Past Ciborowski Lab Members
Below you can find a list of past Ciborowski graduate students, along with their thesis titles and abstracts. PDF versions of full theses are linked where available.
Carsten Slama (M.Sc. 2010)
Thesis Title: Sediment Oxygen Demand of Wetlands in the Oil Sands Region of North-eastern Alberta.
Thesis Abstract: Coming soon...
Jesse Gardner Costa (M.Sc. 2010) - Full Thesis Text
Thesis Title: Spatial and temporal variation in sediment-associated microbial respiration in oil sands mine-affected wetlands of north-eastern Alberta, Canada.
Thesis Abstract:We measured whether carbon loss in the form of sediment-associated microbial respiration differed between unvegetated sediments of recently constructed oil sands process-affected (OSPM) and reference wetlands. Constituents of OSPM-wetlands (increased salinity, conductivity) were expected to influence respiration, increasing gas (methane and carbon dioxide) flux and sediment oxygen demands (SOD) compared to reference wetlands. However, OSPM-wetlands released 1/10th the methane of reference wetland sediments but did not differ in CO2 ebulition. Sediment oxygen demand (SOD) rates were twofold higher in OSPM than reference wetlands; chemical SOD exceeded biological SOD for both wetland classes (~90% of total SOD). OSPM-wetland sediments, likely have less microbial activity and more chemical oxidation than reference wetlands. Carbon accrual is necessary for reclaiming Alberta boreal wetlands. Low microbial activity may promote carbon sequestration within OSPM-wetlands but high chemical SOD may limit available oxygen for benthos respiration.
Josh Martin (M.Sc. 2010) - Full Thesis Text
Thesis Title: The nucleolar organizer of the salivary gland polytene chromosomes as a measure of recent growth in laboratory-reared and field-collected Chironomus spp. (Diptera: Chironomidae) LARVAE
Thesis Abstract: Midge larvae possess giant polytene chromosomes. Genes on these chromosomes undergoing transcription are visible as puffs. The nucleolar organizer (NOR), an especially large puff, shrinks when a larva is stressed. Two feeding experiments were conducted to examine how NOR size changes as a function of Chironomus riparius growth. NOR size was linearly related to an individual’s recent growth rate, independent of its body size.
Chironomids were collected from wetlands constructed with oil sands mine water and tailings (OSPM), and reference wetlands to evaluate the utility of the NOR as a field-based measure of larval growth and condition. Small larvae (< 9mm) did not yield sufficient quality preparations. Five karyotypes were identified, revealing cryptic diversity in the wetlands. NOR size was measured in a single karyotype; no measures were obtained from OSPM-affected wetlands. NOR size has potential as a surrogate growth measure that can facilitate estimation of chironomid secondary production.
Lyndon Barr (M.Sc. 2009) - Full Thesis Text
Thesis Title: Influences of tailings water, sediments, macrophytes and detritus on zoobenthic community development in constructed wetlands- Results of a reciprocal transplant study
Thesis Abstract: Constructed wetlands using oil sand process materials are being used by the oil sands mining corporations to reclaim the post-mining landscape. A reciprocal sediment transplant study was conducted to measure effects of sediment, water, plant cover, detritus mass and year to year variation on zoobenthic richness, density and relative abundance. Density did not change between wetlands, but the oil sand process water-affected wetland had lower richness than the reference wetland. Zoobenthic relative abundance was influenced by water type, macrophyte density and amount of accumulated detritus in sediment. Zoobenthos density was significantly positively associated with amount of plant cover and detritus combined. Sediment did not directly influence zoobenthic abundance or richneses. However, its inhibition of plan percent cover caused an indirect effect.
Jian Zhang (M.Sc. 2008) - Full Thesis Text
Thesis Title: Zoobenthic community composition and Chironomidae (Diptera) mouthpart deformities as indicators of sediment contamination in the Lake Huron-Lake Erie corridor of the Laurentian Great Lakes
Thesis Abstract: Zoobenthos are widely used indicators of ecological quality, integrating
changes in habitat condition over time. This thesis investigated community
composition and incidence of larval chironomid mouthpart deformities to assess
benthic condition in the Lake Huron-Lake Erie Corridor.
