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Dissertations / Theses on the topic 'Natural salinity'
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Bleppony, Rueben Arnoldz. "Increased Salinity of Drilled Wells in Stockholm County – analysis of natural factors." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171823.
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Almost 50 % of drinking water in Sweden comes from aquifers. The sustainability of groundwater resources in Stockholm County is threatened by increased salinity although most of the drinking water comes from Lake Mälaren. For a region known to be located within the areas covered by seawater after the last glaciation, the health and socio-economic development of the county is in a balance as development plans are challenged by high risk of salt groundwater. It is therefore important to know the extent and spread of salinity within the areas and the factors that correlate well with the salinity in the first attempt to study the risk of the areas to high salt content of groundwater. This paper looks at the distribution of salinity within the county and analyses the correlation between salinity and several natural factors. Using well co-ordinates and chemical data (compiled by Stockholm County Administration), and digital topographical, geological and land use data (from SGU and Swedish Land Survey), it is possible to project and visualize wells and salinity over the area, spatially develop and extract natural factor values to respective wells based on their co-ordinates, and finally perform statistical analyses on a resultant well attributes table, with the aid of Surfer, ArcGIS and Statistica Software. Results showing the spatial distribution of wells’ salinity and graphs of variance between the salinity of wells and respective natural factors of topography, depth, predominant soil cover, land use and distance from the sea, are further discussed.
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McNeil, Vivienne Heather. "Assessment methodologies for very large, irregularly collected water quality data sets with special reference to the natural waters of Queensland." Thesis, Queensland University of Technology, 2001.
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Morris, Kay. "Salinity and nutrients : growth and water use of aquatic macrophytes under controlled and natural conditions /." Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phm876.pdf.
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Jahan, Amreen. "The effect of salinity in the flora and fauna of the Sundarbans and the impacts on local livelihood." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-364971.
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Albarracin, Maria Teresa. "Bottom-up and top-down effects on insects herbivores along a natural salinity gradient in a florida salt marsh." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001002.
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Long, Amy K. "Control of lysogeny in marine bacteria : studies with phiHSIC and natural populations." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001737.
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Bourhane, Zeina. "Anthropogenic impacts on microbial communities in agriculture aride zones." Electronic Thesis or Diss., Pau, 2021. http://www.theses.fr/2021PAUU3071.
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Les milieux aquatiques et ses alentours, dans les régions arides et semi-arides, sont soumis à une forte pression anthropique provenant des activités agricoles et industrielles. Ces zones uniques sont caractérisées par une salinité naturelle et des fluctuations saisonnières drastiques. Cette thèse apporte des informations pour mieux comprendre les facteurs qui influencent les assemblages des communautés microbiennes et leurs adaptations aux polluants dans des conditions environnementales extrêmes, informations permettant de définir des bioindicateurs potentiels. Ces bioindicateurs microbiens constituent des outils prometteurs pour la surveillance environnementale en évaluant le statut écologique et la santé des écosystèmes. Ainsi, ce travail de thèse a pour but de déchiffrer les règles qui affectent les assemblages des communautés microbiennes habitant les sols et les sédiments des zones arides et semi-arides. Nous avons étudié les communautés microbiennes autour du lac Ichkeul (Tunisie) et des "Saladas de Bujaraloz-Sástago" (Salineta, Monegros, Espagne), deux écosystèmes aquatiques emblématiques RAMSAR. Nous avons combiné des approches métagénomiques basées sur le séquençage des gènes 16S rRNA, des analyses chimiques et des indices microbiens pour déterminer les relations entre la composition microbienne et les paramètres environnementaux. Nous avons identifié l'impacts des polluants, tels que les hydrocarbures, les pesticides et les métaux lourds, sur les communautés microbiennes des sols et des sédiments et caractérisé la dynamique des communautés microbiennes en fonction des variations saisonnières. Nous avons défini des bio-indicateurs microbiens pertinents, identifié des taxons microbiens spécialistes particulièrement adaptés aux conditions environnementales, en particulier à la salinité naturelle. Enfin, cette étude ouvre de nouvelles perspectives pour le développement des outils de bio-surveillance, nécessaires pour la gestion et la restauration des écosystèmes aquatiquesAquatic environments and their surroundings in arid and semi-arid regions are subjected to strong anthropogenic pressure resulting from agriculture and industrial activities. These unique areas are characterized by natural salinity and drastic seasonal fluctuations. The thesis provides information to better understand the factors shaping the microbial communities assemblages and their adaptation to pollutants under extreme environmental conditions, in order to examine the possibility to define microbial bioindicators. Such microbial bioindicators constitute promising tools for a careful environmental monitoring, which is required to evaluate the ecological status and environmental health of ecosystems in arid and semi-arid regions. In order to decipher the rules governing the assemblages of microbial communities inhabiting soils and sediments in arid and semi-arid zones, we investigated microbial communities around the Ichkeul Lake (Tunisia) and the “Saladas de Bujaraloz-Sástago” (Salineta, Monegros, Spain), two emblematic aquatic RAMSAR ecosystems. Metagenomic approaches, chemical analyses and integrative microbial indexes were combined to determine the relationships between microbial composition and environmental parameters. We identified the impacts of pollutants such as hydrocarbons, pesticides and heavy metals on microbial communities in soils and sediments and characterized microbial community dynamics according to seasonal variations. We defined relevant microbial bioindicators adapted, identified microbial specialists adapted to the environmental conditions, particularly to natural salinity. Finally, this study provides new insight for developing biomonitoring tools, requested for the management and restoration of aquatic ecosystems
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Sehlinger, Troy. "Analysis of temperature and salinity effects on growth and mortality of oysters (Crassostrea virginica) in Louisiana." ScholarWorks@UNO, 2018. https://scholarworks.uno.edu/td/2515.
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Salinity (S) and temperature (T) control every facet of the eastern oyster (Crassostrea virginica) life cycle, principally reproduction, development, growth, and mortality. Previous studies conducted in in the Breton Sound (BR) and Barataria (BA) estuaries have reported differences in growth and mortality rates between the basins. In the present study, environmental conditions were synchronized to compare growth and mortality rates between basins at similar combinations of T and S. Results indicate that when T and S are the same (synchronized), seasonal oyster growth and mortality rates differ between BR and BA. Seasonal analyses revealed that as salinities increased in both estuaries, growth rates generally increased, while mortality rates generally decreased. These findings suggest that basin-wide adaptations to local environmental conditions may exist.
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Sellami, Jallouli Sahar. "Etude de l'homéostasie des sucres en réponse à une forte salinité chez Arabidopsis thaliana : impact sur l'anatomie des tissus vasculaires dans la hampe florale et rôle dans la tolérance Arabidopsis natural accessions display adaptations in inflorescence growth and vascular anatomy to withstand high salinity during reproductive growth Salinity Effects on Sugar Homeostasis and Vascular Anatomy in the Stem of the Arabidopsis Thaliana Inflorescence." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS549.
