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Title: The Salmon Disturbance Regime: Effects on Biofilm, Sediment and Water.
Contributors: Sam J. Albers (author), Ellen Petticrew (Thesis advisor), University of Northern British Columbia (Degree granting institution)
Abstract: Recent work in salmon spawning streams has shown that sediment resuspended during nest construction aggregates with salmon organic matter to form suspended particles called flocs. These nutrient-rich flocs interact with streambed biofilms suggesting a potential floc trapping mechanism that drives biofilm growth. Using the Horsefly spawning channel, the role of biofilms in trapping fine sediment was evaluated as a mechanism of salmon-derived nutrient processing. In the active spawn period, biofilm was reduced in abundance while the streambed sediment infiltration was at its highest level. During salmon die-off, downstream biofilm abundance recovered to pre-spawn values indicating a nutrient pulse over a small scale. With the re-established biofilm layer, sediment was increasingly trapped at the streambed surface by biofilms. This increase in biofilm abundance will likely influence the nutrient dynamics at all levels of the stream foodweb. Biofilms transfer increases in productivity to higher trophic levels. This transfer has a positive effect on the next generation of juvenile salmon growth and survivorship. --P.ii.
Discipline: Environmental Science
Content Model: info:fedora/ir:thesisCModel
Date added: 2011

Title: The effects of floods and sockeye salmon on streambed morphology.
Contributors: Ronald Poirier (author), Ellen Petticrew (Thesis advisor), University of Northern British Columbia (Degree granting institution)
Abstract: Streambed changes resulting from floods and spawning activity of sockeye salmon were monitored in two gravel bed streams in Stuart-Takla Experimental Watersheds of the Upper Fraser River basin, British Columbia, Canada. The streams have a forced pool-riffle morphology, and are utilized yearly by 7,000 to 10,000 sockeye salmon for spawning. Streambed mapping was performed before and after nival floods, summer floods and sockeye salmon spawning events in 1996 and 1997. Flood transport moves gravel out of pools, increases gravel bar heights, creates scour holes, and establishes a distinct thalweg. Sockeye spawning, which follows the floods, removes gravel from the edges and surface of the bars, and fills in the pools, scour holes and thalweg. The stream morphology is thus altered in opposing fashion by two different processes. It was found that the cut and fill volumes are similar in magnitude but that the two processes affect the stream in a very different manner.
Discipline: Environmental Science
Content Model: info:fedora/ir:thesisCModel
Date added: 2005

Title: Systematic variability in proton and copper(II) complexation by dissolved organic matter from surface freshwaters.
Contributors: Chad D. Luider (author), Ellen Petticrew (Thesis advisor), University of Northern British Columbia (Degree granting institution)
Abstract: No abstract available.
Discipline: Natural Resources & Environmental Studies
Content Model: info:fedora/ir:thesisCModel
Date added: 2004

Title: Evaluating the impacts of forest harvesting and natural disturbance events on sediment yields in small watersheds throughout British Columbia, Canada
Contributors: Christian Percival Spicer (author), Ellen Petticrew (Thesis advisor), University of Northern British Columbia (Degree granting institution)
Abstract: Evaluating the impacts of logging, wildfire and earthquakes on sediment yields in small catchments throughout coastal and interior regions of British Columbia, Canada -- Determining the relationship between harvesting, roading and morphometric variables to historical sediment yield variability of coastal and interior catchments of British Columbia, Canada.
Discipline: Environmental Science
Content Model: info:fedora/ir:thesisCModel
Date added: 1999

Title: Influence of dissolved organic carbon on aggregation and aggregate characteristics.
Contributors: David James Arkinstall (author), Ellen Petticrew (Thesis advisor), Jeff Curtis (Thesis advisor), University of Northern British Columbia (Degree granting institution)
Abstract: No abstract available.
Discipline: Natural Resources & Environmental Studies
Content Model: info:fedora/ir:thesisCModel
Date added: 2006