To test the "Reference-Degraded Continuum" multivariate approach of
zoobenthic community assessment, a series of analyses were used to identify two
unique groupings of least-contaminated reference sites, each with characteristic
relative abundances of zoobenthic genera and associated habitat features. Statistically
significant negative relationships between biological condition and sediment
contamination were found for each group. Indicator taxa were identified.
Six of 43 Chironomidae genera were assessed for mouthpart deformities.
Overall incidence of deformities varied from 0.57% to 5.88% among zones. Only
Chironomus exhibited significant among-zone variation, reflecting gross levels of
The combined use of community and individual indicators was more diagnostic
of benthic habitat quality than use of either approach alone.
Leanne Baker (M.Sc. 2007) -
Full Thesis Text
Thesis Title: The effects of petroleum coke amendments on macrophytes and aquatic invertebrates in northern Alberta, Canada constructed wetlands
Thesis Abstract: The oil-sands operators of Fort McMurray, Alberta produce six million tonnes of petroleum coke per year. The use of coke to stabilize clay-dominated mine tailings in constructed wetlands is being studied in landscape reclamation. We studied 'in situ' effects of petroleum coke amendments placed in three wetlands constructed with different materials over two years. Coke amendments did not significantly increase concentrations of trace metals in sediment pore waters or associated biota in plots. Growth of resident macrophyte species was not prohibited by coke amendments. Coke plots in a reference wetland contained fewer stress-intolerant invertebrates, than reference plots, likely due to avoidance of coke substrates. Adding peat reduced 'Chara' cover and biomass in the reference wetland, but had no impact on plants or invertebrates in the wetlands with little organic content. Overall, local coke amendment effects were detected in a reference wetland but not in two wetlands constructed with other oil sands process materials.
Christine Daly (M.Sc. 2007)
- Full Thesis text
Thesis Title: Carbon sources, microbial community production, and respiration in constructed wetlands of the Alberta, Canada oil sands mining area.
Thesis Abstract: Carbon sources, microbial community production, and respiration were determined in 9 wetlands in northeastern Alberta subject to oil sands mining. A stable isotope mixing model estimated the proportion of carbon sources (primary production, sediment and petroleum) assimilated by microbes. The proportions of petroleum-derived carbon from oil sands process material (OSPM) affected wetlands ranged from 62-97%. Bacterioplankton production was quantified by monitoring 3 H-leucine incorporation into bacterial proteins. Production and methanogenesis were inhibited by sulphate and/or salinity. Amending wetland sediments with topsoil, a reclamation strategy, did not affect bacterial production, or stimulate decomposition. Unvegetated wetland sediments were small net exporters of C (0.61 mg/m2/d) and do not appear to be on a trajectory to becoming net sinks in these early stages of development. Overall, microbial functional processes in OSPM-affected wetlands are markedly different from processes in reference constructed wetlands of equivalent age and do not correspond to those in a natural wetland.
Yakuta Bhagat (M.Sc. 2005)
- Full Thesis Text
Thesis Title: Fish indicators of anthropogenic stress at Great Lakes coastal margins
Thesis Abstract: Two commonly applied approaches to assessing the health of an aquatic habitat are the multimetric index of biotic integrity (IBI) and the multivariate approach. Fish community composition and local environmental conditions were measured at 143 sites across the entire U.S. coastline between 2002 and 2003, using overnight-set fyke nets (a large collaborative study to develop environmental indicators at Great Lakes coastal margins (GLEI)). Of these sites, data from 55 wetlands were used in an attempt to develop IBIs for the Northern Great Lakes (NGL) ecoregion and the Erie and Ontario (EOL) ecoregion. Candidate metrics were evaluated with respect to agricultural stress measured at drainage basin and immediate watershed topographical scales. An IBI could be developed only for the NGL ecoregion, based on a criterion requiring inclusion of at least 4 metrics representing attributes of a natural habitat. Fish community metrics in the NGL ecoregion varied more strongly with stress at the larger segment-shed scale. A further test of the IBI approach was done using independently developed IBIs for Typha and Scirpus aquatic plant zones of Great Lakes coastal wetlands (Uzarski et al. 2005). IBI scores were calculated for 32 wetlands with dominant Typha and Scirpus vegetation using data collected through the GLEI project. The results indicated that both the Typha and Scirpus IBI were selectively responsive to anthropogenic stressors. The Typha IBI varied most significantly as a function of population density-related stress and the Scirpus IBI most strongly reflected agriculture-related stress.