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Chez Arabidopsis thaliana au stade reproducteur la hampe florale joue un rôle important dans l’approvisionnement en nutriments par les tissus vasculaires des siliques et des graines. Elle constitue un modèle pour l’étude de l’allocation du carbone et de l’homéostasie des sucres lors de réponse à des stress abiotiques. L’objectif de cette thèse était d’étudier les modifications de l’anatomie des tissus vasculaires et de l’homéostasie des sucres dans la hampe florale en réponse au stress salin, avec ou sans acclimatation, afin de comprendre leurs contributions dans les processus adaptatifs et d’acclimatations. Dans un premier temps, nous avons étudié la variabilité naturelle de la croissance de la hampe florale, de l’accumulation des sucres et de l’anatomie des tissus vasculaires dans la hampe florale dans trois accessions d’Arabidopsis thaliana et une espèce halophyte proche « Thellungiella salsuginea ». Cette étude a montré des modifications intervenant dans le développement de la hampe florale, dans l’accumulation des sucres et dans l’anatomie des tissus vasculaires en réponse au stress salin, selon le niveau de tolérance de l’écotype. Nous avons également montré que certaines de ces modifications sont liées aux processus adaptatifs au stress salin. Ces résultats suggèrent que la régulation de la croissance de la hampe florale et l’ajustement de l’anatomie des tissus vasculaires contribuent à la tolérance au stress salin. Dans un second temps, nous avons étudié chez l’accession Columbia d’Arabidopsis les modifications du transport et du métabolisme des sucres, en relation avec des changements dans l’anatomie des tissus vasculaires et la composition de la paroi secondaire dans le xylème. Les résultats montrent une accumulation des sucres associée à une dérégulation de gènes qui codent pour le transport et le métabolisme des sucres. Des modifications de l’anatomie des tissus vasculaires et de la composition de la paroi secondaire dans les vaisseaux de xylème ont été aussi observées. Ces résultats suggèrent une régulation de la répartition des sucres dans la hampe florale en réponse au stress salin qui peuvent contribuer à la tolérance au stress. L’ensemble de ces travaux permettent de proposer un modèle des régulations agissant sur l’homéostasie et le transport des sucres en réponse au stress salin dans la hampe florale, même si nos résultats ne permettent pas de conclure si ces processus sont favorables à la production des graines et interviennent dans l’adaptation ou l’acclimatation au stress salinIn Arabidopsis thaliana at the reproductive stage, the inflorescence plays an important role in the supply of nutrients through the vascular tissues of siliques and seeds. It is a model for the study of carbon allocation and sugar homeostasis in response to abiotic stress. The objective of this thesis was to study changes in the anatomy of vascular tissue and homeostasis of sugars in the main floral stem in response to salt stress, with or without acclimation to understand their contributions in the adaptive process and acclimation. First, we studied the natural variability of the growth of the inflorescence, the accumulation of sugars and the anatomy of vascular tissue in the scape in three accessions of Arabidopsis thaliana and related species halophyte «Thellungiella salsuginea ». This study showed changes in floral stem development, sugar accumulation, and vascular tissue anatomy in response to salt stress, depending on the level of tolerance of the ecotype. We have also shown that some of these modifications are related to adaptive processes to salt stress. These results suggest that the regulation of growth of the inflorescence and the adjustment of the anatomy of vascular tissues contribute to salt stress tolerance. Secondly, we studied changes of sugar transport and metabolism in Columbia accession of Arabidopsis thaliana in relation to changes in the anatomy of the vascular tissue and the composition of the secondary wall in xylem. The results show an accumulation of sugars associated with a deregulation of genes that encode for the sugar transport and metabolism. Changes in vascular tissue anatomy and in the composition of secondary wall in xylem vessels have also been observed. These results suggest a regulation of the distribution of sugars in the stem in response to salt stress that may contribute to stress tolerance. All of this work makes it possible to propose a model of the regulations acting on the homeostasis and the transport of sugars in response to salt stress in the floral stem, even if our results do not allow concluding if these processes are favorable to the production seeds and intervene in adaptation or acclimation to salt stress
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Wallin, Isa. "Why are fish in the Baltic Sea so small? : A study of somatic and gonad growth in relation to salinity in turbot (Scophthalmus maximus)." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-230310.
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It has been shown that fish of both marine and limnetic origin display increased growth at intermediate salinities. Furthermore, it has been shown that fish in the brackish water Baltic Sea are smaller compared to their conspecifics in the Atlantic, where salinities are higher. Also, it has been suggested that fish produce more eggs at the edges of their distribution range as a response to inferior environmental conditions. In this study, I investigated if there is a trade-off in energy investment between somatic and gonad growth in relation to salinity. To do this, I performed a growth experiment and a literature review. In the growth experiment, juvenile turbot were reared in salinities of 6, 10.5, 15 and 30 ‰. I found that turbot juveniles from Gotland grew equally well in all salinities investigated. In the literature review, data from the Baltic Sea was tested against data from the North and Black Seas. Data of turbot total energy investment (somatic and gonad growth) was analyzed. I found that energy content at age differed significantly between the populations investigated with lower energy content for the Baltic Sea populations. Also, growth rate in relation to energy content (size) was analyzed for the different populations, but no difference for growth rate in relation to energy content occurred. The result of the analysis of growth rate indicates that the change in allocated energy is the same, regardless of population, and thus that fish from the Baltic Sea display growth rates similar to those of other populations. It was also established that energy investment in gonads increased along with decreasing salinities. The smaller size of turbot in the Baltic Sea is therefore probably the result of a difference in size at maturity, possibly because less energy is allocated to somatic growth and more energy to start producing eggs. It is probably also the consequence of that the Baltic Sea turbot, post sexual maturity, continue to invest more energy in egg production.
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Silva, Ana Luísa Patrício. "Impact of natural and/or chemical stressors on the freeze-tolerant and euryhaline enchytraeid, Enchytraeus albidus." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/16009.
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Doutoramento em BiologiaRapid climatic changes are taking place in Arctic, subarctic and cold temperate regions, where predictions point to an increase in freeze-thaw events, changes in precipitation, evaporation and salinity patterns. Climate change may therefore result in large impacts in ecosystem functioning and dynamics, especially in the presence of contaminants due to intense anthropogenic activities. Even though multiple stress approaches have received increasing interest in the last decades, the number of such studies is limited. In particular, knowledge on the effect of freezethaw events and salinity fluctuations on ecotoxicology of soil invertebrates is lacking, especially important when considering supralittoral species. Therefore, the aim of this thesis was to investigate the effects of low temperature and salinity fluctuations, singly and in combination with contaminants, in the freeze-tolerant and euryhaline enchytraeid Enchytraeus albidus. The assessment of population level endpoints (survival and reproduction), along with physiological and biochemical parameters such as levels of cryoprotectants, ice/water content, oxidative stress biomarkers, cellular energy allocation, and tissue concentration of chemicals (when applied), provided new and valuable knowledge on the effects of selected physical and chemical stressors in E. albidus, and allowed the understanding of adjustments in the primary response mechanisms that enable worms to maintain homeostasis and survival in harsh environments such as polar and temperate-cold regions. The presence of moderate levels of salinity significantly increased freeze-tolerance (mainly evaluated as survival, cryoprotection and ice fraction) and reproduction of E. albidus. Moreover, it contributed to the readjustments of cryoprotectant levels, restoration of antioxidant levels and changed singnificantly the effect and uptake of chemicals (copper cadmium, carbendazim and 4-nonylphenol). Temperature fluctuations (simulated as daily freeze-thaw cycles, between -2ºC and -4ºC) caused substancial negative effect on survival of worms previsouly exposed to non-lethal concentrations of 4-nonylphenol, as compared with constant freezing (-4ºC) and control temperature (2ºC). The decrease in cryoprotectants, increase in energy consumption and the highest concentration of 4-nonylphenol in the tissues have highlighted the high energy requirements and level of toxicity experienced by worms exposed to the combined effect of contaminants and freezing-thawing events. The findings reported on this thesis demonstrate that natural (physical) and chemical stressors, singly or in combination, may alter the dynamics of E. albidus, affecting not only their survival and reproduction (and consequent presence/distribution) but also their physiological and biochemical adaptations. These alterations may lead to severe consequences for the functioning of the ecosystems along the Arctic, subarctic and cold temperate regions, where they play an important role for decomposition of dead organic matter. This thesis provides a scientific basis for improving the setting of safety factors for natural soil ecosystems, and to underline the integration of similar investigations in ecotoxicology, and eventually in risk assessment of contaminants.
