identify bloom from observations. Such criteria were then tested in a complementary observation-based approach (with satellite and in-situ data) to characterise different bloom phenologies and its spatial distribution in the SO. The second aspect (bloom intensity and future change) was also addressed by a twofold approach. First, using the 1D model, I studied how seasonal variability of vertical mixing combine light and Fe limitation to drive PP. Secondly, I used such an analysis to interpret PP trends observed in 8 coupled model climatic projections (CMIP5 models). My PhD thesis results allow for a better understanding of the physical and biological processes controlling phytoplankton growth. My conclusions also suggest how an alteration of these processes by Climate Change may influence PP in the whole SO, a key region for future climate evolution
Dalan, Fabio 1975. "Sensitivity of climate change to diapycnal diffusivity in the ocean." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/30129.
Full textIncludes bibliographical references (leaves 61-67).
The diapycnal diffusivity of the ocean is one of the least known parameters in cur- rent climate models. Measurements of this diffusivity are sparse and insufficient for compiling a global map. Inferences from inverse methods and energy budget calculations suggests as much as a factor of 5 difference in the global mean value of the diapycnal diffusivity. Yet, the climate is extremely sensitive to the diapycnal diffusivity, as shown by studies using single-hemispheric ocean General Circulation Models (GCMs) and 2-dimensional coupled models. In this thesis we study the sensitivity of both the current climate and the climate change to the diapycnal diffusivity - using, for the first time, a coupled model with a 3-dimensional global ocean component and idealized geometry. Our results show that, at equilibrium, the strength of the thermohaline circulation in the North Atlantic scales with the 0.44 power of the diapycnal diffusivity, in contrast to the theoretical value of 2/3. On the other hand, the strength of the circulation in the South Pacific scales with the 0.63 power of the diapycnal diffusivity. The implication is that the amount of water upwelling from the deep ocean may be regulated by the diapycnal diffusion in the Indo-Pacific ocean. The vertical heat balance in the ocean is controlled by: in the downward direction, (i) advection and (ii) diapycnal diffusion; in the upward direction, (iii) isopycnal diffusion and (iv) bolus velocity (GM) advection. The size of the latter three fluxes increases with diapycnal diffusivity.
(cont.) The thickness of the thermocline also increases with diapycnal diffusivity leading to greater isopycnal slopes at high latitudes, and hence enhanced isopycnal diffusion and GM advection. Larger diapycnal diffusion compensates for changes in isopycnal diffusion and GM advection. Little changes are found for the advective flux because of compensation between changes in downward and upward advective fluxes. We present sensitivity results for the hysteresis curve of the thermohaline circulation. The stability of the climate system to slow freshwater perturbations is reduced as a consequence of a smaller diapycnal diffusivity. This result confirms the findings of 2-dimensional climate models. However, contrary to the results of these studies, a common threshold for the shutdown of the thermohaline circulation is not found in our model. In our global warming experiments, the thermohaline circulation slows down for about 100 years and recovers afterward, for any value of the diapycnal diffusivity. The rates of slowdown and of recovery, as well as the percentage recovery of the circulation at the end of 1000-year integration, is variable but a direct relation with the diapycnal diffusivity cannot be found. The steric height gradient is divided into a temperature component and a salinity component. It appears that, in the first 70 years of simulated global warming, temperature variations dominate the salinity ones in weakly diffusive models, whereas the opposite occurs in strongly diffusive models. The analysis of the vertical heat balance reveals that, in global warming experiments, deep ocean heat uptake is due to reduced upward isopycnal diffusive flux and GM advective flux ...
by Fabio Dalan.
S.M.
de, Lavaissiere de Lavergne Casimir. "Cessation of southern ocean deep convection under anthropogenic climate change." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119766.
Full textEn 1974, des observations satellite nouvellement disponibles révélèrent la présence d'une géante surface d'eau libre au sein de la glace de mer entourant l'Antarctique, qui persista tout au long de l'hiver et réapparut les deux hivers suivants. Les recherches qui suivirent montrèrent que les eaux étaient maintenues libres de glace par la convection profonde, permettant à une grande quantité de chaleur de remonter des profondeurs pour être ensuite libérée dans l'atmosphère. Si la polynya continue de susciter l'intérêt des climatologues, elle n'est cependant pas réapparue depuis 1976. Nous utilisons ici des expériences de modélisation pour montrer que la convection profonde dans l'Océan Austral, commune dans les modèles de climat actuels, est fortement sensible au forçage anthropique, et cesse dans beaucoup de modèles quand ceux-ci sont forcés par un scénario de fortes émissions. Le ralentissement de la ventilation profonde résulte de la baisse progressive de la salinité des eaux de surface, une tendance corroborée par les observations des dernières décennies. Nos résultats suggèrent que la convection profonde dans l'Océan Austral sera moins fréquente dans le futur, et a peut-être déjà été significativement affaiblie relativement à la période préindustrielle, avec d'importantes conséquences pour la circulation océanique et le climat.
