Dissertations / Theses on the topic 'Environment and Earth Sciences'
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Black, Benjamin A. (Benjamin Alexander). "Volatiles as a link between planetary interiors and the environment." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/84920.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 163-179).
Volatiles derived from planetary interiors influence magma evolution and environmental processes. Over appropriate timescales, Earth's mantle, crust, ocean, and atmosphere constitute coupled systems. The apparently synchronous Siberian Traps eruption and end-Permian mass extinction offer an ideal test case to study the interactions between magmatism and climate. In this thesis, I use experimental petrology, numerical modeling, geochemical measurements, and field observations to investigate the petrologic sources, eruptive transfer, and climatic effects of volatiles released during emplacement of the Siberian large igneous province. In an extreme variation on terrestrial volatile cycling, I also explore the erosional history of Titan as recorded in valley networks carved by rivers of liquid hydrocarbons.
by Benjamin A. Black.
Ph.D.
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Johnson, Sarah Stewart. "Mars in the late Noachian : evolution of a habitable surface environment." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45605.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references.
This dissertation addresses whether simple life forms might have existed on Mars during the late Noachian epoch, and whether those life forms, or their traces, can be detected today. It begins by analyzing the ancient Martian climate in light of new evidence that sulfur chemistry played a prominent role in the planet's early evolution. It finds that sulfur-induced greenhouse warming could have periodically heated the planet enough to support liquid water, thereby creating warm, wet, clement conditions. Moreover, it finds that those warming pulses, while short-lived over geologic time, may have persisted for hundreds of years. If sulfur helped create environmental conditions capable of hosting life, however, it also created conditions that were adverse to sustaining it. In particular, dissipation of sulfur volatiles cooled the climate, and sulfur rainout contributed to the acidity of Martian surface waters. The dissertation therefore proceeds to analyze the potential for persistence and detection of life in terrestrial environments with Mars-like characteristics. It first investigates the potential for detecting ancient life by searching for lipid biomarkers in sulfur-rich acid salt lakes, concluding that a variety of biomarkers may be more resistant to decay than previously believed. It then analyzes soil samples from permafrost, discovering the oldest independently authenticated viable organisms ever found, and positing low-level metabolic activity and DNA repair as a survival mechanism in ancient cells. Finally, the dissertation uses deep sequencing to examine prokaryotic diversity in a terrestrial Mars-like river characterized by low pH and high concentrations of iron and sulfur, with results considered in light of the implications for life detection approaches incorporating new, in situ "PCR in a chip" technology. The dissertation concludes by proposing future work, including the ultimate goal of developing a life detection instrument for Mars.
by Sarah Stewart Johnson.
Ph.D.
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Mloszewski, Aleksandra. "Environmental and microstructural controls of short-term shell degradation in temperate, macrotidal environments." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40807.
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Depositional conditions early post-mortem influence net shell alteration prior to fossilization. This study assesses the progressive degradation of experimentally deployed Mytilus edulis shells and natural aragonite crystals during 13 months at and 10 - 20 cm below the sediment surface in High- and Mid-Marsh Salt Marsh Ponds, a Beach and a Cove (Bay of Fundy, NB, Canada). Changes in net weight, macroscopic, and microstructural features are examined in the context of environmental conditions. Results show that: 1) early degradation processes act very quickly, causing significant changes in shell condition within 13 months post-deposition. 2) The sloughing off of shell crystallites loosened by maceration, bioerosion and maceration, in order of importance, dominate shell degradation in the study environments. 3) Dissolution contributes relatively little to the overall taphonomic signature during early shell degradation.L’état de préservation des coquilles d’organismes marins dépend directement des conditions environnementales dans lesquelles elles se dégradent. Cette étude a pour but de déterminer les conditions de dégradation progressive de coquillages (Mytilus edulis) et de cristaux abiotiques d’aragonite déployés à l’interface eau-sédiment ainsi qu’enfouis (à 10-20 cm) durant treize mois, dans les zones haute et moyenne d’un marais salant, une plage et une crique de la Baie de Fundy (NB, Canada). Les changements macroscopiques, microscopiques et de masse sont discutés relativement aux conditions environnementales. Nos résultats montrent que: 1) la dégradation et les processus agissent très tôt après la déposition, et produisent des changement d’état significatifs en deçà de 13 mois post-mortem. 2) Dans les environments ci-dessus, la mue des tablettes de nacre de la surface de la coquille est le processus le plus efficace, suivi par la bioérosion, et la macération. 3) La dissolution joue un rôle secondaire durant la dégradation précoce des coquillages.
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Dunn-Sigouin, Etienne. "Evaluation of northern hemisphere blocking climatology in the global environment multiscale (GEM) model and in the present and future climate as simulated by the CMIP5 models." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110589.
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The performance of the Global Environmental Multiscale (GEM) model, Canadian operational numerical model, in reproducing atmospheric low-frequency variability is first evaluated in the context of Northern Hemisphere blocking climatology. The validation is conducted by applying a comprehensive but relatively simple blocking detection algorithm. Comparison to reanalysis reveals that the maximum blocking frequency over the north Atlantic and western Europe is generally underestimated and its peak season is delayed from late winter to spring. This contrasts with the blocking frequency over the north Pacific which is generally overestimated during all seasons. The biases in blocking frequency are found to be largely associated with the biases in climatological background flow. Specifically, modelled stationary wave shows a seasonal delay in zonal wavenumber 1 and an eastward shift in zonal wavenumber 2 components. Next, we extend our methodology to preliminary analyses of Northern Hemisphere blocking climatology from a subset of climate models participating in the Coupled Model Inter-comparison Project phase 5 (CMIP5). Historical integrations reveal that the maximum Euro-Atlantic blocking frequency is generally underestimated during the cold season and that significant overestimation of maximum Pacific blocking frequency occurs throughout the year in some models, as compared to reanalysis. In contrast, RCP8.5 integrations show a weak hint of reduced blocking frequency over the Pacific sector in comparison to historical integrations. However, no significant trend in terms of block duration within the RCP8.5 integrations is found.Les performances du modele Global Environment Multiscale (GEM), qui est le modele numerique operationel Canadien, a reproduire les variabilites atmospheriques de basse frequence sont evaluees en premier lieu dans le contexte de la climatologie de bloquage atmospherique dans l'hemisphere Nord. Afin de valider le modele, un algorithme de detection de bloquage qui est a la fois comprehensif et relativement simple est applique aux donnees atmospheriques. Les resultats montrent que la frequence maximum de bloquage au dessus de l'Atlantique Nord et l'Europe de l'Ouest est generalement sous-estimee et il y un delai dans la saison d'amplitude maximale puisqu'elle se produit au printemps au lieu de tard en hiver. De plus, la frequence de bloquage est generalement sur-estimee au dessus du Pacifique Nord. Il a ete trouve que les erreurs dans la frequence de bloquage sont grandement associees aux erreurs dans la circulation climatologique de l'atmosphere. En fait, les ondes stationnaires modelisees montrent un delai saisonnier dans le nombre d'onde zonal 1 et un deplacement vers l'Est des composantes du nombre d'onde zonal 2. Ayant confiance en la capacite de notre index pour identifier des bloquages atmospheriques, nous appliquons notre methodologie sur des analyses preliminaires de bloquage climatologique dans l'hemisphere Nord a partir d'un sous-ensemble de modeles climatologiques faisant partie du Coupled Model Inter-Comparison Project Phase 5 (CMIP5). Les integrations historiques revelent que la frequence maximale de bloquage sur l'Euro-Atlantique est generalement sous-estimee durant la saison froide et que la sur-estimation de la frequence maximale de bloguage sur le Pacifique se produit tout au long de l'annee dans certains modeles. En comparaison, les integrations de type RCP8.5 montrent un leger indice d'une reduction de la frequence de bloquage sur le Pacifique meme si aucune tendance significative en terme de duree de bloquage n'a ete trouvee.
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Meredith, Laura Kelsey 1982. "Field measurement of the fate of atmospheric H₂ in a forest environment : from canopy to soil." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/79283.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 245-254).
Atmospheric hydrogen (H₂ ), an indirect greenhouse gas, plays a notable role in the chemistry of the atmosphere and ozone layer. Current anthropogenic emissions of H₂ are substantial and may increase with its widespread use as a fuel. The H₂ budget is dominated by the microbe-mediated soil sink, and although its significance has long been recognized, our understanding is limited by the low temporal and spatial resolution of traditional field measurements. This thesis was designed to improve the process-based understanding of the H₂ soil sink with targeted field and lab measurements. In the field, ecosystem-scale flux measurements of atmospheric H₂ were made both above and below the forest canopy for over a year using a custom, automated instrument at the Harvard Forest. H₂ fluxes were derived using a flux-gradient technique from the H₂ concentration gradient and the turbulent eddy coefficient. A ten-fold improvement in precision was attained over traditional systems, which was critical for quantifying the whole ecosystem flux from small H2 concentration gradients above the turbulent forest canopy. Soil uptake of atmospheric H₂ was the dominant process in this forest ecosystem. Rates peaked in the summer and persisted at reduced levels in the winter season, even across a 70 cm snowpack. We present correlations of the H₂ flux with environmental variables (e.g., soil temperature and moisture). This work is the most comprehensive attempt to elucidate the processes controlling biosphere-atmosphere exchange of H₂ . Our results will help reduce uncertainty in the present-day H₂ budget and improve projections of the response of the H₂ soil sink to global change. In the lab, we isolated microbial strains of the genus Streptomyces from Harvard Forest and found that the genetic potential for atmospheric H₂ uptake predicted H₂ consumption activity. Furthermore, two soil Actinobacteria were found to utilize H₂ only during specific lifecycle stages. The lifecycle of soil microorganisms can be quite complex as an adaptation to variable environmental conditions. Our results indicate that H₂ may be an important energetic supplement to soil microorganisms under stress. These results add to the understanding of the connections between the environment, organismal life cycle, and soil H₂ uptake.
by Laura Kelsey Meredith.
Ph.D.
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Chan, Gabriel Angelo Sherak. "Trade and the environment : the political economy of CO₂ emission leakage with analysis of the steel and oil sands industries." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/115466.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.Thesis: S.B., Massachusetts Institute of Technology, Department of Political Science, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 113-116).
Introduction: In 2007, scientists and governmental officials from around the world contributed to the United Nations-authorized Intergovernmental Panel on Climate Change's (IPCC) Fourth Assessment Report. Through peer-reviewed scientific research and governmental review, the IPCC came to the conclusion that "warming of the climate system is unequivocal," and that "most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations." The IPCC Fourth Assessment states that humans have "more likely than not" contributed to the phenomena of more frequent "warm spells/heat waves," larger "area[s] affected by droughts," more "intense tropical cyclones.. .and heavy precipitation events," and "extreme high sea level[s]." Citing "high agreement" and "much evidence," the IPCC states that "with current climate change mitigation policies and related sustainable development practices, global GHG [greenhouse gas] emissions will continue to grow over the next few decades." (Intergovernmental Panel on Climate Change, 2007)
by Gabriel A. Chan.
S.B.
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Rapopo, Mafusi. "Petrogenesis of the syntectonic Matok Pluton in the Limpopo Belt (South Africa) and its implications of the geodynamic environment." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17993.
