Developing critical loads for nitrogen (N) in the Athabasca Oil Sands Region (AOSR) requires an understanding of the hydrological connectivity and potential for N transport among uplands, fens and bogs typical in the wetland-rich Boreal region of northern Alberta. The Cumulative Environmental Management Association’s (CEMA) overarching mandate is to determine a nitrogen critical load specific to the Boreal region of northern Alberta. To this end, nitrogen amendment experiments were initiated at two Boreal wetland sites: an upland – rich fen gradient at Jack Pine High (JPH) and an upland – fen – bog mosaic at Mariana Lakes (ML), 45 km north and 100 km south of Fort McMurray respectively. The objectives of this study are to use geochemical and isotopic tracers to describe baseline hydrogeochemical variability and connectivity between bog, fens and upland areas in the AOSR. Sites were instrumented with piezometer nests and water table wells along transects that cover the targeted landscape units (n = 108 sampling locations). Fieldwork related to this thesis was conducted during the open-water season: in June and August 2011, and in May, July, and September 2012. Field campaigns also included a snow survey (March 2012), and spring melt/freshet sampling (April 2012). The analysis of spatiotemporal variability of water isotopes and geochemistry in the years 2011-2012 yielded: i) a characterization of baseline conditions from which perturbations can be assessed, and ii) evidence of connectivity among landscape units. No evidence for elevated concentrations of nitrogen related to the amendment experiments was found in 2011 or 2012. The baseline characterization and annual monitoring did show increasing concentrations of inorganic ammonium with increasing depth associated with increasing solute concentrations: average concentrations of inorganic ammonium were 23 mg/L at deepest sampling locations (7 m) at ML bog and ML fen landscape units. These ammonium concentrations in porewaters, given a porosity of 0.90 for peatlands, constitute a store of ammonium that may be a significant source of nitrogen if the hydrology is altered due to co-occurring changes in vegetation (due to, for example, elevated nitrogen inputs), climate and/or landuse. Hydrologic connectivity at JPH is likely driven by topography. Hydraulic head in 2011 and 2012 field seasons showed that flow persisted from the upland to the fen. The consistent and distinct geochemical signatures and isotopic labelling of mid-depth and deep groundwater samples of fen and upland landscape units is consistent with such a stable groundwater continuum. Near-surface water samples at JPH fen however varied hydrogeochemically in response to seasonal changes in precipitation inputs, water levels, and biogeochemical productivity. At ML, hydrological connectivity is a function of antecedent moisture conditions (which determines run-off) and low and variable (10-6 to 10-9 m/s) hydrological conductivity of the peatland substrate (which may result in lateral flow where hydraulic head shows potential for vertical re- or discharge). Near-surface samples showed greater temporal than spatial variability as snowmelt inputs, variations in antecedent moisture conditions and seasonal changes in biogeochemical process rates affected nutrient and solute concentrations. In contrast, shallow, mid-depth and deep samples showed greater spatial than temporal variability. The spatial distributions of parameters could be associated to some degree with vegetation, distance along a surficial flowpath, or depth to mineral substrate or distance from the upland/edge transition. / Graduate / 0996 / 0388 / 0425 / cbkusel@yahoo.ca