Title: The effect of pulp mill effluent on fine-grained sediment morphology and storage in the Fraser River at Prince George, B. C.
Contributors: Simon Biickert (author), Ellen Petticrew (Thesis advisor), University of Northern British Columbia (Degree granting institution)
Abstract: A growing body of literature is examining the degree of and effects of the flocculation of fine riverine sediments. It has been shown that flocculation changes the morphology of the fine riverine sediment in the water column. The implications of these changes are as yet incompletely understood, but assumed to cause increased sediment deposition. Some recent studies have investigated the effect of pulp mill effluent as a flocculant, but have not satisfactorily ascertained the relationship between the effluent and flocculation. In this study, measurements of the fine sediment morphology upstream and downstream of a pulp mill were compared to measure the effect of pulp mill effluent as a flocculant. The observations were repeated weekly throughout the annual cycle of temperature, sediment concentration and discharge, allowing the effect of the pulp mill effluent to be put into the context of the natural variation of flocculation of river sediments. To measure the actual fine sediment deposition rates with and without the presence of the pulp mill effluent, a series of sediment traps were deployed during low and medium flow conditions. The size fractions trapped in them provided insight into the natural level of deposition and the amount of enhancement associated with the effluent. The data show that the natural size of floes in the Fraser River, as represented by differences in the effective and absolute particle size distribution, is small when compared to results from measurements in other rivers. Floc sizes are larger under low-flow conditions, especially under winter ice. The annual range of floc sizes of the natural sediments(~ 10 um) was much larger than the increase measured due to the presence of pulp mill effluent(~ 1 um). No statistically significant increase in the rate of fine sediment accumulation in the sediment traps was noted due to the influence of the pulp mill effluent, indicating that, at least in the near-field plume (300m), it has no effect on deposition.
Discipline: Environmental Science
Content Model: info:fedora/ir:thesisCModel
Date added: 1999

Title: Dependencies of food web and nutrient cycling dynamics on dissolved organic matter (DOM) and inorganic nutrient concentrations in lake enclosures.
Contributors: Erinn Honor Radomske (author), Ellen Petticrew (Thesis advisor), Jeff Curtis (Thesis advisor), University of Northern British Columbia (Degree granting institution)
Abstract: An autotrophic-allotrophic gradient was established in 12 lake enclosures across a natural DOM concentration gradient. Phytoplankton were co-regulated by solar irradiance and inorganic nutrient concentrations, whereas bacterioplankton were strongly dependent on DOM in the reference enclosures. Nutrient scavenging in the reference enclosures was limited by efficient biotic incorporation and recycling, across the full DOM gradient. Nutrient enrichment stimulated a strong autotrophic response across the autotrophic-allotrophic gradient due to increased phytoplankton productivity. Bacterioplankton productivity was still strongly dependent on DOM, but bacterioplankton productivity also increased either as a direct or indirect result of nutrient enrichment. Carbon, nitrogen, and phosphorus were effectively scavenged from the water column by incorporation into biomass at high rates and then deposited in the sediments in the nutrient enriched enclosures, producing nutrient-rich sediments. The data further suggest that at DOM concentrations greater than 14 mg L -1, allotrophy would dominate regardless of inorganic nutrient enrichment.
Discipline: Environmental Science
Content Model: info:fedora/ir:thesisCModel
Date added: 2005