Davis, Michael A. "Cloud-Radiative Feedback and Ocean-Atmosphere Feedback In the Southeast Pacific Ocean Simulated by IPCC AR4 GCMs." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1313350254.
Full textTinder, Phaedra C. "Ocean-Ice Interactions at Breiðamerkurjökull Glacier, Southeast Iceland." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1339663923.
Full textCampbell, Justin E. "The Effects of Carbon Dioxide Fertilization on the Ecology of Tropical Seagrass Communities." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/693.
Full textHow, Penelope. "Dynamical change at tidewater glaciers examined using time-lapse photogrammetry." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31103.
Full textWall-Palmer, Deborah. "Response of pteropod and related faunas to climate change and ocean acidification." Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/1398.
Full textYamazaki, Kuniko. "Exploring the impact of ocean representation on ensemble simulations of climate change." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497159.
Full textDudeja, Gayatri. "Detection and attribution of climate change in satellite records of ocean productivity." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/377297/.
Full textWang, Guangyao. "An Investigation of Phase Change Material (PCM)-Based Ocean Thermal Energy Harvesting." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100989.
Full textDoctor of Philosophy
Levang, Samuel J. (Samuel James). "The response of ocean salinity patterns to climate change : implications for circulation." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122329.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 121-133).
Global patterns of ocean salinity arise from the exchange of freshwater between the sea surface and the atmosphere. For a quasi-steady state system, these surface fluxes are balanced by compensating transports of salt in the ocean interior. In a warming climate, the atmosphere holds additional water vapor which acts to intensify the global water cycle. Amplified freshwater fluxes are then absorbed at the surface and propagate along ocean circulation pathways. Here, we use coupled model results from the CMIP5 experiment to identify coherent responses in the atmospheric water cycle and in ocean salinity patterns. Some aspects of the response are consistent across models, while other regions show large inter-model spread. In particular, the salinity response in the North Atlantic subpolar gyre, where the mean salinity plays a role in maintaining high surface density for deep-water formation, has low confidence in CMIP5 models.
To understand how differences in ocean circulation may affect this response, we use two techniques to diagnose the role of salt transports in the present-day climate. The first is a salt budget within the surface mixed layer, which identifies major transport processes. The second is a Lagrangian particle tracking tool, used to understand the regional connectivity of water masses. From this analysis, we find that anomalous freshwater signals become well mixed within the ocean gyres, but can be isolated on larger scales. The subpolar Atlantic salinity response generally shows freshening at the surface, but is sensitive to the transport of anomalously salty water from the subtropics, a largely eddy-driven process. As CMIP5 models use a range of eddy parameterizations, this is likely a source of uncertainty in the salinity response.
Finally, we investigate the effect of salinity changes on the deep overturning cells and other circulations, and find a complex influence that also depends on the details of advective pathways. In a warming scenario, water cycle amplification actually works to strengthen the Atlantic meridional overturning circulation due to the influence of enhanced subtropical evaporation.
by Samuel J. Levang.
Ph. D. in Physical Oceanography
Ph.D.inPhysicalOceanography Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution)
Manighetti, Barbara. "The glacial to holocene sedimentary regime in the Northeast Atlantic Ocean." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308359.
Full textTakano, Yohei. "Understanding the mechanisms of dissolved oxygen trends and variability in the ocean." Diss., Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54994.
Full textWelton, R. "Coastal tourism : the response of Indian Ocean island tourism destinations to climate change." Thesis, Nottingham Trent University, 2012. http://irep.ntu.ac.uk/id/eprint/266/.
Full textWigham, Benjamin Doull. "The Amperima Event : analysis of community change in the abyssal northeast Atlantic Ocean." Thesis, University of Southampton, 2002. https://eprints.soton.ac.uk/406867/.
Full textBourgain, Pascaline. "The upper Arctic Ocean variability at a time of rapid Arctic climate change." Paris 6, 2012. http://www.theses.fr/2012PA066010.
Full textThe Arctic climate underwent strong modifications over the past decades. Thanks to a data base gathering more than 18000 observations collected in the entire deep basin of the Arctic Ocean since 1997, we focused on the interannual variability of the upper ocean. The subsurface Summer Pacific Water warmed up since the late 1990s. Notably, a particularly warm flux entered the Arctic Ocean in 2004 was documented all along its propagation in the Canadian basin. These analyses suggest a possible influence of the subsurface waters on the sea ice evolution in the Arctic region. At depth, observations confirm the propagation of warm Atlantic water pulses, in particular a warm anomaly of 0. 8°C detected for the first time in 2004 West of Svalbard. Nevertheless, we did not find evidence for any gradual warming trend of this water mass. The double diffusion process seems to be a widespread phenomenon in the entire deep basin. The vertical heat fluxes transmitted through the interfaces between two mixed layers increased since the 1980s, notably because of the “supersteps” appearance, characterized by a strong temperature increase at the interface. Above the thermocline, the halocline remained relatively robust over the past decade. Its stratification intensified in 2007-2008 in the Canadian basin due to a freshwater content increase probably in response to the atmospheric forcing. As a consequence, the warm Atlantic waters remained insulated from the surface waters and did not contribute to the changes observed at the surface over this period
Agudelo, Paula A. "Analysis of spatial distribution in tropospheric and sea surface temperature trends." Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-04122005-120850/unrestricted/agudelo%5Fpaula%5Fa%5F200505%5Fmast.pdf.
