Poster Presentations

April 10, 2018

1. Baloun, Dylan E. Lane Lehmkuhl/McLoughlin
2. Balzer, Zachary S. Davis Gray/Lehmkuhl
3. Beadle, Joel D. Hudson Baulch/Niyogi
4. Braun, Kelton A. Davis Ambrose/Cota-Sanchez
5. Diyes, Chulantha P. Chilton Davis/Lane
6. Elgin, Andrew S. Morrissey/Clark Gurney/Lane
7. Espinoza-Ulloa, Sebastian A.  Andres/Chilton Morrissey/Niyogi
8. Guerrero Chacon, Adriana L. Lane Marchant/Angrini
9. Hendriks, Anouk G. Wei Ambrose/Wilson
10. Johnsen, Kirsten E. McLoughlin/Fortin Chivers/Ferrari
11. Johnston, Dylan Davis Ambrose/Cota-Sanchez
12. Pecylak, Stephen Ferrari McLoughlin/Chivers
13. Pusz-Bochenska, Karolina Gurney McKeller/Morrissey
14. Sadat, Mohammad Kaminskyj Ham/Wei
15. Salahinejad, Arash Chivers/Niyogi Ferrari/Morrissey
16. Thoroughgood, Jessica T. Chilton Marchant/Todd
17. Yunik, Matthew E. Chilton Davis/Gray
18. Zhang, Liyong Ambrose Wei/Wilson
 Posters Presentations on April 10th, 2018 
Posters 1, 4, 7, 10, 13 and 16 will be presented from 10:30 am – 11:30am
Posters 2, 5, 8, 11, 14, and 18 will be presented from 11:30 am – 12:30pm
Posters 3, 6, 9, 12, 15, and 17 will be presented from 12:30 pm – 1:30pm

Oral Presentations

April 11, 2018

9:15 #19. de Albuquerque, Igor  Ken Wilson  Cota-Sanchez/Todd
9:30 #20.  Rivet, Danielle R. Douglas Clark/Ken Wilson  Angrini/Benson
9:45 #21. Bas, Kyla  Bob Clark  Gurney/Hudson
 10:00 #22. Wishart, Andrea Jeff Lane  Ferrari/Gurney
 10:15 #23.  Luff, Katelyn M.  Kirsty Gurney Ferrari/McKellar
BREAK 10:30 - 10:45
Session 2. Chair:  Jillian Kusch
10:45 #24. Shafiei, Farshad  Phil McLoughlin Wilson/Chivers
11:00 #25. Kellett, Dana Ray Alisauskas  Chivers/Clark
11:15 #26. Bryshun, Reid   Maud Ferrari/Mike Pollock  Clark/McLoughlin
11:30 #27. Vera Velaz, Roy Hugo Cota-Sanchez  Ambrose/Davis
LUNCH 12:00 – 1:15
Session 3.  Chair: Mohammad Naderi
1:15 #28.  Waddell, Brandon  Carlos Carvalho  Kaminskyj/Wei
1:30 #29.  Srayko, Stephen Doug Chivers/Tim Jardine Davis/McLoughlin
1:45 #30.  Kodzhahinchev, Vladimir I.  Som Niyogi/Lynn Weber  Hudson/Morrissey
2:00 #31.  Superbie, ClaraPhil Phil McLoughlin Lane/Morrissey
2:15 #32.  Tomchuk, Patricia A.  Phil McLoughlin  Lane/Chedrese

BREAK  2:30 -2:45 

Session 4. Chair:  Kevin Bairos-Novak
2:45 #33. Marquez Mellidez, Carmen Ken Wilson Bonham-Smith/Wei
3:00 #34.  Abirhire, Oghenemise  Jeff Hudson Evans/Niyogi
3:15 #35.  Attaran, Anoosha  Doug Chivers/Som Niyogi  Benson/Marchant
3:30 #36.  Abrams, Joseph S.  James Benson  Kaminskyj/Todd
3:45 #37.  Imtiazy, MD NOIM  Jeff Hudson  Evans/Niyogi

Presenter Abstracts

Poster Presentation Abstracts

 #1 10:30  DYLAN E. BALOUN & JEFFREY E. LANE. Quantifying intrinsic and environmental factors that influence allocation of resources to life-history trade-offs in North American red squirrels (Tamiasciurus hudsonicus). Department of Biology, University of Saskatchewan, Saskatoon, SK. 

Animals in the wild have limited resources to allocate to life-history traits that are critical for reproduction and survival. Trade-offs, therefore, exist between these traits forcing animals to “choose” which trait to invest this limited energy in, thus resulting in negative correlations between traits. However, when there is access to a greater abundance of resources, trade-offs can collapse resulting in positive correlations between traits, as animals are not resource limited. I am interested in decomposing observed phenotypic variation into its associated components (genetics, maternal effects, vs. environmental), and exploring how their inherent capacity to process energy (i.e., metabolic rate) influences allocation of energy to various life-history traits (i.e., parturition date, litter size, growth rate, etc.). Using a >30 year (10-generation), long-term life-history trait dataset from the Kluane Red Squirrel Project (collected in the northern boreal forest). I am researching to understand how and why North American red squirrels, in a boom-bust resource system (due to the masting nature of white-spruce in this area), manage trade-offs in years of varying resource availability, how resource management strategies may be inherited, and how animals choose what to invest resources in and balance the multitude of life-history trait investments.


#2 11:30  ZACH S. BALZER & ARTHUR R. DAVIS. Hitching a Ride: Adaptations of First Instar Stylops sp. (Strepsiptera) Larvae for Locating and Travelling on Their Hosts. Department of Biology, University of Saskatchewan, Saskatoon, SK. 