Title: Quantifying the major sinks and sources of phosphorus in Tabor Lake: implications for management and remediation
Contributors: Sean Simmons (author), Ellen Petticrew (Thesis advisor), University of Northern British Columbia (Degree granting institution)
Abstract: A study of Tabor Lake and its watershed during the open water season of 1995 was conducted in order to quantify the major sinks and sources of phosphorus, and the timing of phosphorus transfer between these sources and sinks. The results of this thesis are useful to help determine appropriate management strategies aimed at reducing phosphorus availability in Tabor Lake's water column and understanding some of the processes that control phosphorus availability in the lake. An exploratory modeling exercise was undertaken to evaluate morphometric and watershed variables in predicting spring phosphorus for 39 lakes in the region, including Tabor Lake. Two multiple linear regression models were constructed. The first model uses a stepwise technique to select statistically significant variables, and the second model uses variables found in the literature which have been shown to influence phosphorus loading. These two models account for 70% and 59% of the variation in spring phosphorus, respectively, and may provide managers with an expected phosphorus loading based on easily measured morphometric and watershed variables. The models predict that Tabor Lake should have a spring phosphorus concentration of 20 and 18 ug/L, respectively. The models are useful to establish the limits of water quality improvement for Tabor Lake. Another model was developed to estimate the quantity and timing of external sinks and sources of phosphorus in Tabor Lake for 1995. Phosphorus loading into Tabor Lake was estimated from runoff (136 kg) and atmospheric deposition (60 kg). Phosphorus output from Tabor Lake through the outlet creek was estimated at 188 kg for the entire year. Based on this input-output model, there was a net gain of 8 kg phosphorus into Tabor Lake during 1995. These results indicate that external phosphorus inputs and output is approximately balanced. Results from a prior monitoring program indicate that Tabor Lake experienced internal loading of phosphorus during periods of hypolimnetic anoxia. However, phosphorus loading also occurred when oxygen was present in the hypolimnion, suggesting another phosphorus loading mechanism was active in Tabor Lake. A specific effort was made to evaluate the role of senescing macrophytes (primarily Elodea canadensis) as a source of this phosphorus during the 1995 sampling season. Two experiments were conducted, one invitro and the other in-situ, to estimate phosphorus leaching from senescing macrophytes. The first in-vitro experiment used weeds collected August 8, 1995 and show that 87% (S.E.= 6%) of the total plant phosphorus is leached from these macrophytes, whereas the second in-vitro experiment, using samples collected September 22, 1995, show that only 9% (S.E.= 1%) of the phosphorus is leached from macrophytes. The difference between the two leaching estimates is believed to be the result of overwintering development and expected starch accumulation in the September samples. The in-situ study provided the best prediction of phosphorus leaching from senescing macrophytes, estimating 1958 kg of phosphorus (S.E.= 867 kg) was released from senescing macrophytes in 1995. The results from both the input-output model and the internal loading estimates show that Tabor Lake is dominated by the internal cycling of nutrients beginning in June and continuing until September. Furthermore, it quantifies two important phosphorus sources and the timing of phosphorus delivery from these sources. The quantification and timing of phosphorus delivery in Tabor Lake is useful to managers establishing remediation strategies which try to reduce the total phosphorus present in the water column. This research also shows that mechanical harvesting of macrophytes removes more phosphorus from the lake than exits through the outlet and can be useful in reducing the total phosphorus available to internal loading cycles in Tabor Lake.
Discipline: Natural Resources & Environmental Studies
Content Model: info:fedora/ir:thesisCModel
Date added: 1997

Title: Aboriginal values, sacred landscapes, and resource development in the Cariboo Chilcotin region of BC.
Contributors: Titilope I. Kunkel (author), Ellen Petticrew (Thesis advisor), Robert Ellis (Thesis advisor), University of Northern British Columbia (Degree granting institution)
Abstract: The Aboriginal values and epistemologies of Indigenous peoples in the Cariboo and Chilcotin region of British Columbia are nested within one of the province's resource development hinterlands. These geographic locations are the birthplace of various cultures, legends, and stories of Indigenous groups. Resource developments at these locations continue to highlight the collision of values arising from urban-remote interactions. Using a hybrid approach of grounded theory and Indigenous research methodology, this dissertation uses two case studies to capture (1) the struggles and resistance of the Indigenous Tsilhqot'in communities as they defend their land against an incumbent mining company and (2) insights into Aboriginal community planning through documenting the Nazko First Nation's Comprehensive Community Planning process. Major themes addressed in this study are (1) Aboriginal values expressed during a Federal Panel Assessment of a proposed mine development in the Cariboo Chilcotin region (2) the contemporary culture of the Tsilhqot'in people including how some women continue to survive on the land and (3) geothermal energy as a potential primary resource. Outcomes of this research study highlight the critical Aboriginal values within the Cariboo Chilcotin region, and how these values are important considerations in resource development decisions. These outcomes provide new insights into how cultural values are embedded within traditional activities and landscapes. Furthermore, the findings show that despite contemporary challenges, community values continue to influence resource development considerations and choices made by the Aboriginal people. This research concludes with new theory propositions about Native Space and why the location and ecological footprint of resource development within the traditional territories of Aboriginal people are important in meeting the needs of their daily lives. --Leaf ii.
Discipline: Natural Resources & Environmental Studies
Content Model: info:fedora/ir:thesisCModel
Date added: 2015

