251 resultados para Saltwater encroachment.


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Public opinion polls in the United States reveal that a great majority of Americans are aware and show concern about ecological issues and the need to preserve natural areas. In South Florida, natural resources have been subjected to enormous strain as the pressure to accommodate a growing population has led to rapid development. Suburbs have been built on areas that were once natural wetlands and farmlands, and the impact today shows a landscape where natural places have all but disappeared. This dissertation examines the intersection between the perceptions that individuals living in the South Florida region have with respect to the natural environment and local ecological problems with where their relationship to nature takes place. ^ The research is based upon both quantitative and qualitative data. The principal methodology used in this research is the ethnographic method, which employed the data gathering techniques of in-depth interviewing and participant observation. The objective of the qualitative portion of the study was to determine how people perceive and relate to their immediate environment. The quantitative portion of the study employed telephone survey data from the FIU/Florida Poll 2000. Data collected through this survey provided the basis to statistically test responses to the research questions. ^ The findings show that people in South Florida have a general idea of the relationship between the human population and the environment but very little knowledge of how they individually affect each other. The experience of private places and public spaces in everyday life permits people to compartmentalize cultural values and understandings of the natural world in separate cognitive schemas. The appreciation of the natural world has almost no connection to their personal sense of obligation to preserve the environment. That obligation is only felt in their home space even though the South Florida environment overall struggles desperately with water shortages, land encroachment, and a rapidly expanding human population whose activities continuously aggravate an already delicate natural balance. ^

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A combination of statistical and interpolation methods and Geographic Information System (GIS) spatial analysis was used to evaluate the spatial and temporal changes in groundwater Cl− concentrations in Collier and Lee Counties (southwestern Florida), and Miami-Dade and Broward Counties (southeastern Florida), since 1985. In southwestern Florida, the average Cl− concentrations in the shallow wells (0–43 m) in Collier and Lee Counties increased from 132 mg L−1 in 1985 to 230 mg L−1 in 2000. The average Cl− concentrations in the deep wells (>43 m) of southwestern Florida increased from 392 mg L−1 in 1985 to 447 mg L−1 in 2000. Results also indicated a positive correlation between the mean sea level and Cl− concentrations and between the mean sea level and groundwater levels for the shallow wells. Concentrations in the Biscayne Aquifer (southeastern Florida) were significantly higher than those of southwestern Florida. The average Cl− concentrations increased from 159 mg L−1 in 1985 to 470 mg L−1 in 2010 for the shallow wells (<33 m) and from 1360 mg L−1 in 1985 to 2050 mg L−1 in 2010 for the deep wells (>33 m). In the Biscayne Aquifer, wells showed a positive or negative correlation between mean sea level and Cl− concentrations according to their location with respect to the saltwater intrusion line. Wells located inland behind canal control structures and west of the saltwater intrusion line showed negative correlation values, whereas wells located east of the saltwater intrusion line showed positive values. Overall, the results indicated that since 1985, there was a potential decline in the available freshwater resources estimated at about 12–17% of the available drinking-quality groundwater of the southeastern study area located in the Biscayne Aquifer.

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Saltwater intrusion and inundation can affect soil microbial activity, which regulates the carbon (C) balance in mangroves and helps to determine if these coastal forests can keep pace with sea level rise (SLR). This study evaluated the effects of increased salinity (+15 ppt), increased inundation (−8 cm), and their combination, on soil organic C loss from a mangrove peat soil (Everglades, Florida, USA) under simulated tides. Soil respiration (CO2 flux), methane (CH4) flux, dissolved organic carbon (DOC) production, and porewater nutrient concentrations were quantified. Soil respiration was the major pathway of soil organic C loss (94–98%) and was approximately 90% higher in the control water level than the inundated treatment under elevated salinity. Respiration rate increased with water temperature, but depended upon salinity and tidal range. CH4 flux was minimal, while porewater DOC increased with a concomitant, significant decline in soil bulk density under increased inundation. Porewater ammonium increased (73%) with inundation and soluble reactive phosphorus increased (32%) with salinity. Overall, the decline in soil organic C mineralization from combined saltwater intrusion and prolonged inundation was not significant, but results suggest SLR could increase this soil’s susceptibility to peat collapse and accelerate nutrient and DOC export to adjacent Florida Bay.

