The Indiana waters of Lake Michigan were sampled weekly from May until August in 2009, 2011, and 2012 to determine the extent of yellow perch reproduction and the role Indiana waters play in yellow perch life history. Experimental gill nets were used to collect fish before, during, and after the spawning season from randomly selected sites along the Indiana shoreline. Yellow perch were then taken to an onshore processing station where they were weighed, measured, and visually examined to determine sex and maturity. Maturity stages of adult yellow perch were used to estimate the timing and duration of yellow perch spawning. Yellow perch population demographics were also compared to determine if different groups of yellow perch were present before and after the spawn. My data suggests that yellow perch spawning is strongly influenced by temperature and that Indiana waters are seasonally used by adult yellow perch for feeding. / Department of Biology

A dual stable isotope approach (delta13C and delta15N) was used to assess the importance of pelagic organic carbon in littoral secondary production and explore its predictability. Forty-seven sites were sampled in Lake Memphremagog (Quebec--Vermont) to characterize the isotopic position of the primary producers and filter-feeding freshwater mussels, as well as macrophyte biomass, chlorophyll-a concentration, and site exposure. The different sites spanned a wide range in the three environmental variables. For each site, littoral, terrestrial, and pelagic contributions to the diet of the mussels were calculated from mussel isotopic position, corrected for trophic enrichment. The mean contributions were: littoral---8%, terrestrial---27%, and pelagic---65%. However, the magnitude of the pelagic contribution was not related to macrophyte biomass, site exposure or chlorophyll-a concentration. The finding that the unionid mussels, a major littoral zone filter-feeder, obtain about two-thirds of their nutrition from pelagic zone particles washed into the littoral zone provides evidence for a close coupling in carbon flow of the littoral and pelagic zone. This study represents an important step towards a better understanding of carbon flow in aquatic food webs.

Most researchers who study rock image sites tend to be interested in the meaning of images, even though they could obtain more empirical information about these images and their physical location. Furthermore, very little of the work done in the past on rock image sites has been systematic. In this thesis I address the dearth of detailed information on the images and their context. This thesis presents a thorough examination of the images of the twenty-seven pictograph sites in the Lake of the Woods, in the Canadian Shield. These pictograph sites were selected because they exhibit traits evident in rock image studies in other parts of the world. / This study is based on data collected during three months of fieldwork conducted in 2001. Images were found on cliff faces and inside caves. New images and new sites were found and identified. / Here, as elsewhere, the choice of theoretical approach influences the fieldwork, analysis, and search for meaning. Each prescribes the types of questions asked and determines the levels of understanding obtained about whichever form of archaeological evidence is being considered. The different but complementary theoretical approaches should be employed in a definite order. The same data must be examined in sequential order using these different approaches to increase the potential quantity and quality of information gained. Archaeologists should use the following sequence of approaches: culture-historical, contextual, followed by either the homological, or analogical approaches, or a combination of the latter two. / Classifying and describing any image is very difficult, since the level of description given to an image affects the way in which it can be analysed, and heavily influences the possible outcome of any discussion of perceived meaning. A rigorous examination of the images of these sites was conducted to (a) identify the possible vocabulary of images, (b) determine whether combinatory, rules exist, (c) reconstitute the life history of each site, and (d) ascertain whether the images can be related to other indigenous images to determine if this can provide information about the meaning(s) of the rock images. In assessing the meaning of the rock images, the images of a few birch bark scrolls were considered, since it was posited that a detailed investigation of the scrolls, the ethnographic record, and their pictographs might provide some answers regarding the meanings of the images found on the rock faces.

