An expansive panel of well exposed (periglacial) strata of the Upper Kaza Group permitted a detailed study of the stratal architecture of proximal basin floor deposits in the Neoproterozoic Windermere turbidite system. Detailed stratigraphic and petrographic analyses identified six lithofacies: poorly-sorted, clast-rich mudstone (F1), thin-bedded siltstone and mudstone (F2), thick-bedded, massive sandstone (F3), medium-scale, cross-stratified sandstone (F4), mudstone-clast breccia (F5), and medium-bedded turbidites (F6). The spatial distribution of these facies identify five architectural elements: heterolithic feeder channel deposits (FA1), thin-bedded intralobe turbidites (FA2), terminal splay deposits (FA3), distributary channel deposits (FA4), and isolated scours (FA5). FA 1-4 are genetically related and form the basic building blocks of large-scale basin floor depositional lobes. FA 5, which is isolated to the stratigraphic top of the study area, is interpreted to have formed in a base-of-slope setting, and its superposition on FA 1-4 suggests the long-term progradation of the Windermere turbidite system.

This study investigates the relation between channel instability and sediment transport along an 80 km reach of lower Fraser River, British Columbia. The major processes governing instability, bank erosion and sedimentation were investigated by analyzing the patterns of morphologic change along the river over the last century. Morphologic changes were documented using historical maps and air photographs. The method of approach can be considered a "macroscopic" one since the investigation focused primarily on the gross patterns of change that occurred over periods of years to decades. It was found that this interval is the most appropriate time scale for investigating channel instability and sedimentation processes on a large stream such as the Fraser River. This is because the major features governing instability and sedimentation also develop over comparatively long time periods. Several examples are presented to illustrate how sequences of major channel instability have propagated along the river over periods of 10 to 30 years. These disturbances often initiated new patterns of sedimentation, local erosion and subsequent channel instability further downstream. The most common diagnostic feature associated with these travelling disturbances are relatively large, low amplitude, linguoidal-shaped "gravel sheets" that attach to more stable lateral bars and islands. These bars may cause strong flow impingement against previously stable banks and islands. As a result, rapid scour and erosion may be initiated even during periods of low discharge. Four different approaches were used to estimate the long term gravel transport rate along the river. These methods included direct measurements using trap samplers (carried out by Water Survey of Canada over a period of 12 years), a sediment budget calculation which related changes in transport through a reach to changes in the volume of sediment stored in the channel determined by surveys, a morphologic approach which used a simple model of sediment transfers through a reach, and finally theoretical bed load formulae. It was found that the sediment budget and the morphological model provided the most reliable and most generally applicable results. This was because the methods rely on observations of sediment movement over periods of years or decades. It was found that on Fraser River, the time scales of the major processes governing gravel bed load transport were also measured in years or decades. As a result, short term measurements such as from bed load trap samplers show only a poor correlation between transport rate and flow variables. Therefore, to estimate long term transport rates with these data, a very large number of observations is required to integrate the transport rates over time. / Arts, Faculty of / Geography, Department of / Graduate

Shippagan Gully is a highly dynamic tidal inlet located on the Gulf of St-Lawrence near Le Goulet, New Brunswick. This tidal inlet is highly unusual due to the fact that the inlet has two open boundaries with phase lagged tidal cycles that drives flow through the inlet. Over the past few decades, the shipping activities through the inlet have been threatened due to the narrowing of the navigation channel caused by deposited sediment on the east side of the channel. Many engineering projects have been undertaken at Shippagan Gully in order to try and mitigate the deposition problem. However, these attempts have either been unsuccessful or the engineered structures have deteriorated over the years. This study uses the CMS-Flow and CMS-Wave numerical models to provide guidance concerning the response of the inlet to various potential interventions aimed at improving navigation safety.