As alterações climáticas estão a atingir rapidamente as regiões do Ártico, SubÁrtico e as regiões temperadas, apontando as previsões para um aumento de eventos de congelamento-descongelamento, bem como mudanças nos padrões de precipitação, evaporação e de salinidade. Estas alterações climáticas poderão resultar em impactos francamente negativos no funcionamento e dinâmica de ecossistemas, especialmente quando associados à presença de contaminantes resultantes da intensa atividade antropogénica. Embora a incorporação de stressores múltiplos em estudos de ecotoxicidade tenha recebido um crescente interesse pela comunidade científica, o seu número é ainda reduzido. Particularizando, o conhecimento dos efeitos de eventos de congelamento-descongelamento e de flutuações de salinidade permanecem desconhecidos, especialmente quando se consideram espécies supra-litorais. Neste contexto, o objetivo geral da presente tese consistiu em investigar os efeitos das flutuações de temperaturas e salinidade, individualmente ou em combinação com contaminantes, no enquitraídeo tolerante ao frio e eurialino - o Enchytraeus albidus. A avaliação de parâmetros populacionais (sobrevivência, reprodução e bioacumulação), fisiológicos (níveis de crioprotetores, conteúdo em gelo / água, temperatura de fusão e sobrecongelamento) e bioquímicos (biomarcadores de stress oxidativo, alocação de energia celular) permitiu compilar novas e valiosas informações sobre os efeitos dos stressores físicos e químicos selecionados no enquitraídeo e compreender quais os reajustes nos mecanismos de resposta primários que lhes permitem manter a homeostasia e sobrevivência em ambientes inóspitos como as regiões Polares e temperadas-frias. A presença de níveis moderados de salinidade aumentou significativamente a tolerância a temperaturas congelantes (essencialmente avaliada como sobrevivência, crioprotecção e fracção de gelo extracelular) e a reprodução do E. albidus. Além disso, contribuiu para a regulação de crioprotectores, restauração dos níveis de antioxidantes nestes organismos e alterou significativamente o efeito e a incorporação/absorção de substâncias químicas (cádmio, cobre carbendazim e 4-nonilfenol). As flutuações de temperatura (simuladas como ciclos diários de congelamento-descongelamento, com temperaturas entre 2ºC e -4ºC) causaram um efeito substancialmente negativo na sobrevivência de organismos previamente expostos a concentrações não letais de 4-nonilfenol, quando comparados com organismos expostos a uma temperatura congelante constante (-4ºC) ou à temperatura controlo (2ºC). A diminuição na crioproteção, o aumento no consumo de energia e a maior concentração de 4-nonilfenol nos tecidos vieram sublinhar o elevado gasto energético e o nível de toxicidade sofrido pelos organismos expostos à combinação de contaminantes e eventos de congelamento e descongelamento. Os resultados apresentados nesta tese demonstram, assim, que a presença de stressores naturais (físicos) e químicos, isoladamente ou em combinação, podem alterar a dinâmica do E. albidus, afetando não só a sua sobrevivência e reprodução (e consequente presença / distribuição), mas também as suas adaptações fisiológicas e bioquímicas. Essas alterações podem levar a consequências graves para o funcionamento dos ecossistemas do Ártico, subÁrtico e regiões temperadas-frias, uma vez que estes organismos desempenham um papel importante para a decomposição de matéria orgânica morta. Esta tese fornece ainda uma base científica para melhorar a atribuição de coeficientes de segurança para os ecossistemas naturais do solo, alertando para a integração de investigações semelhantes em ecotoxicologia, e, eventualmente, para a avaliação de risco ecológico de contaminantes.
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Proust, Katrina Margaret, and kproust@cres10 anu edu au. "Learning from the past for sustainability: towards an integrated approach." The Australian National University. Centre for Resource and Environmental Studies, 2004. http://thesis.anu.edu.au./public/adt-ANU20050706.140605.
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The task of producing policies for the management of Earth’s natural resources is a problem of the gravest concern worldwide. Such policies must address both responsible use in the present and the sustainability of those finite resources in the future. Resources are showing the adverse results of generations of exploitation, and communities fail to see the outcomes of past policies that have produced, and continue to produce, these results. They have not learned from past policy failures, and consequently fail to produce natural resource management (NRM) policies that support sustainable development.¶
It will be argued that NRM policy makers fail to learn from the past because they do not have a good historical perspective and a clear understanding of the dynamics of the complex human-environment system that they manage. It will also be argued that historians have not shown an interest in collaborating with policy makers on these issues, even though they have much to offer. Therefore, a new approach is proposed, which brings the skills and understanding of the trained historian directly into the policy arena.¶
This approach is called Applied Environmental History (AEH). Its aims are to help establish an area of common conceptual ground between NRM practitioners, policy makers, historians and dynamicists; to provide a framework that can help NRM practitioners and policy makers to take account of the historical and dynamical issues that characterise human-environment relationships; and to help NRM practitioners and policy makers improve their capacity to learn from the past.
Applied Environmental History captures the characteristics of public and applied history and environmental history. In order to include an understanding of feedback dynamics in human-environment systems, it draws on concepts from dynamical systems theory. Because learning from the past is a particular form of learning from experience, AEH also draws on theories of cognitive adaptation.¶
Principles for the application of AEH are developed and then tested in an exploratory study of irrigation development that is focused on the NRM issue of salinity. Since irrigation salinity has existed for centuries, and is a serious environmental problem in many parts of the world, it is a suitable NRM context in which to explore policy makers' failure to learn from the past. AEH principles guide this study, and are used, together with insights generated from the study, as the basis for the design of AEH Guidelines.
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Taulis, Mauricio. "Groundwater characterisation and disposal modelling for coal seam gas recovery." Thesis, University of Canterbury. Civil Engineering, 2007. http://hdl.handle.net/10092/3104.
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Coal Seam Gas (CSG) is a form of natural gas (mainly methane) sorbed in underground coal deposits. Mining this gas involves drilling a well directly into an underground coal seam, and pumping out the water (CSG water) flowing through it. Presently, CSG is under exploration in New Zealand (NZ); however, there is concern about CSG water disposal in NZ mainly because of the controversy that this activity has generated in some basins in the United States (US). The first part of this thesis studies CSG water from a well in Maramarua (NZ) and compares it to water from US basins. The NZ CSG water from this well had high pH (7.8), alkalinity in the order of 360 mg/l as CaCO₃, high sodium (334 mg/l), bicarbonate (435 mg/l), and chloride (146 mg/l). These ions also occur in US CSG waters, and their concentrations follow the same trend - high sodium, bicarbonate, and chloride with low calcium, magnesium, and sulphate concentrations. Prior to this work, little detailed analyses of CSG water quality variability from a well had been carried out. A Factor Analysis of 33 Maramarua samples was conducted and revealed that about one third of the variations were due to sample degassing, which induced calcium carbonate precipitation - this was supported by experimental work (sample sparging) and geochemical modelling (MINTEQA2). This finding is important for CSG water management because, as calcium concentrations decrease, higher SAR values are generated, and this can cause problems if CSG waters are disposed on land. In the second part, this thesis assesses the potential environmental effects of disposing CSG waters in NZ by formulating management options and a simple wastewater treatment system. This was carried out by studying the ecological response (soils, plant, and aquatic life) resulting from CSG water disposal operations in the US, and by applying relevant salinity and sodicity guidelines to the interaction between soils and CSG waters from Maramarua. This work showed that similar problems are likely to occur in NZ if CSG water disposal takes place without proper controls. Such a study has never been carried out in a region before actual CSG development has taken place, so this work shows how to quantify the effects arising from CSG water disposal prior to full scale production. This can be particularly useful for CSG stakeholders wanting to develop this resource in other regions around the world. A simple treatment system using Ngakuru zeolites has proven effective in reducing the SAR of Maramarua CSG water. Laboratory results indicate that these zeolites work by exchanging sodium cations in the water by other cations contained within the zeolite structure but with slow ion exchange kinetics. The calculated sodium absorption capacity for these natural zeolites ranged from 11.3 meq/100g to 16.7 meq/100g (flow-through conditions without previous regeneration). In addition, these experiments showed that the ion exchange process is accompanied by some dissolution (sulphate, boron, TOC, sodium, calcium, magnesium, potassium and reactive silica), but mainly at the beginning of the treatment process. Nevertheless, using this system, 180 grams of zeolite material were used to treat an initial 1.83 litres of Maramarua CSG water thus reducing potential soil infiltration problems to nil. As more CSG water was treated, the zeolites kept reducing SAR values but at a lesser rate until 4.53 litres of CSG water had been treated. A step-by-step methodology to assess treatment design options for these materials has been developed and will aid future researchers and engineers. This thesis presents the first comprehensive study of CSG water management in NZ. It also presents an ion exchange treatment system using natural zeolites already available in NZ. In conclusion, the research finds that, whether through adequate management or active treatment, CSG waters can be safely disposed without creating major environmental problems, and can even be used in beneficial applications.
