Arsenic (As) contamination presents an ecosystem and human health risk at Giant Mine, a historic gold mine near Yellowknife, NWT currently undergoing the final stages of assessment for remediation. Arsenic concentration is elevated in sediments at Giant Mine due to contamination from several forms of mine waste including flotation tailings, roaster calcine and impoundment spills. The Giant Mine Remediation Project has stated aims to remediate the surface of the site, including Baker Creek which runs through the property, to a condition that is a productive environmental habitat and spawning ground. Environmental scanning electron microscope (ESEM) and synchrotron-based micro- X-ray Absorption Near Edge Spectroscopy (µXANES), micro-X-ray fluorescence (μXRF) and micro-X-ray diffraction (μXRD) techniques were employed to characterize the As-host phases and determine the solid-phase speciation of As in mine waste and sediments. Arsenopyrite, Fe-oxides, Fe-root plaque, and As_2 O_3 were the major phases identified. Sediment toxicity was measured using 10-day Chironomus dilutes and 21-day Pimephales promelas exposure tests. The toxicity tests found responses ranging of from 100% mortality at the most contaminated site to no statistical difference to the control groups in the least As contaminated site. Toxicity test chamber conditions were directly monitored with dialysis probes (mini-peepers) and Diffusive Gradients in Thin Films (DGTs). DGT and mini-peeper deployment in the test beakers allowed for direct correlation of their measurements to trace metal uptake and bioaccumulation during the toxicity tests. Linear regression and ANOVA statistics were used to correlate, when possible, As tissue concentrations in Chironomus dilutes and Pimephales promelas to DGT, mini-peeper and surface water concentration measurements. Statistical analysis was also conducted for Co, Cr, Cu, Ni, Pb, Zn, and Sb though these other metal/metalloids were not always suitable for analysis due to constraints caused by detection limits. It was found that DGT As was statistically correlated (r2=0.836 and p<0.0005) to uptake in Pimephales promelas but that total element concentrations were also statistically relevant and slightly better at predicting uptake (r2=0.873 and p<0.0005). Mini-peepers could not be analyzed statistically due to challenges in their use within some highly vegetated sediment samples. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2014-05-01 11:47:59.482

Individuals within a species often compete for resources in both space and time. In dominance hierarchies individuals with the greatest competitive ability will occupy prime locations during optimal periods to increase efficiency in gathering a resource. Subdominant individuals with low competitive abilities may be forced to reside in habitats of poor quality relative to dominant individuals. In this study I examined the long term patterns of giant kokopu distribution, movement, growth, habitat use, and social interaction between fish in relation to invertebrate drift (food supply). The habitat quality and abundance of food along a one km section of Alex�s Creek was monitored for a two year period. Though the physical structure of Alex�s Creek was relatively homogenous there were significant spatial differences in the density of drifting invertebrates sampled between riffles and pools over this long temporal period. In general, more drifting invertebrates were sampled in riffles of relatively long length and area. Within Alex�s Creek the distribution of giant kokopu, Galaxias argenteus, was determined by patchy distributions of food supply, specific physical factors of pools, and interactions between fish in dominance hierarchies. Over the 20 month study period, the most important biotic factor determining fish biomass was the total number of drifting invertebrates within pools while the most important abiotic factor determining fish abundances within pools was the pool size (surface area). The growth rate of individual fish correspondingly varied between fish residing within pools of different quality. Growth rates were higher for individual fish residing in pools with a relatively high density of drifting invertebrates. The differences in individual growth rates of giant kokopu may determine when fish leave a particular habitat patch (pool) and move to a new one. Fish that moved had lower growth rates (before moving) than fish that remained resident within home pools. Overall the movement of giant kokopu within Alex�s Creek was very restricted due to a relatively consistent distribution of food, however there were differences in the mobility of giant kokopu among different social ranks. The most dominant fish in pools were largely sedentary while fish ranked directly below fish 1 (i.e. fish 2 and 3 in social hierarchies) were relatively mobile. The ability of dominant fish to exclude subdominant fish from the most preferred feeding positions during optimal feeding times had consequences for overall giant kokopu activity. Under normal food supply conditions dominant fish were predominantly nocturnal and maintained large home ranges at night. Conversely subdominant fish occupied large home ranges by day, but were generally not observed at night. When the food supply was limited the utilization of pools was determined by social rank. Dominant fish from each pool increased daytime activity, home range size, aggressiveness, and the capture of food items offered by day while simultaneously reducing the spatial and temporal activity and habitat use of subdominant fish. These results indicate that behavioral changes in large dominant fish influence and reduce the amount of resources available to subdominant fish.

