Graduate Students

Ryan Boudens (Coadvisor Dr. Christopher Weisener) M.Sc. Candidate (Great Lakes Institute for Environmental Research) Thesis Title: Chemical and biological responses to gamma irradiation treatment of oil sands fluid fine tailings

Project Summary: Exploitation of the oil sands in northeastern Alberta has created large volumes of waste materials termed fluid fine tailings (FFT). These materials are stored in large settling basins to allow adequate separation of the oil sands process water and the FFT. The separated water in these holding areas is used in onsite bitumen extraction processing or in some cases allowed to settle before reclamation into functional wetlands.  A major concern is the presence of naphthenic acids (NA); these are considered toxic and comprise recalcitrant groups of carboxylic acids naturally released from bitumen during the extraction process. To date several treatment options have been investigated, ranging from chemical to biological and photo-catalysis treatments. These treatments are designed to enhance the degradation process and reduce the potential toxicity of NAs. A less explored treatment option is gamma irradiation, used to break down complex, recalcitrant organics in industrial wastewaters and contaminated groundwater. This treatment has two potential benefits as it can suppress activity of microbes responsible for greenhouse gas emissions and potentially can disrupt long chain hydrocarbons in a manner similar to ozonation.  My study will assess the development of chemical REDOX gradients, and kinetic responses of indigenous microbes inoculated into two gamma treated oil sand waste products (fresh and aged). My goal is to track differences in chemical gradient structure and the effects of gamma irradiation as a bacterial stimulus. This research will contribute to our understanding of the biogeochemical processes of FFT treated with gamma irradiation to degrade NAs and provide insight into our understanding of the stability of recalcitrant compounds after gamma irradiation

Jeff Buckley M.Sc. Candidate Thesis Title: Assessing the accuracy of fish-based biological indicator models as indicators of wetland condition at Great Lakes coastal margins using receiver-operator characteristic curve analysis.

Project Summary: Coastal wetlands are an important component of the Great Lakes ecosystem, providing services such as nutrient retention, disturbance regulation, and essential aquatic habitat. However, they are at risk of degradation from human activities, necessitating tools to measure the amount of anthropogenic stress. Biological indicator models measure risks of disturbance and assess 'ecological condition' based on the biological community. Although several fish-based biological indicator models have been proposed for use in Great Lakes coastal wetlands none have been well validated against independent data.

My research is comparing several wetland fish biological condition models and determines which can accurately and consistently indicate a wetland’s ecological condition. Receiver operating characteristic (ROC) curve analysis is commonly used in medicine and machine learning to evaluate diagnostic test accuracy. Using data collected through the Great Lakes Environmental Indicator (GLEI) project and through the Great Lakes Coastal Wetland Monitoring Consortium, I derived ROC curves to determine whether these models are able to accurately show the 'health' of a wetland. By objectively determining which models can best indicate anthropogenic stress I will help researchers and decision-makers choose tools to better manage and protect coastal wetlands.

 

Chantal Dings-Avery M.Sc. Candidate Thesis Title: Diversity and net ecosystem production in wetland community mesocosms: Is gamma radiation effective at detoxifying naphthenic acids in oil sands tailings water and sediment?

Project Summary: Biodiversity is often used as a measure of the successfulness of ecological restoration, but the relationship between biodiversity and ecosystem function or services (the benefits that ecosystems provide, such as carbon storage or regulating water flow) is poorly understood. Within the Alberta oil sands area, environmental regulations require that the post-mining landscape be as productive as it was in its pre-industrial state. Two of the most prevalent factors limiting aquatic invertebrates in the reclamation of Alberta oil sands tailings ponds are high salinity and elevated levels of naphthenic acids which are acutely toxic to many organisms. My research examines the effectiveness of using gamma radiation in detoxifying the naphthenic acids in mine tailings water and sediment. Although other treatments are in development, methods such as ozone or ultraviolet light penetrate only water. Water and sediment from three freshwater wetlands, three saline wetlands and three tailings ponds were collected and placed in 68-L mesocosms. Materials placed in one-half of the mesocosms had been gamma irradiated.  I am monitoring the development of biodiversity and community assemblages of colonizing aquatic invertebrates as a measure of biological condition, and determining net ecosystem production as an ecological service. My research will determine whether gamma irradiation is effective at detoxifying tailings material and the extent to which this is reflected in differences in productivity.

Kellie Menard M.Sc. Candidate Thesis Title: Early community composition and development of terrestrial and semi-aquatic invertebrate communities of constructed fens in northeastern Alberta.

 

Project Summary: The objective of my research is to document terrestrial and semi-aquatic invertebrate species composition colonizing a recently-constructed boreal fen. Sandhill Fen (52 ha) is the first full-size fen to be constructed in the post-mining landscape of an oil sands lease near Fort McMurray, Alberta. My research documents the distribution of fauna of saturated and upland areas of the fen as a function of soil moisture and salinity, and habitat (herbaceous vegetation) diversity. I collected invertebrates using vacuum sampling, pitfall traps, and sticky traps to sample vegetation-and-soil-associated, surface-dwelling and flying fauna, respectively. Local reference fens varying in productivity, hydrology and vegetative community will be sampled for comparative purposes. In addition to documenting factors associated with invertebrate biodiversity I will identify species or assemblages that can serve as bioindicators of the ecological condition of a reclaimed fen.