Our knowledge of how oil spills affect coastal environments is severely limited by the shortage of research that addresses the impact of these events on phytoplankton, the single most important group of organisms in the marine ecosystem. This scarcity of knowledge is mainly attributed to the absence of baseline data, preventing the comparison of pre- and post-spill populations. This unique study aims to identify how dinoflagellates and diatoms, the two major groups of phytoplankton in coastal marine environments, have been affected by the 1989 Exxon Valdez oil spill in Prince William Sound (PWS), Alaska. To do this, sedimentary records of dinoflagellate cysts, produced during a dinoflagellate's life cycle and preserved in the sediment, and biogenic silica, a proxy for diatom abundance, were analyzed prior to, during and after the oil spill. The analysis of two well-dated cores in PWS reveals marked increases during the oil spill in the concentrations of total cysts of the species Operculodinium centrocarpum sensu Wall and Dale, (1966) and Dubridinium spp. Total cyst concentrations doubled in core P-10 from 362 to 749 per g, while in core P-12 the increase was from 1175 to 1771 cysts g-1. During this peak in cyst concentrations, total concentrations were 3 and 2 standard deviations greater than the mean in cores P-10 and P-12, respectively. Dubridinium spp. showed a five and sevenfold increase in concentrations in cores P-10 (4 to 20 cysts g-1) and P-12 (16 to 110 cysts g-1), respectively, while O. centrocarpum sensu Wall and Dale, (1966) doubled in concentrations in the two cores (P-10: 117 to 276 cysts g-1; P-12: 268 to 495 cysts g-1). Biogenic silica values did not show significant changes throughout the cores, with values varying between 8% and 9% in core P-10 and 9.0% to 10.9% in core P-12. These changes lie within or very close to the standard deviation of the analyzed standards, suggesting that much of the changes could be analytical noise. The dinoflagellate cyst signals seen in this study are comparable to those seen as a result of nutrient enrichment in estuarine systems, suggesting that the 1989 Exxon Valdez oil spill and its remediation had a stimulatory effect on some taxa of cyst- producing dinoflagellates. This impact appears to be short-lived, with cyst concentrations returning to pre-spill levels within two years of the event. The lack of change in diatom abundance, on the other hand, suggest that diatom abundance remained relatively constant during the entirety of the sample period. / Graduate / 2020-07-10