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This document summarizes the activities that were accomplished in 2008, the sixth year of the research project “Effect of hydrologic restoration on the habitat of the Cape Sable seaside sparrow”, a collaborative effort among the US Army Corps of Engineers, Everglades National Park, Florida International University, and the US Geological Survey (Florida Integrated Science Center). The major activities in 2008 included field work, data analysis, and presentations. Jay Sah presented the results of 6th year field work at the Cape Sable seaside sparrow (CSSS) Fire Meeting 2008, held on December 2-3 at the Krome Center, Homestead, Florida. In the same meeting, Mike Ross presented results from a related USFWS-funded project on encroachment pattern of woody plants in Cape Sable seaside sparrow habitat.

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In the fall of 2005, U.S. Fish and Wildlife Services (USFWS) contracted with Florida International University (FIU) to study the physical and biological drivers underlying the distribution of woody plant species in the marl prairie habitat of the Cape Sable Seaside Sparrow (CSSS). This report presents what we have learned about woody plant encroachment based on studies carried out during the period 2006-2008. The freshwater marl prairie habitat currently occupied by the Cape Sable seaside sparrow (CSSS; Ammodramus maritimus mirabilis) is a dynamic mosaic comprised of species-rich grassland communities and tree islands of various sizes, densities and compositions. Landscape heterogeneity and the scale of vegetative components across the marl prairie is primarily determined by hydrologic conditions, biological factors (e.g. dispersal and growth morphology), and disturbances such as fire. The woody component of the marl prairie landscape is subject to expansion through multiple positive feedback mechanisms, which may be initiated by recent land use change (e.g. drainage). Because sparrows are known to avoid areas where the woody component is too extensive, a better understanding of invasion dynamics is needed to ensure proper management.

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Fire, which affects community structure and composition at all trophic levels, is an integral component of the Everglades ecosystem (Wade et al. 1980; Lockwood et al. 2003). Without fire, the Everglades as we know it today would be a much different place. This is particularly true for the short-hydroperiod marl prairies that predominate on the eastern and western flanks of Shark River Slough, Everglades National Park (Figure 1). In general, fire in a tropical or sub-tropical grassland community favors the dominance of C4 grasses over C3 species (Roscoe et al. 2000; Briggs et al. 2005). Within this pyrogenic graminoid community also, periodic natural fires, together with suitable hydrologic regime, maintain and advance the dominance of C4 vs C3 graminoids (Sah et al. 2008), and suppress the encroachment of woody stems (Hanan et al. 2009; Hanan et al. unpublished manuscript) originating from the tree islands that, in places, dominate the landscape within this community. However, fires, under drought conditions and elevated fuel loads, can spread quickly throughout the landscape, oxidizing organic soils, both in the prairie and in the tree islands, and, in the process, lead to shifts in vegetation composition. This is particularly true when a fire immediately precedes a flood event (Herndon et al. 1991; Lodge 2005; Sah et al. 2010), or if so much soil is consumed during the fire that the hydrologic regime is permanently altered as a result of a decrease in elevation (Zaffke 1983).

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This multi-disciplinary research project explores the religious and cultural foundations within the “master commemorative narratives” that frame Israeli and Iranian political discourse. In articulating their grievances against one another, Israeli and Iranian leaders express the tensions between religion, nationalism, and modernity in their own societies. The theoretical and methodological approach of this dissertation is constructivist-interpretivist. The concept of “master commemorative narratives” is adapted from Yael Zerubavel’s study of ritualized remembrance in Israeli political culture, and applied to both Israeli and Iranian foreign policy. Israel’s master commemorative narrative draws heavily upon the language of the Hebrew Bible, situating foreign policy discourse within a paradigm of covenantal patrimony, exile, and return, despite the unrelenting hostility of eternal enemies and “the nations.” Iran’s master commemorative narrative expresses Iranian suspicion of foreign encroachment and interference, and of the internal corruption that they engender, sacralizing resistance to the forces of evil in the figurative language and myths of pre-Islamic tradition and of Shi‘a Islam. Using a constructivist-interpretive methodological approach, this research offers a unique interpretive analysis of the parallels between these narratives, where they intersect, and where they come into conflict. It highlights both the broad appeal and the diverse challenges to the components of these “master” narratives within Israeli and Iranian politics and society. The conclusion of this study explains the ways in which the recognition of religious and cultural conflicts through the optic of master commemorative narratives can complement the perspectives of other theoretical approaches and challenge the conventions of Security Studies. It also suggests some of the potential practical applications of this research in devising more effective international diplomacy.