Full textDr. Judith A. Curry, Committee Chair ; Dr. Robert Dickinson, Committee Member ; Dr. Peter Webster, Committee Member. Includes bibliographical references.
Cowburn, Benjamin. "Coral reefs and climate change in the Indian ocean : a case study of Watamu Marine National Park, Kenya and other Indian Ocean locations." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:22c16252-bdf9-4724-a2f8-dbd4c6fe7f09.
Full textLindh, Markus V. "Bacterioplankton population dynamics in a changing ocean." Doctoral thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-38712.
Full textHälften av all fotosyntes på vår planet utförs av växtplankton. De producerar organiskt material som utgör grunden för näringskedjan i havet. Ungefär hälften av det organiska material som produceras av växtplankton utnyttjas inte direkt, utan omsätts istället av bakterieplankton som lever och växer fritt i vattenmassan eller på olika partiklar. Bakterieplankton spelar därmed en nyckelroll i ekosystemet genom sin konsumtion av organiskt kol som för energi högre upp i näringskedjan. Trots deras nyckelroll i akvatiska miljöer vet vi fortfarande mycket lite om bakteriernas detaljerade säsongsmönster, mekanismer bakom rumsliga mönster och hur olika populationer kan komma att svara på klimatförändringar. Målet med denna avhandling var att undersöka hur specifika populationers dynamik och ekosystemfunktion påverkas av naturliga eller klimatorsakade förändringar i havsmiljön. Våra resultat av högupplöst säsongsbunden dynamik i Östersjöns bakteriesamhälle avslöjar en liknande bred uppdelning av ekologiska strategier inom varje större grupp av bakterier, både i relativ abundans och temporal fördelning. Utbredning i rum och tid av många lokalt ovanliga populationer jämfört med få lokalt vanliga populationer förklarades genom stokastisk variation i kolonisations- och utdöendehastigheter. Vidare tyder experimentella studier med tillsatser av olika kolkällor på att marina bakterier har olika ekologiska strategier, där populationer är specialister eller generalister i utnyttjandet av enskilda kolkällor. Med hjälp av experiment med naturliga bakteriesamhällen bekräftade vi tydliga temperatureffekter på bakteriesamhällets sammansättning, och en mindre effekt av lägre pH - som dock tillsammans med förhöjd temperatur bidrog till en tydlig synergistisk effekt på artsammansättningen. Ökad temperatur tillsammans med tillsats av terrestert kol gav också en stor effekt på bakteriesamhällets struktur och ekosystemfunktion och pekar på en potentiellt viktig påverkan av ökad framtida nederbörd och avrinning från vattendrag till havet. Samtliga tre experiment med fokus på klimatpåverkan bekräftade förekomsten av populationer som försvann eller minskade i relativ abundans vid klimatpåverkan (känslighet), medan andra var stabila (resistens). Samtidigt svarade många populationer positivt på klimatorsakade förändringar i havsmiljön och ökade i relativ abundans (respons) samtidigt som bakteriernas ekosystemfunktion påverkades positivt. Sammanfattningsvis visar denna avhandling att vissa nya bakteriepopulationer kan etablera sig och ersätta andra samtidigt som vissa befintliga populationer anpassar sin livsstrategi och ekologi till förändringar i havsmiljön. Vi visar också vikten av regionala effekter, d.v.s. kolonisation och utdöende, för bakteriesamhällets struktur, viktigt för tolkningen av biogeografiska mönster och den genomiska potentialen hos specifika populationer. Denna avhandling poängterar därmed betydelsen av att koppla studier av ekologiska mekanismer till både rumsliga och temporala spridningsmönster hos bakterier och till populationers kapacitet att svara på och anpassa sig till förändringar i havsmiljön.
Swezey, Daniel Sergio. "Ocean Acidification on the California Coast| Responses of Marine Bryozoa to a High CO2 Future." Thesis, University of California, Davis, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10036209.