The ice melting and lateral cavity formation caused by in situ burning (ISB) of liquid fuels in ice-infested waters was studied in order to improve predictions on the removal efficiency of this oil spill mitigation method. For this purpose, several experimental studies were conducted to increase the fundamental understanding of the mechanisms that lead to ice melting and lateral cavity formation. The findings of the experimental studies provided the required knowledge to mathematically formulate the ice melting problem. Mathematical scaling analysis of ice melting during burning of oils in the vicinity of ice was performed to create a tool to estimate the extent of melting that occurs during ISB in ice-infested waters. A series of lab-scale experiments were designed to systematically investigate the ice melting problem. The first set of experiments were conducted in cylindrical shaped ice cavities with a 5.7 cm diameter. Burning of n-octane from ignition to natural extinction and the subsequent geometry change of the ice, fuel thickness, and fuel temperature were measured. The preliminary experimental observations showed that the melting of the ice walls was higher in areas where the fuel layer was in contact with ice compared with places of flame exposure. Based on these observations, a hypothesis that suggested the convective flows in the liquid fuel (driven mainly by surface tension and buoyancy) were contributing in melting of the ice was proposed to explain the origins of the lateral cavity. To evaluate this hypothesis, two dimensionless numbers (Marangoni and Rayleigh) were calculated as the indicators of the mechanisms of convection in the fuel layer. The comparison between the melting speed and these dimensionless numbers indicated surface tension driven flow was dominant while the role of buoyancy was negligible. In another set of experiments, Particle Image Velocimetry (PIV) was used to study the flow structure within the liquid-phase of n-octane pool fire bound on one side by an ice wall. Experiments were conducted in a square glass tray (9.6 cm × 9.6 cm × 5 cm) with a 3 cm thick ice wall placed on one side of the tray. Burning rate, flame height, and melting front velocity were measured to analyze the effect of heat feedback on melting of the ice. The melting rate of the ice increased from 0.6 cm/min for the first 50 seconds after ignition to 1 cm/min for the rest of burning period. Meanwhile, the measurement of the burning rates and flame heights showed two distinctive behaviors; a growth period from self-sustained ignition to the peak mass loss rate (first 50 seconds after ignition) followed by a steady phase from the peak of mass loss rate until the manual extinguishment. Similarly, the flow field measurements by a 2-dimensional PIV system indicated the existence of two different flow regimes. In the moments before ignition of the fuel, coupling of surface tension and buoyancy forces led to a combined one roll structure in the fuel. This was when a single large vortex was observed in the flow field. After ignition the flow field began transitioning toward an unstable flow regime (separated) with an increase in number of vortices around the ice wall. As the burning rate/flame height increased the velocity and evolving flow patterns enhanced the melting rate of the ice wall. Experimentally determined temperature contours showed that a hot zone with thickness of approximately 3 mm was present below the free surface, corresponding to the multi-roll location. The change in the flow field behavior was found to relate to the melting front velocity of ice. To further study the lateral cavity phenomena, a parametric experimental study on melting of ice adjacent to liquids exposed from above to various heat fluxes was conducted in order to understand the role of liquid properties in formation of cavities in ice. Multiple liquids with wide variety and range of thermophysical properties were used in order to identify the key influential properties on melting. The melting rate of the ice and penetration speed of the liquid in a transparent glass tray (70 mm × 70 mm × 45 mm) with a 20 mm thick ice wall (70 mm × 50 mm × 20 mm) was measured. The melting front velocities obtained from experiments were then compared to surface flow velocities of liquids obtained through a scaling analysis of the surface flow to elucidate the influence of the various thermophysical properties of the liquids on ice melting. The surface velocity of the liquids correlated well to the melting front velocities of the ice which showed a clear relationship between the flow velocity and melting front velocity. As the final step of this work, to extend the findings of the experimental studies conducted herein to larger sizes comparable to realistic situations in the Arctic, an order of magnitude scaling analysis was performed to obtain the extent of ice melting. The scaling considered the heat feedback from the flame to fuel surface, the convective heat transfers toward the ice, and the melting energy continuity of ice. The existing experimental data on the size of lateral cavity were also collected and were correlated to the results of the scaling analysis using a nonlinear regression fitting technique. The mathematical correlation that was obtained by the scaling analysis can be used to predict the size of the lateral cavity for a given fuel, pool fire diameter, and burning time. This correlation will provide a predictive tool to estimate the size of a potential lateral cavity formed during ISB of a given spill scenario. In general, the ability to predict the ice melting caused by burning of spilled oil in ice-infested waters is of great practical importance for assessment of the response outcome. This would assist with quantifying the geometry change of the burning medium which in turn will define oil burning rate and extinction condition. Knowledge of burning behavior and extinction condition indicate the burned volume which can directly be used to define the removal effectiveness of ISB. Nevertheless, this analysis was conducted on a generic interaction of oil and ice and the specific details that are observed in actual application of ISB in ice-infested waters were neglected for simplicity. Extending the outcome of this study to more specific (scenario-based) oil-in-ice situation and improving the predictability of the melting correlation with large-scale experiments are the next steps to develop this work.