Title: The flocculation feedback loop: Delivery of marine derived nutrients in Pacific salmon streams.
Contributors: John F. Rex (author), Ellen Petticrew (Thesis advisor), University of Northern British Columbia (Degree granting institution)
Abstract: Pacific salmon contribute significant quantities of marine derived nutrients (MDN) to their natal streams. Post-spawning carcasses fertilize and stimulate stream productivity as they decay. Until now, there has been no complete description of a nutrient delivery mechanism for natal streams. The salmon-floc feedback loop proposed here is a positive feedback system that delivers salmon derived nutrients and organic matter to the streambed where they can be retained and metabolized by benthic food webs to stimulate stream productivity and provide sustenance for juvenile salmon. The three stages of the salmon-floc feedback loop were verified using the controlled environment of flumes and field verified concentrations of salmon organic matter and inorganic particulates. Stage one, floc formation was found to occur in the water column in the presence of salmon organic matter as well as salmon organic matter and clay. During the salmon organic matter treatments the particle size distribution of suspended sediment shifted toward larger particles indicating the formation of flocs. Stage two, floc sedimentation was identified by an increase in the effective particle size distribution of fine sediments in the gravel bed after the addition of salmon organic matter and clay. Water column flocs settled or were sequestered on the flume bed by advective and intergravel flow through porous, raised, gravel bed sections. Stage three, floc dissociation and nutrient release was identified by the increase in nutrient, bacterial, and biochemical oxygen demand levels of fine sediments that were captured and retained within intergravel pores. Floc formation and streambed delivery/retention required sufficient quantities of organic matter from decaying salmon, sufficient but not excessive inorganic sediment levels, bacterial populations, low-flow stream conditions, porous raised gravel bed areas, and hyporheic exchange to be an effective MDN vector. The verification of the salmon-floc feedback loop is an important step toward furt
Discipline: Natural Resources & Environmental Studies
Content Model: info:fedora/ir:thesisCModel
Date added: 2009

Title: The delivery, seasonal storage, and trophic transfer of marine-derived nutrients within a stream-riparian ecotone
Contributors: Leah M. Vanden Busch (author), Ellen Petticrew (Thesis advisor), John Rex (Thesis advisor), University of Northern British Columbia (Degree granting institution)
Abstract: The objectives of this study were to evaluate nutrient delivery, storage, and trophic transfer between the Horsefly River spawning channel and its riparian zone during the 2011 sockeye salmon run and subsequent 2012 spring. The hyporheic zone was investigated as a pathway for nutrient exchange, transformation, and storage by analyzing water movement and ammonium (NH⁴⁺) concentration. Using stable isotopic analysis, the assimilation and storage of marine-derived nutrients (MDN) were evaluated through multiple trophic levels. Results identified lateral hyporheic flow as a dominant pathway for MDN delivery to deep-rooted vegetation, specifically willow trees <7-m from the streambank. Amphipods and chironomids appeared to assimilate MDN in the fall and maintained high spring biomass, indicating an important nutrient linkage in the salmon feedback loop. Finally, a temporal reversal in NH⁴⁺ concentration across the stream-riparian interface and a seasonal shift in nutrient fluxes revealed reciprocal subsidies that highlight the interconnectedness of these adjacent systems. --Leaf ii.
Discipline: Environmental Science
Content Model: info:fedora/ir:thesisCModel
Date added: 2015

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