Full textAs a result of human activities, the level of CO2 in the Earth’s atmosphere has increased by nearly 40% since the industrial revolution. The rate of green house gas emission is accelerating, with current trends exceeding those predicted by “worst case” global climate change scenarios. The chemistry of the ocean is fundamentally changing as a result of increasing atmospheric CO2, which dissolves in seawater, making it more acidic, a process referred to as ocean acidification (OA). A rapidly expanding body of science is now being generated to understand the impact of this global environmental change. To date, most studies evaluating OA effects have centered on simplified laboratory analyses that expose single populations to short-term treatments in order to quantify responses of individuals. These designs offer a limited assessment of the degree to which phenotypic plasticity and local adaptation might influence the response of populations to OA.
To address these questions, I carried out studies on members of Phylum Bryozoa, a species-rich clade of calcified colonial marine invertebrates distributed throughout the global ocean. Bryozoans were selected as a model system for this work because the clade exhibits a broad array of growth and calcification strategies, and because of the relative paucity of data regarding their expected response to future acidification. In addition, bryozoans can be subdivided into genetically identical replicate clones, which can then be assigned to separate treatments, allowing variation across treatments to be uniquely partitioned into the variance components of statistical models. In order to culture bryozoans for comparative experiments, I designed and constructed a new flow-through OA system at the Bodega Marine Laboratory, capable of finely manipulating both the temperature and carbonate chemistry of seawater, allowing for controlled laboratory experiments of long duration.
In Chapter 1, I performed a comparative 9-month laboratory experiment examining the effects of ocean acidification on the native Californian bryozoan Celleporella cornuta. C. cornuta was sampled from two regions of coastline that experience different oceanographic conditions associated with variation in the intensity of coastal upwelling. Under different CO2 treatments, the biology of this bryozoan was observed to be remarkably plastic. Colonies raised under high CO2 grew more quickly, invested less in reproduction, and produced skeletons that were lighter compared to genetically identical clones raised under current atmospheric values. Bryozoans held in high CO2 conditions reduced their investment in skeletal carbonate, changed the Mg/Ca ratio of skeletal walls and increased the expression of organic coverings that may serve a protective function. Differences between populations in growth, reproductive investment, and the frequency of organic covering production were consistent with adaptive responses to persistent variation in local oceanographic conditions.
In Chapter 2, I tested whether skeletal mineralogy can vary plastically in some invertebrates using the cosmopolitan bryozoan Membranipora tuberculata as a model. In a 6-month laboratory experiment, I cultured genetic clones of M. tuberculata under a factorial design with varying food availability, temperature, and dissolved CO2 concentrations. Elevated food availability increased growth in colonies while cold temperatures and high CO2 induced degeneration of colony zooids. However, colonies were able to maintain equivalent growth efficiencies under cold, high CO2 conditions, suggesting a compensatory tradeoff whereby colonies increase the degeneration of older zooids under adverse conditions, redirecting this energy to the maintenance of growth. Elevated food and cold temperatures also decreased Mg concentrations in skeletal material, and this skeletal material dissolved less readily under high CO2 conditions. This suggests that these factors interact synergistically to affect dissolution potential in this and other species.
Finally, in Chapter 3, I explore stable isotope values for δ 18O and δ13C in the calcium carbonate structures of the bryozoan Membranipora tuberculata. I tested whether this species accurately records both temperature and pH variability during periods of coastal upwelling by analyzing δ18O and δ 13C in colonies grown in the field and in controlled laboratory cultures. Field-grown colonies were out planted next to a Durafet® pH sensor, which provided a high-resolution record of the temperature and pH conditions these colonies experienced. δ13C was found to negatively co-vary with pH in both laboratory and field growth, and calculated field temperatures derived from laboratory δ18O temperature calibrations aligned with the records from the pH sensor. δ18 Oc values were more depleted under low pH in laboratory trials, which stands in contrast to patterns observed in other taxa. This may indicate that Membranipora utilizes bicarbonate ion (HCO 3-) in its calcification pathway, and could help explain why many bryozoan species appear to exhibit enhanced growth under high CO 2 conditions. (Abstract shortened by ProQuest.)
Spray, James Francis. "Sedimentological and oceanographic change in the Northwest Atlantic Ocean across the Eocene Oligocene Transition." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/421108/.
Full textBarton, Benjamin I. "Climate change in the Barents Sea : ice-ocean interactions, water mass formation and variability." Thesis, Brest, 2019. http://www.theses.fr/2019BRES0053.