André Bachteram (M.Sc. 2004) - Full Thesis Text
Thesis Title: Bioturbation by Hexagenia larvae (Ephemeroptera: Ephemeridae) and its implications for sediment suspension in Lake Erie
Thesis Abstract: Burrowing activities of aquatic benthic organisms can influence sediment suspension and nutrient cycling. The burrowing mayfly Hexagenia is a dominant benthic organism in western Lake Erie, and Hexagenia bioturbation can potentially influence water quality and other benthic organisms. Using laboratory experiments, I determined bioturbation-induced sediment suspension rates of fine Lake Erie sediment caused by Hexagenia larvae of varying body lengths (13-28 mm) at densities of 70-1111 larvae/m2 and water temperatures ranging from 10-25°C. Bioturbation rates (sediment suspension, g/m2/h) were estimated by nonlinear regression from measurements of suspended sediment concentrations in jars, taken twice-daily for 14 d. Sediment settling rates were also estimated from twice-daily measurements of suspended sediment concentrations collected for an additional 18 d in the surface water from the bioturbation experiments.
MiSun Kang (M.Sc. 2003) - Full Thesis Text
Thesis Title: The relationship between athropogenic disturbance and the distribution of a nonindigenous species, Echinogammarus ischinus Stebbing, 1989 (Amphipoda: Gammaridae), at Great Lakes Coastal Margins
Thesis Abstract: Invasive species are becoming increasingly common components of Great Lakes zoobenthic communities. Elton (1958) proposed that biotic resistance against exotic species establishment is greater in intact communities than in those disturbed by human activities. However, Baltz and Moyle (1993) suggested that if abiotic conditions are appropriate, invasion is likely, regardless of the biota already present. I tested these hypotheses by investigating the distribution of Echinogammarus ischnus Stebbing, 1898, an exotic amphipod, at U.S. Great Lakes coastal margin sites influenced by varying degrees of anthropogenic stress. Thirty-nine sites supporting Gammarus fasciatus Say, 1818, a common amphipod with habitat preferences similar to Echinogammarus ischnus, were evaluated (out of a total of 74 sites sampled across the entire U.S. Great Lakes coastline). A highly significant association was detected between Echinogammarus ischnus and Gammarus fasciatus (Yates corrected χ2 = 7.94, d.f. = 1, p = 0.020, n = 74), consistent with the expectations of Baltz and Moyle's hypothesis.
Christel Leonhardt (M.Sc. 2003) - Full Thesis Text
Thesis Title: Zoobenthic Succession in Constructed Wetlands of the Fort McMurray Oil Sands Region: Developing a Measure of Zoobenthic Recovery
Thesis Abstract: This study investigated the effect of oil sands process material (OSPM) on the zoobenthic community of constructed wetlands in the Fort McMurray oil sands region. The unique characteristics of OSPM-affected wetlands may modify the successional trajectory of invertebrate communities compared to that of high or low-conductivity reference wetlands. The zoobenthic community of 31 wetlands, aged 0 to 30 years, was simultaneously sampled, allowing inference into the chronological sequence of change that results with wetland succession. Wetlands were categorised 'a priori' into one of three classes: low conductivity (<700 µS/cm) or high conductivity (700-2,500 µS/cm) reference wetlands or OSPM-affected wetlands (700-4,000 µS/cm) containing tailings and/or water from bitumen extraction. Invertebrate communities in each wetland were assessed using core, artificial substrate, and sweep net sampling methods. Principal components analysis and discriminant function analysis were used to classify each OSPM-affected wetland as being 'equivalent to young' or 'equivalent to mature' reference wetlands. Restoration of mined areas to pre-mining conditions of diversity and abundance of habitat types, using wetlands as a component of a reclamation strategy, is a viable option.