Strepsiptera are a peculiar order of endoparasitic insects that infect several other insect orders. Stylops infects numerous mining bees, including Andrena milwaukeensis in Saskatoon. To find a suitable host, mobile first instar larvae must locate and travel phoretically on a bee host to its subterranean nest, where they must encounter an immature stage to infect. Several unique adaptations, found using SEM, can be observed on these larvae to aid them in their journey. Sensory setae and olfactory pits are present on the head to help the strepsipteran larva detect the phoretic host and eventually its permanent host. The thorax and abdomen of these miniature parasites are covered in spinules to help the larvae stay on the bee during flight or grooming. The pro- and mesothoracic tarsi are elongated and dilated, perhaps having a suction cup-like function, allowing larvae to stay attached to, but also move around, a flying bee. Finally, the last abdominal segment has two long caudal filaments, each with a dilated tip, also potentially allowing a secure grip on the bee host during flight


#3 12:30  JOEL BEADLE1, KRISTINE HUNTER1, DAVID M. VANDERGUCHT2, JEFF J. HUDSON1. Effects of Aquaculture Operations on Water Quality in Lake Diefenbaker.  1Limnology Lab, University of Saskatchewan, Saskatoon, SK; 2Saskatchewan Water Security Agency, Regina, SK. 

Lake Diefenbaker (LD) is a large reservoir located in southern Saskatchewan. The reservoir provides source drinking water for 45% of Saskatchewan. It also supplies water for industrial and agricultural purposes, generates hydroelectricity, provides flood control and recreation. Residents on the reservoir have complained of increased algal blooms indicative of decreased water quality. Some residents have attributed the perceived decrease in water quality to increased nutrient loading from the aquaculture operations. To address this concern, I have examined a set of water quality immediately in the embayment that contains the aquaculture farm and downstream of the embayment. To add further context to the potential impact of the fish farm, I will compare the nutrient loading from the farm with that from the South Saskatchewan River.  A four year database (2011-2014) is being analyzed to conduct this study. An additional year of field study will be completed pending low flows in the South Saskatchewan River in 2018. This additional low flow year will be in direct contrast to the high flow years of 2011 to 2014. We anticipate that nutrient loads from the fish farm will be more relevant during low flow periods, and may lead to water quality issues.


#4 10:30  KELTON T. BRAUN & ARTHUR R. DAVIS. Nectary structure and vascularization in relation to phylogeny among members of tribe Astereae of the family Asteraceae. Department of Biology, University of Saskatchewan, Saskatoon, SK. 

Nectar, the sweet substance insects and other animals feed upon when visiting flowers, is secreted by structures known as nectaries. These poorly studied structures occur in a majority of the 25,000 species of the sunflower family (Asteraceae). Within this family, floral nectaries are frequently of the annular type, forming a ring of tissue surrounding the base of the style atop the inferior ovary, filling the space between the style and the corolla tube. Because the nectaries are located deep within the corolla tube, photosynthesis by these cryptic glands is negligible, meaning for nectar to be formed, sugars must be supplied to the nectaries through vascular tissue originating elsewhere in the capitulum. The vascularization of nectaries in many genera throughout the North American clade of Astereae (a tribe within Asteraceae) is being investigated using resin and paraffin wax sectioning, whereas the nectary morphology is being examined using scanning electron microscopy. Floral nectaries potentially hold important information regarding phylogenetic relationships between species. The data obtained from this research will be analysed to determine if both nectary vascularization and morphology can be utilized as characters to advance our phylogenetic understanding within this clade and, if successful, extrapolated to other groups within this large dicot family. 


#5 11:30  Chulantha P. Diyes & Neil B. ChiltonMicrobiomes of Dermacentor andersoni and Dermacentor variabilis females Department of Biology, University of Saskatchewan, Saskatoon, SK. 

Tick microbiomes (i.e. microbial communities) contain both pathogenic and non-pathogenic (= endosymbiotic) bacteria, some of which affect tick reproductive fitness and survival. The Rocky mountain wood tick (Dermacentor andersoni) and the American dog tick (D. variabilis) are of medical and veterinary significance in North America because they are vectors of microbial pathogens to humans, livestock, companion animals and wildlife. Despite this, little is known of the microbiomes of D. andersoni and D. variabilis in Canada. We will determine which bacterial species occur within the microbiomes of D. variabilis and D. andersoni females that have fed on vertebrate hosts, and determine which bacteria are maternally inherited (i.e. transmitted transovarially from female ticks to the egg and larval stage). The effect of ambient temperature on egg development and microbiome composition will also be examined. Genomic DNA will be extracted and purified from engorged female ticks, their eggs (individuals and pools) and the larvae that hatch from eggs. Bacterial species diversity and abundance will be determined using a next-generation sequencing approach. The 16S and cpn60 genes will be used as molecular markers. This methodology will be applied to eggs that have been maintained at different temperatures. 


#6 12:30 ANDREW S. ELGIN1, ROBERT G. CLARK1,2, TIMOTHY D. JARDINE3, CHRISTY A. MORRISSEY1,3. Does nutrient export from prairie wetlands offset effects of intensive cropping on aerial insectivorous birds? 1Department of Biology, University of Saskatchewan, Saskatoon, SK; 2Environment and Climate Change Canada, Prairie and Northern Wildlife Research Centre, Saskatoon, SK; 3School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK

 Prairie wetlands are important breeding and foraging habitat for many bird species; however, more than half of these wetlands have been lost, primarily due to agricultural activity such as drainage. Intensive agriculture has also been implicated in farmland bird population declines. Despite concomitant loss of wetlands and farmland birds, the ecological value of wetlands to passerine birds breeding on farmland has rarely been assessed. Tree Swallows (Tachycineta bicolor­) are aerial insectivorous birds which readily breed in farmland environments and display dependence on aquatic insect prey. I will use Tree Swallows as a model to examine if and how prairie wetlands offset adverse effects of agriculturally-induced stressors of birds. Using miniaturized GPS units, I will investigate whether wetlands are selected as foraging habitat by Tree Swallows. I will also test the hypothesis that aquatic insects derived from wetlands act as a source of long-chain omega-3 fatty acids important to Tree Swallow nestling development, and I will evaluate whether these fatty acids reduce the impact of pesticides on Tree Swallows. The results of these investigations have implications for conserving prairie wetlands and aerial insectivores and may inform sustainable agricultural development.