Full textWinter sea ice has declined in the Barents Sea and there is growing evidence that the low sea ice here coincides with cold, winter surface air temperature in Europe and Asia. Atlantic Water (AW) transported into the Barents Sea is warming and its temperature variability is correlated with variability in sea ice extent. As AW extends into the Barents Sea it is modified into a cooler, fresher water mass called BarentsSea Water (BSW). There are limited observations of BSW despite its importance in the Arctic Ocean system, leading to the question, how does the seasonal sea ice impact ocean stratification and mean flow?First, satellite observations are used to find the Polar Front, a water mass boundary between BSW and fresher Arctic Water to the north. The sea ice extent was found to be independent of the Polar Front until the mid-2000s when warming AW prevented the extension of winter sea ice south of the front.Second, by combining satellite and in situ data, it is shown that sea surface temperature can approximate heat content in the Barents Sea. Using heat content with satellite steric height, freshwater content can also be estimated, showing the potential for remote monitoring of BSW properties.Third, a high-resolution model is used to calculate the volume, transport and flux budgets within the AW and BSW domain south of the Polar Front. The model shows BSW volume minimum years in 1990 and2004. Both events were preceded by extensive winter sea ice and substantial summer sea ice melt, a result of preceding, cool AW. The event in 2004 was more extreme and allowed warming AW a greater volume in the Barents Sea
Campbell, Anna Louise. "Sperm pHertility : male gamete responses to ocean acidification and other stressors." Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/25994.
Full textChan, Bin-san, and 陳辯宸. "Climate change impacts on the serpulid tubeworm Hydroides elegans : a biomineralization perspective." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196468.
Full textpublished_or_final_version
Biological Sciences
Doctoral
Doctor of Philosophy
Opie, Brandon. "Seasonal and long-term change in the abundance, accumulation and distribution of beach litter within Table Bay, Cape Town, South Africa." Master's thesis, Faculty of Science, 2021. http://hdl.handle.net/11427/33933.
Full textCrawfurd, Katharine. "Marine phytoplankton in a high CO2 world." Thesis, University of Dundee, 2010. https://discovery.dundee.ac.uk/en/studentTheses/82b46f33-e436-4eff-9862-e464f2761dca.
Full textGoddard, Paul Brent, and Paul Brent Goddard. "Oceanic Controls of North American East Coast Sea Level Rise and Ocean Warming of the Antarctic Shelf." Diss., The University of Arizona, 2018. http://hdl.handle.net/10150/626684.
Full textSchoepf, Verena. "Physiology and Biogeochemistry of Corals Subjected to Repeat Bleaching and Combined Ocean Acidification and Warming." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1376923711.
Full textLang, David. "Continental climate and ocean circulation change during the Pliocene-Pleistocene intensification of Northern Hemisphere Glaciation." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/385217/.
Full textSchaneen, Heather L. "Coral Persistence to Ocean Warming via Developmental Acclimation." NSUWorks, 2016. http://nsuworks.nova.edu/occ_stuetd/420.
Full textShimura, Tomoya. "Long Term Projection of Ocean Wave Climate and Its Climatic Factors." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199255.
Full textAcosta, Navarro Juan Camilo. "Anthropogenic influence on climate through changes in aerosol emissions from air pollution and land use change." Doctoral thesis, Stockholms universitet, Institutionen för miljövetenskap och analytisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-137077.
Full textAlbright, Rebecca. "Effects of Ocean Acidification on Early Life History Stages of Caribbean Scleractinian Corals." Scholarly Repository, 2011. http://scholarlyrepository.miami.edu/oa_dissertations/574.
Full textAgarwal, Atul. "Long-term analysis of the wave climate in the North East Atlantic and North Sea." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/10467.
Full textKnapp, Jarred Lee. "The effects of ocean acidification and temperature change on the West Coast rock lobster (Jasus lalandii)." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97802.
Full textENGLISH ABSTRACT: The West Coast rock lobster (WCRL), Jasus lalandii, is a critical marine fisheries resource for South Africa and may in future be negatively affected by the changes in seawater parameters associated with the ongoing anthropogenic carbon dioxide (CO2) emissions. These CO2 emissions have been linked to a global decrease in ocean pH (termed “ocean acidification”) and an increase in temperature. There are strong estimates that these changes are to worsen in coming centuries. This warranted research because of 1) the low current level of the resource (2.6% of pristine) and 2) the relatively unexplored physiological- and other biological responses of the WCRL to environmental stressors. This information is essential for the sustainable management of the resource by government scientists in times of global- and regional climate change. In the short term, it was found that the WCRL was able to rapidly and reversibly respond to acute changes in seawater pH (pH 7.4), this was achieved primarily through the active