Resumo: Este estudo propõe-se realizar o mapeamento de sensibilidade ambiental a derramamentos de óleo - Cartas SAO - do Parque Estadual da Ilha do Cardoso e áreas do entorno - SP. Para tanto, foi aplicada a metodologia indicada pelo MMA atualmente utilizada no Brasil. Para o melhor detalhamento da avaliação da sensibilidade das praias arenosas, foi elaborada uma subclassificação do índice de sensibilidade do litoral (ISL) das praias em áreas de erosão, transporte e deposição de sedimentos. Devido a características importantes atualmente não avaliadas para os litorais rochosos, propõe-se um refinamento da classificação da sensibilidade destes destes em função dos parâmetros geomorfológicos (textura da rocha, hidrodinamismo e localização). Elaborou-se uma proposta de integração dos índices de sensibilidade dos ambientes costeiros, estuarinos e fluviais da área estudada, levando-se em consideração os mesmos parâmetros atualmente utilizados para a classificação destes ambientes quanto a sensibilidade a derramamentos de óleo. Foram elaboradas áreas de proteção (áreas onde os esforços de combate e limpeza devem ser priorizados)e áreas de sacrifício (setores onde os esforços podem ser secundarizados ou utilizados para atividades de remoção do óleo). Devido a grande sensibilidade da região a derramamentos de óleo sugere-se a instalação de um Centro de Emergência Ambiental e de um plano de emergência para o combate a acidentes na área. / Abstract: This study purpose is to draw the oil spill environmental sensitivity mapping of Cardoso Island's State park and surrounding regions - SP. Thus, the suggested methodology for MMA, usually used in Brazil, was applied. For a better evaluation of the sensitivity of sandy beaches, a subclassification of the shoreline sensitivity index of beaches in erosion, transport and deposition zones of sediments was formulated. Due to important characteristics, so far not evaluated yet, found in rocky shores, it has been suggested a refined classification of sensitivity of those rocky shores according to geomorphologic parameters (rock grain, wave energy and localization). A suggestion of coastal, estuarine e riverine integration of environmental sensitivity index for the study area proposal was elaborated, taking into account the same parameters currently used to the classification of these environments related to the oil spill sensitivity. Priority zones of protection (sectors where the aactions and clean up must be priorities) and sacrifice zones (sectors where the actions must be retard or used to actions of removal oil) were formulated. Due to the great oil spill sensitivity in this region, the installation of an Environmental Emergency Central and a emergency plan to combat oil spill accidents in the region, is higly suggested. / Orientador: Dimas Dias Brito / Coorientador: João Carlos Carvalho Milanelli / Banca: Paulina Setti Riedel / Banca: Gabriel Henrique da Silva / O Atlas foi elaborado junto ao Grupo de Trabalho de Sensibilidade Costeira no Âmbito do Programa de Formação de Recursos Humanos - PRH 05 da UNESP, Rio Claro / Mestre

The Deepwater Horizon blowout occurred on April 20th, 2010 and released nearly 5 million barrels of crude oil into the northern Gulf of Mexico causing pollution of the water and sediment inhabited by many fishes for at least 87 days while the wellhead went uncapped. Populations of the Gulf of Mexico Red snapper, Lutjanus campechanus, an important fish to the ecology and economy in the region, exhibit affinity to shallow water oil infrastructure such as the Deepwater Horizon making them especially vulnerable to crude oil contamination. The objective of this study is to determine growth of Red snapper before, during and after the DWH spill and to assess factors potentially explaining such growth variation. Sagittal otoliths were collected from individuals sampled in 2011 - 2013 from scientific, demersal long-line surveys in the northern Gulf of Mexico (GoM) and West Florida Shelf (WFS). Age and otolith increment width analyses were performed. No annual variation in von Bertalanffy growth parameters was determined among the three catch years. The L∞ , K and t0 estimated from the complete data set (2011-2013) were 82.91, 0.20 and 0.43, respectively. However, significant differences in otolith increment width-at-age were observed in increment numbers three - seven in years following the DWH event, with declines of 13%, 15% and 22% occurring in the fourth -sixth increments. To asses the potential significance of exogenous environmental variables to observed yearly growth variation I evaluated five parameters - meridional (V) winds, zonal (U) winds, wind stress curl which is a measure of upwelling, Mississippi River discharge, and mean sea level anomaly - using a linear mixed effects model. Hypothesis testing via reduced maximum likelihood estimates indicated that variation in U winds and River discharge could significantly explain the variation in increment width. However, further work must be done in order to determine the natural, inter-annual variability in age specific growth before the results from model fitting can be considered conclusive. Mean back-calculated weight-at-age measurements were obtained in order to assess potential variation in productivity changes. Results from forward difference and reverse helmert contrast-coding indicated that weight at age three+, four+ and five+ declined by 16%, 15% and 11% in 2010, respectively. These analyses indicate a significant decline in fish growth in 2010 coincident with the DWH event, followed by a return to pre-spill rates.