#7 10:30  ESPINOZA-ULLOA SEBASTIAN & ANDRES JOSE. Genomes to the rescue: Saving Darwin’s mockingbirds (Mimus spp.) from extinction. Department of Biology, University of Saskatchewan, Saskatoon, SK. 

Nearly one-quarter of all birds are either threatened.  Genetic studies in endangered avian species have often focused on the effects of demographic decline in genetic variability and population differentiation. To date, little attention has been paid to decipher the genomic landscape of deleterious mutations, an insidious consequence of population fragmentation and the preponderance of genetic drift in small populations. The mocking birds of the Galapagos Islands (Mimus spp.), a complex of four isolated species with contrasting demographics, are a good model system to study the extent and nature of deleterious variations in natural populations of different sizes. My current goal is to carry out a complete genome sequence analysis to identify dramatic population bottlenecks that could have left a sharp increase in the deleterious heterozigosity in the Darwin’s mockingbirds genome. As first step to provide genome-scale insights into the near-extinction of this bird, I have assembled the genome of the San Cristobal mockingbird (Mimus melanotis). This species, characterized by a relatively large population size, will serve as a reference to determine the genomic consequences of small population size and population bottlenecks. Ultimately, my results will set the basis for a genetic for a marker assisted rescue program of Darwin’s mockingbirds.


#8 11:30  ADRIANA L. GUERRERO-CHACÓN & JEFFREY E. LANE. Intraspecific variation in the energetics of reproduction and growth in Columbian ground squirrels (Urocitellus columbianus). Department of Biology, University of Saskatchewan, Saskatoon, SK, S7N 5E2.

Energy is a temporally and spatially limited resource. Consequently, life-history evolution theory is predicated on the assumption that energy spent on one trait must be traded off against another. However, the actual expenditure of energy on life history traits is rarely quantified and these costs could be masked by: differential access and availability of resources, individual variation in resources stored (body composition), or by the metabolic costs associated with these traits. Our main objective is to evaluate how intraspecific variation in resting metabolic rates and endogenous fat stores of Urocitellus columbianus are related to individual variation in female reproductive output and juvenile growth rate. We will test two models of energy allocation strategies, the increased-intake and the allocation models. To do so, we will measure resting metabolic rate (through open-flow respirometry) and body composition (through quantitative-magnetic resonance) of females and juveniles at standardized points throughout the active season in one population of ground squirrels located in Sheep River Provincial Park, Alberta. We will estimate reproductive output as total litter mass at parturition and weaning. This project will expand our understanding of how energy is partitioned in a mammalian hibernator, thereby testing some of the key assumptions of life-history evolution theory. 


#9 12:30  WILHELMINA (ANOUK) G.H.M  HENDRIKS  & DR. YANGDOU WEI. Pythium cryptoirregulare: a novel oomycete pathogen on the host Arabidopsis. Department of Biology, University of Saskatchewan, Saskatoon,  SK.

 Phytopathogenic Pythium sp. causes seedling damping off on a wide range of crop species worldwide.  Pythium cryptoirregulare was recently discovered to be an oomycete pathogen of the model plant Arabidopsis thaliana. To understand pathogenesis on the host, A. thaliana seeds and seedlings were inoculated with P. cryptoirregulare and were observed using histological approaches. The majority of previous studies presented Pythium sp. as a necrotrophic pathogen. However, evidence was collected that contradicts this statement as P. cryptoirregulare initially produced biotrophic primary hyphae that are large-diameter and entirely intracellular, followed by necrotrophic secondary hyphae that are narrower and either intercellular or intracellular. Interestingly, during the inoculation process a reduced growth rate of the seedlings was observed when P. cryptoirregulare was present, suggesting that P. cryptoirregulare secretes growth inhibitors for greater infection success. Future experiments will include pathogenicity assays of this pathogen on several Arabidopsis mutants and ecotypes to develop a better understanding of the defense response associated with this new pathogen and therefore also its infection strategy. Also, live cell imaging and the use of transgenic A. thaliana lines expressing fluorescent protein-tagged organelle markers will be used to clearly determine the cellular locations of the hyphal structures and host cell viability.


#10 10:30  KIRSTEN JOHNSEN1, DR. DANIEL FORTIN2, & DR. PHILIP MCLOUGHLIN1. Potential Differences in the Foraging Strategies of the Sable Island Horse. 1Department of Biology, University of Saskatchewan, Saskatoon, SK. 2Department of Biology, Université Laval, Québec, QC. 

The Sable Island Horse (Equus ferus caballus) provides a unique opportunity to study how constraints affect time budgets and foraging behaviors without the factors of predation and interspecific competition. In the west, where there are permanent ponds, the horses do not spend as much time acquiring water as their eastern counterparts who dig wells in order to drink. I aim to test if there are different foraging strategies that stem from this main difference in their time budgets. There are also differences in parasite loads on the island and I will study how this constraint can affect foraging behaviors within the differences that may be caused by water source preference. I will test these ideas by estimating net energy intake while assuming that more energy translates to greater success. Energy intake will be estimated by measuring bite rates as well as the average vegetation quality by community. Energy losses will be estimated by considering available energy from each community and losses due to performing different activities in the time budgets. Then differences in net energy intake between groups will be tested using generalized linear models while accounting for variability between individuals as Sable Island has a long running census program.