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Thesis (MSc)--Stellenbosch University, 2011.ENGLISH ABSTRACT: The ~2.67 Ga Matok pluton comprises calc‐alkaline pyroxene (px)‐bearing and px‐free granitoids. The pluton was constructed by means of two episodes of intrusion each of which had co‐magmatic px‐bearing and px‐free granitoid groups. All the granitoid groups (px‐bearing and px‐free) are characterised by non‐porphyritic and porphyritic varieties. The phenocrysts in both episodes of intrusion are plagioclase ± alkali feldspar and are aligned parallel to the trend of the Limpopo Belt, attesting to a syntectonic emplacement. The time gap between the first and second intrusion is insignificant and magma was most likely stored in the chamber after the first intrusion. Petrography and geochemical signature of both px‐bearing and px‐free granitoid samples have been studied and a petrogenetic model which accounts for the coeval px‐bearing and px‐free granitoids is proposed. The relevance of the syntectonic emplacement of the Matok pluton ie n the Limpopo Belt is also addrssed. Px‐bearing granitoids always have clinopyroxene but orthopyroxene is not always present. Magnetite and ilmenite are present in both px‐bearing and px‐free granitoids but are more abundant in the px‐bearing granitoids and subordinate in the px‐free granitoids. Plagioclase in both px‐bearing and px‐free granitoids is of oligoclase (An12‐30) composition but is relatively more calcic and increases in modal abundance in the px‐bearing granitoids. Alkali feldspar is more dominant in the px‐free granitoids. Hornblende is present in all the px‐bearing granitoids and the px‐free granitoids with ≤71 wt.% SiO2 but is absent in the px‐free granites with >71 wt.% SiO2. Both magmatic epidote and titanite occur exclusively in the px‐free granitoids with ≤71 wt.% SiO2 and are absent in all the px‐bearing granitoids as well as the px‐free gra nites with >71 wt.% SiO2. Px‐bearing granitoids are mainly of dioritic and granodioritic and have subordinate granitic composition while px‐free granitoids are mainly of granitic and granodioritic and have subordinate dioritic composition. All the rocks define well correlated variation of SiO2 with the rest of the major elements. However, there is always a hiatus between the granites with >71 wt.% SiO2 and all other rocks. Px‐bearing and px‐free granitoids at the same SiO2 concentrations tend to have approximately equal concentrations of MgO, CaO and TiO2, whereas K2O concentration is distinctively higher for the px‐free granitoids. The distribution of the high field strength elements (HFSE; Nb, Ta, Zr and Hf) and rare earth elements (REE) is similar in both px‐bearing and px‐free granitoids. On contrary, Th, U, Cs and Rb are characteristically higher in the px‐free granitoids. All granitoids are characterised by negative anomalies of the HFSE (Nb, Ta and Ti) and the LILE (Th, U and Sr) on primitive mantle normalised diagrams. On the one hand, concentrations of compatible elements (Cr, Ni and Mg) in the Matok pluton granitoids are rather low for a mantle source. On the other hand, all the granitoids have superchondtritic Nb/Ta ratios that overlap with those of the Ventersdorp continental flood basalts which extruded in the Kaapvaal Craton at ~2.7 Ga. The continental crust typically has subchondritic Nb/Ta ratio, and superchondtritic Nb/Ta ratios are widely accepted to resemble a mantle source. The implication is that the Matok pluton granitoids had inherited the superchondtritic Nb/Ta ratio from their source; juvenile underplated mafic magmas that had ponded owing to the impact of the Ventersdorp mantle plume. The large volumes of ponded magma s probably induced the high grade metamorphism in the Limpopo Belt. All the granitoids of the Matok pluton are probably products of one partial melting event. One possible way to account for the co‐existence of px‐bearing and px‐free granitoids in the Matok pluton is by means of, at least, two magma chambers; one which was filled with anhydrous magma and the other which was filled with hydrous magma. An alternative model would be that in which there was only one chamber. In the one chamber scenario, the magma was hydrodynamically sorted into zones that differed mostly in fH2O and concentrations of highly fluid‐mobile elements but conserved the uniformity in fluid immobile elements. Regardless of the number of chambers, magma batches intruded in the form of feeder dikes which minimally interacted, thus avoiding the hydration of pyroxene in the px‐bearing granitoids.
SELELEKELA: Plutone ya Matok e fumanehang profinsing ya Limpopo sebakeng seo ho digeologist se tsebahalang ka hore ke Lebanta la Limpopo e ile ya aheya dilemong tse 2.67 biliyone tse fetileng. Plutone ena eile ya aheya ka mekgahlelo e mmeli, mme mokgahlelo ka mong o ne o bopilwe ka majwe a nang le pyroxene le a senang yona. Majwe kaofela ke a mofuta wa calc‐alkaline. Phapang e kgolo dipakeng tsa mefuta ena e mmedi ya majwe ke boteng ba pyroxene le boteng ba epidote le titanite majweng a nang le pyroxene le a senang pyroxene ka ho latellana. Ha e le diminerale tse ding kaofela tsona ha likgethe mofuta wa lejwe; liteng mefuteng ya majwe ka bobedi. Kgonahalo ya hore plutone ya Matok e ahwe ka mefuta ena e mmedi (px‐bearing and px‐free) e tlile ka mekgoa e mmedi kapa o mong wa mekgwa ena yo ka bobedi e ka etsahalang. (1)Tlaase semelong sa lesheleshele moralla (magma) hone ho ena le didiba tse pedi, seseng se tshetse lesheleshele le chesang haholo ebile le le metsi a fokolang (anhydrous magma) ha se seng se ne se tshetse lesheleshele le metsi a mangata (hydrous magma). Ho tloheng moo didibeng tse pedi ho tla moo plutone ea Matok eleng teng kajeno masheleshele ana a ne a tla ka mokgwa wa di‐dike tseo kaofela phello ya tsona e neng e le sebakeng se le seng‐plutone ya Matok. (2) Mokgwa wa bobedi ke haeba ho ne ho ena le sediba se le seng sa lesheleshele moralla, mme ka sedibeng ka moo ho ne ho ena le maqulwana (zones) a neng a fapane ka bongata ba metsi. Ho tloha sedibeng moo masheleshele ana a ne a tloha ka bona boqulwana boo entse ele ka mokhwa wa di‐dike, mme kaofela phello ya di‐dike ene ele plutone ya Matok. Kaofela majwe a plutone ya Matok a na le feldspar eo boholo ba nako e patlameng ho ya nqa bophirimela‐bochabela (W‐E), e leng nqa eo Lebanta la Limpopo le phatlaletseng ka teng. Hona ho tiisa hore plutone ya Matok e aheile nakong yo Lebanta la Limpopo le neng le ntse le aheya le lona. Ke dilemong tse kabang 2.7 biliyone tse fetileng ha dikarolong tse ding tsa Cratone ya Kaapvaal ho ne ho aheya majwe a moralla a Ventersdorp. Majwe ana ke a hlahang tlaase botebong ba lefatshe (mantle), mme a susumeditswe ke plumo. Karolo boholo ya lesheleshele moralla hae ya ka ya nyoloha ho fihla hodimo lefatsheng. Empa mofuthu o mongata ho nyoloha leshelesheleng moo ke ona oileng wa 'pheha' majwe ho phatlalla le Lebanta la Limpopo. Ho nyoloha hona ha plumo ho etsahetse ka nako e lengwe le ho tsukutleha ho hoholo ho potapota le Cratone ya Kalahari, mme bobedi diketsahalo tsena diile tsa tswala Lebanta la Limpopo. Hobane plutone ya Matok e aheile hanghang ka mora hore lesheleshele la moralla le dule tlaase ho lekgapetla la lefatshe (crust), dielemente tse ratang haholo diminerale tsa ditemperetjha tse hodimo diile tsa feela jwalo di nkile lefa hotswa lesheleshele moralleng la Ventersdorp.
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Wilkinson, John L. "Occurrence, bioaccumulation, fate and transport of pharmaceuticals, plasticisers, illicit drugs and perfluorinated compounds in the aquatic environment." Thesis, Kingston University, 2017. http://eprints.kingston.ac.uk/39283/.
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Mass produced chemicals have revolutionised the way in which humans live and has led to both a significant increase in quality of life and a concomitant change in the way we pollute our habitats. Such chemicals include pharmaceuticals, plasticisers, perfluorinated compounds and metabolites which enter rivers via sources such as sewage treatment works (STW) effluent outfalls. The presence and distribution of these contaminants is of concern due to their increasing use and ability of some to biologically affect non-target aquatic organisms at trace (ng/L) levels. This work investigated the fate and distribution of selected pharmaceuticals, plasticisers, illict drugs, perfluorinated compunds (PFCs) and metabolites are investigated in three rivers of southern England. Specific objectives included establishing spatial distribution patterns of selected contaminants along the entire course of rivers receiving inputs from multiple STWs, their partition between bound (to suspended particulate material) and dissolved phases of river water, accumulation in sediment, bioaccumulation in primary producers including plants and biofilm/ periphyton, bioaccumulation in benthic aquatic organisms, adsorption of studied contaminants to polyethlene microparticles (similar to those used in cosmetic products) both in the lab and in rivers, and adsorption to 'natural' replacements for polyethylene microparticles (MPs). Spatial distribution analysis showed that selected contaminants are ubiquitous in the studied rivers with trace levels of plasticisers and perfluorinated compounds identified in river headwaters and beyond. Within the rivers studied in this work, pharmaceuticals were shown to be exclusively introduced by STW effluent and persisted exclusively in the dissolved phase of river water through the studies areas. Plasticisers and PFCs however were additionally introduced via runoff from streets, at times at higher concentrations than in SFWs effluent outfall and bound to suspended particulate material. Only PFCs and plasticisers were found to be bioaccumulative or very bioaccumulative in aquatic plants, biofilm. periphton and benthic organisms, and accumulated in sediment. Illicit drugs were only found in STW effluent and downstream river flow, almost exclusively in the dissolved phase of collected water. Laboratory assessment of adsorption to polyethylene MPs showed adsorption largely occurred via a linear isotherm and only for PFCs. However, trace levels of pharmaceuticals and an illicit drug urinary metabolite were extracted from polyethylene MPs deployed downstream from STW effluent outfalls in three rivers. Investigation of a 'natural' alternative to polyethyle MPs (walnut husk Mps) showed adsorption to these replacement particles occurred to a greater amount with more of the studied contaminants than to polyethylene MPs. This work significantly contributes to the knowledge of organis contaminant occurrence, bioaccumulation, fate and distribution in the aquatic environment. Future research should focus on elucidating the fate and distribution of conugated pharmaceuticals and metabolites in the aquatic environment, establishing organism-specific contaminant bioaccumulation guideline, the effect of microparticle fragmentation on contaminant adsorption, identification of adsorption-free MPs for use in cosmetic products and developing study designs to incorporate environmental epigenetics with toxicology and chemistry in the aquatic environment.
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Adelman, Jessica. "Mineral interactions in a gold mining environment: change in oxidation rate of stibnite as affected by the addition of varying amounts of pyrite in an oxygenated flow through system." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=92390.
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It is thought that a significant mechanism of stibnite (Sb2S3) oxidation in mine wastes is through contact with a mineral of greater rest potential (whereby the outer valence shell electrons operate at a higher energy level), such as pyrite (FeS2). The goal of this research is to determine if the oxidation of stibnite in an oxygenated flow through system was increased through contact with minerals of greater rest potential such as pyrite and arsenopyrite (FeAsS) and whether this electro-chemical reaction was affected by various ratios of stibnite to pyrite (or arsenopyrite) and slightly acidic (pH 5) to alkaline (7.5) pH conditions. Four column leaching experiments were carried out using various ratios of stibnite and pyrite (or arsenopyrite). When the two minerals were mixed in columns and leached with water, the treatment with the greatest amount of pyrite and least amount of stibnite (95% pyrite) had the highest cumulative amount of dissolved Sb (Exp #2- 16 730 mg Sb/kg stibnite). X-ray absorption near-edge structure (XANES) analysis of the solid phase revealed that the 95% pyrite treatment had the highest proportion of total Sb as Sb(V)-O species compared to all other mixed treatments and 100% stibnite. These results indicate that galvanic interactions had occurred between stibnite and pyrite. Using a solution buffered to pH 7.5, it was possible to determine the effect of a high pH environment on these galvanic interactions between stibnite and pyrite. Under slightly alkaline pH conditions, the 95% pyrite treatment had the highest cumulative amount of dissolved Sb (Exp #3- 18 090 mg Sb/kg stibnite) and this amount was similar to the 95% pyrite treatment in experiment #2. XANES analysis revealed a smaller proportion of total Sb as oxide species in this experiment compared to experiment #2, possibly due to the formation of a soluble Sb complex with HCO3-. In Experiment #4, the leaching with deionized water of a mixed system containing stibnite and arsenopyriteOn croit qu'un des mécanismes importants de dissolution de la stibnite (Sb₂S₃) dans les résidus miniers est par contact avec un minéral ayant un plus fort potentiel électrique, tel que la pyrite (FeS₂). L'objectif de la recherche était de déterminer l'impact du ratio stibnite vs. pyrite et l'effet du pH sur le taux de dissolution de la stibnite. Quatre essais de lessivage en colonnes ont été réalisés. Les deux premiers essais de lessivage avec de l'eau déionisée ont montré que le traitement contenant la plus forte proportion de pyrite (95% pyrite) a résulté en la plus grand quantité cumulative de Sb dissous (Exp #2-16730 mg Sb/kg stibnite). L'analyse spectroscopique par absorption des rayons-X (XANES) de la phase solide a révélé que la proportion de Sb total sous forme Sb(V)-O était plus importante dans le traitement 95% pyrite comparé à tous les autres traitements mixtes et au traitement contrôle de 100% stibnite. Ces observations indiquent que des interactions galvaniques ont eu lieu entre la stibnite et la pyrite. En utilisant une solution tamponnée à pH 7.5, il fut possible de déterminer l'effet d'un pH légèrement alcalin sur ces interactions entre la stibnite et la pyrite. Dans ces conditions, la quantité maximale de Sb dissous a été atteinte dans le traitement 95% pyrite (Exp #3-18090 mg Sb/kg stibnite), ce qui est comparable au traitement 95% pyrite dans l'expérience #2 de lessivage à l'eau. Cependant, l'analyse XANES a révélé une proportion moindre du Sb total sous forme d'oxide dans l'essai de lessivage à pH 7.5, possiblement en raison de la formation d'un complexe soluble entre Sb et HCO₃-. L'expérience #4 a testé l'impact de l'arsenopyrite sur la dissolution de la stibnite lors d'un lessivage à l'eau. Dans ce cas, le traitement 95% arsenopyrite (Exp #4-10311 mg Sb/kg stibnite) a libéré moins de Sb en solution comparé au traitement 95% pyrite de l'expérience #2, et ce résultat s'explique par la plus p
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Williams, Jeni Kimberly. "Inquiry learning in the earth science classroom." CSUSB ScholarWorks, 2004. https://scholarworks.lib.csusb.edu/etd-project/2641.