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Sánchez, Vanessa. "Characterization of Rhizobial Diversity and Relationship of Rhizobial Partner and Legume Performance in Four South Florida Pine Rockland Soils." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1124.
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Pine rocklands are endangered ecosystems unique to south Florida, the Bahamas and Cuba. As a result of their karstic calcium carbonaterich soil, these systems are limited in phosphorus and nitrogen, making symbiotic associations critical to plant growth. Four leguminous species (Cajanus cajan, Chamaecrista fasciculata, Tephrosia angustissima, and Abrus precatorious) were used to determine the relationship between rhizobial partners and plant performance, and the symbiosis related gene nifH was amplified to characterize the diversity of rhizobial symbionts. Plants were grown in soils from four different south Florida pine rocklands, and a salinity treatment was added to determine how storm surge and sea level rise could affect this symbiotic relationship. While plant performance and nodulation were highly impacted by soil type, salinity did not represent a significant effect. Phylogenetic analysis determined that all four plant species were found to associate with Bradyrhizobium spp. and no rhizobial shift between salinity treatment and soil type was found.
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Ogurcak, Danielle E. "The Effect of Disturbance and Freshwater Availability on Lower Florida Keys’ Coastal Forest Dynamics." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2288.
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Coastal forest retreat in the Florida Keys during the 20th century has been attributed to a combination of sea level rise and hurricane storm surge impacts, but the interactions between these two disturbances leading to forest decline are not well understood. The goal of my research was to assess their effects over a period spanning more than two decades, and to examine the relationships between these press and pulse disturbances and freshwater availability in pine rockland, hardwood hammock, and supratidal scrub communities. Impacts and recovery from two storm surges, Hurricanes Georges (1998) and Wilma (2005), were assessed with satellite-derived vegetation indices and multiple change detection techniques. Impacts were greater at lower elevations, and in hardwood hammock, spectral signatures indicative of plant stress and productivity returned to pre-disturbance levels within a few years. In pine rockland, impacts were predominately related to Hurricane Wilma, however, a similar return to pre-disturbance conditions was absent, suggesting that trajectories of disturbance recovery differed between the two communities. Long-term monitoring of forest composition, structure, and groundwater salinity showed that compositional shifts in the low shrub stratum were associated with salinization of the freshwater resource attributable to sea level rise. Throughout the course of twelve months of climate and groundwater monitoring (2011-2012), groundwater salinity generally decreased in response to large precipitation events. Modeling of geophysical data indicated that groundwater salinity was an important predictor of community type. Isotopic analysis of d18O in plant stem water and foliar d13C was used to determine temporal and spatial patterns in water use and plant stress in two community dominants, slash pine, Pinus elliottii var. densa, and buttonwood, Conocarpus erectus. Both species relied heavily on groundwater, and plant stress was related to increasing groundwater salinity. The results of this work suggest that the interaction of press and pulse disturbances drive changes in community composition by causing mortality of salt-sensitive species and altering the freshwater resource.
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Fumelli, Leonardo. "Lo stoccaggio di gas naturale in sotterraneo: esperienze in acquiferi salini profondi." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amslaurea.unibo.it/355/.
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O'Brien, Patricia Ann, and patricia o'brien@rmit edu au. "COncepts and costs for the maintenance of productive capacity: a study of the measurement and reporting of soil quality." RMIT University. Accounting and Law, 1999. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20040930.170346.
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This thesis studies the role accounting plays in the monitoring and reporting of soil quality in one sector of the agricultural industry, broadacre farming. A survey was conducted with broadacre farmers in the Loddon Catchment, Victoria, Australia. The primary aim was to determine the effectiveness accounting plays in providing information to decision makers relative to the productive capacity in soil quality and not just on profits. The capital asset in this study was defined as soil quality. Soils and soil quality in particular, are major elements in determining land value. The concern is decisions are being made by potential buyers and other decision makers, particularly policy makers, with regards to soil quality on the basis of incomplete and often misleading information. It is proposed that a major reason is due to the fact that different participants in the agricultural and accounting industries require and use different information. The accounting systems used by farmers are those that have been developed for the manufacturing sector which may not be appropriate for managing long-term, complex resources such as soil. The farmers themselves did not find formal accounting reports useful for decision making because these reports are based on uniform standards and market prices. The topic of soil quality and land degradation is viewed from two perspectives. In one perspective, the proprietary view; the accounting emphasis is on the ownership of assets and the change, both in income and capital, in these assets over time. In this case the accounting equation is seen as assets - liabilities = equities. The proprietor takes all the risk. A more recent perspective in accounting, the entity view, emphasises the assets whether financed from equity or debt and where the accounting equation is seen as assets = equities. The emphasis changes to the income flow from these assets and more interest is shown in current market prices as a reflection of the future value of these assets Profit is not necessarily a good indicator of what farmers are doing for their capital asset. There needs to be greater emphasis on costs undertaken for the conservation of soil. Those costs should be considered an investment and put into the balance sheet and not the profit and loss statement. The major finding of study demonstrates that decision making groups have different
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Kim, Ji Yeon. "The role of naturally occurring waterholes in determining the distribution of Florida Key Deer." Thesis, [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2845.
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Simó, Josa Iolanda. "The european framework for soil sustainability: mapping soil quality in model areas in Catalonia." Doctoral thesis, Universitat de Lleida, 2016. http://hdl.handle.net/10803/385616.
Full textAbstract:
Soil degradation is defined as a decrease in soil quality, which is caused by non sustainable soil
management. When the soil is losing its functionality is directly related with decreasing soil
quality.
This PhD proposes a scheme of intrinsic soil indicators for determining soil quality. This scheme
includes three different sets of soil quality indicators derived from basic soil use criteria. Such
criteria is based upon indicator availability, suitability and usefulness. These indicators are
grouped according to three different soil threats; declining organic matter, desertification and soil
salinity. These indicators were chosen under a European framework (COM (2002) 179 final) and
by natural processes. With respect to this framework, these indicators should be interpretable in
the context of soil quality, whilst also providing an auditable pathway through which soil
management decisions can be made.
The methods selected showed helpful results determining soil quality being well selected for the
use of soil indicators. EM measurements provide relevant information on within-field variability
of soil salinity. SOC distribution is important to be calculated in space and in depth. The
MEDALUS and RUSLE models can assess the extent, intensity and severity of desertification
processes in the target area.La degradació dels sòls es defineix com la disminució de la seva qualitat causada per un mal ús per part de l’espècie humana, o bé per causes generals. Així doncs, la pèrdua de funcionalitat del sòl està lligada a la disminució de la seva qualitat. En aquesta tesi s’ha estudiat el comportament d’indicadors de qualitat del sòl escollits sota un marc polític de la Unió Europea (COM(2002)). En concret, s’han estudiat indicadors relacionats amb tres amenaces/qualitat del sòl, contingut de matèria orgànica, grau de desertificació de les terres i estat de salinitat dels sòls, amb l’objectiu de validar la seva funcionalitat per qualificar el sòl. Els estudis s’han portat a terme en dues àrees ben diferenciades de Catalunya, al marge esquerra del Delta de l’Ebre i a una zona concreta del municipi de Canalda-Odén (Solsona) a la Catalunya central. Els mètodes seleccionats han mostrat donar bons resultats en la determinació de la qualitat del sòl, sent ben seleccionats com indicadors de qualitat del sòl. L’ús de l’electromagnètic sensor proporciona bona informació per a l’estudi de la variabilitat de la salinitat del sòl. La distribució carboni orgànic del sòl és important calcular-lo per veure com canvia tan en l'espai com en profunditat. Els models MEDALUS i RUSLE han mostrat avalar l'abast, la intensitat i la gravetat dels processos de desertificació a la zona d’estudi.