up-regulation of bicarbonate levels in the haemolymph. Maintaining extracellular pH protects oxygen transport mechanisms, which are sensitive to pH changes due to the large Bohr effect that this study also revealed, in the respiratory protein, haemocyanin of adult WCRL. The energy cost of actively maintaining extracellular pH, however, is expected to affect growth and potentially survival in the long term. This was tested on juvenile WCRL that were exposed to a reduced seawater pH of 7.3 (18.8 °C) over a period of 28 weeks. Results revealed that survival was not influenced and acid-base regulation in the hypercapnia-exposed lobsters was maintained throughout the duration of the trial, however, this led to a reduced growth rate. Subsequently, in order to replicate field conditions more closely, a combination of effects, namely seawater pCO2 (pH 8 and 7.3) and different temperatures (15.6 and 19 °C) on the growth of juvenile WCRL were assessed over an exposure period of 48 weeks in a second chronic trial. In contrast to the initial trial (28 weeks), where hypercapnia was assessed separately, lobsters exposed to hypercapnia had a higher growth rate than those at the same temperature exposed to a “natural” (normocapnic) seawater pH. The difference was interpreted as an indication that food availability/quality may negatively affect stress response, as feeding in the first trial was later considered “sub-optimal” in comparison to that of the second trial. In the latter, although both hypercapnia and temperature affected growth rates, temperature was the largest contributor to differences observed between treatments. The order of growth rates for lobsters from different treatments was: hypercapnia/high temperature > normocapnia/high temperature > hypercapnia/low temperature > normocapnia/low temperature. In this trial too, irrespective of treatment, lobsters were able to maintain extracellular pH within a relatively narrow range over the extent of the trial and survival was not negatively affected by hypercapnia or high temperature. In order to compare the sensitivity of juvenile WCRL to that of adults, with regards to the effect of changes in extracellular pH on oxygen transport, and to assess the impact of chronic hypercapnia, haemocyanin from juveniles was studied in detail after the first growth trial. This revealed that juvenile WCRL have a similar Bohr effect to that of adults. In addition, the haemocyanin of hypercapnia-exposed juveniles showed an increased affinity to oxygen caused by an intrinsic change in its molecular structure. This was interpreted as an energy-saving mechanism, because at the same time, haemocyanin concentration in these animals was lower than in normocapnic lobsters. At the termination of the second chronic trial, the immunological response to the combined stressors was assessed, namely total circulating haemocyte counts (THC) and the ability to clear/inactivate an introduced dose of a bacterium, Vibrio anguillarum. A pilot experiment on non-treated juveniles revealed a similar resting THC to that of other lobster species, and culturable V. anguillarum was rapidly cleared from their haemolymph. The effect of chronic exposure to a combination of effects, namely hypercapnia and different temperatures, was subsequently tested after termination of the second chronic trial. There were no differences between treatments in a) baseline THC (i.e. before bacterial challenge) and 2) the capability to clear culturable bacteria from haemolymph. The only difference was the circulating THCs post-bacterial challenge, as they were reduced in the hypercapnic-, high temperature treatment, compared with all other treatments. The reason is unknown, but it is speculated that it may have been linked to an increased metabolic demand in these lobsters. Overall, these results demonstrate the great plasticity of the WCRL at the molecular-, biochemical and physiological level. They provide important initial information for government fisheries scientists to aid in predicting future development of, and potential threats to the WCRL resource, as well as providing a platform from which the direction of future studies can be determined.
AFRIKAANSE OPSOMMING: Die Weskus-seekreef, Jasus lalandii, is ’n belangrike seevisseryhulpbron vir Suid-Afrika en kan in die toekoms negatief geraak word deur die veranderinge in seewaterparameters wat met voortgesette antropogeniese vrystellings van koolstofdioksied (CO2) verband hou. Hierdie CO2-vrystellings word met ’n wêreldwye daling in die pH van seewater (oftewel “oseaanversuring”) en ’n temperatuurstyging verbind. Alles dui daarop dat hierdie veranderinge in die volgende eeue sal vererger. Dít regverdig navorsing weens 1) die huidige skaarste aan dié hulpbron (2,6% van oorspronklike getalle), en 2) die betreklik onverkende fisiologiese en ander biologiese reaksies van die kreef op omgewingstressors. Hierdie inligting is noodsaaklik om staatswetenskaplikes in staat te stel om die hulpbron te midde van wêreldwye en streeksklimaatsverandering volhoubaar te bestuur. Op kort termyn word daar bevind dat die Weskus-kreef vinnig en omkeerbaar op akute veranderinge in die pH van seewater reageer (pH 7,4). Dít is hoofsaaklik deur die aktiewe opwaartse regulering van bikarbonaatvlakke in die hemolimf vasgestel. Die handhawing van ekstrasellulêre pH beskerm die meganismes wat suurstof vervoer, wat