#11 11:30  DYLAN W. JOHNSTON & ARTHUR R. DAVIS. Nectar production dynamics of the bifurcated floral nectar spur of Impatiens hybrida (Balsaminaceae). Department of Biology, University of Saskatchewan, Saskatoon, SK. 

Floral nectar spurs are narrow and hollow outgrowths of either the sepal or petal whorls that most often serve to hold pollinator-attracting nectar. These structures are hypothesized to have a strong influence in the evolution of floral diversity and plant-pollinator coadaptation and are considered key innovations. Floral nectar spurs are present in at least 21 families (19 dicot, 2 monocot) of angiosperms; in some families it is a universal feature, whereas in others only certain genera possess spurs. Even more interesting and less understood are subgroups of spur producing species that generate multiple spurs, such as double or bifurcated spurs. Accordingly, nectar production dynamics of the bifurcated floral nectar spur of Impatiens hybrida was followed throughout nine stages, based on bud size and morphological changes. A general trend was identified in nectar volume and sugar concentration, whereby both increased to a peak and then decreased until floral abscission (suggesting nectar reabsorption). Statistical differences were observed between stages for both nectar volume and sugar concentration. Preliminary investigations into the nectar production mechanism were also performed by analysis of ultra-thin sections by transmission electron microscopy. This research provides key insight into the nectar production dynamics of rare and previously uninvestigated bifurcated nectar spurs.


#12 12:30  STEPHEN PECYLAK.  Effects of early developmental experience on later cognitive abilities in fathead minnows (Pimephales promelas).  Department of Biology, University of Saskatchewan, Saskatoon, SK.

 Information gained during early developmental experiences can carry-over to later life stages, affecting the individual more than similar experiences later in life.  Recently, a study has shown that the presence of single feeding event during a critical period in the viviparous lizard can alter an individual’s dispersal behaviour, fecundity, and survival.  Multiple cognitive abilities may also be influenced by a single event during a critical period.  Fathead minnows are already used as cognitive model systems for risk associative learning.  Fathead minnows can release alarm cue, which can generate quick associations between novel cues and risk.  Repeated exposure to a novel cue without reinforcement results in latent inhibition of the cue, allowing fathead minnows to learn about safe environments.  The aim of this study is twofold: the first will test whether an early exposure to either a risky or safe odour will affect the ability of fathead minnows to learn about novel risky odours at later life stages.  The second is to determine if the generalization gradient of this response changes based on the timing of the first exposure.  Fish antipredator behaviour will be observed after the injection of a novel odour to test generalization of the target response.



#13 10:30  KAROLINA PUSZ-BOCHENSKA1, KIRSTY GURNEY2 & ANDRES LOPEZ3. Gene-based shorebird diet identification to better understand avian feeding ecology with an emphasis on optimization & validation of techniques. 1 Department of Biology, University of Saskatchewan, Saskatoon, SK; Environment and Climate Change Canada (ECCC) / Government of Canada, 115 Perimeter Road, Saskatoon, SK; 3 College of Fisheries and Ocean Sciences, 207A O'Neill Building, Fairbanks, AK. 

Noninvasive reconstruction of diets is challenging if foraging cannot be directly observed. This is particularly true in birds nesting in the North. DNA techniques have been developed more recently to overcome the limitations but little is known about factors that limit molecular quantitative approaches in bird diet studies. The goal of this research is to better understand avian feeding ecology using gene-based methods. In order to realize this objective, the project has 3 components. The first component of the study will focus specifically on quantification of total genomic material recovered from arthropods and test for family dependent measures. Additionally, taxon specific barcodes will be developed for identification purposes. The second part of this research will be a captive feeding experiment. Its goal is to estimate degradation of arthropods during digestion. To accomplish this objective, target model avian species will be fed with a strictly controlled diet, fecal samples will be collected and the DNA deriving from prey items in feces will be quantified. The last component of this research is to incorporate the findings and techniques to examine samples collected from nesting shorebirds in the Canadian Arctic. Finally, quantitative analysis of prey DNA and diet composition will be undertaken.



#14 11:30  Muhammad Sadat & Susan Kaminskyj. Can fungal endophyte strain FSJ3 help plants to grow on fuel-contaminated soil? Department of Biology, University of Saskatchewan, Saskatoon SK 

Many fungi are symbiotic partners with plants. Rather than causing disease, fungal symbionts (unlike organisms that grow together) can provide plant benefits such as abiotic stress tolerance in return for photosynthetic nutrients. FSJ3 is a systemic (colonizing roots, shoots, and leaves) fungal symbiont strain. FSJ3 was isolated from a northern B.C. plant growing on soil so highly contaminated by a liquid fuel spill that it could be set on fire. Our society routinely uses oil and gasoline as energy sources for industry, heating, and transportation. However, fuel use often results in accidental spills and leaks. These can seep into soil and water, poisoning plants and other organisms. Our lab recently showed that plants containing a fungal symbiont called TSTh could help bio-remediate (decontaminate) oily soils without causing more environmental disruption. My plan is to identify FSJ3, and to determine if it can help colonized plants grow on fuel-contaminated soil. I will be using tomato seedlings as a model plant system, and diesel oil as a model fuel.