La degradación de los suelos se define como la disminución de su calidad del suelo causada por un mal uso por parte de la especie humana, o bien por causas generales. Así pues, la pérdida de la funcionalidad del suelo está ligada a la disminución de calidad de éste. En la presente tesis se ha estudiado el comportamiento de indicadores de calidad del suelo escogidos bajo un marco político de la Unión Europea (COM(2002)). En concreto, se han estudiado indicadores relacionados con tres amenazas del suelo, contenido de materia orgánica, grado de desertificación de las tierras y estado de salinidad de los suelos, con el objetivo de validar su funcionalidad para cualificar el suelo. Los estudios se han realizado en 2 áreas bien diferenciadas de Catalunya, en el margen izquierdo del Delta del Ebro y una zona concreta del municipio de Canalda-Odén (Solsona) en la Catalunya central. Los métodos seleccionados han mostrado dar buenos resultados en la determinación de la calidad del suelo, siendo bien seleccionados como indicadores de calidad del suelo. El uso del sensor electromagnético proporciona buena información para el estudio de la variabilidad de la salinidad del suelo. La distribución carbono orgánico del suelo es importante calcularlo para ver cómo cambia tanto en el espacio como en profundidad. Los modelos MEDALUS y RUSLE han mostrado avalar el alcance, la intensidad y la gravedad de los procesos de desertificación en la zona de estudio.
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Isla, Climente Ramón. "Efecto de la salinidad sobre la cebada (Hordeum vulgare L.). Análisis de caracteres morfo-fisiológicos y su relación con la tolerancia a la salinidad." Doctoral thesis, Universitat de Lleida, 1996. http://hdl.handle.net/10803/8324.
Full textAbstract:
La superfície agrícola del nostre planeta afectada per salinitat i/o alcalinitat és de prop de mil milions d'hectàrees (Szabvolcs, 1989) varia, segons les fonts consultades, des de valors de 230 milions fins gairebé mil milions d'hectàrees (Epstein et al., 1980), estant present en tot s els continents. Altres estimacions (Reeve i Fireman, 1967) indiquen que un terç de la superfície mundial de baix reg (unes 230 milions d'hectàrees) es troben afectades en major o menor grau per la salinitat. A pesar de les discrepàncies en les xifres, pel fet que es tracta de meres estimacions i no a a el resultat d'una cartografia adequada, la dimensió del problema és important ja que, al costat de la sequera, és el factor abiòtic que produeix un major descens en el rendiment dels conreus. En alguns països com Paquistan, 16 milions d'hectàrees han estat salinizades en processos de salinització secundaris induïts per la posada en regadiu, sent un dels problemes econòmics més importants del país (Ahmad, 1965).La superficie agrícola de nuestro planeta afectada por salinidad y/o alcalinidad es de alrededor de mil millones de hectáreas (Szabvolcs, 1989) varía, según las fuentes consultadas, desde valores de 230 millones hasta casi mil millones de hectáreas (Epstein et al., 1980), estando presente en todos los continentes. Otras estimaciones (Reeve y Fireman, 1967) indicanhablan de que un tercio de la superficie mundial de bajo riego(unas 230 millones de hectáreas) se encuentran afectadas en mayor o menor grado por la salinidad. A pesar de las discrepancias en las cifras, debido a que se trata de meras estimaciones y no a al resultado de una cartografía adecuada, la dimensión del problema es importante ya que, junto a la sequía, es el factor abiótico que produce un mayor descenso en el rendimiento de los cultivos. En algunos países como Paquistán, 16 millones de hectáreas han sido salinizadas en procesos de salinización secundarios inducidos por la puesta en regadío, siendo uno de los problemas económicos más importantes del país (Ahmad, 1965).
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Modéran, Julien. "Estuaire de la Charente : structure de communauté et écologie trophique du zooplancton, approche écosystémique de la contamination métallique." Phd thesis, Université de La Rochelle, 2010. http://tel.archives-ouvertes.fr/tel-00541019.
Full textAbstract:
Les estuaires sont des systèmes hautement dynamiques où interagissent des processus biogéochimiques complexes qui influent sur le devenir de la matière organique et non organique. La confrontation des eaux fluviales et marines induit des changements rapides des principaux facteurs structurant la distribution des organismes vivants et gouvernant la spéciation de certains éléments traces entre phase particulaire et dissoute, ex : gradient de salinité, teneurs en matières en suspension (MES). Ce travail vise à étudier l'estuaire de la Charente, principal fleuve influançant le bassin de Marennes-Oléron (première zone ostreicole française) afin (i) de caractériser la structure de la communauté zooplanctonique en relation avec les paramètres environnementaux, (ii) le fonctionnement de la base du réseau trophique de l'estuaire (identification des sources de matière organique exploitée par les organismes zooplanctoniques et suprabenthiques) et (iii) d'établir un état de contamination par les métaux des compartiments biotiques. L'estuaire de la Charente se distingue par des concentrations en MES extrêmement élevées, présentant néanmoins une contribution importante de la matière organique (efflorescence phytoplanctonique printanière en zone mésohaline et production microphytobenthique). La zone de turbidité maximale semble correspondre à un écotone qui contrôle les flux de matière organique et la distribution des organismes. Le mélange physique des particules issues des systèmes dulcicoles et marins adjacents à l'estuaire avec cette forte charge de matériel resuspendu conduit à une homogénéisation des signatures isotopiques et métalliques particulaires en été et automne le long du gradient de salinité. Les quatre assemblages zooplanctoniques identifiés sont structurés spatialement par la salinité et la concentration en MES et temporellement par les variations de température et de débit fluvial. Malgré la dominance quantitative du matériel détritique au sein du pool de matière organique particulaire (MOP), il semble que les 5 taxons planctoniques ou suprabenthiques dominants étudiés (Eurytemora affinis, Acartia spp., Daphnia spp., Neomysis integer, Mesopodopsis slabberi) présentent une sélectivité importante vis-à-vis de sources primaires distinctes. Cette succession spatio-temporelle d'espèces sélectives conduit à une multiplication des flux trophiques et semble ainsi optimiser à l'échelle annuelle l'exploitation de la MOP disponible. Les concentrations en Cd, Cu, Hg, Pb, V et Zn ont par ailleurs été mesurées dans près de 40 taxons estuariens (zooplancton, benthos, poissons). Malgré des concentrations en métaux dissous et particulaires plus faibles que dans les grands estuaires européens subissant une pression anthropique importante (Seine, Gironde), les niveaux de contamination mesurés dans les différents compartiments biotiques semblent globalement équivalents. Les évènements brefs (crue hivernale, efflorescence phytoplanctonique printanière) altèrent toutefois fortement ce schéma général en modifiant les sources primaires de matière organique disponibles et les concentrations métalliques particulaires (Cd notamment).
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Diep, Thi My Hanh. "Influence des contraintes édaphiques sur la nutrition minérale, le développement et la production du cocotier (Cocos nucifera. L. ) dans les sols sulfatés acides salés ou non salés du delta du Mekong : effet améliorant d'un apport de phosphate naturel." Paris 12, 1994. http://www.theses.fr/1994PA120047.