gevoelig is vir pH-veranderinge weens die beduidende Bohr-effek in die respiratoriese proteïen, hemosianien, by die volwasse kreef – nóg ’n bevinding van hierdie studie. Tog sal die energiekoste verbonde aan die handhawing van ekstrasellulêre pH na verwagting groei en moontlik ook oorlewing op lang termyn beïnvloed. Dít is getoets op jong Weskus-krewe wat oor ’n tydperk van 28 weke aan seewater met ’n verlaagde pH van 7,3 (18,8 °C) blootgestel is. Resultate dui daarop dat oorlewing nié geraak word nie, en dat suur-basis-regulering in die hiperkapnie-blootgestelde krewe vir die volle duur van die proef gehandhaaf is, hoewel dit tot ’n verlaagde groeitempo gelei het. Ten einde natuurlike omstandighede akkurater na te boots, is ’n kombinasie van uitwerkings, naamlik pCO2 van seewater (pH 8 en 7,3) en verskillende temperature (15,6 en 19 °C), op die groei van jong krewe oor ’n blootstellingstydperk van 48 weke in ’n tweede chroniese proefneming beoordeel. In teenstelling met die aanvanklike proef (28 weke), is hiperkapnie afsonderlik beoordeel en het krewe wat aan hiperkapnie blootgestel is ’n hoër groeitempo getoon as dié by dieselfde temperatuur wat aan seewater met ’n ‘natuurlike’ (normokapniese) pH blootgestel is. Dié verskil is vertolk as ’n aanwyser dat voedselbeskikbaarheid/-gehalte ’n negatiewe uitwerking op stresreaksie kan hê, aangesien voeding in die eerste proefneming later as ‘suboptimaal’ beskou is vergeleke met dié van die tweede proef. In die tweede proef, hoewel hiperkapnie én temperatuur groeitempo’s beïnvloed het, was temperatuur die grootste bydraer tot die verskille wat tussen behandelings opgemerk is. Die orde van die kreefgroeitempo’s met die verskillende behandelings was: hiperkapnie/hoë temperatuur > normokapnie/hoë temperatuur > hiperkapnie/lae temperatuur > normokapnie/lae temperatuur. In die tweede proef kon die kreef ook, ongeag behandeling, ekstrasellulêre pH vir die volle duur van die proefneming binne ’n betreklik beperkte bestek handhaaf, en het nóg hiperkapnie nóg hoë temperatuur ’n negatiewe invloed op oorlewing gehad. Om die gevoeligheid van jong Weskus-krewe met dié van volwasse krewe te vergelyk wat betref die uitwerking van veranderinge in ekstrasellulêre pH op suurstofvervoer, en om die impak van chroniese hiperkapnie te bepaal, is die hemosianien van jong krewe deeglik ná die eerste groeiproef bestudeer. Dít het aan die lig gebring dat die jong kreef ’n soortgelyke Bohr-effek as volwassenes toon. Daarbenewens toon die hemosianien van hiperkapnie-blootgestelde jong krewe ’n verhoogde affiniteit tot suurstof, wat deur ’n intrinsieke verandering in molekulêre struktuur veroorsaak word. Dít is as ’n energiebesparingsmeganisme vertolk, aangesien hemosianienkonsentrasie by hierdie diere terselfdertyd laer was as by normokapniese kreef. Aan die einde van die tweede chroniese proefneming is die immunologiese reaksie op die gekombineerde stressors beoordeel, naamlik totale sirkulerende hemosiettellings (THC) en die vermoë om ’n toegediende dosis van die bakterie Vibrio anguillarum op te ruim/te deaktiveer. ’n Toetseksperiment met niebehandelde jong krewe dui op ’n soortgelyke rustende THC as dié van ander kreefspesies, en kweekbare V. anguillarum is vinnig uit die hemolimf opgeruim. Die effek van chroniese blootstelling aan ’n kombinasie van faktore, naamlik hiperkapnie en verskillende temperature, is vervolgens na afloop van die tweede chroniese proef getoets. Die verskillende behandelings lewer dieselfde a) THC op die basislyn (met ander woorde voor toediening van die bakterie), en 2) opruimingsvermoë van kweekbare bakterieë uit die hemolimf op. Die enigste verskil was die THC’s ná toediening van die bakterie, wat laer was met die hiperkapniese hoëtemperatuurbehandeling as met alle ander behandelings. Die rede hiervoor is onbekend, maar hou vermoedelik verband met ’n verhoogde metaboliese vereiste by hierdie krewe. Oor die algemeen toon hierdie resultate die beduidende plastisiteit van die Weskus-seekreef op molekulêre, biochemiese en fisiologiese vlak. Dit bied belangrike aanvanklike inligting vir staatsvisserywetenskaplikes om die toekomstige ontwikkeling van én moontlike bedreigings vir die kreefhulpbron te voorspel, en voorsien boonop ’n platform van waar die rigting van toekomstige studies bepaal kan word.
Lauderdale, Jonathan Maitland. "On the role of the Southern Ocean in the global carbon cycle and atmospheric CO2 change." Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/191935/.
Full textBallinger, Thomas Justin. "The Influence of Atmosphere-Ocean Teleconnections on Western Arctic Sea Ice and Surface Air Temperature." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1311889468.
Full textAuerbach, David I. "Climate change mitigation via ocean disposal of power-plant-generated CO₂ : a comprehensive environmental and political analysis." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10820.
Full textShi, Jie. "Integrated modelling of hydrological and hydrodynamic processes, dynamic bacteria decay with climate change and intensive farming in riverine and estuarine water." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/98617/.
Full textHood, Lon L., and Boris E. Soukharev. "The Lower-Stratospheric Response to 11-Yr Solar Forcing: Coupling to the Troposphere–Ocean Response." American Meteorological Society (Boston, MA), 2012. http://hdl.handle.net/10150/623318.