The stable isotopes of oxygen and hydrogen have been employed worldwide as natural hydrological tracers, and most successfully in areas where extremes of climatic seasonality or relief exist. This project aims to assess the viability of the stable isotope technique for studies in the U.K. Systematic sampling was undertaken over two years in the Malham (Carboniferous limestone) and Lambourn (Chalk) areas. The monthly isotopic input signal in precipitation was found to be clearly definable, but less strongly seasonal than found elsewhere. Larger isotopic variations were revealed in weekly and within-storm samples. Snowmelt appeared to provide the most reliable 'spike' for tracing purposes. An attempt to relate weekly precipitation δ¹⁸0 values to air mass characteristics was encouraging for further investigations. Variations of isotope signal with altitude were erratic and not in accordance with normally accepted relationships. Isotopic variations in groundwaters of both areas, and in surface waters of the Lambourn area, rarely exceeded measurement error, and were close to mean annual values in precipitation. This indicated complete mixing of the input waters over one year or more. The isotopic range in precipitation was reduced by ~60% in surface waters of the Malham area. Early mixing and storage of water in the soil and/or upper karstic zone were indicated by comparison of the isotope data with conventional hydrological measurements at resurgences, and supported by strong signal attenuation measured in soil moisture. At certain sites, isotopic evidence revealed a persistence of winter recharge into summer baseflow. A smooth and strongly seasonal isotope signal, discovered in the waters of Malham Tarn, was attributed to evaporation processes and suggests important practical uses. It is concluded that the general application of the stable isotope technique may be more restricted in the U.K. than elsewhere, but that its provision of a new dimension to conventional data should contribute significantly in the future to selected hydrological studies.

Given p independent, symmetric random walks on d-dimensional integer lattice that are the domain of attraction for a stable distribution, we calculate the moderate deviation of the intersection of ranges of the random walks in the case where the walks intersect infinitely often as time goes to infinity. That is to say, we establish a weak law convergence of intersection of ranges to intersection local time of stable processes and use this convergence as a link to establish deviation results.

Diverse fish species consume fruits and seeds in the Neotropics, in particular in the lowland reaches of large rivers, such as the Amazon, Orinoco, and Parana in South America. Floodplains of the Amazon River and its lowland tributaries are characterized by marked hydrological seasonality and diverse assemblages of frugivorous fishes, including closely related and morphologically similar species of several characiform families. Here, I investigated whether or not these fishes are capable of detecting fluctuations in food availability and if they are, how they adjust their feeding strategies. I tested predictions of optimal foraging, limiting similarity and resource partitioning theories with regard to expansion or compression of niche breadth and reduction in trophic niche overlap among species in relation with fluctuations in the availability of alternative food resources. I monitored fruiting phenology patterns to assess food availability and conducted intensive fishing during the high-, falling-, and low-water seasons in an oligotrophic river and an adjacent oxbow lake in the Colombian Amazon. I combined analysis of stomach contents and stable isotope ratios to evaluate dietary patterns, niche breadth, and niche overlap. Diets of six characiform fish species (Brycon falcatus, B. melanopterus, Myloplus asterias, M. rubripinnis, and M. torquatus) changed in a manner that indicated responses to fluctuations in food availability. Feeding strategies during the peak of the flood pulse were consistent with predictions of optimal foraging theory. During times of high fruit abundance, fish preferentially consumed items to which their phenotype is best adapted, maximizing net energy gain and enhancing fitness. As the flood pulse subsided and the availability of forest food resources was reduced in aquatic habitats, there was not a consistent pattern of diet breadth expansion or compression, even though diet shifts occurred, suggesting interspecific differences in foraging efficiencies. Analyses of diets and isotopic ratios revealed a general pattern of increased dietary segregation as the water level receded. Although there never was complete niche segregation among these fishes, these dietary changes effectively reduced interspecific niche overlap. Implications of these results and contribution of allochthonous food resources to diversity maintenance of floodplain fishes are discussed.