Kevin Ganshorn (M.Sc. 2002)
Thesis Title: Secondary Production, Trophic Position and Potential for Accumulation of Polycyclic Aromatic Hydrocarbons in Predatory Diptera in Four Wetlands of the Athabasca Oil Sands, Alberta, Canada
Thesis Abstract: Larvae of aquatic Diptera are important predators in fishless wetlands of northeast Alberta. Annual production was estimated for benthic (Chironomidae: Tanypodinae) and pelagic (Chaoboridae: Chaoborus) dipteran populations in four wetlands in surface-mined areas of the Athabasca oil sands, two of which received oil sands mine process material (OSPM; containing polycyclic aromatic hydrocarbons (PAHs)), and two of which were reference wetlands. The structure of benthic and pelagic food webs was estimated by measuring stable carbon and nitrogen isotopes. Stable nitrogen isotopes were also used to determine trophic levels of Tanypodinae and Chaoborus in order to determine their potential to bioaccumulate PAHs. Annual production was estimated along with total PAH body burdens to determine the potential for biomass and PAH export by the emergent adult insects. Tanypodinae production (1.55 - 28.77 g/m2/y) consistently exceeded Chaoborus production (0.009-0.372 g/m2/y). Chaoborus trophic position estimates were consistently greater than estimates for Tanypodinae, suggesting greater PAH bioaccumulation potential for Chaoborus. Tanypodinae had greater potential to export PAHs (1.86-37.1 mg/m2/y) than Chaoborus (0.011 - 0.45 mg/m2/y) due to greater production and PAH body burdens.
Erin Swansburg (M.Sc. 2000) - Full Thesis Text
Thesis Title: Effects of Trace Metal Enrichment in Cobble Streams and Rivers on the Aquatic Midge (Diptera: Chironomidae)
Thesis Abstract: Chironomidae (Diptera) are commonly used as indicators of environmental degradation. This study examined the effects of mine drainage on chironomid assemblages in northeastern New Brunswick rivers. At mine drainage receiving sites, significantly elevated concentrations of metals in water (Ba, Fe, K, Mn and Zn; p < 0.05) and in periphyton (Cd, Co, Cu, Mn, Pb and Zn; p < 0.002) were detected. Concentrations in periphyton were 10-100 times higher than in water, suggesting that metal uptake from diet may be a more important source of metals for primary consumers than surrounding water. Chironomid composition was significantly different at mine drainage receiving sites than at reference sites. To assess the effects of metal enriched periphyton on aquatic invertebrates downstream of metal mining facilities, periphyton was collected at mine drainage receiving (MIN) and reference (REF) sites in northeastern New Brunswick rivers and fed to Chironomus riparius in a 10-d bioassay. These results suggest that primary consumers feeding on periphyton are at risk of significant mortality and reduced growth, compromising the viability of most metal intolerant populations. Consequently, metal enrichment of periphyton could explain observed differences in chironomid communities of mine drainage receiving rivers.
Jocelyn Gerlofsma (M.Sc. 1999) - Full Thesis Text
Thesis Title: The Effects of Anoxia and Temperature on the Development and Survival of Hexagenia (Ephemeroptera: Ephemeridae) embryos, and implications for Western Lake Erie
Thesis Abstract: Benthic Hexagenia embryos can be exposed to anoxic hypolimnetic water or can become buried in the sediment. In western Lake Erie, periodic anoxia resulting from transient stratification has eradicated Hexagenia populations. The ability of embryos to survive anoxia and hatch when normoxic conditions return would allow the population to recover after an anoxic event. I studied the survivorship and development of Hexagenia embryos at various developmental stages maintained in anoxic conditions for different time periods, at different temperatures. In 1996, Hexagenia nymphs were absent from several regions in western Lake Erie. I collected sediment cores from two such areas and two other areas supporting nymphs. I studied the effects of hypoxia on embryos by adding eggs to the sediment cores. The results of my studies are that Hexagenia eggs would be able to survive periods of anoxia at different temperatures over its embryological development. This would allow eggs to repopulate an area after a period of epibenthic anoxia that would eradicate the nymphs.