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Fenwick, Emily L. "The impact of an integrative 3-d virtual learning environment in diverse ninth grade earth and space science classes." Thesis, Kansas State University, 2010. http://hdl.handle.net/2097/4231.
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Master of ScienceDepartment of Geology
Iris M. Totten
Problem-based learning in the sciences has been demonstrated to be a successful educational approach to engage students and increase content knowledge. However, the power of collaborative learning to engage students, increase content knowledge and develop problem-solving skills in the sciences has not yet been fully researched. Collaborative learning has an enormous potential not only to foster student learning, but also to increase interest in the sciences and promote cutting-edge education strategies worldwide. Collaborative learning tactics in this study take place within the virtual learning environment entitled “GeoWorlds.” GeoWorlds is an online educational gaming program within the Second Life 3-D Teen Grid. The curriculum was developed as a collaborative, investigative and engaging program to promote learning of Earth science content. The program allows students to be submersed-in and explore different geologic time periods; enabling them to observe species and geological structures while interacting with one another to complete tasks. This study investigates the educational impact, emotional response and overall feedback of the GeoWorlds virtual learning environment on Midwest ninth graders.
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Kalyva, Maria. "Fate of pharmaceuticals in the environment - A review-." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-132995.
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The occurrence of pharmaceuticals in environment originating from human consumption has received increased scientific attention during the last decades due to concerns regarding their combined environmental effects in aquatic and terrestrial environments, in flora and biota and by extent in human health. In this review, I summarized the existing knowledge on the entire life cycle of pharmaceutical substances, from their exposure (sources) and fate to their effects on the natural environment. Since the negative effects of several drugs along with the environmental damage they entail are now known, it can be suggested that pharmaceutical companies make greener pharmaceutical products to reduce these effects to the terrestrial and aquatic environment. The present review could provide suggestions to improve the pharmaceutical environmental management globally, such as methodologies for monitoring systems, that need to be put in place for consistent data collection. Another area of research that is important is the release of pharmaceutical compounds in manufacturing plants as well as from landfill effluent. Finally, one more area with need for further research is green chemistry which could reduce or even eliminate the potential hazards of pharmaceutical compounds that enter the environment, irrespective to the source of entry.
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Ebo, Obiorah Odili. "Evaluation of inquiry-based Learning in high school earth science and biology classrooms: learning environment and attitudes." Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/1299.
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This evaluation of inquiry-based teaching involved 1396 high-school biology and earth science students from Los Angeles County. Inquiry teaching was perceived by students to be more effective than traditional methods in terms of greater teacher support and student involvement. Also inquiry-based instruction was equally effective for male and female students
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James, Michael R. "Electric charge within volcanic plumes on Earth and Io." Thesis, Lancaster University, 1999. http://eprints.lancs.ac.uk/35043/.
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Field, experimental and theoretical investigations have been carried out into the electrification of volcanic plumes. At Sakurajima volcano, Japan, ground-level perturbations of the atmospheric electric potential gradient generated by particulate plumes were recorded. Simultaneous measurements, made at up to five sites around the volcano, are shown to be capable of detecting even very small quantities of volcanic particles, and tracking a continuously produced (over a period of several hours), dilute plume as it was dispersed by the wind. Data collected during one small Vulcanian eruption suggest that charges, about 1 C in magnitude, were generated and then separated, with the positive charge centre residing above the negative charge centre. Experiments have been carried out in order to assess fracto-emission (the release of ions, neutral atoms and various frequencies of electromagnetic radiation from fracture surfaces) as a charging mechanism for the electrification of silicate particles in plumes. Silicate particles, generally less than 100 µm in diameter, were produced by colliding pumice samples together and were shown to have net specific charges of approximately 10-5 to 10-6 C kg-1 (similar to previous field measurements on ashfall). Most (but not all) of the experimental samples produced net negatively charged ash, and demonstrated a positive-above-negative charge separation. Additional charge thought to have been released in the form of ions was also detected, supporting fracto-emission as the charging mechanism for volcanic plumes. The magnitude of the net ash charge is shown to be a function of the particle size, with relative humidity having only a small effect. The polarity of the net charge appears to be a function of a property of individual pumice types, possibly their geochemistry. Experiments during which the particles were separated by their polarity indicate that the net charges reflect only a small imbalance in much larger, individual particle charges (10-3 C kg-1) of both polarities. The particle charges are shown to vary with the sample impact velocity, the number of impacts carried out within an experiment and, to a lesser degree, relative humidity. Variation within the results appears to be partly an effect of particle aggregation within the experiment. Investigation of any effects that this particle charging may have on the plumes observed on Io (one of Jupiter’s moons) suggests that luminous discharges and particle aggregation are both probable in this environment. It is shown that the distinct asymmetries observed in plumes are unlikely to be a result of electromagnetic interactions, but probably represent decompression features and asymmetric vent or crater morphologies.
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Sáenz, James Peter. "Exploring the distribution and physiological roles of bacterial membrane lipids in the marine environment." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59757.
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Thesis (Ph. D.)--Joint Program in Chemical Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2010.Cataloged from PDF version of thesis.
Includes bibliographical references.
Lipids have a legacy in the geologic record extending back to the Archaean. Since the phylogenetic diversity of life is reflected in the structural diversity of biomolecules, lipid biomarkers that are shown to be diagnostic of certain organisms that carry out specific biochemical processes or that are demonstrated to have unique physiological roles can be used to trace the biogeochemical influence of bacteria in modern and ancient environments. In this thesis I explore the application of two classes of bacterial membrane lipids as biomarkers for marine biogeochemical processes in marine environments: ladderanes and hopanoids. Through the detection of ladderane lipids - biomarkers for anaerobic ammonium oxidizing (anammox) bacteria - I demonstrate the presence and distribution of anammox bacteria in a subterranean estuary. Through a survey of hopanoids in marine environments and cultured marine cyanobacteria I show that hopanoids are ubiquitous in the oceans and that their presence in ancient marine sediments could provide information about biogeochemical processes in past environments. Based on novel results demonstrating that hopanoids are resistant to extraction by non-ionic detergent, I propose that they may play a role in lipid ordering and the formation of putative lipid rafts in hopanoid-producing bacteria.
by James Peter Sáenz.
Ph.D.
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Rodriguez, Tablante Johiris Isabel. "Extracting 3D Information from 2D Crooked Line Seismic Data on Hardrock Environments." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6510.
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Seismic methods have been used in sedimentary environment for almost 80 years. During that time, exploration geophysicists have developed a number of techniques to handle specific aspects of working in sedimentary areas. This is not the case for studies in the hardrock environment, where significantly less time and money have been invested on seismic investigations. Therefore, there is still a need to develop the right techniques appropriate for working in hardrock environments. The research presented here, covers aspects of acquisition, processing and interpretation in hardrock environments. A cost-effective alternative for two-dimensional data acquisition is presented. Acquisition parameters are also discussed and recommendations for future work are given. The main effort of this thesis, however, was to find appropriate processing methods to address some of the different problems present in datasets acquired in the hardrock environment. Comparison of two computer programs for first arrival seismic tomography was performed in order to find the most suitable one for processing crooked line geometries. Three-dimensional pre-stack depth migration was also tested to find a detailed near-surface image. A processing method geared to enhance the signal-to-noise ratio was applied to the dataset with the lowest signal amplitudes to improve the quality of the stack. Finally, cross-dip analysis and corrections were performed on two of the three datasets included in this thesis. Cross-dip analysis was also applied as an interpretation tool to provide the information needed for estimation of the true dip of some of the reflectors related to geological structures. The results presented in this thesis indicate that cross-dip analysis and corrections are one of the most powerful tools for processing and interpretation in the presence of complex geology. Therefore, it is recommended to include this method as a standard step in the processing and interpretation sequence of data acquired in hardrock environments.
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Chaisan, Kittisak. "Modelling the environmental transfers of radioactivity following the Fukushima accident." Thesis, University of Portsmouth, 2015. https://researchportal.port.ac.uk/portal/en/theses/modelling-the-environmental-transfers-of-radioactivity-following-the-fukushima-accident(60b31ec7-b843-4878-b374-931c5234b90c).html.
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After the massive tsunami on 11 March 2011, the explosions at 4 reactors of the Fukushima Daiichi (I) Nuclear Power Stations (Fukushima I NPSs) in Japan led to a large radioactive cloud being ejected into the atmosphere. Radionuclides released to the atmosphere were washed out in rain causing an area of remarkably high deposition in the area to the northwest of the Fukushima I NPSs. Activity remaining in the atmosphere was dispersed further to other areas of Japan. At various times during the accident, plumes of contamination were transported from Japan to the Pacific Ocean, the North American continent, crossing the Atlantic Ocean to Europe, and eventually to Asia. Due to the lack of measurements in three major ecosystem compartments i.e. air, soil and surface water, information on the highest impact early-phase after fallout and the interpretation of long-term impacts is limited and unclear. The transfer of contaminated radionuclides to soil and air around the Fukushima I NPSs was studied using ratios of various radioisotopes to the long-lived nuclide 137Cs. It was found that ratios of three radionuclides i.e. 134,136Cs and 132Te were consistent with direction and distance in air and soil while the ratio 131I/137Cs was not. It was shown that, deposited 131I/137Cs had an inverse correlation with 137Cs activity in soil. These nuclides were key in forming the high-gamma dose rates in the early phase, particularly the high gamma energy of 132I from the 132Te/132I decay. The derived ratios of these key radionuclides in soil were used together with available measured gamma dose rates in the early phase (< 30 days) to develop a model to reconstruct and predict external gamma dose rate. Model “blind” tests showed that more than 95% of predictions were within a factor of two of measurements from 15 sites to the north, northwest and west of the power station. It is demonstrated that generic isotope ratios provide a sound basis for reconstruction of early-phase external dose rates in these most contaminated areas. For contamination in surface runoff water, lake water and fish, a previous model developed following the Chernobyl accident (AQUASCOPE) was applied to the Fukushima situation. It was shown that by adjusting for the stronger absorption of radiocaesium in soils in Japan (compared with European countries) the model could be used successfully to predict long-term contamination in aquatic systems affected by Fukushima fall out. The results of the model showed good agreement with measured data, in particular in the long-term period (around 0.5-2 years) after the accident.
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Gu, Ailiang. "Stable Isotope Geochemistry of Sulfate in Groundwater of Southern Arizona: Implications for Groundwater Flow, Sulfate sources, and Environmental Significance." Diss., The University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2005_023_sip1_w.pdf&type=application/pdf.
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Bohlin, Hanna. "The influence by point sources on carbon, nitrogen and metals in two sedimentary environments." Doctoral thesis, Stockholm : Dept. of geology and geochemistry, Stockholm university, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-753.
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Filion, Anna-Belle. "Severe weather intensity index using the 1-km global environmental multiscale limited area model output." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119464.
