Grain size distribution, porosity, and hydraulic conductivity from over 400 unlithified sediment samples were analized. The measured hydraulic conductivity values were then compared to values calculated using 20 different empirical equations commonly used to estimate hydraulic conductivity from grain size analyses. It was found that most of the hydraulic conductivity values estimated from the empirical equations correlated very poorly to the measured hydraulic conductivity values. Modifications of the empirical equations, including changes to special coefficients and statistical off sets, were made to produce modified equations that considerably improve the hydraulic conductivity estimates from grain size data for beach, dune, off shore marine, and wadi sediments. Expected hydraulic conductivity estimation errors were reduced. Correction factors were proposed for wadi sediments, taking mud percentage and the standard deviation (in phi units) into account.

This work examines the use of pedo-properties to identify dune soil system responses to environmental change on the Sefton coast, based on the development of conceptual pedogenic models. Previous environmental change and shoreline dynamics are determined through O.S. maps and aerial photographs, while present day processes are investigated through a dune-toe photographic survey and seasonal monitoring by fixed point photography. Topsoil (0-5 cm) physico-chemical characteristics are presented in a series of baseline GIS maps, displaying spatial pedo-property variation across the dune landscape. Combined with vegetation data, topsoil analysis identifies 10 distinct pedo-environments. Physico-chemical characteristics of associated National Soil Resources Institute (NSRI) soil profile classifications and an exposed stratigraphic section are presented graphically in a proposed sequence of development. Topsoil and soil profile samples are analysed for soil pH, soil organic matter (SOM) content, particle size, geochemical composition and mineral magnetism. Significant differences (p <0.05) are apparent for the suite of topsoil characteristics collated, indicating discrete dune environments are influenced by specific soil properties. Distinct down-profile variations in soil characteristics are also apparent between dune environments, highlighting pedological dynamism. Multivariate Factor analysis groups bare sand and mobile dune communities into ‘frontal dunes’ and fixed dune community, pasture, scrub, deciduous woodland and coniferous plantations into ‘hind dunes’, separating these topsoil environments from heath and slack communities. Factor analysis also identifies linkages between pedo-characteristics within soil profile horizons, suggesting pedogenesis on the Sefton dunes initiates as raw sand, progressing to sand-pararendzinas through leaching of nutrients. Desalinization and decalcification processes lead to brown earth development, followed by increased acidicification, subsequently, resulting in micro-podzol formation. Groundwater gley soils are associated with dune slacks, where drainage is inhibited and anaerobic conditions prevail. Analysis of buried soils suggests such pedo-environment formations are cyclic, responding to phases of shoreline regression/transgression, dune activity and stabilization. Conceptual models are designed to graphically demonstrate pedogenesis under both erosion and deposition regimes on the Sefton coast. Regression equations and correlation coefficients between pedo-properties and distance from mean high water are used as a proxy for soil age, which represent lateral soil maturity from the unstable frontal dunes to the stable hind dunes inland. The models simulate formation and process of the full array of soil properties, accounting for geomorphological impacts and anthropogenic influences. This has great implications for dune managers by raising awareness of pedogenesis as an integral part of nature and associated habitats, which could be incorporated in future shoreline management plans (SMPs).

This dissertation combines studies of aeolian bedforms and aeolian dune-field patterns to create a comprehensive set of tools that can be used in tandem (or separately) to extract information about climate change and landscape evolution, and to identify the controls on formation for specific modern dune fields or ancient aeolian sequences. The spatial distribution of surface processes, erosion/deposition rates, and lee face sorting on aeolian dunes are each a function of the incident angle. This correlation between stratification style and incidence angle can be used to develop a “toolbox” of methods based on measurements of key suites of parameters found in ancient aeolian deposits. Information obtained from the rock record can be used as input data for different kinds of numerical models. Regional-scale paleowind conditions can be used to validate paleoclimate and global circulation models. Understanding the natural variability in the Earth’s climate throughout its history can help predict future climate change. Reconstructed wind regimes and bedform morphologies can be used in numerical models of aeolian dune-field pattern evolution to simulate patterns analogous to those reconstructed from ancient aeolian systems. Much of the diversity of aeolian dune-field patterns seen in the real world is a function of the sediment supply and transport capacity, which in turn determine the sediment availability of the system. Knowledge of the sediment supply, availability, and transport capacity of aeolian systems can be used to predict the amount of sand in the system and where it might have migrated. This information can be extremely useful for development and production of oil and gas accumulations, where a discovery has been made but the spatial extent of the aeolian reservoir is unknown. / text

