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Syncrude Canada’s Base Mine Lake (BML), is the first oil sands pit lake and is being used to evaluate water-capped tailings technology for fluid fine tailings (FFT) management. To be successful, pit lakes must achieve the ecological role of a natural lake, requiring the development of oxygenated water cap capable of supporting macrofauna. Due to the reductive nature of the FFT stored at the bottom, oxygen-consuming constituents (OCC) such as methane, sulfide and ammonium can be mobilized into the water cap of oil sands pit lakes, posing a threat to the success of the reclamation. Results from BML are vital to inform successful pit lake design with a further 10+ pit lakes projected for collective waste reclamation required in the region, currently awaiting permitting. This field study established BML water cap depth dependent oxygen consumption rates (OCR), identified the key OCC driving those rates and modeled the roles of biogeochemical oxygen consumption and physical mixing in establishing water cap oxygen profiles during early stage development (< 5 years post commissioning). The balance between these two discrete processes underpins the likely viability of this management strategy for oil sands FFT. Results identify high OCR, in the range of highly productive eutrophic to hyper eutrophic lakes, in the vicinity of the FFT water interface, i.e. where concentrations of OCC are highest. Observed OCR rates decreased away from the FFT water interface, as concentrations of OCC decreased. The important OCC associated with high OCR were methane and ammonium. While the OCR values in the hypolimnion were extremely high, a minimally oxic FFT water interface persisted (<10 μM O2) contrasting the anoxic hypolimnetic waters typically observed in highly productive systems. Water cap oxygen mass balance modeling revealed physical mixing of oxygen into the hypolimnion from the metalimnetic region of the BML water cap currently slightly exceeds the oxygen being consumed through biogeochemical redox cycling, explaining the persistence of low levels of oxygen to the FFT water interface in the BML water cap (~ 10 m in depth). However, higher mobilization of OCC from the FFT as FFT consolidates, and/or higher rates of microbial biogeochemical cycling as microbial communities continue to establish and grow within BML, and/or decreased physical vertical transport of O2 into the hypolimnion, would all shift the oxygen balance towards greater consumption and thus would result in the migration of the oxic-anoxic boundary and OCC higher up into the water cap where they would directly impact the surface zone oxygen concentrations. Modeling results here identify that without the physical injection of oxygen into the hypolimnion, currently observed, OCR rates would generate anoxic conditions that would reach the middle of the metalimnion within this system within 24 hours. The development of an anoxic zone would facilitate greater generation of OCC directly within the water cap through anaerobic microbial biogeochemical cycling, the high levels of sulfate (~ 2 mM) observed within the BML water cap, which exceeds water cap oxygen concentrations by 3 orders of magnitude, indicate that generation of ΣH2S within this pit lake water cap would be a substantive risk to the development of a stable surface oxic zone that can support macro fauna. In addition, the emergence of nitrification, as one of the main oxygen-consuming reactions, was assessed experimentally to determine the potential effects on the oxygen depletion in BML water. Experimental results identified active nitrification with rates in the comparative range of marine to eutrophic estuary environments, with BML water collected from the metalimnion-hypolimnion interface, i.e. where the highest conversion of ammonia to nitrate was observed in field results. However, a comparison of oxygen consumption due to nitrification based on experimental, nitrification only results versus results from the field where nitrification as well as methanotrophy and other oxygen consuming processes are possible indicate oxygen consumption due to nitrification alone in the field is six times lower than the experimental oxygen consumption observed. These results highlight the competition for oxygen by multiple processes within BML, which suppress nitrification below levels observed under ideal experimental conditions. Characterization and modelling results of BML water cap oxygen concentrations carried out in this doctoral research reveal a new understanding of the important processes driving observed oxygen concentrations. These new insights delineate the potential effects of mobilized reduced constituents in the water cap from FFT and processes that may mitigate or exacerbate these impacts. Thus these results are of significant relevance to both the oil sands industry as well as other natural or anthropogenically impacted environments with high oxygen demand. / Thesis / Doctor of Philosophy (PhD)

No description available.

No description available.