#15 12:30  ARASH SALAHINEJAD, SOM NIYOGI & DOUGLAS P. CHIVERS. The effects of microplastic pollution on antipredator responses of zebrafish (Danio rerio). Department of Biology, University of Saskatchewan, Saskatoon SK S7N 5E2

 The widespread occurrence and accumulation of plastic particles in the environment has become a rising concern, becoming a major threat to the aquatic environment. Despite increased research on the consequences of such pollution on marine organisms, few reports have focused on the consequences of microplastics on fish behavior, particularly with respect to predator avoidance. Fish antipredator behaviors are complex and might be disrupted by these pollutants at sublethal concentrations. In the present study, I plan to explore the potential effects of environmentally-relevant concentrations of microplastic particles (50 and 90 µm polyester) on the antipredator responses of zebrafish (Danio rerio). First, I will expose fish to the two microplastic concentrations over the course of 60 days. Then, on different days during the exposure (day 0, day 30, and day 60), I will assess the alarm reactions of fish to an injection of either injured conspecific chemical cues (i.e., alarm cues) that indicate a predator attack, or to a water control. Behaviors such as shoal cohesion and reaction time will be video monitored. This research targets whether microplastics increase susceptibility of fish to predators via behavioural traits. Follow-up studies will target hormonal levels and gene expression in response to microplastic pollution.



#16 10:30  Jessica T. Thoroughgood and Neil B. Chilton. Examination of fleas and their associated bacteria collected on sciurid rodents in Southern Saskatchewan. Department of Biology, University of Saskatchewan, Saskatoon, Sk. 

Fleas are vectors of a variety of bacterial pathogens that are transmitted to humans, wildlife, and domestic animals. Despite this, little is known as to which flea species parasitize sciurid rodents in Saskatchewan, or the bacteria associated with these fleas. Fleas identification is based on microscopic examination of morphological characteristics, such as the shape and structure of the genitalia, and the presence/absence and distribution of setae, spines and ctenidia. However, this requires chemically clearing each flea which subsequently prevents DNA-based studies of the fleas or their bacteria. Given this, we will use PCR-based techniques, including DNA-sequencing and single stranded conformation polymorphism (SSCP) analysis, to determine which flea species parasitize Richardson’s ground squirrels (Urocitellus richardsonii), thirteen-lined ground squirrels (Ictidomys tridecemlineatus), and black-tailed prairie dogs (Cynomys ludovicianus) in Southern Saskatchewan. Several nuclear and mitochondria genes will be used as genetic markers. In addition, the genomic DNA of individual fleas will be tested, using PCR-based assays, for the presence of bacteria representing four genera (i.e., Bartonella, Francisella, Rickettsia, and Wolbachia), some of which are known to occur in ticks (e.g., Ixodes kingi, I. sculptus, and Dermacentor andersoni) that parasitize the three species of sciurid rodents.



#17 12:30  Matt E. M. Yunik & Neil B Chilton. Bacterial communities associated with two of Canada’s most infamous ticks.  Department of Biology, University of Saskatchewan, Saskatoon, SK. 

The most encountered tick species across the Canadian prairies are the American dog tick (Dermacentor variabilis), which has a predominantly eastern distribution, and the Rocky Mountain wood tick (D. andersoni) found in the west. Both tick species are vectors of human and animal pathogens. Despite this, little is known of the endosymbiotic bacteria within the microbiomes (i.e. microbial communities) of these two tick species, particularly for populations in Saskatchewan. These tick populations are unique because they represent the northern, and eastern or western distributional limits, and include areas of sympatry and allopatry. 

Endosymbiotic bacteria are known to provide essential vitamins and growth factors for their arthropod host, modulate the host’s immune system, increase reproductive fitness, and block pathogen acquisition affecting the host’s vectorial and capacity. Endosymbionts may also alter their host’s ability to endure environmental stressors. In the present study, we plan to use Next Generation Sequencing and other molecular techniques to identify the endosymbionts in D. variabilis and D. andersoni from different geographical locations. In addition, experiments will be conducted to determine how environmental factors influence the composition of tick microbiomes. The information will provide valuable insight into functional roles of endosymbionts and community structure of tick microbiomes.



#18 11:30  LIYONG ZHANG & CHRIS AMBROSE.  Investigating the role of microtubules in the spongy mesophyll morphogenesis of ArabidopsisDepartment of Biology, University of Saskatchewan, Saskatoon, SK. 

The primary photosynthetic tissue of plants is mesophyll, which consists of palisade and spongy layers. The former are tightly packed cells containing abundant chloroplasts to carry out photosynthesis, and the latter are large, irregularly shaped cells that are separated by intercellular spaces to facilitate gas exchange for photosynthesis.  Despite the fundamental importance of spongy mesophyll cells, little is known of how their shape and separation occur. To address this, we performed multi-day time course experiments to follow mesophyll cell morphogenesis in Arabidopsis leaves. We focused on the microtubule cytoskeleton, which plays a central role in plant cell morphogenesis by controlling the positioning and extension of cell walls. Observations began early after leaf emergence, where the young spongy mesophyll cells are still small and closely packed, with no intercellular spaces. Using live-cell imaging of GFP-tagged β-Tublin, we observed the behavior of microtubules inside spongy mesophyll cells as the cells divided, expanded, and separated from one another. Our data reveal a previously unknown dynamic feedback between microtubule organization and mesophyll cell shape.

Oral Presentation Abstracts

#19.  9:15 am IGOR DE ALBUQUERQUE, YANGDOU WEI & KENNETH WILSON. Potential role of naringenin chalcone in plant disease resistance. Department of Biology, University of Saskatchewan, Saskatoon, SK. 