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Severe weather (SW) can have a huge impact on someone's life and property. Presently at Environment Canada (EC), there is no useful automated tool to help the forecasters in their SW forecast. The goal of this thesis was to develop a useful automated tool to help the SW forecasters in their SW predictions. A severe weather intensity (SWI) index was created from the 1-km Global Environmental Multiscale Limited Area Model (GEM-LAM) outputs. The GEM-LAM 1-km was run on summer days in 2008 and 2009 over Alberta, Ontario, and Quebec. The dataset of summer 2009 was used to create algorithms that use the model's outputs to detect severe thunderstorm structural features, compute the quantity of the ingredients needed to initiate severe thunderstorms, and estimate the intensity and the type of SW expected. The post-processed fields were subjectively verified with the SW observations and radar images for the summer of 2009 leading to a decision tree for the SWI index for each region. An object-oriented method was used to verify the SWI index forecasts with the SW observations for the summer of 2008. The results showed that the SWI index forecast was very accurate over Ontario, accurate over Quebec, and much less accurate over Alberta. The lack of SW observations and the model's spin up mainly affected the results. Finally, the skill of the SWI index forecast was compared to the forecaster-derived SW forecast to verify if the index could help the SW forecasters to improve their SW forecast. The results indicate that the SWI index could improve the prediction of SW events, but not the positioning.Le temps violent (TV) estival peut avoir un impact important sur la vie des gens et leurs biens. En ce moment, aucun outil n'est assez performant pour aider les prévisionnistes à prévoir le TV. Cette thèse a pour but de créer un outil automatisé pour aider les prévisionnistes dans leurs prévisions de TV d'été. Un indice d'intensité de TV à été créé à partir des données du modèle global environnemental à multiéchelles à aire limitée (GEM-LAM) avec une résolution horizontale de 1 km. Le GEM-LAM 1-km à été roulé pour tous les jours d'été 2008 et 2009 sur les régions de l'Alberta, le sud de l'Ontario et le sud du Québec. Les données de l'été 2009 ont été utilisées pour créer des algorithmes qui utilisent les sorties du modèle pour détecter les structures particulières aux orages violents, évaluer les quantités de plusieurs éléments nécessaires à la formation d'orages violents, et estimer l'intensité et le type de TV attendu. Les champs post-traités ont été subjectivement analysé avec les observations de TV et les images radar pour l'été 2009 permettant de bâtir un arbre de décision pour l'indice d'intensité de TV pour chaque région. Une méthode par objet a été utilisée pour faire une vérification des prévisions de l'indice d'intensité de TV avec les observations de TV pour l'été 2008. Les résultats montrent que la prévision de l'indice d'intensité de TV est très juste pour l'Ontario, est assez juste pour le Québec, mais l'ai beaucoup moins pour l'Alberta. Le faible nombre d'observations de TV et le temps d'ajustement du modèle affectent les résultats. Finalement, la précision de l'indice d'intensité de TV et celle de la prévision de TV émit par un prévisionniste ont été comparées de façon à vérifier si l'indice peut aider le prévisionniste à améliorer sa prévision. Les résultats démontrent que l'indice d'intensité de TV pourrait améliorer la prévision d'un évènement, mais pas son positionnement.
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Cooke, Melanie. "The synoptic- and planetary-scale environments associated with significant 1000-hPa geostrophic wind events along the Beaufort Sea coast." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86997.
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The substantial interannual variability and the observed warming trend of the Beaufort Sea region are important motivators for the study of regional climate and weather there. In an attempt to further our understanding of strong wind events, which can drive sea ice dynamics and storm surges, their characteristic environments at the synoptic and planetary scales are defined and analysed using global reanalysis data. A dependency on an enhanced or suppressed Aleutian low is found. This produces either a strong southeasterly or northwesterly 1000-hPa geostrophic wind event. The characteristic mid-tropospheric patterns for these two distinct event types show similarities to the positive and negative Pacific/North American teleconnection patterns, but their correlations have yet to be assessed.L'étude du climat régional et du météorologie du Mer Beaufort est motivée par son variabilité interannuelle important et par la réchauffement qui y est observée. En essayant de comprendre les évenements à vents forts, qui peuvent forcer les dynamiques du glace marine et les ondes tempêtes, leurs environnements caractéristiques aux échelles synoptiques et planétaires sont définies et analysées en utilisant la donnée globale réanalysée. Une dépendance sur une dépression Aleutienne augmentée ou diminuée est trouvée. Ca produit un évenement à vents géostrophiques forts à 1000-hPa soit du soud-est soit du nord-ouest. La modèle caractéristique du mi-troposphère pour ces deux types d'évenements distincts démontrent des similarités aux modèles Pacifique/Nord-Américain positive et negative, mais leurs corrélations ont besoin d'être évaluées.
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Hadley, Kershaw Eleanor. "Co-producing Future Earth : ambiguity and experimentation in the governance of global environmental change research." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/49869/.
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The aim of this thesis is to investigate efforts to transform global environmental change research through co-design and co-production (involving non-academic actors in research governance and conduct). Social scientific work to date on this topic has largely taken an evaluative perspective, outlining challenges of and guidelines for co-production on the ground. By contrast, there is little work on how co-production is conceptualised and put into practice through (international) research governance. Yet institutions aiming to govern research are significant arbiters of meaning and power; their efforts to change research are worthy of investigation. The thesis is based on a qualitative case study of Future Earth, a major international research initiative on global environmental change (GEC) and sustainability. Future Earth is unique in its ambition to internationally coordinate and co-design/co-produce new GEC/sustainability research at a global scale. The study is grounded in co-productionist, interpretive science and technology studies, drawing on ideas about political imaginaries of science and experimental approaches to engagement. It is based on thematic analysis of data from documents, interviews, focus groups and observation of Future Earth’s emergence and development between 2010 and 2015. The analysis suggests that visions of Future Earth were ambitious, diverse and sometimes ambiguous, evoking two potential institutional forms: a unified, cohesive ‘flagship’, or a ‘rich tapestry’ of varied initiatives. Ambiguity persisted in how co-production and related concepts were understood, with varying definitions motivated by different rationales for increased (or limited) involvement of non-academic stakeholders, from ensuring relevance to democratising expertise to preserving the objectivity or independence of science. These notions of appropriate engagement were underpinned by disparate conceptions of the value of research (as a service to society, site of democratic deliberation, or public good), reproducing (and challenging) established models of science and democracy. The thesis argues that, from an experimental perspective, this ambiguity in visions of (co-production in) Future Earth can be seen to enable flexibility and allow differences to co-exist. This might require new, perhaps radical, thinking about how to organise, conduct and value research and its outcomes, with an increased emphasis on fostering, appreciating and productively working with diversity and institutional indeterminacy.
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Henry, Christina. "Flash Flooding in Eastern Kentucky: An Analysis of the 3-4 August 2001 Event." TopSCHOLAR®, 2006. http://digitalcommons.wku.edu/theses/275.
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Limited research exists concerning flash flooding in the United States. However, flash floods can occur anywhere and cause more fatalities than any other weather related natural disaster. Eastern Kentucky experienced an average of 41 flash floods per year (1993-2002), yet little research exists for this region. Therefore, this paper presents an analysis of the particularly devastating flash flood event of 3-4 August 2001, which resulted in $15 million worth of property damage and two deaths. Previous studies indicate that flash floods typically occur under relatively 'benign' conditions, the most common characteristics being a quasi-stationary system and high atmospheric moisture. The slow moving nature of these systems, coupled with low dewpoint depressions, leads to the overabundance of precipitation that produces flash floods. Unfortunately, this relatively 'benign' nature of weather systems poses a challenge for accurate forecasting of flash flooding. Furthermore, severe weather threats, such as tornadoes, tend to overshadow the threats posed by flash flooding, sometimes interfering with the timely issuance of flash flood warnings. To improve the accuracy of flash flood forecasting, several methods have been developed. For instance, lightning strike density helps forecasters in the West to locate regions more likely to receive the heavy rains necessary for flash flooding. Numerical forecasting models also help forecasters, especially when necessary data does not exist for the forecast area. One such model is the Penn State/ NCAR Mesoscale Model MM5. This model consists of several options allowing for variations in climate and terrain. MM5 was used to simulate the 3-4 August 2001 flash flood event, since upper air data does not exist for Eastern Kentucky. The model used for this paper utilized the Grell parameterization scheme, which provided better results than the other parameterization schemes tested (Kain-Fritsch). The Eastern Kentucky flash flood event, like the majority of other flash flood events throughout the Contiguous United States, did in fact occur under relatively benign conditions. This event occurred as heavy rains fell ahead of a trough axis associated with a slow-moving cold front. As the west-east oriented front moved southward, it stalled along the Appalachians and pivoted, becoming southwest-northeast oriented. High atmospheric moisture existed from the surface through 500-mb ahead of the front. The winds were weak and from a northerly direction, while the stability indices indicated marginal instability throughout the event. About half of the flash floods reported during this event occurred prior to the issuance of a flash flood warning, while no record of a flash flood watch existed for any of the counties prior to flash flooding. Accurate forecasting of flash floods during this relatively benign event was further hindered by the lack of a flash flood climatology for the region.
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Olstrup, Henrik. "The Arctic Ice Melting Caused by Black Carbon from an Environmental Risk Analysis Perspective." Thesis, Linnéuniversitetet, Institutionen för naturvetenskap, NV, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-15955.
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The purpose with this essay is to highlight the environmental risk that black-carbon aerosols represent to the ice melting in the Arctic. When the ice melting in the Arctic and other climate-related issues are highlighted, the focus is primarily on carbon dioxide and the risks related thereto. Black-carbon aerosols and their environmental effects are much more unknown to most people. The effect that black carbon exerts on the Arctic ice melting is mainly that it causes a decrease in albedo. The term albedo is a measure of the proportion of the sunlight that hits the surface and then is reflected. A reduction in albedo means that a greater proportion of the incoming solar radiation is absorbed by the surface area. This is exactly what happens when black-carbon aerosols end up in the Arctic. Because of the black colour of the aerosols, the surface where the aerosols are deposited becomes darker, which means an increased light absorption, which in turn heats the surface and accelerates the ice melting process. The essay deals with the subject based on the environmental risk paradigm. That means that the focus is placed on the following three steps: the -risk assessment, the -risk communication and the -risk management. The risk assessment is used to assess the threat posed by black-carbon aerosols. Where and how black carbon occurs, and its ability to disperse to the Arctic constitute an important part of the risk assessment. Other environmental risks and especially the health risks associated with black carbon have also to some extent been treated in this essay. This is primarily because of the fact that those other environmental hazards that are not related to the Arctic may be relevant when it comes to increasing the incentives to reduce the emissions of black carbon. The facts that emerge in the risk assessment clearly indicate that Southeast Asia is of great importance when it comes to black carbon that ends up in the Arctic. The risk management is used to analyse the methods which are most appropriate and profitable in terms of reducing the emissions. The available technologies to reduce the emissions of black carbon are also treated. It turns out that the profitability to make emission reductions is greatest in Southeast Asia. The fact that the profitability to make emission reductions is greatest in the part of the world where the emissions are greatest indicates that there is a great potential to overcome the problem. The countries in Southeast Asia may need support from the Western countries when it comes to implementing measures in order to reduce the emissions. The risk communication is a part of the environment risk paradigm that is constantly needed in order to communicate the risks at various levels. An important conclusion of this essay is that the environmental risk communication between researchers and policy makers is insufficient. An improvement of this could lead to more vigorous measures to be taken in order to overcome this problem.
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Strollo, Angelo. "Development of techniques for earthquake microzonation studies in different urban environment." Phd thesis, Universität Potsdam, 2010. http://opus.kobv.de/ubp/volltexte/2011/5380/.
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The proliferation of megacities in many developing countries, and their location in areas where they are exposed to a high risk from large earthquakes, coupled with a lack of preparation, demonstrates the requirement for improved capabilities in hazard assessment, as well as the rapid adjustment and development of land-use planning. In particular, within the context of seismic hazard assessment, the evaluation of local site effects and their influence on the spatial distribution of ground shaking generated by an earthquake plays an important role. It follows that the carrying out of earthquake microzonation studies, which aim at identify areas within the urban environment that are expected to respond in a similar way to a seismic event, are essential to the reliable risk assessment of large urban areas. Considering the rate at which many large towns in developing countries that are prone to large earthquakes are growing, their seismic microzonation has become mandatory. Such activities are challenging and techniques suitable for identifying site effects within such contexts are needed.
In this dissertation, I develop techniques for investigating large-scale urban environments that aim at being non-invasive, cost-effective and quickly deployable. These peculiarities allow one to investigate large areas over a relative short time frame, with a spatial sampling resolution sufficient to provide reliable microzonation. Although there is a negative trade-off between the completeness of available information and extent of the investigated area, I attempt to mitigate this limitation by combining two, what I term layers, of information: in the first layer, the site effects at a few calibration points are well constrained by analyzing earthquake data or using other geophysical information (e.g., shear-wave velocity profiles); in the second layer, the site effects over a larger areal coverage are estimated by means of single-station noise measurements. The microzonation is performed in terms of problem-dependent quantities, by considering a proxy suitable to link information from the first layer to the second one. In order to define the microzonation approach proposed in this work, different methods for estimating site effects have been combined and tested in Potenza (Italy), where a considerable amount of data was available. In particular, the horizontal-to-vertical spectral ratio computed for seismic noise recorded at different sites has been used as a proxy to combine the two levels of information together and to create a microzonation map in terms of spectral intensity ratio (SIR).
In the next step, I applied this two-layer approach to Istanbul (Turkey) and Bishkek (Kyrgyzstan). A similar hybrid approach, i.e., combining earthquake and noise data, has been used for the microzonation of these two different urban environments. For both cities, after having calibrated the fundamental frequencies of resonance estimated from seismic noise with those obtained by analysing earthquakes (first layer), a fundamental frequency map has been computed using the noise measurements carried out within the town (second layer). By applying this new approach, maps of the fundamental frequency of resonance for Istanbul and Bishkek have been published for the first time. In parallel, a microzonation map in terms of SIR has been incorporated into a risk scenario for the Potenza test site by means of a dedicated regression between spectral intensity (SI) and macroseismic intensity (EMS). The scenario study confirms the importance of site effects within the risk chain. In fact, their introduction into the scenario led to an increase of about 50% in estimates of the number of buildings that would be partially or totally collapsed.