In light of the extirpation of a number of elasmobranch species commonly encountered in fresh and estuarine waters elsewhere in the world, 39 river systems were sampled throughout northern Australia to determine the species present. A total of 502 elasmobranchs representing 36 species, in addition to 1531 teleosts representing 46 species, were captured. In regard to elasmobranch species known to frequent riverine habitats, the bull shark Carcharhinus leucas was captured in the highest number, followed by the freshwater sawfish Pristis microdon, the freshwater whipray Himantura chaophraya and the dwarf sawfish Pristis clavata. Although these species were generally captured in low numbers, all were widely distributed throughout the region. Furthermore, the waters of King Sound, Western Australia, and the rivers entering it, i.e. the Fitzroy, May and Robinson rivers, were found to contain far higher numbers of P. microdon and P. clavata than any of the other rivers sampled, as well as the northern river shark Glyphis sp. C, and which subsequently provided an ideal locality to study the biology of these species. The Fitzroy River was shown to act as a nursery for P. microdon and P. clavata, where immature individuals remain for a maximum of four or five years before migrating to marine waters. Investigations of the rostra and rostral tooth morphology of P. microdon indicated their usefulness as a diagnostic tool in differentiating this species from other members of the genus, including P. clavata, and for differentiating between the sexes, i.e. female P. microdon generally possess 17-21 teeth cf. 19-23 teeth in males. However, no significant difference in the number of rostral teeth was found between female and male P. clavata, with both sexes possessing an average of 42. Furthermore, the facts that P. clavata was captured up to 2332 mm in total length and all of the individuals were immature, indicates that the description of this species as a ‘dwarf’ sawfish is erroneous. The use of rivers of northern Australia as nurseries was also apparent for C. leucas, with none of the 111 individuals dissected (ranging in length from 681 to 1365 mm TL) being mature. Furthermore, this species appeared to remain within the rivers for approximately four years. Stomach content analysis and field observations confirmed an opportunistic, and often aggressive, feeding nature, and thus the species may pose some risk to bathers utilising inland waters far upstream (i.e. over 300 km). Morphometrics and radiographs of 10 Glyphis sp. C captured from the macrotidal waters of King Sound (the first capture of this species in Western Australia) indicated that these specimens possessed both a wider range in total vertebral count (i.e. 140-151 cf. 147-148) and number of diplospondylous caudal centra (i.e. 64-70 cf. 65-68) than that previously reported and lent support for its synonymisation with Glyphis gangeticus. Radiographs also revealed the spinal deformation and fusing of vertebrae in three of the ten individuals, which may be attributable to a genetic abnormality indicative of inbreeding within a small gene pool. Analyses of stomach content and stable carbon (ä13C) and nitrogen (ä15N) isotope ratios of fishes occurring in the Fitzroy River indicated that the diets of a majority of the species present are broad, and greatly influenced by the seasonal availability of different prey types. While stomach content analysis suggested that aquatic insects, and to a lesser extent filamentous algae, represent vitally important food sources for many of the species present, stable isotope analysis strongly suggested that this latter food source may not be an important direct energy source, and that prey types which persist throughout the year (e.g. fish, molluscs and Macrobrachium rosenbergii) may in fact be more important sources of the energy than dietary data revealed. Dietary overlap was found to be the highest during the wet season when prey availability was high, decreased in the early dry season as fishes became more specialised in their feeding, before increasing again in the late wet when food became very limited. These analyses also supported the views that juvenile fishes may target high energy food items to attain higher growth rates and a large size rapidly, in order to achieve competitive feeding advantages and reduce the risk of predation, and that many species will maximise their energy intake in response to changes in resource availability.

Thesis (Ph.D.) - University of Queensland, 2003. / Includes bibliography.

Thesis (M.S.)--The University of North Carolina at Greensboro, 2010. / Directed by Anne Hershey; submitted to the Dept. of Biology.

Thesis (Ph. D.)--Drexel University, 2006. / Includes abstract and vita. Includes bibliographical references.