Graduation date: 1992

Landscape evolution is important for mineral and petroleum exploration concepts, especially in dryland continental settings. This study seeks to understand the main issues and controls on landscape evolution that have produced the regolith and young sediments around the western side of Lake Eye, in the arid heart of Australia. Several methods were employed including satellite image analysis, geomorphometry, geological mapping, regolith mapping and surveying. Outcomes indicate that the underlying structural fabric of the basement has controlled the development of the surface morphology of the Umbum Creek Catchment. The arrangement of basement faults is reflected in the distribution of surface landforms and in the topography of the land surface. Significant deformation of the Etadunna and Eyre formations indicate tectonic activity occurred at the end of the Miocene and was probably related to movement in the Lake Eyre Fault Zone. Pleistocene faulting is expressed as minor blind faulting associated with pre - existing basement faults. These faults remain active and current seismic activity is driven by changes in hydrostatic pressure (hydroseismicity). The scale of Pleistocene faulting and modern seismic activity demonstrates that since the Pliocene tectonic activity has been subdued. Climate change caused landforms developed under wet conditions during the Palaeogene and Neogene to be preserved by the development of aridity in the Pleistocene. High erosion rates associated with tectonism and the onset of aridity in the Pleistocene led to topographic inversion of many features. Palaeo-Proterozoic inliers formed inselbergs, silcrete outcrops formed capstones, gypsum hardpans protected underlying sediment from erosion creating plateaux of gypsum patterned ground and palaeo-channels on the Neales Fan were eroded to make heavily armoured mounds and associated sand dunes and sand sheets. The dominant factor influencing the evolution of the landscape in the Umbum Creek Catchment was the deposition of sedimentary sulphides within the Bulldog Shale. The excess sulphur that this sediment supplied to the landscape over time created the necessary conditions for the formation of a range of landscape features that would not otherwise exist. Weathering, oxidation and leaching of the sedimentary sulphides led to the development of silcrete. Subsequent weathering and tectonic activity led to the breakdown of the silcrete and the distribution of silcrete pebbles widely across the landscape forming gibber plains. Sulphur from the Bulldog Shale continued to contribute to the landscape forming intra-formational gypsum and precipitating as gypsum hardpans. This study has implications for petroleum exploration in dryland continental settings as potential reservoirs may be affected by secondary diagenetic processes, such as the formation of gypsum or silcretes, that could act as baffles or result in reduced porosity within the reservoir. The broad-scale architecture of fluvial systems, like the Neales Fan, may not conform to traditional fan-shaped models being, instead, comprised of structurally rearranged channels. In terms of earthquake risk assessment, the identification of hydroseismicity active within the Lake Eye Basin allows for a new level of predictability of earthquake behaviour within Central Australia. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1260856 / Thesis (Ph.D.) -- School of Earth and Environmental Sciences, 2006

A series of tufa mounds is found within the northern basin of Lake Abert, located within southeastern Oregon. The mounds have been divided into 3 main groups and 1 sub-group (A1, A2, B, and C) based upon spatial and textural considerations. Mound groups appear at two different elevations: the 1310 meter elevation (Groups A2, B, and C), and the 1318 meter elevation (Group A1). Published carbon age dating of the Lake Abert 1325 meter strandline and the 1310 meter strandline indicates that the mounds were formed during the Late Pleistocene/Early Holocene. Facies analysis and mineralogical analysis of the mounds indicates that the mounds were primarily formed subaqueously during a lake regression, supporting oxygen isotope data from previous researchers. Magnetometer data within Groups A1 and A2 suggests that the mounds are associated with a series of magnetic lows which are oriented in joint sets (NW-SE, and N-S) which match the orientation of faulting within the region. While there appears to be another early mound building episode, no direct evidence confirms this.

No description available.

No description available.

No description available.

Megginnis Arm of Lake Jackson in Tallahassee, Florida, has experienced rapid eutrophication as a result of development within the contributing area watershed. Bottom sediments were sampled for purposes of mapping, classifying and designating for removal. Sediment desiccation studies were performed to determine the percent of consolidation and sealing characteristics of the soils in the event of a lake drawdown. Restoration alternatives are presented and compared on the basis of field investigations, laboratory testing and analysis, and the desiccation study. Alternative methods are discussed with respect to the cost, the flexibility and the problems inherent in the different proposals. From the geometry of Megginnis Arm, and construction permit limitations, this study was limited to methods of restoration which include dredging, drawdown and excavation, drawdown and compaction, and drawdown with dredging. By comparing the costs, the practicality, and geotechnical investigation and the flexibility of alternative methods, it is concluded that the drawdown and excavation method is the alternative. The dredging and drawdown and dredging alternatives were determined to be uneconomical and risky. These methods are not recommended.