Last, but not least, considering that the approach developed and applied in this work is based on measurements of seismic noise, their reliability has been assessed. A theoretical model describing the self-noise curves of different instruments usually adopted in microzonation studies (e.g., those used in Potenza, Istanbul and Bishkek) have been considered and compared with empirical data recorded in Cologne (Germany) and Gubbio (Italy). The results show that, depending on the geological and environmental conditions, the instrumental noise could severely bias the results obtained by recording and analysing ambient noise. Therefore, in this work I also provide some guidelines for measuring seismic noise.Aufgrund des enormen Wachstums neuer Megastädte und deren Vordringen in gefährdete Gebiete auf der einen Seite sowie der mangelnden Erdbebenvorsorge in vielen Entwicklungsländern auf der anderen Seite sind verbesserte Verfahren für die Beurteilung der Gefährdung sowie eine rasche Umsetzung bei der Raumplanung erforderlich. Im Rahmen der seismischen Gefährdungsabschätzung spielt insbesondere die Beurteilung lokaler Standorteffekte und deren Einfluss auf die durch ein Erdbeben verursachte räumliche Verteilung der Bodenerschütterung eine wichtige Rolle. Es ist daher unabdingbar, mittels seismischer Mikrozonierungsstudien diejenigen Bereiche innerhalb dicht besiedelter Gebiete zu ermitteln, in denen ein ähnliches Verhalten im Falle seismischer Anregung erwartet wird, um daraus eine zuverlässige Basis bei der Risikoabschätzung großer städtischer Gebiete zu erhalten. Aufgrund des schnellen Wachstums vieler Großstädte in Entwicklungsländern ist eine seismische Mikrozonierung zwingend erforderlich, stellt aber auch eine große Herausforderung dar; insbesondere müssen Verfahren verfügbar sein, mit deren Hilfe rasch eine Abschätzung der Standorteffekte durchgeführt werden kann. In der vorliegenden Arbeit entwickle ich daher Verfahren für die Untersuchung in Großstädten, die darauf abzielen, nicht-invasiv, kostengünstig und schnell durchführbar zu sein. Damit lassen sich innerhalb eines relativ kurzen Zeitraums große Gebiete untersuchen, falls der räumlichen Abstand zwischen den Messpunkten klein genug ist, um eine zuverlässige Mikrozonierung zu gewährleisten. Obwohl es eine gegenläufige Tendenz zwischen der Vollständigkeit aller Informationen und der Größe des untersuchten Gebiets gibt, versuche ich, diese Einschränkung durch Verknüpfung zweier Informationsebenen zu umgehen: In der ersten Ebene werden die Standorteffekte für einige Kalibrierungspunkte durch die Analyse von Erdbeben oder mittels anderer geophysikalischer Datensätze (z.B. Scherwellengeschwindigkeitsprofile) bestmöglich abgeschätzt, in der zweiten Ebene werden die Standorteffekte durch Einzelstationsmessungen des seismischen Rauschens für ein größeres Gebiet bestimmt. Die Mikrozonierung erfolgt hierbei mittels spezifischer, fallabhängiger Parameter unter Berücksichtigung eines geeigneten Anknüpfungspunktes zwischen den beiden Informationensebenen. Um diesen Ansatz der Mikrozonierung, der in dieser Arbeit verfolgt wurde, zu präzisieren, wurden in Potenza (Italien), wo eine beträchtliche Menge an Daten verfügbar war, verschiedene Verfahren untersucht. Insbesondere kann das Spektralverhältnis zwischen den horizontalen und vertikalen Seismometerkomponenten, welche für das seismische Rauschen an mehreren Orten aufgenommen wurde, als eine erste Näherung für die relative Verstärkung der Bodenbewegung verwendet werden, um darauf aufbauend die beiden Informationsebenen zu verknüpfen und eine Mikrozonierung hinsichtlich des Verhältnisses der spektralen Intensität durchzuführen. Anschließend führte ich diesen Zwei-Ebenen-Ansatz auch für Istanbul (Türkei) und Bischkek (Kirgisistan) durch. Für die Mikrozonierung dieser beiden Städte habe ich denselben Hybridansatz, der Daten von Erdbeben und von seismischem Rauschen verbindet, verwendet. Für beide Städte wurde nach Gegenüberstellung der Resonanzfrequenz des Untergrunds, die zum einen mit Hilfe des seismischen Rauschens, zum anderen durch Analyse von Erdbebendaten bestimmt worden ist (erste Ebene), eine Karte der Resonanzfrequenz unter Verwendung weiterer Messungen des seismischen Rauschens innerhalb des Stadtgebiets erstellt (zweite Ebene). Durch die Anwendung dieses neuen Ansatzes sind vor kurzem zum ersten Mal auch Karten für die Resonanzfrequenz des Untergrunds für Istanbul und Bischkek veröffentlicht worden. Parallel dazu wurde für das Testgebiet in Potenza eine auf dem spektralen Intensitätsverhältnis (SIR) basierende Mikrozonierungskarte in ein Risikoszenario mittels der Regression zwischen SIR und makroseismischer Intensität (EMS) integriert. Diese Szenariostudie bestätigt die Bedeutung von Standorteffekten innerhalb der Risikokette; insbesondere führt deren Einbeziehung in das Szenario zu einem Anstieg von etwa 50% bei der Zahl der Gebäude, für die ein teilweiser oder gar vollständiger Zusammenbruch erwartet werden kann. Abschließend wurde der im Rahmen dieser Arbeit entwickelte und angewandte Ansatz auf seine Zuverlässigkeit geprüft. Ein theoretisches Modell, das zur Beschreibung des Eigenrauschens verschiedener Instrumente, die in der Regel in Mikrozonierungsstudien (z. B. in Potenza, Istanbul und Bischkek) zum Einsatz kommen, wurde untersucht, und die Ergebnisse wurden mit Daten verglichen, die vorher bereits in Köln (Deutschland) und Gubbio (Italien) aufgenommen worden waren. Die Ergebnisse zeigen, dass abhängig von den geologischen und umgebenden Bedingungen das Eigenrauschen der Geräte die Ergebnisse bei der Analyse des seismischen Rauschens stark verzerren kann. Deshalb liefere ich in dieser Arbeit auch einige Leitlinien für die Durchführung von Messungen des seismischen Rauschens.
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Ravindran, Nimmy. "Hide-Metadata Based Data Integration Environment for Hydrological Datasets." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/36157.
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Efficient data integration is one of the most challenging problems in data management, interoperation and analysis. The Earth science data which are heterogeneous are collected at various geographical locations for scientific studies and operational uses. The intrinsic problem of archiving, distributing and searching such huge scientific datasets is compounded by the heterogeneity of data and queries, thus limiting scientific analysis, and generation/validation of hydrologic forecast models. The data models of hydrologic research communities such as National Weather Service (NWS), National Oceanic and Atmospheric Administration (NOAA), and US Geological Survey (USGS) are diverse and complex. A complete derivation of any useful hydrological models from data integrated from all these sources is often a time consuming process.
One of the current trends of data harvesting in scientific community is towards a distributed digital library initiative. However, these approaches may not be adequate for data sources / entities who do not want to "upload" the data into a "data pool." In view of this, we present here an effective architecture to address the issues of data integration in such a diverse environment for hydrological studies. The heterogeneities in these datasets are addressed based on the autonomy of data source in terms of design, communication, association and execution using a hierarchical integration model. A metadata model is also developed for defining data as well as the data sources, thus providing a uniform view of the data for different kind of users. An implementation of the model using web based system that integrates widely varied hydrology datasets from various data sources is also being developed.Master of Science
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Bassein, Emma (Emma R. ). "A digital path to environmental education." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/114116.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.Cataloged from PDF version of thesis. Pages 25 and 37-39 missing from original thesis.
Includes bibliographical references (page 28).
Digital technology has become completely engrained in the process of scientific research. Grade schools are beginning to incorporate computers and other digital devices into the learning process as tools for learning other subjects, including science. Educators have experimented with a variety of programs that incorporate computers, such as digital tutors, simulations of natural systems, and interactive simulations. This study aimed to demonstrate that handheld computers are a useful resource in problem-based learning environments. A "mini-curriculum", focused on making handheld computer-aided measurements of the key environmental parameters in marine estuaries, was designed and taught to eleven students from the Palmetto Ridge High School in Naples, Florida over a two week period. Students' reactions to both the curriculum and the computers were overwhelmingly positive. This proof-of-concept trial indicates that handheld computers have the potential to be a very useful tool in problem-based learning.
by Emma Bassein.
S.B.
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Gydemo, Östbom Viktor. "Lake water chemistry and the changing arctic environment : Topographic or climatic control?" Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-155903.
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The arctic is expected to be one of the regions most affected by ongoing climate change, with relative changes in air temperatures significantly higher than the global mean. Lakes are recognized for their potential role in the global climate system and as ecosystems of importance for local societies. As such, there is a scientific interest regarding how arctic lakes and their geochemistry will respond to climatic changes. Lakes around Kangerlussuaq (66.99 N, 51.07 W), south-west Greenland, are known for their unique geochemical composition, including oligosaline lakes, of which some are enriched in colourless dissolved organic carbon (DOC). The origin of this DOC and the importance of local catchment properties for the general water chemistry is currently being debated. This thesis aimed at: i) exploring the extent and effect of catchment morphology on lake-water chemistry in the Kangerlussuaq area; ii) determine the predominant origin of DOC, aquatic or terrestrial. I used a remote-sensing approach based on satellite imagery and digital elevation model (DEM) in deciding landscape influence on water chemistry (pH, alkalinity, conductivity, base cations, sulphate, nitrogen and absorbance). To trace the origin of the organic sources behind DOC lake water and sediments, I used a hydrogen isotope tracing method. The remote sensing approach revealed that morphological characteristics serving as proxies for lake water residence time and hydrologic connectivity (e.g. lake altitude difference and absence of outlets) explained up to 77% of the variations in lake water chemistry. The hydrogen isotopic signature of the DOC indicated a predominantly autochthonous origin, i.e. 59 to 78% was estimated to originate from algae. I conclude that lake water chemistry of the lakes in the study area is primarily controlled by the precipitation : evaporation balance, enhanced by static catchment characteristics regulating water age. Thus, the examined lake water chemical properties are likely to remain across future climatic scenarios, providing the current precipitation : evaporation balance prevails.
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Danielson, Richard E. "Environmental influences on cold-season cyclones over the North Pacific Ocean." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19723.
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A quantification of local energy dispersion is employed to distinguish cases of downstream baroclinic development, as described by Orlanski and Sheldon, from among 41 cold-season cyclones that intensified strongly over the eastern North Pacific Ocean. Complete summaries of the eddy energy budget are calculated for each event, and about half are found to be in general accord with the proposed evolution. Almost all of this subset appear to have been influenced by a dispersion of energy from separate cyclones developing over the western North Pacific a day or two earlier. The primary source for eddy energy dispersion downstream and subsequent generation near the eastern cases is a baroclinic conversion associated with ascent in the warm sector of the upstream cyclones. The importance of downstream baroclinic development is confirmed for one eastern North Pacific cyclone in two complementary ways. First, the original eddy energy diagnosis is compared to one based on wave activity. In terms of local group velocity, only minor differences are found during much of the initial evolution. It is only once the tropopause undulations lose their wave-like appearance that the group velocity calculated using eddy energy becomes faster than that depicted by wave activity. Second, by employing numerical simulations, the importance of downstream baroclinic development to the intensification of this cyclone is quantified. Various initial conditions are produced using potential vorticity inversion. Simulations in which an upstream trough/ridge couplet are removed from the initial conditions result in both the absence of a downstream baroclinic development and a weakening of the downstream surface cyclone. The remainder of this study investigates the relationship between cold-season cyclones and sea surface temperature anomalies for small groups of strong cyclones occurring in the western North Pacific region. Previous studies have emphasized the importance of the western ocean boundary currents and their strong sea surface temperature gradients to rapid cyclone development. Physical mechanisms governing this relationship have been studied extensively elsewhere. Here, proxy evidence of systematic changes in the role of surface heat and moisture fluxes during the cold season is presented. Cyclones of similar intensification rates are grouped according to their occurrence either during midwinter or during the early and late cold season. Systematic differences in sea surface temperature anomalies beneath these two groups are interpreted as a proxy for corresponding differences in preconditioning by the upperoceanic mixed layer. Submonthly sea level pressure variations for the same North Pacific cyclones appear to support an interpretation in terms of an upward oceanic influence. It is suggested that the role of preconditioning heat fluxes in cyclones varies because of large-scale seasonal changes in baroclinicity and in the availabilitv of water vapour already in the atmosphere. Similar differences are obtained using a group of strong western North Atlantic cyclones.
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Jensen, Mai-Britt Mose. "Geophysical tools for prognosis of deformation in hardrock environments." Doctoral thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25779.