The Summitville high-sulfidation gold deposit is hosted by a volcanic dome consisting of the South Mountain Quartz Latite that was erupted 23 Ma ago during formation of the Platoro Caldera complex in the San Juan volcanic field of south central Colorado. Alteration and mineralization developed during or shortly after dome emplacement as a result of metal-rich magmatic fluids and vapor emanating from a crystallizing intrusion at depth. Copper, arsenic, silver and gold are enriched in the deposit with two of the last paragenetic stages, the barite-base metal sulfide and goethite stages, containing the highest gold grades. Barite contains magmatic sulfur with a range of δ34S values (19.3 – 31.8 ‰) that reflects SO42– – H2S isotopic equilibration over a temperature range of 115 to 180 °C, which is consistent a calculated temperature of 147 °C based on the sulfur isotopic fractionation between intergrown barite and galena. Barite δ18O values (19.3 – 31.8 ‰) indicate the barite fluids contained a minor component of meteoric water. Barite growth zones with acicular crystals (wires) of emplectite (CuBiS2), a mineral not previously reported from Summitville, contained primary fluid inclusions that yielded a wide range of vapor to liquid homogenization temperatures as a result of stretching but consistent freezing point depressions that infer an average salinity of 5.1 wt. % NaCl equivalent. These data indicate that the barite fluids were modestly enriched in magmatic sulfur and metals (Cu, As, Bi, Pb, Zn, Au, Ag) and that barite precipitation was likely triggered by cooling during mixing with meteoric waters. The goethite stage developed during weathering of the deposit that likely occurred during uplift and exposure around 9 to 7.7 Ma ago based on 40Ar/39Ar dates on jarosite. The assemblage goethite + hematite ± jarosite ± scorodite ± gold filled open spaces and coated barite of the barite-base metal sulfide stage. Inclusions of barite and bladed alunite in the iron oxide/hydroxide (FeOx) matrix have the texture, composition and isotopic values of their earlier formed counterparts in the deposit and therefore represent residual material that survived the weathering event. Three 40Ar/39Ar dates on the bladed alunite ranged from 23.15 to 22.88 Ma, confirming their origin as magmatic hydrothermal alteration alunite. Layers of compositionally zoned, small rhombohedral crystals of alunite were also discovered in the FeOx matrix. Although these could not be successfully dated, they had a distinct texture, chemistry and isotopic composition (δ34S = 0.8 ‰ δ18O = 4.7 ‰) that indicated they formed during the weathering event. The acidic, oxidizing supergene fluids remobilized and broadly enriched the top of the deposit in Cu and Ag and locally in native gold (5 wt. % Ag).

Tomatoes (Lycopersicon esculentum L.) require high amounts of nitrogen to maximize fruit production. The type of nitrogen and timing of fertilizer applications are important in tomato production systems to reduce nitrogen losses while optimizing yields. A two-year greenhouse study was conducted to determine the effects of organic and inorganic fertilization treatments on nitrogen and carbon isotopic compositions of tomato plant leaves and fruit at immature and mature stages of plant growth. The carbon and nitrogen isotopic ratios together will also help to better depict trends that develop from conventional versus organically grown tomatoes and their resulting water use efficiency (WUE). ‘Better Bush’ tomatoes were grown in 8 L plastic pots filled with 1:1:1 steamed-sterilized sand:silt loam soil:peat mix. Eight fertility treatments were evaluated: no fertility, synthetic Miracle Grow® (MG), organic bonemeal and bloodmeal (BB), BB with liquid Earthjuice (BBL), BB with 25% vermicompost (VC), BBL with 25% VC, MG with 25% VC, and no fertility with 25% VC. The results indicated that for both growth stages, δ15NAir differed (P ≤ 0.05) between fertility treatments, while no major differences were observed for δ13CVPDB (P > 0.05), although conventionally fertilized tomatoes with MG and MG with 25% VC tended to have lower δ13CVPDB values suggesting a greater transpirational water loss through open stomata. The organic treatments with VC had higher δ15NAir values than the conventional or no added fertility treatments for all five leaflets from three different branches, fruit skins from the first two fruit clusters, fruit juices from the first two clusters and soil samples. Generally, the 15N/14N stable isotope values of tomato foliage and fruit are distinctly different between organic and conventional fertilizers, which could provide a powerful forensic tool in fingerprinting tomatoes grown by organic farming methods. Therefore, nitrogen isotopes can distinguish among different fertility treatments and also help to label the VC applications, which are thought to provide better fertility management due to less soil leaching and volatilization.