The hydrodynamics of a relatively deep semi-enclosed micro-tidal stratified coastal embayment and its adjacent waters is investigated through a combination of observational and analytical modelling techniques. The relative importance of hydrodynamic processes influenced by baroclinic and barotropic mechanisms, at time scales from hourly to annual, is detailed. The field site for the investigation is Cockburn Sound and surrounding waters, off southwest Australia. It is shown that for either a homogeneous or two-layered coastal embayment that is separated from the ocean by relatively shallow sill openings, a wind-stress will result in free surface and interface variations which approximate those of a geometrically equivalent closed basin; the similarities become greater as the sills become shallower. This is achieved through the development, validation and application of an analytical hydraulic model of throughflow, free surface and interface variation (ie upwelling), based on the Bernoulli and Momentum theorems. It is demonstrated that simple analytical methods originally developed for the calculation of mean dynamical motions and upper mixed layer deepening in closed basins can be applied, without undue loss of accuracy, for the same purposes in semi-enclosed embayments such as Cockburn Sound. The hydrodynamics of Cockburn Sound and adjacent waters (south to about Wambro Sound) is shown to progress through a characteristic annual cycle, within which it transforms from being a Region of Freshwater Influence (named the Swan-Canning ROFI) during mid-winter to spring, to a Region of Evaporation Influence (named the Perth ROEI) during autumn. The ROFI regime relates to the hydrodynamic influence of strong salinity gradients set up through coastal freshwater buoyancy fluxes derived from estuarine outflows of the Swan-Canning Estuary. The concept of a ROEI regime, which relates to the hydrodynamic influence of strong salinity gradients set up through evaporation and/or hypersaline estuarine discharges, is introduced in this thesis. South of Cockburn Sound, the coastal waters between Dawseville and Warnbro Sound are affected by estuarine discharges from the Peel-Harvey Estuary and local evaporation and hence also undergo a characteristic intra-annual ROFI to ROEI transition. The region is accordingly named the Peel-Harvey ROFI for the mid-winter to spring period and the Peel-Harvey ROEI for the autumn period. The work of this thesis supplements the global understanding ofROFls (Simpson, 1997a) and introduces the concept of the ROEl, through the baseline study of two newly defmed ROEl regimes. It is shown that wind-stress and density gradients are the primary influences on the mean basin-scale hydrodynamic behaviour of Cockburn Sound and its adjacent waters throughout the year. During Cockburn Sound's ROFl regime, full-depth mixing occurs on average about once per synoptic cycle (ie about weekly), when frontal systems, originating in the 'Roaring Forties', bring strong storm winds from the northwest and southwest quadrants (10-15 m s⁻¹). Following these events, the wind pattern tends to southwesterly-southeasterly and weakens <10 m s⁻¹), and deep-water renewal takes place as relatively dense ocean water plunges into the embayment via the sill openings. This results in the establishment of stable vertical stratification, characterised by a parent pycnocline between the relatively dense inflow and resident embayment water. Surface waters are advected out of the embayment. This process continues as the wind remains weak-moderate and swings through the southeast quadrant. The wind then continues to swing through the northeast and northwest quadrants, gradually strengthening to about 10 m s⁻¹, while driving buoyant plumes of brackish Swan-Canning Estuary water southwards into the embayment, assisted by Coriolis force. The cycle then returns to the severe mixing phase, as the next storm front passes the area. Throughout the cycle, notwithstanding severe storm mixing, incomplete vertical mixing of the water column (down to about the depth of the parent pycnocline) occurs via surface processes associated with diurnal winds and penetrative convection. In contrast, during the ROEl regime evaporative processes lead to strong vertical salinity stratification in the embayment, and full-depth mixing is not as regular as during the ROFl regime. Although the average occurrence of storms (which fully mix the embayment) appears to also be, on average, about 4-5 times per month (as per the ROFI regime), the essential factor that was clarified through the observations and analyses is that up to 3 weeks may pass between these events. The mean density of the embayment is greater than that of the adjacent ocean. Hence, mixing within the embayment is followed by relatively buoyant inflows of ocean water. Flushing of the embayment as a whole is therefore less regular than during the ROFl regime, and this influences the poorer water quality (due to eutrophication) that characterises the ROEl regime. During summer (ie between the ROPI and ROEI regimes), seabreezes and penetrative convection regularly mix the water column to the bottom (on almost a daily basis), due to the relatively strong nature of mixing agents and the relatively weak buoyancy fluxes at this time of the year. The analytical and observational clarifications of the hydrodynamic influence of density gradients, both within Cockburn Sound and between the embayment and adjacent ocean, have improved the qualitative and quantitative understanding of the nature and rates of exchange and mixing in these waters. In turn, this has provided a better understanding of the biological characteristics of the embayment, such as the annual occurrence of nuisance algal blooms and de-oxygenation during the ROEI regime. Numerical hydrodynamic models were applied in a major study of the ecology of the Perth coastal zone, ie the Southern Metropolitan Coastal Waters Study (Simpson et al, 1996). The results ofthis thesis guided the choice, application, calibration and validation of the models. It is shown that baroclinic models are appropriate for the relatively strongly stratified ROPI and ROEI regimes, and that barotropic models are suitable otherwise, such as during summer when full-depth mixing occurs almost daily and the density difference between the embayment and adjacent ocean is relatively small.