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Underground mining of the Kiirunavaara iron mineralization is causing large-scale deformation of the hangingwall of the orebody. To understand and possibly predict future deformation, a structural model of the hanging wall and a good understanding of the petrophysical and mechanical properties of the constituent rocks is necessary. This thesis presents results from the study of Anisotropy of Magnetic Susceptibility (AMS), magneto-mineralogy, fracture frequency (F/m), rock quality (RQD), rock strength (Point Load) and P-wave velocity and anisotropy of the rocks from the hanging wall, as well as seismic reflection surveying and gravity modelling. The results are combined into a structural model of the hanging wall and further used for analysis of the correlation between petrophysical and rock mechanical parameters.In total, 76 samples from 12 outcrops and 295 samples from three drillcores in the hanging wall have been included in the AMS study. Axial and diametrical P-wave velocity was measured on 25 water-saturated samples and 156 samples were used for the Point Load tests. F/m and RQD data for the drillcores already existed. The drillcores are located along the eastern end of the seismic profiles and consist of both crystalline and sedimentary rocks.A high degree of magnetic anisotropy observed in the crystalline rocks indicates a low degree of metamorphism. AMS data also indicates the presence of a magnetic foliation in the rocks. The dip of the magnetic foliation plane (F) and the degree of magnetic anisotropy (Pj) measured in samples from outcrops was plotted as iso-maps and shows that both F and Pj decreases towards the east, which was confirmed by data from the drillcores. The decrease in both parameters is primarily a reflection of a change in rock type, but is also changing within the crystalline rock sequence.A good correlation (r > 0.6) between Pj, and F and RQD, and F and F/m was observed in one drillcore for both crystalline and sedimentary rocks; and between the shape parameter (T) and F/m in crystalline rock in another drillcore. This suggests the AMS parameter may be used as an indicator of rock mechanical properties. AMS data was also correlated to joint strike orientations and it was concluded that AMS can also be used to predict joint orientation.Two parallel reflection seismic profiles were shot within the town of Kiruna i order to locate deformation zones and lithological boundaries in the hangingwall. No deformation zones were found, but five seismic reflectors corresponding to five lithological boundaries were located, and their strike and dip calculated. The result of the seismic survey was used to constrain the gravity model, as was density measurements of 230 samples from the drillcores. The gravity model has a depth of three km, and indicates that the crystalline rock in the hanging wall can be separated into two parallel N-S trending blocks.Godkänd; 2011; 20111021 (maimos); DISPUTATION Ämnesområde: Tillämpad geofysik/Applied Geophysics Opponent: PhD Satu Mertanen, Geological Survey of Finland, Åbo Ordförande: Professor Sten-Åke Elming, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Tid: Måndag den 19 december 2011, kl 10.00 Plats: F531, Luleå tekniska universitet
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Green, Sarah A. "Applications of fluorescence spectroscopy to environmental chemistry." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/13167.
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Szucs, Andrea. "Geochemical Landscape Analysis for the Risk Assessment of Acid Mine Drainage in a Wetland Environment." Doctoral thesis, Uppsala universitet, Institutionen för geovetenskaper, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6992.
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Attenuation of acid mine drainage (AMD) metals originating from abandoned mines and waste rock dumps is investigated in this thesis at Slättberg in central Sweden, where acid mine leachate has been discharging for over 70 years into the receiving wetland stream and mire. Risk assessment of AMD and related polluted lands requires a holistic approach that is able to study the complexity of pollution emissions and impacted landscapes. In this thesis a link between geochemical contaminant fate modelling and landscape analysis is presented for AMD risk assessment. A simple geochemical landscape analysis tool is developed to analyse and model geochemical abundances, geochemical gradients, geochemical flow patterns and geochemical barriers in the studied stream and mire sediments. Sampling locations at geochemical barriers are identified using landscape geochemical and GIS methods. A sequential chemical extraction procedure is used to investigate fractions which are expected to act as potential sinks of the six studied metals (Cu, Fe, Mn, Ni, Pb and Zn) in the sediments. For data modelling robust statistical methods of Exploratory Data Analysis are used to treat small sample sizes with multimodal character and outlying values. The spatial variability of metal retention in the sediments is studied by multivariate data analysis methods. Results show that the developed simple geochemical landscape analysis method can be used efficiently for the risk assessment of toxic mine contaminants in the complex receiving wetland landscape. It is suggested by the analysis that the oxidising geochemical barrier in the stream sediments can be sufficiently characterised by the distribution of Fe fractions. At the AMD discharge location metal sulphide formation and organic matter adsorption control metal retention in the mire. Mires are very sensitive to changes in hydrological conditions and drying of the sediments leads to erosion and hence the release of adsorbed metals to the environment.
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Newman, Sharon Audrey. "Taphonomic studies of fossil preservation in coarse-grained siliciclastic environments." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/115777.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, February 2018.Cataloged from PDF version of thesis.
Includes bibliographical references.
Ediacaran and early Cambrian sandy and silty sediments commonly preserve microbial fossils and textures as well as the fossils of soft-bodied organisms. The rarity of similar fossils and textures in coarse-grained siliciclastic strata of the later Phanerozoic suggests that a taphonomic window facilitated this mode of fossil preservation. However, environmental and biological factors that promoted fossilization remain unclear. To experimentally identify mechanisms of preservation in siliciclastic sediments, cyanobacteria and soft tissues (scallop adductor muscles) were incubated in silica sand or clay minerals for up to two months. Clay mineral veneers coated both cyanobacterial filaments and the surfaces of soft tissues and were formed by two main processes: 1) the adhesion of fine particles from the sediment and 2) the precipitation of authigenic minerals. Photosynthetic, sheathed microorganisms were best preserved in the presence of high concentrations of dissolved silica (>0. 1 mM) and suspended fine particles (>5.6 mg/L) in solution. We showed that these organisms could be preserved in oxic environments and that the degradation of cyanobacteria by heterotrophic microorganisms was not necessary for fossilization. In contrast, soft tissues buried in sand/clay were preserved under anaerobic conditions and mineral veneers around them contained reduced iron. All scallops decayed in the presence of endogenous bacteria and the redox cycling of iron that included the microbial reduction of iron(III). We showed that the early precipitation of silica and the formation of microbial death masks is not critical for preservation. Additionally, when the degradation of soft tissues advanced within the first 15 to 30 days, all soft tissues decayed completely and left no morphological imprint. Taken together, these results show that the early microbial reduction of iron(III) present in sedimentary minerals and the formation of mineral veneers are critical for the preservation of organic material. The same processes may have facilitated the formation of exceptionally preserved fossils and textures throughout the Ediacaran and early Cambrian. Future studies should focus on the roles of iron redox cycling, sediment composition and microbial metabolisms in the preservation of soft tissues to better understand mechanisms for Ediacaran-style preservation in siliciclastic environments.
by Sharon Audrey Newman.
Ph. D.
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Nolan, Marie. "Levee stability and the evolution of 'A'a lava flow-fields." Thesis, University of Portsmouth, 2014. https://researchportal.port.ac.uk/portal/en/theses/levee-stability-and-the-evolution-of-a-a-lava-flowfields(d2bf4697-8120-4645-97fa-a2cc1f05b8bb).html.
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The capability to predict the final dimensions of an ‘a’a flow-field and the timeline for emplacement is key to effective lava hazard management. Levee breaching and the subsequent generation of secondary flows has been recognised as an intrinsic process in flow-field development. However, the conditions, locations and mechanisms for levee failure are not fully understood and so a multidisciplinary approach was taken utilising field studies of extant flow-fields on Mount Etna and Tenerife, analogue modelling and uniaxial compression tests to investigate levee failure. The experimental results were used to define three stages of flow-field development – lengthening, widening and thickening, a modification of the classification of Kilburn and Lopes (1991). Levee breaching was identified to be a key process by which flow-fields widen during stage two of emplacement. Four mechanisms for breaching are identified, providing a classification system for levee failure. Secondary flows originating from breaching consistently formed at an angle of 30 – 50o to the original channel, significantly contributing to overall flow-field width. Uniaxial compression tests were performed to quantify the mechanical properties of levees. Levee strength was shown to change with direction according to the size, orientation and distribution of vesicles. Samples with vesicle alignment orientated obliquely to the angle of principal stress were consistently weaker. A set of conditions, relating to the mechanical properties of the levee, is therefore identified under which levees are more susceptible to failure. The results of the study have been combined to produce a set of guidelines to the locations and conditions under which levee breaching is more likely to occur, aiding decision making for lava hazard management.
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Argyriou, Athanasios. "A methodology for the rapid identification of neotectonic features using geographical information systems and remote sensing : a case study from western Crete, Greece." Thesis, University of Portsmouth, 2012. https://researchportal.port.ac.uk/portal/en/theses/a-methodology-for-the-rapid-identification-of-neotectonic-features-using-geographical-information-systems-and-remote-sensing(0f0ae683-6170-49f2-b8a6-7e00d821377c).html.
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The investigation of neotectonic activity is of high priority when dealing with inaccessible regions where a lack of data and a limited knowledge of the tectonic activity is often typical. There are various individual analyses that investigate features associated with neotectonic activity (for example geoinformatics, geophysical methods and field surveys). However, none of these methods combine low cost techniques based on geospatial and geophysical technologies with field validation of the outcomes. This study offers a methodology that covers all aforementioned approaches for detecting zones of neotectonic activity, linking computer-based observations with actual field observations and geophysical measurements. The combination of satellite imagery and DEM analysis can provide a cost-effective alternative to satellite radar interferometric analysis (InSar) and differential GPS monitoring. Crete is a complex, tectonically active region: an ideal “natural laboratory” to assess the interaction between neotectonic processes and geomorphological processes in landscape evolution and to test the effectiveness of geomorphometric methods for determining zones of neotectonic activity. Geoinformatic and geomorphometric techniques have been used here to assess landscape evolution in tectonically active zones. The results provide new information about the influence of tectonic and erosional processes on geomorphological evolution, with specific insights into the interactions between neotectonic deformation, faulting and drainage networks. Geomorphic indices have been used here to evaluate neotectonic behaviour at regional and local scales, identifying uplifted blocks, valley-floor tilting and zones of relatively intense neotectonic activity. Landsat ETM+ imagery and DEMs were used to discriminate lithological boundaries and identify lineaments. Field and VLF geophysical surveys verified that the lineaments coincide with faults. The GIS based multi-criteria decision analysis (MCDA) was considered as a strong approach to integrate the various factors associated with tectonic activity and to highlight, spatially, the potential zones undergoing active tectonic control.
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Enea, Cornelia Florentina. "Rutile : a new petrogenetic tool to investigate old subduction zones." Thesis, University of Portsmouth, 2012. https://researchportal.port.ac.uk/portal/en/theses/rutile(a2054ec4-89ca-42a7-ae9e-dcabac80e73c).html.
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The timing of onset of modern plate tectonics is currently in conflict. Some believe that it began in the Archaean whereas others prefer a Neoproterozoic onset. At issue is the lack of reliable recorders of changing styles of subduction. Whilst high-pressure rocks (eclogite and high-P granulites) are present in the rock record from Archaean times, low-temperature, high-pressure and ultrahigh- pressure rocks only appear in the Neoproterozoic. This latter association is the hallmark of steep subduction of cold oceanic crust and is central to the argument. Their disappearance from the rock record older than c.600 Ma may be real or it may be a matter of preservation potential. The scope of this project is to investigate this question by the novel use of detrital rutile, which shows great potential as a provenance indicator for high-pressure metamorphism and tectonic settings. The best recorders of subduction are blueschists, which are present in the rock record only to ca. 600 Ma ago. Rutiles in blueschist-facies mafic rocks from Syros and pelitic samples from the Sesia Lanzo Zone have been investigated and results show that the Nb vs. Cr diagram is a reliable tool for high-pressure/low temperature conditions, regardless of the lithology of the source rock. Further, rutiles in ultrahigh-pressure/high temperature rocks from the Dora Maira Massif and the Western Gneiss Complex have been analysed. Grains from the first location plot on the correct area of the chart, but do not correlate with the detrital record, whereas grains from the second location show a mixed Nb/Cr signatures, with eclogites plotting along the metamafic – metapelitic borderline, or even on the pelitic region. This indicates that the discrimination diagram requires special care when using it on high grade rutiles. Provenance studies on Syros and the Sesia Lanzo showed a good host rock – detrital record correlation. Moreover, in the Western Alps, Po River contains a higher percentage of low-temperature rutiles (97%) compared to high temperature grains (3%), that might suggest that the rivers could control this concentration or most likely that the source rocks supply more rutile thus biasing the final population. These results further demonstrate the capability of detrital rutile to provenance highpressure/ low-temperature source rocks, mafic or pelitic, in large riverine systems. The Zr-in-rutile thermometer gives values consistent with previous estimations for both Syros and the Sesia Lanzo samples, using the calibration with a silica activity of 1. The pressure-dependant calibration has a too big correction for lower pressure and temperature conditions. Moreover, quartz-bearing rocks give almost identical temperatures with quartz-free rocks, suggesting that the silica activity does not have a major effect on the thermometer. This latter thermometer has been used for ultrahigh-pressure/high temperature rutiles from Dora Maira and the Western Gneiss Complex, giving slightly lower results for the first location and considerable higher values for most of the samples from the second location. In the first case, a partial re-setting of the zirconium concentration could be the explanation, whereas in the second case, the study concludes that the Zr-in-rutile thermometer gives more consistent results than any exchange geothermometers. Therefore, this thermometer can be safely applied to rocks from blueschist- to granulite-facies rocks, giving good estimations where diffusion did not took place.