Investigations of the nitrogen fixing (nif) genes in the cyanobacterium Nostoc commune UTEX 584 revealed a gene encoding a hemoprotein, named cyanoglobin. The cyanoglobin gene was isolated and subcloned into Escherichia coli previously. Cyanoglobin possesses a high oxygen affinity. The study presented here investigated the functional role of cyanoglobin, and encompassed the determination of the kinetic basis for the high oxygen affinity of cyanoglobin through kinetic studies utilizing stopped-flow spectrophotometry and flash photolysis. In addition, studies of cyanoglobin, in the presence of a variety of ligands, employed as structural probes of the distal pocket architecture, are presented. These data are interpreted in terms of structural models of cyanoglobin produced by homology modelling and hemoglobins with known crystal structures. Cyanoglobin coordinated oxygen and a variety of ligands with high rates of association, which explained the high oxygen affinity of cyanoglobin. Cyanoglobin possessed high rates of autoxidation and hemin loss. The ligand binding behavior of cyanoglobin was more similar to leghemoglobin than to sperm whale myoglobin. The ligand binding behavior of cyanoglobin is explained in terms of a highly reactive, and solvent exposed, heme-iron. The 5' region of glbN interacted with NtcA, the global regulator of nitrogen metabolism in cyanobacteria, which may provide an indication of the nitrogen deprivation signal required for cyanoglobin expression in vivo. Finally, the isolation and N-terminal sequencing of a potential cyanoglobin homolog in Anabaena sp. strain PCC 7120 is presented. Collectively, the data obtained in this study may support the model of cyanoglobin function described by Hill, et al., that cyanoglobin sequesters oxygen, and presents it to, or is a part of, a terminal cytochrome oxidase complex in Nostoc commune UTEX 584 under microaerobic conditions, when nitrogen fixation, and thus ATP demand, is maximal. / Ph. D.

No description available.

New Zealand's five endemic mudfish (Neochanna spp.) species have distributions that differ both geographically and by habitat type. Differences in habitat preferences between species have led to the proposal of an evolutionary series within the group. A morphological cline can be observed from the galaxiform Chatham Island and Canterbury species inhabiting lakes and streams, respectively, to the anguilliform Northland and brown mudfishes of ephemeral wetlands. Morphological specializations proposed for wetland dwelling include loss of pelvic fins, reduced eyes, enlarged nostrils, development of caudal flanges, and elongation of dorsal and anal fin bases to become almost confluent with the caudal fin. Another expectation of adaptation to wetland dwelling is specializations in respiratory physiology to obtain oxygen from highly hypoxic or acidic waters, and the ability to cope with seasonal exposure to air during the drought season. Expected respiratory specializations to wetland dwelling include high oxygen affinity haemoglobins, high levels of cooperative oxygen binding, the presence of multiple haemoglobins and the ability to aestivate and survive long periods of emersion. The four mainland Neochanna species were examined to determine if differences in haemoglobin expression as well as differences in haemoglobin oxygen binding correlated with differing habitats and treatments. Whole blood oxygen affinity was determined at several pH levels (6.5, 7.0, 7.5 and 8.0) and temperatures (10'C, 15'C and 20'C), as well as different treatments (aestivating, fasting and control) using a Hemox analyzer. The presence of multiple haemoglobins was determined by isoelectric focusing. All four species displayed high oxygen affinities (p50 = 6.5 to 9.5 mm Hg at pH 7.5 15'C), moderate levels of cooperativity (Hill coefficients = 1.75 to 2.00 at pH 7.5 15'C), pH sensitivity (Bohr coefficients = -0.62 to -0.94 between pH 7.5 and 7.0 at 15'C), temperature sensitivity (ΔH = -2.20 to -15.78 k cal mol-1 between 10'C and 15'C) and the presence of multiple haemoglobins. Black, brown and Northland mudfish were able to survive aestivation for six weeks but there were no changes between air-breathing and water-breathing individuals with respect to oxygen binding characteristics. Although there is evidence of habitat specialization in haemoglobin physiology between mudfish species, differences between species did not correlate with the evolutionary series proposed for specialization to dwelling in ephemeral wetlands and latitudinal distributions of mudfish species appear to strongly dictate oxygen binding properties of mudfish whole blood.