Four diagrams in pocket in back of book. / Thesis (M.S.)--Florida State University, 1982. / Bibliography: leaves 146-149.

This thesis examines the mineral suite of undeveloped heavy-mineral deposits in the Cretaceous of the Northern Mississippi Embayment and compares them to the developed deposits of the Atlantic Coastal Plain. The hypothesis presented here is that Cretaceous heavy-mineral deposits of the eastern Mississippi Embayment had the same provenance, the Appalachian Piedmont, as did the younger sediments of the U.S. Atlantic Coast. Kyanite/sillimanite and staurolite were recognized in all samples, and represent strong evidence for an Appalachian Provenance. Alternatively, the overall lack of epidote in the HM suite points away from a Mississippi River related provenance. The dominant heavy minerals found in the Mississippi Embayment samples are ilmenite, leucoxene, zircon, rutile, kyanite/sillimanite, staurolite, and monazite. This suite of heavy minerals compares favorably to those represented along the Atlantic Coastal Plane, and supports an Appalachian Provenance. Southwest trending Paleozoic paleovalleys were likely sedimentation pathways from the Appalachian region.

No description available.

Sewage pollution from humans, animal and domestic sources (land and agricultural run-off) are recognized as a major cause of deteriorating water quality along Australia's coastline. Management of water quality has primarily relied on the use of bacterial indicator methods. However the validity and source-specificity of these methods have been met with increasing reservations for several years now. A relatively recent methodology uses a different chemical biomarker approach using 'sterols', a group of compounds related to the common bio-membrane lipid cholesterol and its derivatives. Sterols can offer an additional diagnostic tool to distinguish and discriminate between sources of faecal contamination in marine, freshwater and estuarine environments in both sediments and the water column. This study investigates for the first time, the degradation of coprostanol and selected faecal sterols in 'natural' sediments from a highly mixed (marine and estuarine) sub-tropical environment following a simulated pollution event (primary effluent); the use of faecal sterols as an additional indicator for determining non-point source sewage discharges at popular anchorages in the Moreton Bay and Gold Coast Broadwater system; and the use of sterol ratios in the determination of the fate and transportation of nutrients from a Sewage Treatment Plant (STP) point-source outlet pipe during plant malfunction. The microcosm degradation experiment revealed that faecal and selected sterols are continually synthesised and degraded over time by auto- and hetero trophic organisms within the sediment matrix. Coprostanol was the only sterol to degrade continually, with only minor fluctuations over a time period of two months. Results from this degradation experiment further revealed a sharp decline of coprostanol within the first week. From this it could be concluded that, without any further addition, external inputs of coprostanol are reduced to background levels within this time period. Therefore, removal of coprostanol after six days was 94% and 73% in mud and sand, respectively. The removal of coprostanol was much higher in mud than sand, reflecting a higher level of microbial activity in muddy sediments for assimilation of sterols. The field study undertaken at popular anchorages in Moreton Bay and the Gold Coast Broadwater revealed extremely low levels of sterols and bacterial indicators over both a spatial and temporal scale consistent with a shallow, oligotrophic, highly dynamic sand dominated system. Even though sterols analysed were found at extremely low levels (mostly in the nano-gram range), they were found to be highly correlated and were successful in identifying an unexpected once off pollution event from a point source at Moreton Bay Island. Other than this one incident, both sterol and bacterial levels were consistently low even when anchorages were at full capacity. Thus, sewage from recreational vessels was found to have very little, if any, effect on the water quality at anchorages in Moreton Bay and Gold Coast Broadwater. The point-source study conducted during a local sewage treatment plant malfunction revealed that even though absolute concentrations of sterols did not change during this event, the distribution of sterols within the samples changed, hence changing the sterol ratios. Further, nutrients (mainly nitrogen) can be transported several kilometres by currents, flocculate out of the water column and settle out into the sediment in areas with low tidal and hydrological flushing. There, the nutrients can cause in situ production of sterols in sediments changing sterol ratios. Overall, this study revealed that analyses of sterol biomarkers have the potential to indicate nutrient inputs (such as nitrogen) as well as sewage, post-hoc pollution events at extremely low levels/high dilutions in coastal sediments.

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 25, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Brent L. Rosenblad. Vita. Includes bibliographical references.

No description available.

Thesis (Ph. D.)--Missouri University of Science and Technology, 2009. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 4, 2009) Includes bibliographical references (p. 243-265).