Full textAbstract:
La production d'huile vegetale est un enjeu economique majeur au viet nam. Cependant, l'extension de la culture du cocotier a des sols sulfates acides ou sulfates acides sales, carences en phosphore et en calcium, a entraine une chute importante de la production par comparaison aux sols alluviaux. Ces carences ont ete confirmees par le diagnostic foliaire mais aussi racinaire. Les potentiels hydriques eleves montrent que le cocotier ne souffre pas de stress hydrique dans le delta du mekong meme en saison seche. Par contre, pendant cette saison, dans les zones soumises a l'influence de la maree, la salinite elevee provoque la fermeture des stomates et la baisse de l'assimilation photosynthetique. Le taux de sodium et un milieu asphyxique sont les causes d'une inhibition de la croissance des systemes racinaire et aerien. L'augmentation excessive des teneurs en ions toxiques (fe#3#+, al#3#+, na#+) dans les racines par rapport aux feuilles a montre leur role filtrant. Un essai conduit avec des jeunes plants arroses a l'eau salee, a permis de determiner un niveau de salinite optimum (5 pour mille) et confirme le role de filtre des racines. L'apport de phosphate naturel augmente le nombre de noix et le poids de coprah par cocotier, l'effet etant relativement plus important avec les sols sulfates acides sales. La solubilite de l'engrais phosphate et sa teneur en calcium jouent un role essentiel dans l'efficacite du traitement: le calcium remonte le ph ce qui diminue l'activite des ions al#3#+ et ameliore la structure du sol, le phosphore corrige sa carence et complexe une partie de al. En se limitant aux zones ou la salinite est inferieure a 10 pour mille de nouvelles plantations pourraient etre developpees sur plus de 100. 000ha dans le delta du mekong
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Santos, João Filipe Rodrigues Pereira. "Salinity as a key selector on the activity and diversity of ammonia oxidizers in estuarine systems." Dissertação, 2016. https://repositorio-aberto.up.pt/handle/10216/88578.
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Ferreira, Pedro Filipe Gonçalves. "Development of a Synechocystis chassis: evaluation of its tolerance to salinity and characterization of an oxygen consuming device." Dissertação, 2013. https://repositorio-aberto.up.pt/handle/10216/70285.
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Santos, Miguel Eduardo Gomes. "Salinity effects on selected tomato genotypes from the Solanum lycopersicum cv. 'Moneymaker' x S. habrochaites LYC4 introgression line population." Dissertação, 2015. https://repositorio-aberto.up.pt/handle/10216/83454.
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Santos, João Filipe Rodrigues Pereira. "Salinity as a key selector on the activity and diversity of ammonia oxidizers in estuarine systems." Master's thesis, 2016. https://repositorio-aberto.up.pt/handle/10216/88578.
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Ferreira, Pedro Filipe Gonçalves. "Development of a Synechocystis chassis: evaluation of its tolerance to salinity and characterization of an oxygen consuming device." Master's thesis, 2013. https://repositorio-aberto.up.pt/handle/10216/70285.
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Santos, Miguel Eduardo Gomes. "Salinity effects on selected tomato genotypes from the Solanum lycopersicum cv. 'Moneymaker' x S. habrochaites LYC4 introgression line population." Master's thesis, 2015. https://repositorio-aberto.up.pt/handle/10216/83454.
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Hiralal, Omitha. "Leaf ultrastructural studies of Avicennia marina in response to salinity under natural conditions." Thesis, 2007. http://hdl.handle.net/10413/1047.
Full textAbstract:
In Richards Bay Harbour, the mangrove Avicennia marina exhibits a distinct natural productivity gradient. The fringe site, which is regularly inundated twice daily by tides, supports luxuriant adult A. marina trees that are 6-10 m tall and which form a dense, well-developed canopy. The landward site which is only inundated during high spring tides, supports diminutive or dwarf A. marina that are less than 1.5 m in height. In this study we compared leaves from fringe and dwarf sites with respect to morphology, ultrastructure and ecophysiology. Alterations in leaf morphology, ultrastructure and physiology of A. marina were compared at the fringe site (35 ‰) and dwarf site (60 ‰) using morphometric measurements, light (LM), transmission (TEM) and scanning microscopy (SEM). SEM and light microscopy revealed that multicellular salt glands were located on the thick, cutinised adaxial surface from leaves of both sites. The glands appeared to be scattered and protruding from individual crypts in fringe mangrove leaves whilst they appeared sunken and occluded by cuticular material in dwarf mangrove leaves. The salt glands on the abaxial surface were not sunken but obscured by the indumentum of peltate trichomes. Ultrastructural changes observed in dwarf mangrove leaves were associated with cuticle, cell walls, chloroplasts, mitochondria of mesophyll tissue and salt glands. Fringe mangrove leaves had chloroplasts with typical well-developed grana and stroma. Ultrastructural changes of chloroplasts were evident in dwarf mangrove leaves and included swelling and separation of thylakoids, disintegration of granal stacking and integranal lamellae, as well as loss of the integrity of the chloroplast envelope. Multivesicular structures were commonly found in vacuoles and associated with chloroplasts and mitochondria in both leaf types. In fringe mangrove leaves, mitochondria appeared spherical to tubular with a relatively smooth outer membrane and a highly convoluted inner membrane. Swelling and vacuolation of mitochondrial membranes, cristae and mitochondrial clustering in the cytoplasm around the chloroplasts were evident in dwarf mangrove leaves. Extensive lipid accumulation in the form of large, dense plastoglobuli occurred in the chloroplasts of dwarf mangrove leaves. There were characteristic differences in salt gland morphology of fringe and dwarf mangrove leaves, namely in the cell walls, vacuoles, and vesicle formation. In salt glands of dwarf mangrove leaves, a distinct withdrawal of the cytoplasm from the cell wall was observed. This feature was not observed in salt glands of fringe mangrove leaves. Numerous large vacuoles were observed in the secretory cells of glands of dwarf mangrove leaves compared to those of fringe plants. Multivesicular structures, vesicles and mitochondria were common features in both leaf types. Physiological studies involved a comparison of osmotic and ionic relations as well as whole plant responses in fringe and dwarf mangrove leaves. Relative leaf water content decreased by 7.8 % and specific leaf area by 17 % in dwarf compared to those of fringe mangroves. Dwarf mangrove leaves were 27.6 % thicker and leaf cuticle thickness 37.4 % higher than those from fringe mangroves. Fringe mangrove leaves displayed higher total chlorophyll contents by 27 %, with chlorophylls a and b being 22 % and 39.6 % higher, respectively than those of dwarf mangroves. Salt gland frequencies were higher in the apex, mid-lamina and base of fringe than dwarf mangrove leaves by 36 %, 45 % and 51 %, respectively. The concentration of glycinebetaine, a compatible, N-containing osmolyte was significantly higher by 40 % in dwarf than in fringe mangrove leaves. Concentrations of proline were 27 % lower in dwarf than in fringe mangrove leaves. The predominant inorganic ion detected in mature leaves was Na+, which was 19 % higher in dwarf than fringe mangrove leaves. Phosphorus was an element that appeared deficient in dwarf mangrove leaves, being 50 % lower compared to fringe mangrove leaves. The results of this investigation indicated that there were cytomorphological alterations as well as differences in physiological responses in leaves of A. marina at fringe and dwarf sites.Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2007.
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Lobo, Gaspar Senosiain Mendes. "Effect of dietary seaweed supplementation on growth performance, antioxidant and immune responses in European Seabass (Dicentrarchus labrax) subjected to rearing temperature and salinity oscillations." Dissertação, 2016. https://repositorio-aberto.up.pt/handle/10216/90652.
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Lobo, Gaspar Senosiain Mendes. "Effect of dietary seaweed supplementation on growth performance, antioxidant and immune responses in European Seabass (Dicentrarchus labrax) subjected to rearing temperature and salinity oscillations." Master's thesis, 2016. https://repositorio-aberto.up.pt/handle/10216/90652.
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Lee, Chi Hun. "Impacts of Natural Salt Pollution on Water Supply Capabilities of River/Reservoir Systems." Thesis, 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7820.
Full textAbstract:
Salinity is a major determinant of where and how water resources are used
worldwide. Natural salt pollution severely constrains the beneficial use of large amounts
of water in Texas and neighboring states. High salinity loads in several major
river/reservoir systems, including the Brazos River, originate largely from salt seeps and
springs in isolated areas of the upper river basins located in the Permian Basin geologic
region.
Research objectives were (1) to improve salinity simulation capabilities of the
Water Rights Analysis Package (WRAP) modeling system, and (2) to develop a better
understanding of the occurrence, transport, and impacts of salinity in the Brazos River
and Lakes Possum Kingdom, Granbury, and Whitney. Water volume budgets and total
dissolved solids load budgets were developed for five river reaches covering 405 miles
of the upper Brazos River. Methodologies were developed for creating and applying
WRAP salinity input datasets. The WRAP modeling system was expanded and applied to the entire Brazos River Basin to investigate alternative modeling premises and
impacts of salinity and salinity control measures on water supply capabilities.