This study set out to investigate the shear stress behaviour at the bed under combined wave and current action. The intention of the study was to make experimental measurements to determine how wave and current shear stresses combine, so that theoretical models describing the combined flow condition could be proposed. Two types of experiment were conducted, and theoretical models for the combined flow were assessed. One set of experiments attempted to use a shear plate to make direct measurements of the combined flow shear stress, and of the shear stresses for the component waves and steady currents. This approach failed because the large correction terms introduced by the non-uniform wave pressure field could not be accurately estimated. The second set of experiments used a laser doppler anemometer to make detailed velocity profile measurements over flat sediment beds. The onset of sediment motion was used as a criterion to carefully control the experiments. It is assumed that the threshold of sediment motion represents a specific shear stress intensity at the bed for sediments of narrow size ranges. As the shear stresses can be determined from the velocity fields under waves and currents, their additive nature under combined flow conditions could be investigated. For each sediment size range, it is shown that the same maximum velocity very near the bed can be used to specify the threshold of sediment motion condition for all flow types, be they under waves, currents, or combined waves and currents. It is also shown that the near-bed velocity under a laboratory wave can be predicted accurately from second order wave theory and that the velocity under a current can be predicted from combining Manning's relation with the universal log velocity law. It is further shown that the near-bed velocity under a combined wave and current can be described by the vectorial addition of the maximum component wave velocity and the average component current velocity. The shear stress for the onset of motion is calculated for the steady current using Manning's relation, for the wave by combining the oscillatory shear stress formula with Kamphuis's rough turbulent friction factor relation, and for the combined wave and current by the simple vectorial addition of the component shear stresses, and is shown to be comparable with Shields's threshold criterion for nearly all conditions tested. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Turbidity currents, both continuous flow and surge-type, have been detected with acoustic sounders operating at 42.5, 107 and 200, kHz. The turbidity currents are associated with the discharge of mine tailing into Rupert Inlet. A linear relation is obtained between the backscattered acoustic signal at 200 kHz and the one-half power of suspended particulate concentration from 10 to 1000 mg 1⁻¹. This relation is consistent with Rayleigh scattering theory in form and (relative to a standard target) amplitude, and is used to generate a cross-sectional profile of sediment concentration in the discharge plume. Estimates of surge speeds from the acoustic records based on a universal shape for density current heads range from 30 to 120 cm s⁻¹. The excess density of one surge was estimated from the reverberation amplitude to be 0.12 g cm⁻³. The additional attenuation of sound waves by suspended particles is important in turbidity currents and may be used to estimate suspended particulate concentration. Thermal processes contribute very little to the additional attenuation by particles with the grain densities of common minerals. A leveed submarine channel extended from the point of the tailing discharge (outfall) over the surface of the tailing deposit as early as 1974. The upper reach of this system was buried in 1978, and by late 1979 a new channel had developed. In 1976-77, the original channel consisted of: (1) a left-hooking upper reach with an average slope of 2.2°, (2) a middle reach (1° slope) with pronounced meanders (700-1100 m wavelengths) "increasing in curvature with distance downstream and (3) a straight lower reach (0.5° slope). The cross-sectional area of the channel decreased with distance downstream, excepting an increase in the first 100-200 m, until the channel disappeared about 5.5 km from the outfall. Acoustic records of the discharge plume in bends indicate overspill from the outer bank and an upward tilt of the upper interface away from the centre of bend curvature. The interfacial slope is steeper than indicated by the cross-channel difference in levee heights. These records together with observed tidal currents suggest that the left hook in the upper reach is caused by a mechanism similar to that which has been suggested for deep-sea channels. Turbidites in gravity cores from the levees are present as layers of vertically-graded, Cu-rich and Fe-poor sand and silt, some of which have load-casted flame-structures or load-pockets at their basai contacts. These layers comprise more of the sediment column with distance down-channel, suggesting that levee-building by overbank spillage from continuous flow becomes less important, and that most of the material transported through the lower reach is carried by turbidity surges. Surge recurrence intervals of 2-5 d are obtained from the number turbidites per core and the local deposition rate. The latter ranged from 0.3-4 m yr⁻¹, as given by changes in water depth, in tailing thickness from seismic reflection surveys, and in diatom frustule abundance in the cores. A model of continuous turbidity flow in submarine channels including entrainment is applied to the Rupert Inlet channel. Results are consistent with a sediment budget based on changes in the tailing deposit volume, and with turbidity surge recurrence intervals. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Pollutants and contaminants are a huge problem in the world. To protect the natural environment and human health, countries within the EU have worked together to develop different protection programs. Natura 2000-sites is an example of one of these programs. Certain areas were chosen to be part of this program due to their extreme sensitivity to changes in ecosystems and biodiversity. Therefore, these particular areas are extra important to preserve by working towards and reaching a good chemical and ecological status.  This study focus on a Natura 2000-site, where the chemical status does not meet the criteria. The site is lake Näsnaren, located in the county of Södermanland, Sweden. The objective of this study was to analyze the contamination data from sediment samples, obtained at the Environmental office in Katrineholm. However, unfortunately I discovered that the data is lacking important information, in order to reconstruct the status of Näsnaren. It is thus difficult to interpret if there are real trends in the contaminant concentrations and if the current data is enough to make decisions for potential measures. The conclusion is that more controlled sediment sampling has to be conducted in order to evaluate the status of Näsnaren. / Föroreningar och miljögifter är ett stort problem i världen. För att hjälpa till att skydda allt i naturen och människan har EU-länderna tillsammans arbetat fram olika skyddsprogram. Ett exempel på ett skyddsprogram är införandet av Natura 2000-områden. Dessa områden är extra känsliga mot miljögifter och andra föroreningar som kan orsaka stora förändringar i ekosystem och den biologiska mångfalden. Därför är dessa områden speciellt viktiga att bevara genom att leva upp till en god status inom de kemiska och ekologiska områdena. I detta arbete har ett Natura 2000-område undersökts där halten av kemiska föroreningar inte uppnår god status. Området är en sjö lokaliserad i Katrineholms kommun i sydvästra Södermanland. Syftet med detta arbetet var att undersöka den mängd data som existerade hos Katrineholms kommun gällande miljögifterna i Näsnaren. En slutsats skulle sedan dras om denna data var tillräcklig för att bestämma Näsnarens välmående, visa miljögifternas trender samt om den var tillräcklig för att fatta beslut om åtgärder. Mängden data som hittades var mycket liten och inga utmärkande miljögiftshalter påträffades. Slutsatsen tyder på att betydligt fler provtagningar måste utföras i Näsnaren för att ge ett tillräckligt dataunderlag och ge en korrekt bild över Näsnarens välmående.