The fungi powdery mildew (Erysiphe cichoracearum) and anthracnose (Colletotrichum higginsianum) can both cause disease symptoms in the model plant Arabidopsis thaliana. We discovered that when grown under long days, the tt5 mutant of Arabidopsis exhibits reduced growth but enhanced resistance to the above pathogens. The TT5 gene encodes Chalcone Isomerase, a key enzyme in the flavonoid pathway which converts naringenin chalcone to naringenin. Studying the tt5 plants, we found that they exhibited increased cell death in leaves and cotyledons. They also constitutively expressed transcripts encoding the pathogenesis related proteins: PR1 and PR2. To isolate the cause of these phenotypes, tt4 (Chalcone Synthase) and tt4 tt5 mutants were also examined. Neither exhibited the pathogen resistance, cell death, or PR expression phenotypes. Interestingly, when tt5 plants were grown under short days, they behave like wild type plants with respect to growth pattern, pathogen resistance, cell death, and PR expression. There are no reports that naringenin chalcone possesses antifungal activity, thus, we are investigating its possible role in plant defense. 


#20.  9:30 am DANIELLE R. RIVET1 & DOUGLAS CLARK2. Evaluating the efficacy of camera trapping as a valid study method for monitoring polar bear (Ursus maritimus) behavior. 1Department of Biology, University of Saskatchewan, Saskatoon, SK.; 2School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK. 

Detection of animals by camera traps is affected by ecological and observational processes occurring at both the local scale of the camera trap detection zone and the broader scale of the surrounding landscape. Thus, it is difficult to know the efficacy of trail cameras in monitoring populations in the field. My study tests the assumption that cameras in the field capture a photograph of every polar bear that passes in front of the cameras within the detection radius. I installed trail cameras in the Assiniboine Park Zoo polar bear enclosures at similar angles and detection distances used at the remote field camps. Cameras were left in place, in a variety of weather conditions (temperatures, wind speeds/directions, precipitation, etc.), and ran both day and night. Thus, the efficacy of the cameras in various circumstances is tested and compared to the cameras already installed in the field. I hypothesize that certain factors, including weather conditions, bear behaviors, and camera angles, will affect camera effectiveness, resulting in imperfect detection of polar bears. Transparency in methods, assumptions, and biasing factors, will facilitate efforts to evaluate and improve the reliability of camera trap surveys, ultimately leading to stronger inferences and helping to meet needs for effective ecological investigation.



#21.  9:45 am  KYLA E. BAS1 & ROBERT G. CLARK1,2Effects of spring phenology, density dependence and predator-prey cycles on productivity of boreal-breeding ducks. 1Department of Biology, University of Saskatchewan, Saskatoon, SK; 2Prairie and Northern Wildlife Research Centre, 115 Perimeter Road, Saskatoon, SK. 

Offspring production is a key component of population growth in many duck species.  My research seeks to evaluate the effects of climatic and biotic drivers of productivity in lesser scaup (Aythya affinis; scaup), a diving duck species of conservation concern, and four other duck species.  Scaup population growth is particularity sensitive to changes in productivity, although our understanding of factors limiting scaup production is incomplete.  Using long-term data (1985-2017) at a scaup boreal-breeding site (Yellowknife, NWT), I evaluate the mechanisms driving productivity in scaup by testing three main hypotheses: (H1) density dependence (H2) regional climate and (H3) predator-prey dynamics.  Consistent with predictions of H1, I found evidence of negative density dependence between brood production and pair abundance in all five species. Controlling for density dependence, breeding pair population size was positively related to the previous year’s pair count and productivity in three dabbling duck species, but related only to previous population size in two diving duck species.   I also examine whether duckling production in fixed, late-nesting species are generally lower than those of flexible, early-nesting species during springs with earlier ice melt (H2).  Finally, I assess if production is higher in years when local small mammals are most abundant (H3). 



#22. 10:00 am  ANDREA E. WISHART1 , STAN BOUTIN2, ANDREW G. MCADAM3, MURRAY M. HUMPHRIES4, BENJAMIN J. DANTZER5,6, & JEFFREY E. LANE1. Individual variation in caching activity by North American red squirrels (Tamiasciurus hudsonicus). 1Department of Biology, University of Saskatchewan, Saskatoon, SK; 2Department of Biological Sciences, University of Alberta, Edmonton, AB; 3Department for Integrative Biology, University of Guelph, Guelph, ON; 4Natural Resource Sciences, MacDonald Campus, McGill University, Ste-Anne-de-Bellevue, QC; 5Department of Psychology, University of Michigan, Ann Arbor, MI; 6Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI. 

In species with high site fidelity (e.g., territorial animals), it can be difficult to distinguish between the effects that individual quality and habitat quality have on fitness, as both are frequently correlated with reproductive success. Discerning between these influences requires studying individuals across gradations of territory quality. To identify the relative contributions towards reproductive success by individual quality and habitat quality, I am studying a fully-censused population of North American red squirrels (Tamiasciurus hudsonicus) that has been monitored in the southwest Yukon for 30 years by the Kluane Red Squirrel Project. Squirrels defend individual territories year-round and typically remain in the same location for life. Squirrel primarily feed on seeds of white spruce (Picea glauca), which they cache on their territories to buffer against low cone crops. In addition to inter-annual fluctuations, white spruce show intraspecific variation in cone production, creating heterogeneity in habitat quality. Using annual measures for cone production across our study area and reproductive success of squirrels calculated from a genetically determined pedigree, I observe spatial variation in total offspring production associated with squirrel territories and predict that this is positively correlated with habitat quality, but that individual quality may interact with territory quality through food-caching.