Water and salinity budget analyses of the Brazos River system based primarily
on measured stream flow, reservoir storage, and total dissolved solids data compiled by
the U.S. Geological Survey were performed to explore the characteristics of flow and
storage volumes and salinity loads and concentrations in the river/reservoir system.
WRAP salinity input datasets were developed based on results from the salinity budget
study. One dataset was designed and applied specifically for testing salinity routing
methods and calibrating salinity routing parameters. A second complete basin salinity
dataset was developed and applied to simulate the Brazos River Basin for alternative
management strategies. The results of the simulations demonstrate, for example, that
previously proposed salt control impoundments can significantly reduce salinity loads
and concentrations in the three reservoirs and at all locations on the Brazos River from
the impoundments downstream to the Gulf of Mexico.
The WRAP salinity simulation features are designed to provide flexibility in
combining water quantity simulation datasets from the Texas Water Availability
Modeling System or other sources, which may be very complex, with available salinity
data which varies in extent and format between different river basins. The modeling
capabilities demonstrated by the Brazos River Basin study can be applied in other river
basins as well.
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Salgado, Paula Liliana Vila Nova. "Influence of Salinity on Dimethyl Sulfide and Methanethiol Formation and its side Effect on Nitrous Oxide Emissions." Master's thesis, 2013. https://repositorio-aberto.up.pt/handle/10216/70984.
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Salgado, Paula Liliana Vila Nova. "Influence of Salinity on Dimethyl Sulfide and Methanethiol Formation and its side Effect on Nitrous Oxide Emissions." Dissertação, 2013. https://repositorio-aberto.up.pt/handle/10216/70984.
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Morris, Kay. "Salinity and nutrients : growth and water use of aquatic macrophytes under controlled and natural conditions / by Kay Morris." Thesis, 1998. http://hdl.handle.net/2440/19224.
Full textAbstract:
Bibliography: leaves 217-229xvi, 229 leaves : ill. ; 30 cm.
Salinity and eutrophication are regarded as significant threats to freshwater habitats - Addresses issues related to these problems.
Thesis (Ph.D.)--University of Adelaide, Dept. of Botany, 1998?
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Chou, Ping-I., and 周秉毅. "Effects of Dissolved Oxygen, pH, Salinity and Natural Organic Matter on the Kinetics of Oxidative Dissolution of Sedimental Metal Sulfides." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/59527196464711185105.
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碩士國立臺灣大學
環境工程學研究所
103
Metal sulfides can stabilize toxic soluble heavy metals in anaerobic sediments. However, sediments may suspend and expose to aerobic conditions during storm events or in the estuary with tidal effects. This may cause oxidative dissolution of metal sulfides and increase metal bioavailability that can harm the ecosystem. The objective of this research is to investigate the effects of dissolved oxygen (DO), pH, natural organic matter (NOM) and salinity on the kinetics of oxidative dissolution of copper sulfide (CuS), lead sulfide (PbS) and zinc sulfide (ZnS). Batch experiments were conducted using a continuous aeration setup that can control the dissolve oxygen concentrations (0 mg/L, 5mg/L and 8.4 mg/L) for a period of 3 d. Results demonstrated that oxidative dissolution of CuS, PbS and ZnS truly occur in the presence of DO and the rate showed the following sequence: PbS >CuS>ZnS. Low pH and high salinity generally cause more and faster metal release. Humic acid can inhibit the metal release of CuS and PbS but promote the metal release of ZnS. FE-SEM analysis showed that the morphology of three metal sulfides became rounded and aggregated in the 10mg/L HA reaction, morphology change of CuS also found in brackish water reaction but PbS and ZnS had no changed.
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Chung, Chang-Hung, and 鍾昌宏. "Comparisons of switches of Na+/K+-ATPase α-isoform proteins between kidneys of two euryhaline teleots, tilapia (Oreochromis mossambicus) and milkfish (Chanos chanos), from different primary natural habitats in response to salinity challenge." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/83141009798850892940.
Full textAbstract:
碩士國立中興大學
生命科學院碩士在職專班
96
Mozambique tilapia (Oreochromis mossambicus) is a kind of freshwater teleost whose natural habitats are in fresh water of southern Africa. Milkfish (Chanos chanos) is a kind of marine teleost widely distributed throughout the tropical and subtropical Indo-Pacific. Both Mozambique tilapia and milkfish are euryhaline teleosts and can survive in a broad range of salinity. Since the activity and Na+ and K+ affinities of branchial Na+/K+-ATPase (NKA) changed with environmental salinities, it is suggested that the difference may be due to the switches of NKA α-subunit isoforms. The kidney is another important organ responsible for ion-regulation in teleosts. However, few studies addressed on the mechanisms of ion-regulation in kidney. In order to compare the ion-regulation mechanism between two euryhaline teleosts from different primary natural habitats in response to salinity challenge, this study focus on the switches of renal NKA α-isoform proteins between tilapia (Oreochromis mossambicus) and milkfish (Chanos chanos). Mozambique tilapia and milkfish were acclimatized and reared in seawater (35‰) and fresh water, respectively, for more than two weeks before sampling. In Mozambique tilapia, the protein abundance of renal NKA α-subunit, α1-, and α3-isoform in seawater-acclimatized fish was significantly higher than in freshwater acclimatized group. On the other hand, the α2-isoform was significantly lower in freshwater acclimatized individuals. In freshwater acclimatized milkfish, the protein abundance of renal NKA α-subunit and α1-isoform was significantly higher than in seawater-acclimatized group. As for α2- and α3-isoform, the protein abundance reveals no significant difference between different salinity groups. In conclusion, the protein abundance of renal NKA α-subunit was significantly higher in SW-acclimatized Mozambique tilapia and FW-acclimatized milkfish, and the protein abundance of renal NKA α-isoforms was influenced by environmental different salinities. In addition, the switches of renal NKA α-isoforms, especially α1-isoform, may be involved in the mechanisms of ion regulation in FW- and SW-acclimatized Mozambique tilapia and milkfish.
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Proust, Katrina. "Learning from the past for sustainability: towards an integrated approach." Phd thesis, 2004. http://hdl.handle.net/1885/48001.
Full textAbstract:
The task of producing policies for the management of Earth’s natural resources is a problem of the gravest concern worldwide. Such policies must address both responsible use in the present and the sustainability of those finite resources in the future. Resources are showing the adverse results of generations of exploitation, and communities fail to see the outcomes of past policies that have produced, and continue to produce, these results. They have not learned from past policy failures, and consequently fail to produce natural resource management (NRM) policies that support sustainable development. ¶ It will be argued that NRM policy makers fail to learn from the past because they do not have a good historical perspective and a clear understanding of the dynamics of the complex human-environment system that they manage. It will also be argued that historians have not shown an interest in collaborating with policy makers on these issues, even though they have much to offer. Therefore, a new approach is proposed, which brings the skills and understanding of the trained historian directly into the policy arena. ¶ This approach is called Applied Environmental History (AEH). Its aims are to help establish an area of common conceptual ground between NRM practitioners, policy makers, historians and dynamicists; to provide a framework that can help NRM practitioners and policy makers to take account of the historical and dynamical issues that characterise human-environment relationships; and to help NRM practitioners and policy makers improve their capacity to learn from the past. ¶ ...
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Costa, Paula Cristina de Oliveira. "Effects of mixture of nanoparticles under different salinity in the clams Ruditapes philippinarum and Ruditapes decussatus." Master's thesis, 2015. http://hdl.handle.net/10400.1/7625.