Nas últimas décadas, a praia de Massaguaçu vem sofrendo processos erosivos intensos, cujos segmentos possuem taxas de recuo acentuadas, denominadas Zonas de Erosão Acentuada (ZEAs). Partindo deste problema este trabalho se propôs a entender a dinâmica sedimentar do arco praial de Massaguaçu e das possíveis causas de formação e manutenção das ZEAs. A coleta de dados se baseou no levantamento batimétrico e do clima de ondas, bem como no levantamento sonográfico de varredura lateral e na coleta de amostras de sedimento de superfície da antepraia de Massaguaçu. Para processar os dados se optou pela aplicação da modelagem numérica utilizando o modelo SWAN (propagação de ondas em águas profundas) e o modelo SMC (módulos OLUCA, COPLA e EROS, que trabalham, respectivamente, com propagação de ondas em águas rasas, simulação de correntes e simulação de transporte sedimentar). Para a formulação da discussão foram selecionados os 6 (seis) casos que apresentaram as condições de ondas mais representativas. Tais casos mostraram que a dinâmica sedimentar e os processos costeiros responsáveis pela formação e manutenção das ZEAs são controlados por dois padrões distintos de ondas incidentes. O primeiro padrão está relacionado às ondas vindas de NE - E, que geram correntes longitudinais para o sul. Suas correntes longitudinais e transversais à costa são de baixa intensidade resultando em um transporte sedimentar e em variações da morfologia praial menos intensos, além de formar células de circulação em vórtices. O segundo padrão, por sua vez, está relacionado às ondas oriundas SSE - SE - ESSE, cujas correntes litorâneas longitudinais rumam ao norte. Tais correntes longitudinais e transversais à costa, apresentam uma intensidade maior, portanto o transporte sedimentar e as variações da morfologia ao longo do arco praial são maiores bem como as células de circulação em vórtices. Partindo desses resultados, percebeu-se que as ZEAs em Massaguaçu estão ligadas a um possível aumento na frequência e na intensidade das tempestades ao longo das últimas décadas e até o presente momento, não há mecanismos naturais que revertam esta retração da linha de costa. / Over the past decades in Massaguaçu beach has happening a strong erosion process with segments that have higher retreat rates, commonly termed as Erosional Hot Spots (EHSs). This research aims the understanding of the sedimentary dynamics along the Massaguaçu embayment and also the possible causes of the formation and maintenance of the EHSs. The methodology was separately on two steps. At first we collected bathymetry, wave and side-scan sonar data, and samples of the surface sediments from the shoreface of Massaguaçu beach. Later, to analyze majority data, we chose to use numerical modeling based on the SWAN model (propagation of waves in deep water) and SMC model (modules OLUCA, COPLA and EROS, that work respectively with the propagation of waves in shallow water, the simulation of currents and finally the simulation of sediment transport). After modeling, we were able to select the 6 (six) most representative wave conditions cases. Those results show that the control of the sediment dynamics and the coastal processes responsible for the formation and the maintenance of ZEA are based on the characteristics of the incident waves. On trying to explain that process, it was possible to recognize two distinct patterns. The first pattern observed is associated with the NE - E waves, generating longshore currents to the south. In this case, both the longshore and the crosshore currents are less intense, forming cells circulation in vortex, resulting in minor variations in sediment transport and beach morphology. The second pattern is related with the SSE - SE - ESE waves, generating longshore currents to the north. In this case both the longshore and the crosshore currents are more intense, although still with occurrence of forming cells circulation in vortex, resulting in a larger sediment transport and morphological changes along the beach. Finally, what we have seem was that the ZEAs in Massaguaçu are possibly linked to a potential increment on storms frequency and intensity over the past decades and unfortunately, at present, there is still no mechanism to recover this natural retreat of the coastline.

Lake whitefish (Coregonus clupeaformis) are an ecologically, culturally and economically important species throughout the Great Lakes. Studying the larval period of ontogeny is important to increasing knowledge of population dynamics and monitoring ecological changes in lake whitefish populations. Larval lake whitefish have been studied across the Great Lakes since the 1930’s; however, there are major gaps in our understanding of the factors that affect distribution and abundance of larval lake whitefish. The goal of this study was to investigate the distribution and abundance of larval lake whitefish in a Great Lakes embayment, using Stokes Bay, Lake Huron as a case study. Plankton samples and environmental data were collected from mid-spring to early summer during 2011 and 2012. Plankton tows in 2011 (n=71, 21 April-03 June) revealed relatively high densities of larval lake whitefish as compared to other Great Lakes studies. Overall there was little relationship between environmental variables (temperature, dissolved oxygen, conductivity, depth) and larval lake whitefish distribution and abundance. Plankton tows in 2012 (n=25, 25 April-23 May) revealed a virtual absence of larval lake whitefish in Stokes Bay. The apparent 2012 year-class failure was concurrent with unseasonably warm temperatures and reduced ice coverage. Temperature-related hypotheses are evaluated in context with other possible explanations of a general year-class failure of lake whitefish during early life history. / Saugeen Ojibway Nation (SON)