#23. 10:15 am KATELYN M. LUFF1 & KIRSTY E. B. GURNEY2. Sources of variation in mercury levels in Arctic-breeding shorebirds. 1Department of Biology, University of Saskatchewan, Saskatoon, SK; 2Environment and Climate Change Canada, Prairie and Northern Wildlife Research Centre, 115 Perimeter Road, Saskatoon, SK. 

Mercury is disproportionally deposited in the Arctic ecosystem through long-distance atmospheric transport and can accumulate in wetlands during spring thaw. Coupled with the increased climatic variability currently being experienced in the Arctic, it is unclear whether earlier spring onset will influence contaminant levels found in local biota. Shorebirds are at increased risk for mercury exposure due to their propensity for foraging in wet areas, and some studies have indicated Arctic shorebirds may be responding to earlier spring conditions by shifting their nesting phenology. Whether earlier nest initiation will influence contaminant levels in these species is unknown. This study investigated the extent to which timing of nesting influenced total mercury levels in the eggs and blood of two locally common shorebird species: semipalmated sandpiper (Calidris pusilla) and semipalmated plover (Charadrius semipalmatus). The extent to which spatial, temporal and life history variables impacted mercury levels in tissues were also assessed. Shorebird samples were collected over two years at two locations in the Canadian low Arctic. All samples were analyzed for total mercury concentration using a direct mercury analyzer. Total mercury was found in detectable levels in all samples in 2016 and 2017 and implications associated with reported mercury levels will be discussed.



#24. 10:45 am FARSHAD SHAFIEI, Characterization of nutrient budget in Lake Diefenbaker. Department of Biology, University of Saskatchewan, Saskatoon, SK. 

We examined and quantified the most important nutrient pathways of the Lake Diefenbaker (LD) and its nutrient retention to assess inter-annual variation in its nutrient budget which are likely to be greatly affected by hydrological forces. This provide an understanding of the sensitivity of LD to changes in nutrient loads as affected by extreme flows (climate related events). Extreme flows entered the reservoir from the South Saskatchewan River in early summer (June to early July) in all four years which resulted in highest nutrient load and export in early summer. Large loads of total P (TP), total dissolved P (TDP), total dissolved N (TDN) and total N (TN) were significantly correlated with peak flows in early summer (2011-2014). Annual water retention was lowest (-16%) in 2011, but highest (-3%) in 2013. The reservoir acted as sink of nutrient with 92% of TP, 38% of TDP and 19% of TN retained; while, it acted as a source of TDN (-3%). 2011 was the only year in which the reservoir acted as a source of TN (-18%) and TDN (-39%). Overall, the result shows the important role of hydrological forces and their inter-annual variations in characterization of nutrient budget in LD.



#25. 11:00 am  DANA KELLETT1, 2 & RAY ALISAUSKAS1,2. The influence of grazing on lowland vegetation communities in a freshwater arctic ecosystem: an exclusion experiment. 1Department of Biology, University of Saskatchewan, Saskatoon  SK; 2Environment and Climate Change Canada, Prairie and Northern Wildlife Research Centre, 115 Perimeter Road, Saskatoon  SK. 

Large populations of lesser snow and Ross’s geese (Anser caerulescens caerulescens, A. rossii) have modified vegetation communities over extensive scales in northern ecosystems. We investigated influence of grazing geese on lowland habitat in a freshwater ecosystem in central Nunavut. Vegetation plots exposed and not exposed to grazing by geese (n=18 pairs) were located within the nesting colony at Karrak Lake and at distances of 15-60 km from Karrak Lake.  We used mixed models to assess differences in above- and below-ground biomass, plant species composition, and soil temperature between grazed and ungrazed plots, while controlling for random site effects.  Above-ground biomass was higher in ungrazed (7.5 g (95% CI: 5.8-9.3 g) than grazed plots (2.9 g (1.1-4.7 g), p<0.001), and similar results were obtained for below-ground biomass (4.0 g (2.9-5.2 g) versus 2.9 g (1.8-4.0 g), p=0.03).  Despite removal of above-ground biomass by grazing geese, below-ground reserves remain available for potential regeneration of grazed areas. Graminoid species were more prevalent on ungrazed (73.7% (62.0-85.3%)) than grazed plots (49.2% (37.6-60.8%), p=0.003)), whereas moss species were more prevalent on grazed (39.9% (28.1-51.6%)) than ungrazed plots (13.8% (2.1-25.5%), p<0.001)). Soil temperature was higher in grazed (6.3°C (5.3-7.4°C)) than ungrazed plots (4.9 °C (3.9-6.0°C), p<0.001). 



#26. 11:15 am REID N. BRYSHUN1, MAUD C. O. FERRARI1,2 & MICHAEL S. POLLOCK3. Where the buffalo roam: Tracking and aging a fish species at risk. 1Department of Biology, University of Saskatchewan, Saskatoon, SK.; 1.2.Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK.; 3Saskatchewan Watershed Authority, 101-108 Research Drive, Saskatoon SK. 

Bigmouth buffalo (Ictiobus cyprinellus) is a fish species at risk in the Qu’Appelle River system. At present they are considered a species of “special concern” under the Species at Risk Act (SARA). This designation essentially means that there is little to no current information about the status of their population and that more studies are required. Therefore, one of the core aspects of my thesis is determining buffalo movement patterns and habitat use, while another is studying their population age structure to see if there are any missing age classes. In the 2017 field season, we aged roughly 500 buffalo scales to get an estimation of their population age distribution. We also captured and surgically implanted 62 buffalo with acoustic telemetry tags which were picked up by various acoustic receivers placed throughout the Qu’Appelle River. These results can help explain which habitat is key for the protection of buffalo, as well as the ages at which buffalo are most at risk.