A thorough understanding of nucleosynthesis and element formation in stars of all evolutionary phases is of vital importance in stellar astrophysics. It provides information about internal structure, conditions and nuclear processes occurring in the stellar interior. The heavy elements formed in a star throughout its life are returned to the interstellar medium through mass loss processes. New populations of stars are then formed from this previously enriched material. This continues the cycle of element recycling in the Universe and has great consequence for galactic chemical evolution. As both modelling and observing techniques advance, more surveys are required to ensure there is agreement between the two. It is hoped that when a thorough understanding of the internal processes in giant stars is reached, the evolutionary models will reproduce the observed elemental yields. This work provides an internally self-consistent analysis of the element abundances produced via nucleosynthesis and s-process element formation occurring in giant stars in different stellar environments. High resolution spectroscopic observations have been taken of Asymptotic Giant Branch (AGB) and Red Giant Branch (RGB) stars in three different stellar environments. Spectrum synthesis has been used to determine s-process element abundances for RGB stars in the Hyades open cluster, RGB and AGB stars in the globular cluster, 47 Tucanae, and AGB stars in the galactic field. It was found that the two Hyades giant studied showed solar, or near-solar, abundances of s-process elements. Enhancements in the light s-process elements, Y and Zr, of +0.02 to +0.11 were observed, while enhancements in the heavy s-process elements, La, Pr and Nd, ranged from +0.06 to +0.16. These results are consistent with previous findings of enhancements in Y of ~+0.12, and of ~+0.15 for the heavy s-process elements. The results from 47 Tucanae suggest a genuine star-to-star scatter in the s-process element abundances in the giant stars of this globular cluster. This is unexpected due to the fact that stars in a globular cluster are thought to have the same formation and chemical history. However, spreads in s-process element abundances of as much as +-0.7 dex are observed between this study and three other studies of similar stars in the same cluster. A range of field stars along the AGB phase, ranging from M to MS to S to SC, have been analysed for s-process enrichment. The observed element abundances are compared with those predicted by recent modelling of the AGB phase of evolution. Enhancements in s-process element abundances range from [s/Fe]~0.00 for M stars, to ~+0.50 for MS stars, through to ~+0.95 for S stars. The comparison of these enhancements with those predicted by modelling provides an indication of the success of these models and will enable theoreticians to further refine their understanding of the internal nucleosynthetic processes present in giant stars.

Thesis (Ph. D.)--University of California, San Diego, 1998. / Vita. Includes bibliographical references.

Thesis (M.S.)--Missouri State University, 2008. / "August 2008." Includes bibliographical references (leaves 70-81). Also available online.

Thesis (M.A.)--California State University, Fresno, 1980. / Includes bibliographical references (leaves [104]-108).

Thesis (Ph. D.)--University of California, 1959. / Bibliography: leaves 62-65.

Thesis (M.A.)--Boston University

The effectiveness of giant cane [Arundinaria gigantea(Walt.) Muhl.] as riparian buffer vegetation has been demonstrated through research and has gained interest from state and federal agencies to support restoration efforts. Unfortunately, little is known about the physical and chemical properties of the soils below canebrakes and how soil characteristics influence aboveground and belowground biomass production. To determine what physical attributes of the plant influence its success as riparian buffer vegetation and also to determine the interactions with underlying soils, fourteen canebrakes were sampled throughout Southern Illinois. Objective one was to develop an allometric equation to quantify belowground biomass based on aboveground parameters of canebrakes. Previous research found that successful propagation was dependent on rhizome length, the number of internodes and the number of rhizome buds present, but no data exists regarding the yield of rhizomes for a given area. By harvesting all aboveground biomass (culms and leaves) and belowground biomass (roots and rhizomes) to a depth of 25 cm from a 1-m2 plot at each site, morphometric characteristics were quantified and biomass allocation throughout the plant was determined. A significant linear relationship between total aboveground biomass (live and dead) and belowground biomass in giant cane was evident (R=0.865, p<0.001). Although this is a strong relationship, it may be impractical for a manager to harvest, process, and weigh all of the aboveground biomass to speculate the biomass below ground. Therefore, metrics were explored for predicting the length of rhizome, number of rhizome internodes and number of rhizome buds an area will yield using multiple regression and models were developed that estimate these parameters. Using the equation that predicts the number of rhizome buds for a given area, the yield of propagules can then be estimated. Although this equation does not account for all variation of belowground characteristics, it will provide a general guideline for land managers restoring giant cane. The second objective was to estimate biomass allocation of giant cane roots/rhizomes beneath canebrakes by depth (i.e., at 25-cm increments to a depth of 150 cm). Results showed that 67% of giant cane's belowground biomass was within the top 25 cm of the soil profile and accounted for 65% of all belowground biomass encountered at that depth. Giant cane rhizomes were documented to a depth of 51-75 cm deep while cane roots existed in the deepest cores at a depth of 126-150 cm with an average density of 0.08 kg m-3. Giant cane belowground biomass declined with increasing depth, but was still the dominant species at 26-50 cm, comprising 61% of all biomass encountered at that depth. These results support the utility of giant cane as an effective riparian buffer species by increasing the soil porosity and promoting infiltration while contributing a significant source of carbon to the soil profile. Chemical and physical soil properties were measured to determine if they related to canebrake characteristics. Significant correlations were found between various soil properties and canebrake characteristics, implying there is an interaction between giant cane and the underlying soil. Results from this research will improve our understanding of the dynamics of giant cane and supplement existing information to help guide restoration efforts.