Full textHelaouet, Pierre. "Large-scale study of Calanus in the North Atlantic Ocean : macroecological patterns and potential impacts of climate change." Thesis, University of Plymouth, 2009. http://hdl.handle.net/10026.1/2656.
Full textBergan, Alexander (Alexander John). "Pteropod shell condition, locomotion, and long-term population trends in the context of ocean acidification and environmental change." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111298.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 159-168).
Thecosome pteropods are planktonic mollusks that form aragonite shells and that may experience increased dissolution and other adverse effects due to ocean acidification. This thesis focuses on assessing the possible biological effects of ocean acidification on the shells and locomotion of pteropods and examining the response of a local pteropod population to environmental change over time. I analyzed shell condition after exposing pteropods to elevated CO₂ as well as in natural populations to investigate the sensitivity of the shells of different species to aragonite saturation state ([omega][subscript A]). The pteropods (Limacina retroversa) from laboratory experiments showed the clearest pattern of shell dissolution in response to decreased [omega][subscript A], while wild populations either had non-significant regional trends in shell condition (Clio pyramidata) or variability in shell condition that did not match expectations due to regional variability in [omega][subscript A] (Limacina helicina). At locations with intermediate [omega][subscript A] (1.5-2.5) the variability seen in L. helicina shell condition might be affected by food availability more than tA. I examined sinking and swimming behaviors in the laboratory in order to investigate a possible fitness effect of ocean acidification on pteropods. The sinking rates of L. retroversa from elevated CO₂ treatments were slower in conjunction with worsened shell condition. These changes could increase their vulnerability to predators in the wild. Swimming ability was mostly unchanged by elevated CO₂ after experiments that were up to three weeks in duration. I used a long-term dataset of pteropods in the Gulf of Maine to directly test whether there has been a population effect of environmental change over the past several decades. I did not observe a population decline between 1977 and 2015, and L. retroversa abundance in the fall actually increased over the time series. Analysis of the habitat use of L. retroversa revealed seasonal associations with temperature, salinity, and bottom depths. The combination of laboratory experiments and field surveys helped to address gaps in knowledge about pteropod ecology and improve our understanding of the effects of ocean acidification on pteropods.
by Alexander Bergan.
Ph. D.
Melatunan, Sedercor. "Biochemical, metabolic and morphological responses of the intertidal gastropod Littorina littorea to ocean acidification and increase temperature." Thesis, University of Plymouth, 2012. http://hdl.handle.net/10026.1/1009.
Full textBilling, Suzannah-Lynn. "The role of agents for change in the sustainable development of wave energy in the Highlands and Islands region of Scotland." Thesis, University of the Highlands and Islands, 2016. https://pure.uhi.ac.uk/portal/en/studentthesis/the-role-of-agents-for-change-in-the-sustainable-development-of-wave-energy-in-the-highlands-and-islands-region-of-scotland(adb7d446-a88e-4451-b39c-a7c0f9acffab).html.
Full textPhelps, Charlie. "Predicting the impact of future climate on ecologically important macroalgae." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2016. https://ro.ecu.edu.au/theses/1785.
Full textAli, Syed Mahtab. "Climate change and water management impacts on land and water resources." Thesis, Curtin University, 2007. http://hdl.handle.net/20.500.11937/202.
Full textFerrero, Bruno. "Estudo comparativo da estrutura e variabilidade das massas de água a partir das simulações numéricas do 4RA/IPCC." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/21/21132/tde-29042010-162547/.
Full textThe development and sophistication of numerical models in recent years has allowed to perform many climate system\'s simulations. Such simulations aim to reproduce the dynamics and variability of the climate and consequently predict future climate and possible climate changes. Oceanic processes such as formation and distribution of water masses have an important role in understanding the oceans as a reservoir of salt, dissolved gases and heat. Considering that changes in such processes may have great impact in global and regional climate this work aims to describe spatial and temporal variability of water masses in the South Atlantic Ocean and Southern Ocean. Data from the numerical simulations used for the preparation of the Intergovernmental Panel on Climate Change Fourth Assessment Report (4AR/IPCC) were used. Four climate models were chosen: ECHAM5/MPI-OM, IPSL-CM4-V1, MIROC3.2, NOAA / GFDL CM2.1. Results from the Climate of the 20th Century (20c3m) and the 1% per year CO2 increase (to doubling) experiment (1pctto2x) were analyzed. The four models show a positive trend of temperature and a freshening trend of the Antartic Intemediate Water (AAIW), Circumpolar Deep Water (CDW) and the Antartic Deep Water (AADW). The densities of these water masses become significantly lighter in the 20c3m scenario. In the 1pctto2x scenario in the AAIW and CDW moved to upper layers. Also in this scenario there is a cooling of the AADW, moving this water mass to deeper layers.