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Brown, Sarah Krystyna. "The distribution and development of eruptive centres and lava flow-field characteristics at Somma-Vesuvius, Italy." Thesis, University of Portsmouth, 2013. https://researchportal.port.ac.uk/portal/en/theses/the-distribution-and-development-of-eruptive-centres-and-lava-flowfield-characteristics-at-sommavesuvius-italy(5ce1bfb2-dc28-4513-b1a4-62d4eaedcff3).html.
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Vesuvius in Southern Italy is among the most densely populated active volcanoes on Earth. Although famous for its Plinian eruption that destroyed Pompeii and Herculaneum in AD 79, its recent activity, between 1631 and 1944, was primarily effusive. Data from field studies, analogue modelling and historical accounts are here combined to investigate Vesuvius’ activity during this latest eruptive phase and to identify behavioural trends of value for enhancing emergency responses during future unrest. The focus of this study is on the activity of 1631-1944, and data have been compiled for 183 eruptions during this period. Further data regarding earlier flank eruptions have been incorporated permitting a more comprehensive examination of these infrequent events. Such flank vents have been concentrated on the southern flanks at about 300m above sea level and a mean distance of 4.2 km from the summit. A submarine pit crater, newly correlated here with the 1861 eruption, highlights the potential for vents to form at almost twice the mean distance from the summit and further than previously considered. Analogue studies of magma injection, using a gelatine model, have shown that the vent distribution is consistent with a regional stress field modified by gravitational stresses due to the size and shape of the volcanic edifice. The study of the 1631 to 1944 lava flow-fields shows that lavas from flank vents reached similar lengths to summit and lateral vent flow-fields, all with mean lengths around 4km. Over half of all lava flow-fields extended to beyond 4km from the crater, and so threatened the principal settlements around the foot of the volcano. The flow-fields had typical surface areas of less than 5 km², and approximately a third reached their maximum length within a week. Flank eruptions normally occurred when the summit crater was full of lava and were commonly preceded by three days of elevated seismicity. Such events can thus potentially be forecast with at least a 24-hour warning and, even after an eruption has begun, several days may be available before a settlement is threatened. The design of an effective emergency response to future effusions is thus a feasible objective.
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Turner, Geraldine Sarah Clinton. "The application of the passive sampling technique diffusive gradients in thin-films (DGT) to the measurement of uranium in natural waters." Thesis, University of Portsmouth, 2013. https://researchportal.port.ac.uk/portal/en/theses/the-application-of-the-passive-sampling-technique-diffusive-gradients-in-thinfilms-dgt-to-the-measurement-of-uranium-in-natural-waters(107c3ce9-2c00-435f-b241-0b668c36bf9b).html.
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This thesis describes the application of a passive sampler, Diffusive Gradient in Thin Films (DGT), to the measurement of uranium in natural waters. Four resins (Chelex-100, manganese dioxide [MnO2], Diphonix® and MetsorbTM) were trialled with the DGT device. In freshwater environments, the MetsorbTM accumulated uranium in line with the DGT equation for 7 d with an acuracy of 75%; Chelex-100 did not accumulate uranium past 2 d; MnO2 accumulated up to 75% of that predicted by the DGT equation for 4 d; and the Diphonix® accumulated uranium for 7 d with an accuracy of ~100%. None of the resins tested in this study accumulated uranium in a marine setting in line with DGT predicted values past 2 d. The application of DGT to regulatory environmental monitoring schemes was investigated with MetsorbTM. The MetsorbTM DGT devices were deployed for 7 days at a time over a 6 month period at two freshwater field sites. Fluctuations in water chemistry were monitored and the size of the diffusive boundary layer (DBL) was measured. The uranium accumulated by the MetsorbTM DGT showed close agreement with the grab samples. The size of the DBL was found to be significant, particularly in low flow conditions. This study showed that DGT could be used as a tool to both monitor radioncludes in the environment, and to obtain information on the speciation and organic interactions. The lability of uranium-humic acid complexes was also examined in this study. Initial data shows that the uranyl-humic complex is labile in low pH environments, but becomes increasingly kinetically limited the higher the pH and the higher the humic acid:uranium ratio. Data is also presented on the penetration parameter of the uranyl ion into the resin gel layer, and how this can be used to indicate lability. Lability is important in determining bioavailability and potential toxicity of uranium.
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McCall, Stephanie Jane. "Investigating the effects of nutrient concentration and light intensity on benthic biofilm development and phytoplankton growth in UK rivers." Thesis, University of Portsmouth, 2014. https://researchportal.port.ac.uk/portal/en/theses/investigating-the-effects-of-nutrient-concentration-and-light-intensity-on-benthic-biofilm-development-and-phytoplankton-growth-in-uk-rivers(5bb096f7-b9fb-4a4f-a714-e2f05271800d).html.
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Phosphorus is often considered the limiting nutrient in rivers, and reducing concentrations has long been a key policy focus. However, experience has shown that many phosphorus mitigation schemes fail to achieve any improvements in ecological status. The primary aim of this thesis is to identify target phosphorus concentrations that need to be attained to improve river ecology. In-stream flume mesocosms were deployed on three UK rivers of varying levels of nutrient enrichment. Phosphorus concentrations were simultaneously increased and decreased (by iron-dosing) to provide a concentration gradient over which periphyton accrual was examined. This identified whether rivers were phosphorus limited, and allowed a phosphorus-limiting threshold to be quantified. The effects of nitrogen, and combined phosphorus and nitrogen addition were also examined. The River Lambourn study simultaneously manipulated light intensity and nutrient concentrations, demonstrating shading to have benefits in improving periphyton quality as a food resource and in reducing periphyton accrual. The near-pristine River Rede showed that increase in river phosphorus concentration had no effect on periphyton growth rate, but that there was a 3.5-fold increase in growth rate when phosphorus and nitrogen were added simultaneously, demonstrating the presence of sequential nutrient co-limitation. By repeating a 2005 study on the River Frome, the 2012 study proved that phosphorus-limiting thresholds change in response to changing river nutrient concentrations. Examination of changes in community structure by the trophic diatom index and flow cytometry provide evidence for a lower ecological threshold in rivers of ca. 30 μg l-1. A fast repetition rate fluorometer was used to assess phytoplankton stress across the Thames catchment throughout an algal bloom and data was examined alongside water quality data. Bloom development and collapse was primarily controlled by residence time and, secondarily, phosphorus concentration. This thesis has challenged traditional beliefs that phosphorus is the limiting nutrient in freshwater ecosystems and has provided insights on how to best meet the requirements of the Water Framework Directive and improve ecological status.
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Giles, David. "Computer-based modelling and analysis in engineering geology." Thesis, University of Portsmouth, 2014. https://researchportal.port.ac.uk/portal/en/theses/computerbased-modelling-and-analysis-in-engineering-geology(091c5104-4dbb-4e90-b897-aaf34702100a).html.
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This body of work presents the research and publications undertaken under a general theme of computer-based modelling and analysis in engineering geology. Papers are presented on geotechnical data management, data interchange, Geographical Information Systems, surface modelling, geostatistical methods, risk-based modelling, knowledge-based systems, remote sensing in engineering geology and on the integration of computer applications into applied geoscience teaching. The work highlights my own personal contributions and publications under this theme as well as collaborations and output emanating from PhD co-supervisions which have included the following projects: A geotechnical and geochemical characterisation of dry oil lake contaminated soil in Kuwait; Dust dispersion monitoring and modelling; Geotechnical properties of chalk putties; The application of airborne multispectral remote sensing and digital terrain modelling to the detection and delineation of landslides on clay dominated slopes of the Cotswolds Escarpment; Domestic property insurance risks associated with brickearth deposits; Development of a knowledge-based system methodology for designing solid waste disposal sites in arid and semi-arid environments; GIS Techniques as an aid to the assessment of earthquake triggered landslide hazards; The application of GIS as a data integrator of pre-ground investigation desk studies for terrain evaluation and investigation planning; The influence of clay mineralogy pore water composition and pre-consolidation pressure on the magnitude of ground surface heave due to rises in groundwater level. My publication record comprises; Pathfinder and seminal papers; Papers from co-supervised PhD programmes; Pedagogic contributions; Encyclopaedia entries; International collaborations; Technical authorship and support; Other published contributions; Confidential development and technical reports and Internal briefing papers.
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Yuangdetkla, Kwanjai. "Distribution of landslides and geotechnical properties within the Hampshire Basin." Thesis, University of Portsmouth, 2013. https://researchportal.port.ac.uk/portal/en/theses/distribution-of-landslides-and-geotechnical-properties-within-the-hampshire-basin(ce5ae2ee-9a68-41e2-bdc1-de067dc0b507).html.
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The Paleogene succession in the Hampshire Basin, southern England is poorly described in terms of its engineering properties.The nature and distribution of landslides across the basin is also poorly described. This thesis describes work carried out to better understand the engineering properties of the Paleogene succession and how this affects landsliding in the region. A new engineering stratigraphy for the Paleogene strata of the Hampshire Basin has been constructed by collating available geological and geotechnical data, including examination of available exposures, database information, published and non-published literature. Similarly landslides across the basin were examined by field mapping, image interpretation and literature review and a new landslide inventory was produced. This new stratigraphy was utilised in a basin wide model of landslide occurrence using an infinite slope based methodology in a GIS. This new model was used to improve the landslide inventory, resulting in the identification of a total of 429 new landslides, a threefold increase on previous knowledge. Results indicate that landslide identification may be greatly enhanced if a geotechnical model is incorporated in the investigation. The research shows that it is appropriate to construct geological models based upon an engineering stratigraphy. For this study area, this model was tested by its incorporation into a slope stability analysis that could then be tested against the results of image interpretation and field surveys. This could be important for other studies where geotechnical information may be incomplete or where it is difficult to collect new data. This may have important implications for similar studies elsewhere.
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Batenburg, Sietske J. "Orbital pacing of Maastrichtian climate : integrated stratigraphy of the Zumaia and Sopelana sections (N-Spain)." Thesis, University of Portsmouth, 2013. https://researchportal.port.ac.uk/portal/en/theses/orbital-pacing-of-maastrichtian-climate(7eb822d4-1fce-4db8-8909-cdac7e65bd91).html.
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By integrated stratigraphy of the Zumaia and Sopelana sections in northern Spain, a detailed astronomical time scale is obtained for the Maastrichtian. The cyclic alternations of hemipelagic limestones and marls at Sopelana and Zumaia display the range of periodicities of eccentricity-modulated precession. The rhythmic bedding pattern is primarily caused by variations in siliciclastic supply and to a lesser extent to variations in biological productivity, both of which controlled by eccentricity modulated precession through its influence on the hydrological cycle. Together, the Zumaia and Sopelana sections span almost the entire Maastrichtian, and encompass thirteen 405-kyr cycles, spanning a total duration of 5.3 Myr. Consecutive 405-kyr minima in the lithological and geophysical data records are tuned to successive 405-kyr minima in the new La2011 eccentricity solution. Assuming a K/Pg boundary age of 65.97 Ma, orbitally tuned ages of biostratigraphic and magnetostratigraphic events are obtained. The bases of Chrons C29r and C30n have been reliably established at Zumaia and their astronomically tuned ages are in good agreement with previous studies. Data from Sopelana provide a refinement of the age of the base of Chron C31r. Planktonic foraminifera and calcareous nannoplankton data from Zumaia, and new calcareous nannoplankton data from Sopelana allow for worldwide correlation of the cyclostratigraphy of the Basque country. Additionally, the orbitally tuned bulk carbonate carbon isotope curve displays a remarkable amplitude of variation. Strong oscillations in δ13C seem regularly paced by the 405-kyr periodicity of eccentricity modulated precession. Sharp negative shifts associated with falls in sea-level occur at regular intervals of ~1.2 Myr. A new global correlation of carbon isotope stratigraphies is presented, with an astronomically tuned age model based on the cyclostratigraphy of Zumaia and Sopelana and site 762C (Exmouth Plateau). The Late Campanian/Maastrichtian carbon isotope correlation scheme displays a series of trends and excursions that can be observed across the different depositional settings. These results suggest that the 405-kyr cycle of eccentricity, and potentially longer periodicities, paced the latest Cretaceous climate and carbon cycle.