Enligt statistiken år 2010 fanns det 26 individer sett från en grupp på 100.000 som var tilldelade oxygenbehandling i hemmet. Oxygenbehandlingen tillför en bestämd mängd oxygen till bäraren då möjligheten att själv förse sig med rätt mängd för överlevnad hämmats. Den dominerande sjukdomen till oxygenbehandling i hemmet är KOL, kroniskt obstruktiv lungsjukdom. Som namnet antyder är det en kronisk sjukdom som ger inflammatoriska förändringar i lungans bronkioler. Dessa förändringar minskar andningsytan vilket resulterar i att individens andningskapacitet reduceras. Projektet använde metoder från dynamisk produktutveckling med användaren i fokus. Detta för att få fram en funktionell prototyp som kunde användas utav avsedd målgrupp och uppfylla det syfte, mål och krav som ställdes på projektets resultat. En viktig komponent som projektet därför arbetade med var insamling av data. För detta användes olika metoder som kunde tillskaffa sig information från både användare och förskrivare av oxygenbehandling.  Samtliga av de metoder som användes var beprövade sedan tidigare och projektet kunde därför med fördel genomföra intervjuer, observationer, matrisuppställningar, riskanalyser samt användartester på patienter med oxygenbehandling. Prototypen som togs fram i projektet resulterade i att avsedd målgrupp kunde utföra testmoment på den utan att det förekom risker med användandet. Resultatet uppfyllde därför syftet och målet med projektet som riktade sig mot att patienter skulle få möjlighet till att förflytta den syrgasslang som används vid oxygenbehandling. Vidare kunde slutsatsen dras att resultatet uppfyllde patienternas önskemål om att ta fram en möjlighet till förflyttning av syrgasslangen i hemmet samtidigt som det besvarade de frågeställningar som projektet strävade efter att besvara. Det fanns inga befintliga lösningar på det problem som beskrevs i projektet och det gav möjlighet att framställa en första prototyp som uppfyllde syftet och målet. / According to statistics, in 2010 there were 26 individuals seen by a group of 100,000 who were depending in home oxygen therapy (HOT). Oxygen treatment adds a certain amount of Oxygen to the patient because the ability to breathe correctly and sufficiently is negatively affected. The dominant disease that leads to HOT is COPD, chronic obstructive pulmonary disease. As the name suggests, it is a chronic disease which gives inflammatory changes to the lung bronchioles. These changes affect the breathing surface which results in that the individuals’ respiratory capacity becomes reduced. The project used methods from dynamic product development with the user in focus. This to obtain a functional prototype that could be used by the target group and to fulfill the purpose, goals and requirements set for the project's results. An important component of the project therefore was to work with the collection of data. For this, various methods were used to obtain information from users as well as prescribers of HOT. All of the methods used have been tested earlier and proven reliable. This project collected information from interviews, observations, matrix arrays, risk analysis and usability testing in patients with HOT. The prototype developed in the project resulted in that the target group could perform live test without any risks during testing. The results showed that the aim and objective for the project were fulfilled, expressed in that patients would be able to move the oxygen tube used in HOT. It was further concluded that the results fulfilled the patients' desire and opportunity to move the Oxygen tube in their home and at the same time answered the questions that the project was to answer. There were no existing solutions to the problem which is included in the project, but it was possible to develop a first prototype that met the purpose and object of the project.

Elite milers, Sir Roger Bannister and Joseph Falcon, have stated that the consumption of carbonated beverages hinders the performance of aerobic events. Oxygen transport is purportedly impaired by the consumption of carbonated beverages. The research on carbonated beverages has been limited to the effects on the digestive system, gastric emptying, and thermal heat stress in animals. The purpose of this study was to investigate the effects of consuming 28 ounces of carbonated beverages per day, for three weeks, on arterial oxygen saturation (Sa0₂), serum hemoglobin concentrations (Hb), and maximal oxygen consumption (VO₂max) in experienced cyclists. Nine competitive cyclists and triathletes (aged 19-24 years, M = 21.67 years), with average weights and percent body fat of 76.51 kg and 11.4 percent respectively, were randomly assigned to a three week period of consuming 28 ounces of carbonated water or a three week period of no carbonated beverages. At the end of each three week period, a 5 c.c. blood sample was taken for Hb determination and the subjects performed a test of maximal oxygen consumption on a cycle ergometer while Sa0₂ was being monitored. The groups then crossed-over with respect to their treatment, and after another three week period, the same variables were measured. The Student's t statistic was used to compare Sa0₂, Hb, and VO₂max. The results showed no significant differences between the carbonated period (C) and the noncarbonated period (NC) in Sa0₂ (94.00 vs 93.22 %, p= 0.21), Hb (13.71 vs 14.12 g/dl, p= 0.11), and VO₂max (4.63 vs 4.65 Imin, p= 0.92). From this study, it appears that the consumption of carbonated beverages does not affect the variables associated with the oxygen carrying capacity of blood (Sa0₂ and Hb) or the test of aerobic performance (V0₂max) / Graduation date: 1992