The Mediterranean has long been recognised as an area that is particularly sensitive to climate change. It is also an area that has been impacted by human activity for millennia. Disentangling climatic and anthropogenic influences on the history of vegetation change in the Mediterranean remains an important challenge. As a contribution to this ongoing debate, this thesis explores the late Holocene environment of part of the coast in Central Italy using a multiproxy approach to investigate the archives of change preserved in dune slack deposits. Distinguishing between natural and anthropogenic signals presents a real challenge in most environmental reconstruction work; however, due to the extensive archaeological research carried out at Castelporziano, it is possible to examine human-environmental interactions in some detail. In order to understand these interactions part of the thesis examines how management has affected recent environmental changes and the current vegetation and whether there is a legacy of Roman landuse at the Castelporziano estate. The key findings of the thesis showed that dune slacks are suitable for palaeoenvironmental reconstruction with proxies such as plant macrofossils, ostracods, molluscs and bryozoans statoblasts. However, the pH and seasonality of the slacks meant proxies such as pollen were badly preserved or absent, and diatoms did not preserve due to the high levels of carbonate on site. Overall the results show the impact of the Romans on site in terms of localised eutrophication and increased fires, but with abandonment, came the formation of wet woodlands.

Machair is a habitat found predominantly in coastal areas of the north–west of Scotland and is characterised by a low-input, rotational arable system interspersed with semi-natural grasslands. Land management is an essential part of the machair system as both intensification and abandonment threaten its future. Little is known about this system in terms of its below ground communities. A survey was conducted over a three season, two year period for molecular determination of bacterial, AM fungal and nematode community structure. Cropped, fallow and undisturbed grassland were sampled; soil and roots associated with two commonly occurring species and composite soil samples were collected. In addition the effect of edaphic factors and vegetation composition on soil communities was assessed, both in the field and in greenhouse experiments. Results show that although all of the examined factors impacted the community structure of the three soil groups to some degree, the strength of this effect varied between groups. Bacterial communities were mainly affected by temporal factors, particularly year, possibly due to variation in soil moisture content. AM fungal community structure also varied considerably with season, but the mechanisms behind this were less obvious, with both abiotic and plant factors playing a role. AM fungal community structure varied with different plant hosts but also with soil moisture content. In contrast to both bacteria and AM fungi, nematode communities showed a strong response to land use although temporal factors and differences between locations were also observed. Grasslands harboured a distinctly different community structure from cropped and fallow, largely as a result of variation in bacterivores and carnivores. Vegetation composition and soil moisture content were also found to affect nematode community structure. This study has revealed that machair soil communities seem to be highly complex, dynamic and adapted to the changeable conditions that persist.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

In this project, I focus on the function of the "amtal" or test of definition or destruction, in Frank Herbert's Dune. It is my argument that these tests "to destruction" determine not only the limits or defects of the person being tested, but also - and more crucially - the very limits and defects of the definition of humanity in three specific cultural spheres within the novel: the Bene Gesserit, the Fremen, and the Faufreluches. The definitions of "amtal" as well as "humanity," like all definitions, are somewhat fluid, changing depending on usage, cultural context, and the political and social needs of the society which uses them. Accordingly, Dune remains an instructive text for thinking through contemporary and controversial notions about the limits of humanism and, consequently, of animalism and posthumanism. / by Adella Irizarry. / Thesis (M.A.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Given the rapidly increasing visitation levels to Fraser Island, there is increasing concern that tourist activities may threaten the long-term ecological health of the region's unique dune lakes. This project aimed to investigate the consequences of tourist use of Fraser Island's dune lakes and to develop appropriate monitoring tools and management objectives in light of the projected increases in visitation levels in the foreseeable future. The initial phase of this research aimed to identify the relative importance of some of the most popular dune lakes on the island as key destinations for tourists. Tourist surveys, in conjunction with the development of a Tourist Pressure Index (TPI), which quantifies logistic, social and natural variables, identified Lakes McKenzie, Allom and Birrabeen as the lakes most at risk from excessive tourist use. In addition, analyses of water quality in 15 lakes on Fraser Island aimed to determine the current trophic status of dune lakes on Fraser Island and the ecological implications of tourist use of these systems. Detailed comparisons of nutrient and chlorophyll a concentrations in five popular dune lakes in February 1990 (data from Arthington et al. 1990) and February 1999 suggested that productivity has increased significantly in the past decade. More detailed examinations of nutrient and algal variables in five popular perched dune lakes revealed that while ambient nutrient and phytoplankton chlorophyll a concentrations remained relatively stable, periphyton chlorophyll a concentrations increased over the course of the 1999-2000 summer in most lakes. Significantly, these increases were found only in heavily visited (disturbed) sites in the clear lakes examined (McKenzie and Birrabeen). In these lakes, where algal growth is likely to be only limited by nutrient availability, tourist nutrient additions may stimulate excessive periphyton production. Experimental algal bioassays identified that phytoplankton and to a lesser degree periphyton growth was stimulated by nutrient additions in all five perched dune lakes. However, the degree to which growth was stimulated was both lake and nutrient (nitrogen versus phosphorus versus nitrogen + phosphorus) dependent, highlighting the variable nature of systems within a relatively small geographic range. Since periphyton biomass was higher in heavily visited areas of lakes and was likely to be stimulated by nutrient additions by tourists, stable isotope analyses of littoral zone food webs were conducted to quantify the percent contribution of periphyton to consumer diets. There was a trend towards higher periphyton contributions in systems identified as key tourist locations (on the basis of their TPI scores) and this indicates that increasing visitation may increase the contribution of periphyton to littoral zone food webs, both via increases in the quantity and quality of periphyton as a food resource. To further explore the contribution of periphyton in littoral zone food webs of heavily visited lakes, a 15N-tracer addition experiment was conducted to establish the fate of nutrient additions within the littoral zone. Nutrients were added in quantities that mimicked those likely from tourists, to enable a realistic appraisal of the fate of tourist additions. As expected, periphyton rapidly assimilated the added 15N-tracer and was found to be the first and most significant sink for nutrients entering the littoral zone. Finally, the results from this research were used to develop a conceptual model of nutrient enrichment for perched dune lakes on Fraser Island. The model indicates that although nutrient additions from tourists may lead to undesirable increases in periphyton biomass, the degree to which this is deemed to be a detrimental ecological outcome is likely to be mediated by water level fluctuations and the consumptive capacity of grazers. Given that excessive periphyton growth is likely to be seen as negative impact of tourism, regular periphyton monitoring (biomass and percent contribution to littoral zone food webs) should be built into an updated monitoring program for this series of dune lakes. Whilst the implementation of periphyton monitoring is likely to enable the early detection of deleterious impacts of excessive tourist use, it is likely that the long-term conservation of the region will, in the future, require the implementation of strict visitation level guidelines, to ensure that the irreversible consequences of long term additions of nutrients are ameliorated.