A new method is presented to provide automatic sequencing of multiple hydrodynamic models and automated analysis of model forecast uncertainty. A Hydrodynamic and oil spill model Python (HyosPy) wrapper was developed to run the hydrodynamic model, link with the oil spill, and visualize results. The HyosPy wrapper completes the following steps automatically: (1) downloads wind and tide data (nowcast, forecast and historical); (2) converts data to hydrodynamic model input; (3) initializes a sequence of hydrodynamic models starting at pre-defined intervals on a multi-processor workstation. Each model starts from the latest observed data, so that the multiple models provide a range of forecast hydrodynamics with different initial and boundary conditions reflecting different forecast horizons. As a simple testbed for integration strategies and visualization on Google Earth, a Runge-Kutta 4th order (RK4) particle transport tracer routine is developed for oil spill transport. The model forecast uncertainty is estimated by the difference between forecasts in the sequenced model runs and quantified by using statistics measurements. The HyosPy integrated system with wind and tide force is demonstrated by introducing an imaginary oil spill in Corpus Christi Bay. The results show that challenges in operational oil spill modeling can be met by leveraging existing models and web-visualization methods to provide tools for emergency managers. / text

Title: Media framing of the Norilsk oil spill Author: Daria Tsymbal Supervisor: Mgr. Jan Miessler, Department of Media Studies, Institute of Communication Studies and Journalism (ICSJ) Abstract: This study examines how the Norilsk oil spill in May 2020 was framed within four factors of Situational Crisis Communication Theory (SCCT): 1. Severity of the damage; 2. Crisis responsibility; 4. Crisis history; 5. Relationship history. Also, this study examines how media ownership and closeness of the media to the government influence the framing of Norilsk Oil Spill. Using content analyses, three Russian newspapers were analyzed - Novaya Gazeta, Rossiyskaya Gazeta, and Kommersant. The results demonstrated differences in usage and frequency of frames according to media ownership and closeness to the government. Also, findings revealed that there are differences in framing concerning time frame. This thesis provides evidence that four factors in SCCT concepts (Severity of the damage, Crisis responsibility, Crisis history, Relationship history) can serve as frames in media framing analyses of crises. In addition, this study provides information for crisis managers and media professionals on how one particular crisis may be differently framed in different newspapers. Keywords: Media, crisis communication,...

Please read the abstract in the thesis. / Thesis (PhD)--University of Pretoria, 2013. / gm2014 / Paraclinical Sciences / Unrestricted

archives@tulane.edu / During the Deepwater Horizon (DWH) oil spill in 2010, approximately 0.5 billion liters (3.1 million barrels) of oil were released into the northern Gulf of Mexico during the largest marine oil spill in history . A significant portion of the released oil was weathered into residues by physical, photochemical, and biological processes prior to landing on 1773 km of coastline, including 754 km of marsh shoreline in Louisiana. Researchers endeavored to describe effects of oil residues in the soil on salt marsh organisms and communities. Many studies focused on two pillars of salt marsh ecology: the microbial communities through which a large portion of the salt marsh food web is connected and Spartina alterniflora, a foundational species of Gulf Coast salt marshes. In this dissertation I describe how cryptic, or difficult to observe, elements of salt marsh ecology, like microbial communities and plant genetics, respond to oil residues in the environment. Using a suite of field, growth chamber, and greenhouse experiments I show that these microbial communities are difficult to characterize and may respond to other factors more strongly than they do to oil residues. I present evidence that the plant is resilient to oil in the environment, and changes in its microbiome, but exerts a measurable influence on the biodegradation of oil residues and the microbiome in the soil. This dissertation provides a greater understanding of the complexity of the salt marsh response to an oil spill. / 1 / Stephen K. Formel

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