Mountain Scholar
Mountain Scholar is an open access repository service that collects, preserves, and provides access to digitized library collections and other scholarly and creative works from several academic entities within the state of Colorado.
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Colorado State University, Fort Collins Explore the Colorado State University community’s scholarly output as well as items from the University at large and the CSU Libraries.Open Textbook Library Archive Access is limited to Open Textbook Library staff only. Visit the Open Textbook Library at https://open.umn.edu/opentextbooks.University Press of Colorado Access is limited to University Press of Colorado members. Non-members: to purchase books, please visit https://upcolorado.com/.
Recent Submissions
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Open Access
Sequence stratigraphic framework for top seal development: examples from the Skull Creek and Graneros shales, Denver basin
(Colorado State University. Libraries, 1999) Edwards, Kimberly, K., author; Sutton, Sally J., advisor; Ethridge, Frank G., advisor; Almon, William R., committee member
In general, the distal open marine shelf setting, typified by the Graneros Shale produces a rock with a greater and more uniform seal capacity relative to the rocks of a proximal open marine shelf setting, such as those of the Skull Creek Shale. A distal setting, which usually corresponds to the time of maximum transgression, may produce better seals because there is less coarse clastic sediment input, which allows slow deposition of clays from suspension to be the dominant depositional process. In this study, the higher capacity seal rocks occur in the upper parts of the TST, either within the condensed section or below it. The Skull Creek locations show seal occurrence to be stratigraphically higher on depositional topographic highs, and lower in areas that were topographically low at the time of deposition. Top seal capacity was quantified with mercury injection capillary pressure (MICP) analysis. Other physical characteristics of these marine shales were studied but only porosity, permeability, total clay, and hydrogen index consistently demonstrated a significant correlation with seal capacity in both units. Shales that are well laminated with a high percentage of total clay and/or total organic carbon with a type I-II (marine) kerogen may or may not qualify as the best seal. Top seal capacity may be more a function of rock fabric rather than mineralogy. For example, two samples may have exactly the same amount of quartz, as shown by XRD analysis, but thin section examination reveals that the majority of quartz in one sample is present as grains and in the other sample as cement. Samples with cement usually provide a better seal because they decrease the pore throat diameter, thus increasing the amount of hydrocarbons that can be trapped. Seal quality in both the Skull Creek and Graneros Shales is quite variable throughout each of the facies within the TST deposits.
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Open Access
Influence of abiotic and biotic factors on the response of benthic macroinvertebrates to metals
(Colorado State University. Libraries, 1995) Kiffney, Peter Michael, author; Clements, Will, advisor; Fausch, Kurt D., committee member; Kondratieff, Boris C., committee member; Chapman, Phillip, committee member
Stream ecologists are well aware that chemical, biological, and physical characteristics of lotic systems vary spatially and temporally. With this in mind, I designed a series of experiments and field studies to examine the role of spatial variation in stream benthic macroinvertebrate communities in response to metals. Specifically, I tested the hypothesis that stream invertebrate communities from pristine streams of different size and altitude varied in their response to metals. To evaluate how metals affected biotic interactions, I manipulated invertebrate density, predation intensity, and metals in stream microcosms. Using stream invertebrate communities, I also designed an experiment and field survey to identify reliable bioindicators of metal contamination in western streams. Results from microcosm experiments and field studies showed that benthic invertebrate populations from high-altitude streams were more sensitive to the effects of metals than invertebrate populations from low-altitude streams. For example, Baetis sp. and Rhithrogena hageni from Little Beaver Creek (LBC), Colorado, (high-altitude stream) were significantly more sensitive to zinc than the same species from the South Fork of the Poudre River (SFP) (low-altitude stream) in stream microcosms. Results from field surveys showed that densities of most groups of aquatic insects (e.g., Ephemeroptera, Plecoptera, Trichoptera) were lower at high-altitude metal contaminated streams than those same groups at low-altitude streams. Other factors, such as variation in water temperature or nutrient concentrations between high- and low-altitude streams, could be lll responsible for these differences. However, because invertebrate responses were similar under controlled and field conditions, I hypothesize that differences in abundances between reference and contaminated locations was a result of metals. To determine if body size contributed to the variation in sensitivity of insects to metals, size measurements were made on species collected from LBC (high-altitude) and SFP (low-altitude). Measurements were also made on species from control and metal-treated stream microcosm. Most species were smaller at LBC (high-altitude stream) than the same species from SFP (low-altitude stream). For example, the mayfly Baetis tricaudatus and the caddisfly Arctopsyche grandis were significantly larger at SFP than LBC. In addition, insect body size was larger in metal-dosed microcosms than in controls. Brachycentrus sp., B. tricaudatus, R. hageni, Eohemerella infrequens, and P. badia were significantly larger in metal-treated microcosms than in controls. Logistic regression indicated survival in metal-dosed microcosms was less for small individuals than for larger individuals of the same species. These results suggest that some insect species from high-altitude streams were smaller than those from low-altitude streams, and that survival was greater for larger lifestages. Thus the variation in response of macroinvertebrates between different altitude streams observed in earlier studies may be due to differences in body size. The effects of low levels of metals (half the chronic levels of Cd, Cu, and Zn) on some species varied in relation to invertebrate density (low and high density) and invertebrate predation (no predators added and predators added). The abundance of Hydropsyche sp. was significantly lower in metal-dosed, high density treatments than in control, high density treatments. Moreover, the effects of an invertebrate predator (Hesperoperla pacifica) on Hydropsyche sp. was significantly greater in metal-dosed microcosms than in controls. These results suggest that metals interact with biotic factors to influence stream invertebrate community structure, and that effects occurred at metal concentrations lower than chronic criteria value. Toxicity experiments in stream microcosms showed that the abundance and species richness of aquatic insects were significantly reduced at 1x, 5x and 10x the United States Environmental Protection Agency chronic levels of cadmium, copper, and zinc (1x=1.1, 5.0, and 110 μg/L Cd, Cu, and Zn, respectively). Mayflies were the most sensitive group, as the abundance of Baetis sp. and Rithrogena hageni were significantly reduced in the Ix treatment. The response of Drunella grandis was size dependent, as small lifestages were significantly more sensitive than large lifestages. Stoneflies were also affected, but their response was more variable with abundances of some species (Pteronarcella badia) being reduced in the Ix treatment, whereas other species were unaffected (Sweltsa sp.). Heptageniid mayflies were consistently less abundant downstream of sources of metal contamination in the Arkansas and Eagle rivers, whereas the response of other measures were more variable. For instance, species richness and total density were greater at a metal-contaminated site on the Arkansas River compared with an upstream reference site. Therefore, results from this experiment and field survey suggest that changes in abundance of heptageniid mayflies may provide a reliable indicator of metal-contamination in western streams.
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Open Access
Faculty information form
(Colorado State University. Libraries, 1994-1995) Colorado State University. Department of Psychology, author
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Open Access
The Counseling Psychology program at Colorado State University, 1994--1995, final version
(Colorado State University. Libraries, 1995-02-24) American Psychological Association, author; Cole, Charlie, author
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Open Access
Life, lemonade, and Landy
(Colorado State University. Libraries, 1995-01-13) Raich, John, author; Hamilton, Scott, author