Mark Whelly (M.Sc. 1999) - Full Thesis Text
Thesis Title: Aquatic Invertebrates in Wetlands of the Oil Sands Region of Northeast Alberta, Canada, with Emphasis on Chironomidae (Diptera)
Thesis Abstract: This thesis describes the effects of oil sands process waters (OSPW) on the benthic macroinvertebrate component of wetland ecosystems through assessment of biological responses at various levels of organization. Comparison of the macroinvertebrate communities among OSPW-affected wetlands and environmentally-similar reference wetlands indicated an insignificant trend of reduced taxonomic richness and abundance. Also, the general benthic macroinvertebrate community and specifically the chironomid community showed differences in community composition between OSPW and reference wetlands, in terms of the presence and relative abundances of dominant taxa. The incidence of chironomid mouthpart deformities, a biomarker of teratogenicity, was low at three pairs of reference and OSPW wetlands. Similarly, there was no evidence to show that OSPW induces mouthpart deformities. However, growth and survival were significantly reduced in both lab and field-derived C. tentans larvae exposed to higher concentrations of OSPW.
George Pardalis (M.Sc. 1997) - Full Thesis Text
Thesis Title: A comparison of the responses of benthic invertebrate individuals, populations, and communities to creosote contamination, with emphasis on Chironomidae (Diptera)
Thesis Abstract: Environmental management strategies include the use of aquatic biota for environmental monitoring and assessment. There exists a need for reliable early warning indicators of impending environmental degradation. This study evaluated the toxicity of creosote as indicated by a 48-h acute toxicity sediment bioassay and various measures of the benthic invertebrate community and chironomid populations in artificial ponds, to which creosote was added. The study also evaluated the potentially useful early warning indicator, chironomid morphological deformities, in determining a toxic response. In the laboratory, a 48-h spiked-sediment toxicity test was conducted by placing 4th instar Chironomus riparius Meigen larvae in formulated sediment (sand, sculptor's clay, potting soil) spiked with creosote (a PAH mixture). The estimated median lethal concentration (LC50) value was 437 µg creosote/g sediment. A toxicity study was conducted in 10,000 L artificial ponds (mesocosms) located at the Turfgrass Institute, University of Guelph, Guelph, Ontario. Ponds received a single application of creosote to produce a logarithmic series of nominal concentrations ranging from 0.053 µL/L to 100 µL/L water. Four community attributes (total invertebrate density, family richness, chironomid density, chironomid generic richness) and two population measures (Procladius density, Psectrocladius density) were tabulated and regressed against creosote concentration. Combined triplicate samples of Procladius larvae from each pond were examined for deformities of various cephalic structures (ligula, paralabial combs, and mandibles).
Andreas Winter (M.Sc. 1994)
Thesis Title: Influence of Oxygen Stress, Temperature and Density on the Growth and Survivorship of Hexagenia nymphs (Ephemeroptera: Ephemeridae)
Thesis Abstract: Burrowing mayflies of the genus Hexagenia are sensitive to conditions of low dissolved oxygen, and their population has been proposed as an ecosystem objective for assessing the recovery from eutrophication of mesotrophic lakes in which they were once abundant. While acute oxygen tolerance limits are known for Hexagenia nymphs, effects of prolonged exposure to sublethal levels of hypoxia have not been previously studied. I conducted 21-day laboratory experiments examining hypoxic stress in relation to different densities (1, 5, 10 and 20 individuals per 70 cm2), and in relation to a range of temperatures (4-20°C) characteristics of their Great Lakes habitat. Increasing density had a significant negative effect on survival in experiments with low overall survivorship. When survivorship was high, the interaction of oxygen stress (2.0-4.3 mg/L (O2)) and density significantly influenced survival, but density alone did not. Density was negatively correlated with growth under oxygen stressed conditions in cultures that had high overall survivorship, and positively correlated with growth in cultures that had low survivorship. Survival of nymphs increased with oxygen concentration up to an asymptote at approximately 7-8 mg/L. Survivorship increased with temperature up to an asymptote at approximately 9.5°C. Higher temperatures aggravated the effects of hypoxia on survivorship. Oxygen and temperature together explained 89% of the variability in survivorship and 71% of the variability in growth among experiments. Within experiment, larger nymphs generally had higher survivorship than smaller nymphs, and this trend exhibited a slight positive correlation with temperature. My data predict a gradual increase for survivorship and total biomass of nymphs in western Lake Erie. Combined with in situ monitoring of oxygen and temperature conditions, these results should enable us to anticipate the time to reestablishment of the Hexagenia population in mesotrophic habitats.