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Heroy, David Carlson. "Sand- and Clay-Size Mineralogy of the Ganges and Brahmaputra Rivers: Records of River Switching and Late-Quaternary Climate Change." W&M ScholarWorks, 2000. https://scholarworks.wm.edu/etd/1539617766.
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Lima, Ana Lúcia Cessel de 1969. "Molecular and isotopic records of the combustion inputs to the environment over the last 250 yrs." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/39413.
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Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and, the Woods Hole Oceanographic Institution), 2004.Includes bibliographical references.
The most ubiquitous source of polycyclic aromatic hydrocarbons (PAHs) to the environment is incomplete combustion. This study generated a high-resolution historical record of pyrogenic PAH emissions since pre-industrial times from anoxic aquatic sediments, allowing for detailed comparison with energy consumption data. We show that an increase in PAH concentrations over the last decade may be due to a rise in emissions from diesel-powered vehicles. Compound-specific radiocarbon measurements demonstrated unequivocally that the proportion of PAHs derived from fossil fuel combustion has increased substantially during the 20th century. [delta]¹³C and [delta]¹⁴C measurements were also used to constrain the relative importance of combustion versus in situ production as sources of perylene. In addition, a comparison of the down-core concentration and isotopic profiles of black carbon (BC) generated by a combination of chemical and/or thermal oxidation methods highlighted the limitations of these methods when applied to sedimentary matrices. Finally, parallel lead and cesium isotopic records revealed two new potential stratigraphic markers in North American sedimentary records. ²⁰⁶Pb/²⁰⁷Pb profiles show a distinct peak in the mid-19th century, while a ¹³⁷Cs peak was found to coincide with the 1986 Chernobyl accident.
by Anna Lúcia Cessel de Lima.
Ph.D.
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Maheras, Anastasia Francis. "Elemental and reactive gaseous mercury deposition and diurnal cycles over terrestrial environments." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/114365.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 88-93).
The atmospheric component of the global biogeochemical mercury cycle was studied to determine the mechanisms behind diurnal trends and amplitudes in elemental and reactive gaseous mercury concentrations over terrestrial environments. This analysis was done using the 3D GEOS-Chem chemical transport model and the creation of a simple one-box model. Mercury is a significant neurotoxin for humans and other species that has been addressed in the policy realm on both national and international levels. Being able to model atmospheric mercury processes correctly is an important part of regulation and policy drafting. GEOS-Chem model results were compared with Weiss-Penzias et al. [2009] measurements for three Nevada, USA sites. The magnitude of elemental mercury concentrations differed by 0.07-0.2 ng/m3 , with GEOS-Chem underestimating concentrations due to an under-representation of mercury emissions at naturally enriched sites. The amplitude of reactive gaseous mercury diurnal variations differed by a factor of 3-4, with GEOS-Chem underestimating the diurnal trend. Based on the diurnal nature of this error, it is hypothesized that GEOS-Chem under represents the magnitude of elemental mercury emissions, the amount of oxidation occurring in the atmosphere, and the scale of entrainment from the free troposphere.
by Anastasia F. Maheras.
S.B.
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Matys, Emily D. "Environmental controls on the distribution of bacterial membrane lipids." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119985.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references.
Since their discovery in ancient sediments, hopanes and their biological precursors, bacteriohopanepolyols (BHPs), have been of great interest for their potential to serve as proxies for bacteria in the geological record. The validation of these and other biomarkers have implications for understanding the coevolution of organisms and the environment throughout Earth's history. 2-Methylhopanoids are of particular interest because their occurrence may be confined to cyanobacteria and alphaproteobacteria. Similarly, a stereoisomer of bacteriohopanetetrol (BHT), BHT II, has been identified exclusively in anaerobic ammonium oxidation (anammox) bacteria. However, the interpretation of sedimentary hopanoids is presently limited by an incomplete understanding of their phylogenetic associations, biological functions, and spatial and temporal disposition throughout diverse environments. I address some of these shortcomings through lipid biomarker characterization of water column and benthic microbial mat samples collected across geochemical and physiochemical gradients in the Eastern Tropical South Pacific oxygen minimum zone off the coast of northern Chile and in two ice-covered lakes of the McMurdo Dry Valleys, Antarctica. The results will enhance our ability to interpret the molecular fossil record, particularly those biomarkers that might preserve evidence of ancient marine and glacial environments. I will provide evidence that supports the use of BHT II as a biomarker for suboxia/anoxia, confirm the biosynthesis of 2- MeBHT in cyanobacteria as a response to photosynthetic stress, and describe improved methods that allow us to better detect, quantify, and interpret these markers in modern environments.
by Emily D. Matys.
Ph. D.
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Maheras, Anastasia Francis. "Assessing United States hurricane damage under different environmental conditions." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78479.
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Thesis (S.M. in Atmospheric Science)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 47-53).
Hurricane activity between 1979 and 2011 was studied to determine damage statistics under different environmental conditions. Hurricanes cause billions of dollars of damage every year in the United States, but damage locations and magnitudes vary from year to year. Seasonal hurricane forecasts predicting the strength of the upcoming hurricane season have the potential to be used by many industries and sectors to reduce and mitigate the effects of hurricanes. However, damage itself is not predicted by these forecasts. This work analyzed trends in hurricane damage due to atmospheric and oceanic conditions, and the results could be applied to and included in seasonal hurricane forecasts, thus increasing forecast applicability and value. This work used synthetic hurricane tracks generated from background climate conditions, a U.S. property portfolio, and a damage function based on wind speed to determine 1979-2011 hurricane damage. Damage was split into La Niña/El Niño and pre-/post- 1995 year sets to determine spatial and temporal trends in U.S. hurricane damage. This work concluded that different regions of the country experienced more or less hurricane damage under different environmental conditions. Knowledge of these trends can be applied to seasonal hurricane forecasts and can influence property owner, regulator, and insurer behavior across the nation.
by Anastasia Francis Maheras.
S.M.in Atmospheric Science
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Kempes, Christopher Andrew Poling. "The physical, environmental, and evolutionary determinants of biological architecture." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/79281.
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Thesis (Ph. D. in Physical Biology)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 201-224).
The relationship between structure and function is a longstanding and central topic in biology, evolution, and ecology. The importance of morphology is clearly visible in the diverse forms taken by innumerable organisms in order to perform a myriad of functions. Examining the great variety of morphological characteristics it would seem that the overall principle of evolution is the only way to generalize the observed diversity: given differences in environments and random biological variation a great multitude of body plans have been invented as adaptations to many dynamic habitats given specific evolutionary histories. In this thesis I will show how focusing on diverse organisms makes it possible to identify common first-order laws of evolutionary organization. More specifically I will show how these common laws derive from a connection between organism structure, physical limitations, environmental constraints, and basic metabolic, biochemical, or energetic principles. Furthermore, I will show how this top level of biological organization holds significant predictive power for regional ecology and for interpreting the general trends of evolutionary history. In Chapter 2 we begin by deriving a model for the growth of single cells and populations of cells. This model is based on the partitioning of metabolic resources and the scaling relationship between metabolism and body size. We show that the growth of diverse classes of organisms is connected by common unit energetics. However there exist striking differences in the broad trends between growth rate and body size across these different classes and we show that this is a consequence of major evolutionary transitions which adjust the partitioning of metabolic resources. We interpret major evolutionary transitions to occur in response to energetic limitations. We also find that multicellular living for unicellular organisms provides a metabolic and reproductive advantage. In Chapters 3 and 4 we further investigate these features in microbial biofilms which exhibit rich spatial patterning. Using a mathematical model and experimentation we find that the tall vertical structures produced by these biofilms have optimal geometry for resource uptake and the growth efficiency of the entire colony. Our model allows us to predict the observed changes in feature geometry given alterations to the environmental conditions that the biofilms are grown in. Furthermore, we are able to show that the morphology of these structures is dependent on single cell physiology. For example, single genetic knockouts of flagellar motility radically alter the temporal dynamics of feature spacing. Our work highlights morphology as a central property in multicellular organisms which mediates the interaction between environmental conditions and physiology. In Chapter 5 we highlight the importance of morphology in complex multicellular life where we develop a general model of tree architecture which we link to physiological success within a given environment. Although this model is general, uses only tree size as a governing parameter, and does not consider speciation we are able use local resource availability to predict broad regional patterns in plant traits such as maximum tree height. Each of these chapters highlights the importance of structure and morphology at multiple biological scales. In Chapter 6 we show how the importance of structure extends to the genetic level where the specific encoding of a gene can have implicit information and functionality beyond the basic translation of codons. We investigate the observed implicit function of dramatic and frequent changes in the mutation rate of an organism given the structure of the mutL gene. We show mathematically that altering mutation rates is an evolutionarily advantageous strategy, and we show bioinformatically that the specific genetic structure that gives rise to this trait is under positive evolutionary selection.
by Christopher Andrew Poling Kempes.
Ph.D.in Physical Biology
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Jackson, Randolph L. "Collaboration and learning within tele-immersive virtual environments /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/7869.
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Molitor, Edvard. "Miljöfarliga transporter till sjöss : Kartläggning och riskanalys." Thesis, Uppsala University, Department of Earth Sciences, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-88854.
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An increasing number of chemicals are being transported by ships along the Swedish coastline. Many of these chemicals may pose a threat to the environment. Accidents and spills are luckily rare, but nonetheless it is important to be prepared for a possible chemical spill. The Swedish Coast Guard is responsible for responding to chemical spills at sea, and has both equipment and trained personnel for the purpose. In order to prepare for a possible accident one also needs to know what is currently being transported at sea. The aim of this project is therefore to survey the chemical transports in Swedish waters.
The survey shows that many of the chemicals transported at sea are environmentally harmful and may harm the environment in the event of a spill. The number of accidents that occur is difficult to determine since not all of the smaller ones are reported. It is clear, however, that the main reasons for accidents are groundings and collisions. The collection of information about chemical transports has been difficult because many of the companies and ports are unwilling to give their information. This is part because of concurrence and part due to the fact that it is considered too much work to gather the data.
The project also aims to make a risk analysis for chemical transports at sea. Because of the insufficient data the risk analysis has only dealt with qualitative assessments for certain chemicals. These assessments show that chemicals which are less environmentally harmful may still pose a threat because of the safety issues for the personnel may delay or even prevent a response action.
International regulations for transports at sea can sometimes be complicated to apply because of the vast number of different chemicals. The classification process takes time because of the extensive research which is needed. Furthermore, many of the chemicals transported are classified in different systems and these do not always correspond. It is therefore difficult to conclude which chemicals that are actually a threat to the environment.
Varje år transporteras allt större mängder kemikalier med fartyg längs Sveriges kust. Många av dessa kan vara farliga för miljön. Olyckor och utsläpp sker lyckligtvis ganska sällan men det krävs ändå en beredskap för att kunna ta hand om ett eventuellt utsläpp. I Sverige har Kustbevakningen ansvaret för miljöräddningstjänst till sjöss och har både utrustning och personal som är speciellt utbildad för att bekämpa just kemikalieutsläpp. För att kunna förbereda sig på en eventuell olycka måste man dock också ha en aktuell bild av vilka kemikalier det är som transporteras till sjöss. Detta projekt har därför syftat till att kartlägga kemikalietransporterna i svenska farvatten.
Kartläggningen visar att flera av de kemikalier som transporteras till sjöss är miljöfarliga och kan skada miljön vid ett utsläpp eller en olycka. Hur många olyckor som sker är svårt att veta eftersom många av de mindre olyckorna inte rapporteras. Däremot kan man tydligt se att de vanligaste olycksorsakerna är kollisioner och grundstötningar. Att få tag i uppgifter om hur mycket kemikalier som transporteras har visat sig vara svårt eftersom flera företag och hamnar inte vill tala om hur mycket som transporteras. Det beror dels på konkurrensen mellan kemikalieföretag och dels på att man tycker att det är för jobbigt att behöva sammanställa informationen.
Projektet har också syftat till att göra en riskanalys över kemikalietransporterna. På grund av det bristfälliga underlaget har riskanalysen endast behandlat kvalitativa bedömningar av ett antal olika kemikalier. Dessa bedömningar visar att även kemikalier som är mindre miljöfarliga kan utgöra en stor risk eftersom de säkerhetsmässiga riskerna för insatspersonalen kan försena eller till och med förhindra en bekämpningsinsats.
De internationella reglerna kring transporter till sjöss kan ibland vara svåra att tillämpa eftersom det finns ett stort antal olika kemikalier. Klassningen av de olika kemikalierna tar också lång tid då det krävs omfattande underlag. Många av kemikalierna som transporteras är dessutom klassade enligt flera olika system och det är inte alltid dessa system överensstämmer. Det kan därför vara svårt att ta reda på vilka kemikalier som egentligen kan anses vara miljöfarliga.