Ecosystem metabolism is an important indicator of aquatic ecosystem function. This thesis concerns ecosystem metabolism as recorded by daily variation in dissolved oxygen (DO) and δ18O-DO in an impacted temperate river network, the Grand River, Ontario, Canada, and specifically addresses the effects of stream size and human disturbance including agriculture, deforestation, and wastewater treatment plants (WWTPs). A suite of 14 sites in the Grand River network was selected with stream sizes varying from 2nd to 7th order. A transient model of river ecosystem oxygen metabolism, ROM-TM, was developed in order to calculate river ecosystem metabolic rates and reaeration rates from field observation of changes in DO and δ18O-DO. ROM-TM is an inverse modeling approach programmed using MATLAB. Key parameters describing the main metabolic processes, gas exchange, and isotopic fractionation, such as maximum photosynthetic rate (Pm), photosynthetic efficiency (a), respiration rate at 20℃ (R20), gas exchange coefficient (k), respiration isotopic fractionation factor (aR), and photorespiration coefficient (βR), can be obtained by matching of model predictions with field data. Besides being capable of teasing apart metabolic processes and gas exchange to provide daily average estimates of metabolic parameters at the ecosystem level, ROM-TM can be used to address issues related to light including light saturation phenomena at the ecosystem level, the effect of cloud cover on metabolic balance and photorespiration. Primary production responses to light along a longitudinal gradient in the Grand River network were described by means of P-I curves. Both light-limited and light-saturated conditions were observed. Production parameters Pm and Ik in the Grand River network exhibited an increase with stream order, while a was independent of stream size. However, a did vary among and within sites. Higher light availability in small and middle-sized streams without riparian trees was associated with high Pm, Ik and Ec, but low a. Ecosystem-level Pm in both small periphyton-dominated streams and large macrophyte-dominated rivers in the Grand River basin were generally less than community-level Pm values from the literature. However, two Grand River sites had comparable Pm to literature-derived Pm due to the prolific growth of macrophytes supported by high nutrient effluents from upstream WWTPs. Ecosystem-level a in my study streams were also less than those at the community level, indicating there was a declining trend of this parameter with scale, from individual, community to ecosystem. Derived parameters (e.g., Ik, Ec, and saturation point) increased from the individual level to the community level, and then to the ecosystem level. From May to early October, metabolic rates in the Grand River network (gross primary production, GPP = 0.4 to 20 and ecosystem respiration, ER = 2 to 33 g O2 m-2 day-1) were within the broad range of metabolic rates occurring in the temperate region, regardless of stream size. The Grand River network is a net heterotrophic system. The total GPP and ER for whole basin was 3.3e+08 and 4.2e+08 g O2 day-1, respectively. Reach geomorphology controls the spatial patterns of stream metabolism in the Grand River network, although the spatial patterns may be modified by effects of human disturbance on riparian vegetation, nutrients and other factors. Stream order and channel width, as measures of stream size, are good predictors of metabolic rates and ratios of GPP: ER from small streams to the central Grand River. Ecosystem metabolic rates and ratios generally increase with stream size, but with site-specific variation. The Grand River network is experiencing effects of human disturbance, mostly downstream of the urban areas and least in small streams with remaining riparian forest. The small and middle-sized streams (2nd to 4th order) without riparian trees in agriculture regions in the Grand River basin did not exhibit significantly different GPP and ER than their counterparts with riparian trees. The stimulative effect of increased light availability due to open canopy on GPP in non-shaded streams may be offset by shading from stream banks and riparian grasses, and unstable sediments resulting from agricultural activities. Large river sites impacted by WWTPs had significantly increased metabolic rates, both GPP and ER, compared to two upstream sites impacted by agriculture only. This result suggests that urban areas cause impacts on the Grand River that are superimposed on the impacts of agriculture. Three aspects of metabolism of the Grand River differ from the general pattern for the temperate regions: (1) a increase trend of GPP: ER ratios with stream size from 2nd to 7th order; (2) overall, human activities in the Grand River watershed have stronger positive effects on the GPP than on the ER; (3) the middle-sized to large river sites (5th-7th order) had greater influence than small to middle-sized streams (2nd-5th order) in the Grand River on overall GPP and ER. The general trend of GPP: ER ratio in tropical, subtropical, temperate, and global data approximately conforms to the predictions of the River Continuum Concept (RCC). However, the maximum ratio of GPP: ER in mid-reaches of river networks is not usually >1 as proposed in the RCC. There is a latitude and stream size shift phenomenon regarding where the peak ratio of GPP: ER occurs in each climate zone. The maximum GPP: ER ratio is higher at higher latitudes and occurs at higher order streams. The study of stream ecosystem metabolism can benefit from the addition of the second oxygen budget, δ18O-DO, in four ways: (1) it is better to use both DO and δ18O-DO budgets, rather than DO only, in sampling protocols with low temporal frequency but high spatial frequency; (2) the δ18O-DO time series data can provide relatively independent constraints on parameter estimation; (3) the addition of δ18O-DO in using two oxygen budgets to quantify metabolic rates provides a way, the cross-plot of δ18O-DO against fraction of DO saturation, to indicate trophic status of an aquatic ecosystem; and (4) the addition of δ18O-DO can provide an estimate of aR at the ecosystem level that can be used to understand factors affecting respiration.