A consequence of stirring sea bottoms within construction sites is that suspended particles are being released. Pollutants such as heavy metals are often bonded to suspended particles which can spread over long distances. Analyzing the levels of particles in the water can either be made in a laboratory, or by measuring turbidity. Turbidity is a measure of the water’s ability to diffuse light and is used to determine the content of suspended material. This thesis is made in collaboration with AFRY who is preforming water sampling during a construction of a new quay area in Kallholmsfjärden, Skellefteå. The purpose of this study has been to investigate if, and how, suspended substances are being spread during water-based constructions that causes stirring of the sea bottom. The study was carried out by analyzing data sampled from Kallholmsfjärden. In summary, the result indicate that water-based constructions may result in suspended substances being spread into the water. Suspended material is correlating with turbidity, which means that turbidity can be used as an indicator for suspended materials. The kind of operation preformed during construction, affects the turbidity and dredging leads to higher particle scattering than padding. The result underlines the importance of taking preventive measures that reduce particle scattering, and one way of doing that is by using silt curtains. According to the result, silt curtains fulfill its purpose by preventing particle scattering. Finally, there is no difference in suspended material between dissimilar depths. The result of this theses is relevant when planning similar projects.

The overarching objective of this study is to assess the effectiveness and performance of ATIs. In doing so, this research provides a fundamental understanding of the flow and sediment propagation through a different combination of porous media (pea gravel and woodchips). The research hypothesizes that the theory of advection and diffusion describes the migration of flow and identifies a myriad of depositional networks of sediment. A key hypothesis of the study is that global and local pressure differentiation affects the flow pathways and distribution with intimate effects of sediment trapping efficiency and distribution within the permeameter. A significant goal of this study is to decompose the key mechanisms that affect this migration of sediment under a fixed value for the head and incoming concentration. The nature of the study is experimental and is supported by limited numerical and field analysis. Although the experimental setup is site specific to the conditions encountered in the study location, it offers a generic way of examining flow and sediment intrusion within a permeable bed. The study in that sense hypothesizes that the intrusion by Einstein is valid and it shows the change in the hydraulic gradient that occurs during an event and during a sequence of events. A secondary goal of this research is to understand the cyclicity in the migration of sediment in a sequence of different events, where the initial conditions of each run constitutes the outcome of the final result of the previous runs. The nature of those experiments is to mimic the occurrence of sequential events in nature, although the continuous examined in the laboratory as reflective of conditions representing extreme runs. This research also treats the hydraulic conductivity as a dynamic entity to reflect the effect of localized clogging on the propagation of flow. The experimental design of this research considers a series of experimental runs to address the aforementioned objectives of this research and test the posed hypothesis.