Elizabeth Hanes (M.Sc. 1993)
Thesis Title: Life History Characteristics and Size Variation of the Burrowing Mayfly Hexagenia (Ephemeroptera: Ephemeridae): Maternal vs. Environmental Constraints
There is tremendous size variation within both laboratory and field populations of the mayfly Hexagenia. I studied the size variation in adults (imagoes) of this mayfly collected in the summers of 1989 and 1990 from Lake St. Clair, Southwestern Ontario (42°20'N; 82°57'W). Additionally, I examined the influence of endogenous factors (egg hatching, egg diapause, maternal size) on size and survivorship of larval Hexagenia. Female imagoes collected early in the emergence period were significantly larger than females collected later in the summer. There was low incidence of parthenogenesis (<5%), egg diapause (<0.01%) and viability of eggs produced through interspecific mating (0%) in the laboratory. Egg size of H. limbata was negatively correlated with collection date. Although egg size did vary among female sizes, there was no clear relationship between egg size and maternal size. Maternal size was negatively correlated with larval size, after 40 d growth. Maternal size and maternal size2 were correlated with per cent larval survival. Maternal parents exhibiting mean body length produced larvae with the highest survivorship after 40 d growth. The length of incubation (days) required for egg hatch was negatively associated with per cent larval survival (40 d) but was positively correlated with larval size (80 d). Of sediments examined from six different waterbodies, Saginaw Bay sediment provided larvae with the best survivorship and the largest size, and when given a choice, larvae selected that sediment type. Subsequently, I developed a standard sediment (STND-3) that mimiced the particle size distribution and organic content of Saginaw Bay sediment.
Donna Bedard (M.Sc. 1990)
Thesis Title: Factors Influencing the Bioaccumulation of Chlorinated Hydrocarbons by Hexagenia nymphs (Ephemeroptera: Ephemeridae)
Zsolt Kovats (M.Sc. 1990)
Thesis Title: Adult Aquatic Insects as Biomonitors of Organochlorine Contamination in Freshwater Habitats
The bottom-dwelling larvae of aquatic insects are useful indicators of organochlorine (OC) contamination in aquatic habitats. However, these animals are often difficult to collect in numbers sufficient for contaminant analysis by gas chromatography. Winged, night-active adults retain accumulated contaminants, and can be collected in large numbers using light traps. Methodology was developed and evaluated for collection and analysis of adult caddisflies (Trichoptera) and mayflies (Ephemeroptera) for monitoring OC contaminant levels in freshwater habitats. Insects were collected using light traps from Great Lakes connecting channels and reference sites, and samples were analyzed for contaminants. Contaminant concentrations in samples of adult insects broadly corresponded to reported levels of chlorinated organic contaminants in sediments of the rivers and lakes of their origin. Spatial pattern of contaminants among insect samples collected along the length of rivers reflected the pattern documented for sediments in all Great Lakes connecting channels. Contaminant concentrations in insects varied with time in the Detroit and St. Clair rivers. Significant differences in contaminant concentration were found in animals of different species from the same location. Light-trapped adult aquatic insects are well suited for use in long-term biomonitoring programs, and for preliminary or synoptic studies of aquatic contamination in previously unsurveyed areas.