Full textAbstract:
Dissertação de mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidadde do Algarve, 2015Few studies have been done to determine the toxicity of Nanoparticles (NPs) on marine ecosystems and its effect on the biota. NPs interaction with Salinity, a major environmental factor, needs particular attention. Organisms in the Venice lagoon, the sampling site of this study, are subject to a wide range of salinity, yet little is known about the combined effect of an environmental stressor and NPs. Thus, this work aimed to evaluate the toxicological effects of salinity/NPs interaction. The study was conducted in two species: R. decussatus, native clams from the lagoon, and R. philippinarum, a clam deliberately introduced that has supplanted the native species. The two clams were exposed for 7 days to nZnO, nTiO2 and fullerene C60 (1 μg/L), at three salinity levels (18, 28, 38), with tissue collections after 1, 3 and 7 days. Biomarkers were evaluated in hemolymph, gills and digestive gland; RNA/DNA ratio and proteins were measured in foot tissue. R. decussatus had a significant increase in micronuclei, nuclear abnormalities, CAT and SOD at higher salinity, whereas LDH and NRU showed significant increases at low salinity. GST showed PCC showed increases at high salinity. RNA/DNA ratio did not show significant differences and the proteins presented significant decreases in medium and high salinity. R. philippinarum showed significant differences in micronuclei and nuclear abnormalities at high salinity and LDH and NRU with differences at lower salinity. CAT showed different values at low and high; SOD showed differences in the higher salinities. GST, LPO and PCC levels showed differences in the lower salinities. RNA/DNA ratio and proteins presented no differences. The results support the premise that R. decussatus is less resistant than the invasive species. This work is among the first to try to determine if the combination salinity/NPs have a synergistic effect on aquatic organisms.
Os impatos antropogénicos nos ecossistemas marinhos são cada vez maiores, entre eles destacam-se os associados á alteração na qualidade e quantidade das águas de drenagem continental. Ao nível da qualidade da água, as atividades industriais em crescimento, como as associadas á nanotecnologia, responsáveis pela criação e manipulação de materiais dentro da nanoescala, têm consequências para o biota que vive nestes meios. As propriedades físicas e químicas das nanopartículas (NPs) diferenciam-se substancialmente da forma bruta desse mesmo material, e permitem uma crescente aplicação em diversos setores industriais e comerciais como a medicina, farmácia, cosmética, produção de energia, eletrónica e ambiente. O crescente desenvolvimento desta indústria é tal que se espera uma produção de 58000 toneladas de NPs até ao ano 2020. Com este número exorbitante de produção é inevitável que muitas NPs cheguem ao ambiente e aos ecossistemas aquáticos, levando a uma interação com o biota. Devido às inúmeras fontes de NPs (fábricas, uso de produtos, processos de combustão, etc…) é ainda impossível determinar exatamente a quantidade de NPs que pode ser encontrada no ambiente. Para ultrapassar a falta de informação quantitativa das NPs estimações obtidas por modelação são usadas em estudos. Contudo é imperativo o desenvolvimento de métodos para contabilizar e caracterizar as NPs para uma melhor avaliação de risco do ambiente. Poucos estudos foram feitos ainda para averiguar a toxicidade destas NPs, pois o que torna as NPs tão desejadas, como as diferentes propriedades que têm quando são reduzidas à nanoescala, também as tornam imprevisíveis quando em contacto com o ambiente e o biota. Com uma grande concentração a entrar nos ecossistemas a informação do efeito da interação destas com o biota é ainda escasso. Por outro lado, a variação da quantidade de água doce que atinge estas zonas de transição, associado às atividades antropogénicas interfere também com as comunidades. A salinidade é um importante fator ambiental que caracteriza um corpo de água, tem efeitos nos processos fisiológicos, como sobrevivência, conteúdo de água dos tecidos e tem outros efeitos subletais. Na lagoa de Veneza, o local de amostragem deste estudo, a variação é grande. Esta variação ocorre durante o ano mas também dentro da lagoa a salinidade diverge entre áreas. Por esta razão os organismos aquáticos ficam sujeitos a vários níveis de salinidade. A lagoa está atualmente bastante poluída, com contaminações vindas das diversas áreas industriais. Ruditapes decussatus, amêijoa nativa da lagoa de Veneza, foi quase completamente substituída pela espécie Ruditapes philippinarum, que foi introduzida propositadamente numa altura em que a produção de organismos nativos estava irregular. Agora R. decussatus ocupa espaços bastante restritos e com densidades mais baixas que a espécie invasora. Poucos estudos foram feitos para averiguar o efeito combinado de fatores de stress ambiental com as NPs. Com as alterações globais é necessário averiguar o potencial efeito que a diferença nos fatores ambientais terá nos organismos e subsequentemente no ecossistema. Deste modo, esta dissertação teve como objetivo avaliar os efeitos toxicológicos da combinação de diferentes níveis de salinidade com uma mistura de NPs. Este estudo foi realizado em duas espécies de amêijoa, R. decussatus e R. philippinarum, uma nativa e outra invasora, para determinar se algum efeito sinergético ocorre e se existe alguma diferença de sensibilidades entre elas. Para compreender se algum efeito combinado existe, as duas amêijoas foram expostas a concentrações ambientalmente relevantes (1μg/L) de nZnO, nTiO2 e fulereno C60, a três níveis de salinidade: 18, 28 e 38. As amêijoas foram mantidas em tanques de vidro de 35 L, alimentadas diariamente e com mudas de água e fornecimento de NPs diárias. Para cada nível de salinidade havia um controlo, ou seja sem fornecimento de NPs, e cada tanque teve uma réplica. A exposição durou 7 dias mas recolhas de tecidos foram feitas depois de 1, 3 e 7 dias de exposição. Foi utilizada uma bateria de biomarcadores na hemolinfa, brânquias e glândula digestiva das amêijoas, nomeadamente biomarcadores de stress oxidativo (enzimas antioxidantes superóxido dismutase, catalase e glutationa S-transferase, peroxidação lipídica e conteúdo de proteína carbonilada), de citotoxicidade (lactato desidrogenase e capacidade pinocitótica) e de genotoxicidade (micronúcleo e aberrações nucleares). Para determinar a condição fisiológica das amêijoas também o conteúdo de RNA, DNA e conteúdo de proteínas foi determinado, em tecido do pé. R. decussatus apresentou aumento significativo em micronúcleos e aberrações nuclear na maior salinidade. Já a enzima LDH e capacidade pinocitótica apresentaram aumentos significativos a baixa salinidade. Nos biomarcadores de stress oxidativo CAT e SOD apresentaram valores altos nas salinidades mais altas, enquanto GST apresentou valores não muito claros. Os níveis de peroxidação lipídica apresentaram diferenças na salinidade mais baixa e mais alta, e proteínas carboniladas com aumentos na salinidade alta. No rácio RNA/DNA R. decussatus apresentou valores mais baixos em salinidades mais altas, mas as diferenças não eram significativas. O conteúdo proteico apresentou decréscimos significativos nas salinidades média e alta. R. philippinarum apresentou aumentos significativos de micronúcleos e aberrações nucleares na salinidade alta, e citotoxicidade alta na salinidade mais baixa. As enzimas antioxidantes mostraram resultados muito diferentes entre enzimas e tecidos. CAT mostrou valores diferentes a salinidade baixa e alta, SOD apresentou diferenças nas salinidades mais altas e GST apresentou diferenças nas salinidades mais baixas. Os níveis de peroxidação lipídica apresentaram diferenças nas salinidades mais baixas e proteínas carboniladas com diferenças nas salinidades mais baixas mas com retorno aos níveis controlo no fim da exposição. O rácio RNA/DNA e o conteúdo proteico não apresentaram diferenças significativas. R. decussatus mostrou resultados consistentes, com maior dano a ser revelados na maior salinidade. R. philippinarum não demonstrou um padrão claro, sugerindo que o efeito depende do biomarcador avaliado e do tecido analisado. Após sete dias de exposição, R. decussatus mostrou estar mais fisiologicamente debilitada, em relação á amêijoa invasiva. Os resultados parecem corroborar a premissa que R. decussatus é menos resistente que a invasiva R. philippinarum. É importante salientar que este trabalho é um dos primeiros a tentar determinar se a combinação salinidade/NPs tem um efeito sinergético nos organismos aquáticos. Com as alterações que estão a ocorrer no ambiente é importante aprofundar esta questão para uma melhor preparação e prevenção.