On sandy coastlines dunes provide a barrier of protection from strong environmental forces that can naturally occur during storm events including storm surges that expose the dunes to large waves. A set of laboratory experiments were used to investigate the morphological processes during the erosion of a steep dune face under bichromatic wave conditions for two different mean water level elevations, corresponding to storm surges and waves that collide with or overwash the dune. In the collision regime, episodic slumping due to the undercutting of the dune resulted in sudden erosional events followed by long periods of wave-driven reshaping at the dune toe. In the overwash regime, dune erosion was faster and occurred at a more consistent rate. Small scale bedforms (ripples) measured during the overwash test evolved in height faster and to greater overall heights than collision test while bedform lengths were not affected by the change in water level. A numerical model, XBeach, was calibrated to examine the ability to predict erosion of the steep dune due to waves in the two water level regimes. XBeach was not able to recreate the spatial variability of the significant wave height profile from the laboratory measurements; however, mean velocities were in good agreement with observations suggesting that bed shear stress is well estimated. During mobile bed simulations of erosion in the two regimes, the model was in agreement with measured dune erosion after initial adjustment. XBeach was very sensitive to several parameters that control the rate of erosion including the critical avalanching slope under water, the threshold water depth and the sediment transport formulation. The model did not perform well at predicting erosion rates until these parameters had been modified. Overall, XBeach performed better when simulating dune erosion in the overwash regime than the collision regime. / Thesis (Master, Civil Engineering) -- Queen's University, 2014-04-01 14:54:35.257

Parks Canada focuses its tourism and conservation efforts in Kouchibouguac National Park along the park's diverse coastline made up of a variety of sensitive ecosystems including salt marshes, stream estuaries and a shifting barrier island lagoon system. The dynamic sediment processes in the park are not fully understood, making it difficult for Parks Canada to make informed decisions as sea-level rise in the region accelerates. In this study, extensive field data were collected in two sediment zones bordering the Kouchibouguac Lagoon. Stream data were collected and used to estimate the monthly average sediment load entering the lagoon. The maximum and minimum monthly average sediment loads were 130 g/s and 11 g/s in April and September, respectively. These freshwater sediments pass through estuaries to deposit at the coastline of the park. Changes in the barrier system surrounding the tidal inlet Little Gully were also monitored over 15 months using modern surveying techniques. The surveys showed a general southward shift in the study area and a landward migration of sediments within the flood tidal delta of the inlet. Dune surface area, volume, and vegetation cover were also examined, and the critical shear stress and velocity of the sediments were calculated. The field investigations revealed that the Kouchibouguac Lagoon was gradually filling in with sediments during the study. It is recommended that a permanent hydrometric station be installed in one of the major streams in the park and that future research along the coastline of the park complement Parks Canada's current monitoring program for the barrier island system.