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Passive samplers are not only a versatile tool to integrate environmental concentrations of pollutants, but also to avoid the use of live sentinel organisms for environmental monitoring. This study introduced the use of magnetic silicone polymer composites (Fe-PDMS) as passive sampling media to pre-concentrate a wide range of analytes from environmental settings. The composite samplers were assessed for their accumulation properties by performing lab experiments with two model herbicides (Atrazine and Irgarol 1051) and evaluated for their uptake properties from environmental settings (waters and sediments). The Fe-PDMS composites showed good accumulation of herbicides and pesticides from both freshwater and saltwater settings and the accumulation mechanism was positively correlated with the log Kow value of individual analytes. Results from the studies show that these composites could be easily used for a wide number of applications such as monitoring, cleanup, and/or bioaccumulation modeling, and as a non-intrusive and nondestructive monitoring tool for environmental forensic purposes.

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Vegetation changes, such as shrub encroachment and wetland expansion, have been observed in many Arctic tundra regions. These changes feed back to permafrost and climate. Permafrost can be protected by soil shading through vegetation as it reduces the amount of solar energy available for thawing. Regional climate can be affected by a reduction in surface albedo as more energy is available for atmospheric and soil heating. Here, we compared the shortwave radiation budget of two common Arctic tundra vegetation types dominated by dwarf shrubs (Betula nana) and wet sedges (Eriophorum angustifolium) in North-East Siberia. We measured time series of the shortwave and longwave radiation budget above the canopy and transmitted radiation below the canopy. Additionally, we quantified soil temperature and heat flux as well as active layer thickness. The mean growing season albedo of dwarf shrubs was 0.15 ± 0.01, for sedges it was higher (0.17 ± 0.02). Dwarf shrub transmittance was 0.36 ± 0.07 on average, and sedge transmittance was 0.28 ± 0.08. The standing dead leaves contributed strongly to the soil shading of wet sedges. Despite a lower albedo and less soil shading, the soil below dwarf shrubs conducted less heat resulting in a 17 cm shallower active layer as compared to sedges. This result was supported by additional, spatially distributed measurements of both vegetation types. Clouds were a major influencing factor for albedo and transmittance, particularly in sedge vegetation. Cloud cover reduced the albedo by 0.01 in dwarf shrubs and by 0.03 in sedges, while transmittance was increased by 0.08 and 0.10 in dwarf shrubs and sedges, respectively. Our results suggest that the observed deeper active layer below wet sedges is not primarily a result of the summer canopy radiation budget. Soil properties, such as soil albedo, moisture, and thermal conductivity, may be more influential, at least in our comparison between dwarf shrub vegetation on relatively dry patches and sedge vegetation with higher soil moisture.

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Survival of a Perverse Nation traces the ways in which contemporary Armenian anxieties are congealing into the figure of the “homosexual.” As in other post-Soviet republics, homosexuality has increasingly become defined as the crisis of the times, and is understood by many as a destructive force linked to European encroachment. In Armenia, a growing right-wing nationalist movement since 2012 has been targeting LGBT and feminist activists. I suggest that this movement has arisen out of Armenia’s concerns regarding proper social and biological reproduction in the face of high rates of emigration of especially men in search of work. Many in the country blame this emigration on a post-Soviet oligarchy, with close ties to the government. This oligarchy, having quickly and massively privatized and liquidated industry and land during the war over the region of Nagorno-Karabagh (1990-1994) with Azerbaijan, created widespread un(der)employment. A national narrative attributing the nation’s survival of the 1915 Genocide and dispersion of its populations to strong morality preserved by institutions such as the Church and the family has now, in the post-Soviet era, ruptured into one of moral “perversion.” This dissertation is based on 15 months of ethnographic research, during which I participated in the work of two local non-governmental organizations: Public Information and Need for Knowledge, an LGBT rights organization and Women’s Resource Center, a feminist organization. I also conducted interviews with 150 households across Yerevan, the capital city, and did in-depth interviews with other activists, right-wing nationalists and journalists. Through psychoanalytic frameworks, as well as studies of kinship, I show how sovereignty – the longed for dream for Armenians over the last century – is felt to have failed because of the moral corruption of the illegitimate figures that fill Armenian seats of authority. I, thus, examine the ways in which a missing father of the household is discursively linked to the lack of strong leadership by a corrupt government, producing a prevalent feeling of moral disintegration that nationalists displace onto the “homosexual.”

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This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

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This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

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This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

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This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

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This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.