The main objective of this thesis was to develop statistical and analytical methods for untargeted analyses of complex environmental matrices like soil and sediment. Untargeted analyses are notoriously difficult to perform in matrices like soil and sediment because of the complexity of organic matter composition within these matrices. This thesis aimed to (1) Develop and compare extraction methods for untargeted analyses of soil and sediment while also developing data handling and quality control protocols; (2) Investigate novel applications of untargeted analyses for environmental classification and monitoring; and (3) Investigate the experimental factors that can influence the organic matter composition of untargeted extractions. CHAPTER TWO is a literature review of metabolomics protocols, and these protocols were incorporated into a proposed workflow for performing untargeted analysis in oil, soil, and sediment. This thesis contains the first application of untargeted analysis to freshwater lake sediment organic matter (i.e. sedimentomics) in CHAPTER THREE, and this has implications for discovering new biomarkers for paleolimnology (APPENDIX ONE). I demonstrated successful extraction methods for both sedimentomics and soil metabolomics studies in CHAPTER THREE and CHAPTER FIVE, respectively, using the proposed workflow from CHAPTER TWO. I also applied sedimentomics to the classification of lake sediments using machine learning and geostatistics based on sediment organic matter compositions in CHAPTER FOUR; this was a novel application of sedimentomics that could have implications for ecosystem classifications and advance our knowledge of organic matter cycling in lake sediments. Lastly, in CHAPTER FIVE I determined microbial activity, extraction method, and soil type can all influence the composition of soil organic matter extracts in soil metabolomics experiments. I also developed novel quality controls and quantitative methods that can help control these influences in CHAPTER FIVE and APPENDIX THREE. APPENDIX TWO was written in collaboration with multiple researchers and is a review of all “omics” types of analyses that can be performed on soil or sediment, and how methods like the untargeted analysis of soil and sediment organic matter can be linked with metagenomics, metatranscriptomics, and metaproteomics for a comprehensive metaphenomics analysis of soil and sediment ecosystems. In CHAPTER SIX the conclusions and implications for each chapter and overall for this thesis are detailed and I describe future directions for the field. In the end the overall conclusions of this thesis were: 1) Quality controls are necessary for sedimentomics and soil metabolomics studies, 2) Sedimentomics is a valid technique to highlight changes in sediment organic matter, 3) Soil metabolomics and sedimentomics yield more information about carbon cycling than traditional measurements, and 4) Soil metabolomics organic matter extractions are more variable and require more quality controls.

Coastal bays and salt marshes are buffer zones located at the interface between land and ocean, and provide ecologically and commercially important services worldwide. Unfortunately, their location makes them vulnerable and sensitive to sea-level rise (SLR), reduced sediment loads and anthropogenic modifications of the shoreline. Sediment budget and sediment availability are direct metrics for evaluating the resilience of salt marshes and coastal bays to various stressors (e.g. SLR). Salt marshes requires adequate sediment inputs to maintain their elevation with respect to sea level. Understanding sediment trajectories, sediment fluxes and sediment trapping capacities in different geomorphic unit facilitates efficient restorations and coastal management. In this research I used remote sensing, field observations and numerical modelling in the Plum Island Sound in Massachusetts, USA, to explore mechanisms controlling sediment dynamics and their feedbacks with SLR. The analysis of remote-sensed suspended sediment concentrations (SSC) reveals that a 5-year record (2013-2018) is sufficient to capture a representative range of meteorological and tidal conditions required to determine the main drivers of SSC dynamics in hydrodynamically-complex and small-scale coastal bays. The interplay between river and tidal flows dominated SSC dynamics in this estuary, whereas wind-driven resuspension had a more moderate effect. The SSC was higher during spring because of increased river discharge due to snowmelt. Tidal asymmetry also enhanced sediment resuspension during flood tides, possibly favoring deposition on marsh platforms. Together, water level, water-level rate of change, river discharge and wind speed were able to explain > 60% of the variability in the main channel SSC, thereby facilitating future prediction of SSC from these readily available variables. To determine the fate of cohesive sediments and spatial variations of trapping capacity in the system, a high-resolution (20 m) numerical model coupled to a vegetation module was developed. The results highlight the importance of the timing between sediment inputs and tidal phase and show that sediment discharged from tidal rivers deposit within the rivers themselves or in adjacent marshes. Most sediment is deposited in shallow tidal flats and channels and is unable to penetrate farther inside the marshes because of the limited water depths and velocities on the marsh platform. Trapping capacity of sediment in different intertidal subdomains decreases logarithmically with the ratio between advection length and the typical length of channels and tidal flats. Moreover, sediment deposition on the marsh decreases exponentially with distance from the channels and marsh edge. This decay rate is a function of settling velocity and the maximum value of water depth and velocity on the marsh platform. Bed sediment compositions were generated to further explore feedbacks between SLR, sediment dynamics and morphological changes. The results show SLR increases tidal prism and inundation depth, facilitating sediment deposition on the marsh platform. At the same time, SLR enhances ebb-dominated currents and increases sediment resuspension, reducing the sediment-trapping capacity of tidal flats and bays, leading to a negative sediment budget for the entire system. This bimodal distribution of sediment budget trajectories will have a profound impact on the morphology of coastal bays, increasing the difference in elevation between salt marshes and tidal flats and potentially affecting intertidal ecosystems. The results also clearly indicate that landforms lower with respect to the tidal frame are more affected by SLR than salt marshes. Therefore, Salt marshes, shallow bays, tidal flats, and barrier islands are inherently and physically connected systems, and evaluating the effect of SLR on salt marshes should involve all these units.