Giant cane (Arundinaria gigantea) is a native bamboo that forms large monodominant stands called canebrakes in bottomlands in the southeastern US. Canebrakes are valuable habitat for wildlife and function as riparian buffers to protect soils and water quality. Currently, only 2% of canebrake ecosystems remain. Thus there is interest in establishing new canebrakes as well as maintaining and expanding existing canebrakes. For field restoration, using cane rhizomes to produce transplants is possible but it is unknown when propagules should be collected and grown. For rehabilitation of existing canebrakes, preliminary studies suggest that fertilization and disturbance such as fire can be beneficial but additional broader-ranging studies are warranted. This research reports on three giant cane studies involving producing transplants from rhizomes and involving managing existing canebrakes with disturbance in southern Illinois. The main objectives of study 1 were to ascertain a) if collection season influences the proportion of rhizome propagules that grow at least one culm (culm production success) and the resultant culm growth when transplanted in a greenhouse b) if specific rhizome characteristics influence an individual rhizome’s ability to produce a culm c) if aboveground biomass could be a predictor of the amount of belowground propagules and d) if aboveground biomass, total rhizome length, number of rhizome nodes, or number of rhizome buds could be a predictor of how many culms could be produced when transplanting. Monthly, for a year, sample plots were randomly selected in the SIUC giant cane nursery. In sample plots aboveground culm measurements were collected included live culm density (#/0.25m2), dead culm density (#/0.25m2), height of the tallest culm (cm), diameter of the tallest culm (mm), and total aboveground biomass (g). Each month rhizomes were dug from the sample plots, measured (length (cm), diameter (mm), # nodes, and # live buds), and transplanted into pots and placed in the greenhouse for approximately 94 days. At that time, measurements were taken of the number of live and dead culms produced per pot and the height of the tallest culm (cm). Results indicate that rhizomes collected and transplanted in the greenhouse during winter and spring months (December-May), had significantly greater culm production success and produced significantly taller culms. Also, rhizomes intermediate in length (18-30 cm) that contained 5 to 12 nodes and 4 to 9 live buds tended to have higher than average culm production. Finally, a positive correlation existed between the amount of aboveground biomass and the number of rhizome nodes, the number of live rhizome buds, and the length of rhizomes found in sample plots. Aboveground biomass can predict the amount of belowground rhizome propagules that can be used for canebrake restoration. Study 2 is a two year continuation of work initiated in 2011 and reported on by Margaret Anderson in 2014 on the effects of fire, fertilization, and fire and fertilization combined on the growth and expansion (culm density, height and diameter) of canebrakes within the Cache River Watershed in southern Illinois. Results showed considerable year to year variability among treatments within the canebrake for some growth parameters. However, three years after disturbance, all treatments tended to have similar culm density and growth values and canebrake expansion occurred for all treatments into exterior plots. Fire alone was similar to controls in growth parameters and did not produce any long-term negative effects. Thus, fire can be used as an effective tool to reduce competition from other species, allowing managed canebrakes to persist longer than those that remain undisturbed. Fertilization used alone and in combination with fire, produced slight growth and density increases, but added costs may not warrant its use in canebrake management. Study 3 compared fire and mowing disturbances on the growth and expansion of remnant canebrakes located in southern Illinois. Eleven replications in remnant canebrakes were established throughout the Cache River watershed. Each replication contained a fire only treatment, a mowing only treatment, and a control. Measurements were taken in the dormant season early in 2012 prior to a single mowing and a single fire in March, and after each growing season thru 2014. Measurements including live and dead culm density (#m2), culm height (cm), and culm diameter (0.01 mm), were taken within subplots in the canebrake interior and exterior. Results from this study showed that mowing can be used as an effective alternative to fire for the management of remnant canebrakes through reductions in competition. Neither fire nor mowing produced negative effects of growth within the measured canebrakes or in adjacent areas. Like the previous study, all treatments including the control experienced an outward expansion of cane culms throughout the course of the study. This study shows that both fire and mowing can be used as effective tools to reduce competition within canebrakes to aid in their continued vigor.