#27. 11:30 am  ROY R VERA1, JORGE E GRIJALVA2 & J HUGO COTA-SÁNCHEZ1 Effect of changes in land use patterns on forest diversity and floristic composition of cocoa chakras in the Northern Ecuadorian Amazon 1Department of Biology, University of Saskatchewan, Saskatoon, SK; 2 Facultad de Medicina Veterinaria y Zootecnia, Universidad Central del Ecuador, Jerónimo Leiton y Gatto Sobral, Quito, Ecuador. 

Traditional agricultural practices developed by Indigenous people in the Northern Ecuadorian Amazon region are known as chakra systems. This farming system amalgamates conservation and production using shifting agriculture in small plots in forest gaps to satisfy food and livelihood necessities. The plots are then abandoned after 2-10 years of farming to allow forest recovery. The chakra is a unique system because the tree diversity is intentionally left by farmers. Thus, this practice is equivalent to a transitional state of disturbance preserving native species and deemed to an effective sustainable forest management alternative to mitigate climate change. However, changes in land use pattern influenced by deforestation, road constructions, and access to market centers have altered the traditional shifting agriculture into a more intensified farming with less recovery time after abandonment. Therefore, it is unclear whether this semi-sedentary agriculture affects the floristic composition of the typical chakra, i.e., less complex tree structure, and whether native trees remain in more intensified systems. My research investigating these issues aims to facilitate the understanding of thresholds in different levels of desertification and conservation of this ecosystem, particularly for endemic endangered and economic species.



#28. 11:45 am  RACHEL H. PARKINSON & JOHN R. GRAY.  A sublethal dose of a neonicotinoid insecticide impairs motion detection and avoidance behaviour in Locusta migratoria. Department of Biology, University of Saskatchewan, Saskatoon SK. 

Neonicotinoid insecticides are used extensively in agriculture in North America, despite known environmental impacts. These insecticides affect foraging behaviour and navigation in non-target insects, although the mechanisms of these effects are not fully understood. A visual motion sensitive neuron in the locust, the Descending Contralateral Movement Detector (DCMD), integrates visual information and is involved in eliciting escape behaviours. The DCMD receives coded input from the compound eyes and synapses with motorneurons involved in flight and jumping. We show that imidacloprid (IMD), a neonicotinoid insecticide, impairs neural and behavioural responses to visual stimuli at sublethal concentrations, and these effects are sustained 24 hours after treatment. Exposure to 10 ng/g IMD attenuates escape manoeuvers while 100 ng/g IMD inhibits the ability to fly and walk. Behavioural effects correlated with attenuated neural responses: IMD disrupted DCMD bursting, a coding property important for motion detection. Specifically, IMD reduced the DCMD peak firing rate within bursts at ecologically relevant doses of 10 ng/g. Thus, IMD causes significant and lasting impairment of an important pathway involved with visual sensory coding and escape behaviours at ecologically-relevant doses. These results show that a neonicotinoid insecticide directly impairs an important, taxonomically conserved motion-sensitive visual network.



#29.  1:15 am BRANDON M. WADDELL & CARLOS DE EGYDIO CARVALHO. Characterization and functional implications of the SGO-1 homolog in Caenorhabditis elegans. Department of Biology, University of Saskatchewan, Saskatoon, SK. 

Cilia are found in many different organisms across a variety of species.  They can be used for motility as well as sensing environmental cues when present in sensory organs.  Chemical ligands or physical stimuli can be detected by cilia allowing an organism to obtain information about the location of food, toxic substances, heat, etc.  The stimulus signal is transmitted via neurons to the nerve center of the organism, where the signal is interpreted and an appropriate response produced.  Defects in ciliary signalling can arise from a loss of the cilia or disruption of their structure, as well as disrupted neuronal connections.  We have uncovered a potential novel role for SGO-1, a homolog of the Shugoshin protein family in C. elegans, in ciliated cells. In other systems, Shugoshin activity is essential to protect the cohesion between sister chromatids during cell division.  In C. elegans however, chromosomes segregate normally without SGO-1, but cilia development and function appears disrupted.  Here I provide for the first time, evidence that Shugoshin functions in a non-proliferating cell type.



#30.  1:30 pm  STEPHEN H. SRAYKO1, TIM D. JARDINE2, IAIN D. PHILLIPS1 & DOUG P. CHIVERS1. Seasonal migration of corixids (Hemiptera: Corixidae) as a linkage between wetland and river ecosystems: the implications of overwintering strategies. 1 Department of Biology, University of Saskatchewan, Saskatoon SK; 2School of Environment and Sustainability, University of Saskatchewan, Saskatoon SK. 

Linkages between spatially separated water bodies can greatly influence ecosystem functioning. Corixids (Hemiptera: Corixidae) that migrate from wetlands into the Saskatchewan River system every fall represent one such linkage. This migration is marked by tremendous increases in the abundance of migratory corixid species in the rivers, and decreased numbers of these migrants in wetlands. However it has been found that several species of corixids do not migrate at all, or have some individuals that do not, and instead remain in wetland habitats to overwinter encased in ice. Results from 2017 and 2018 indicate that the mortality associated with this strategy can be very high, and that certain species may be more tolerant of overwintering in ice than others. An examination of the lipid stores and flight morphology of both migratory and non-migratory corixids will be used to assess the energetic costs associated with both strategies. Understanding the overwintering tolerances of different corixids could allow for predictions as to how the species compositions of these insects over the landscape, and the existence of the wetland-river linkage that is based on their migration, could be altered in the face of varying winter conditions in prairie wetlands.



#31.  1:45 pm Vladimir Kodzhahinchev1, Lynn Weber2 & Som Niygoi1. Interactive effects of waterborne Cadmium and Benzo-a-pyrene exposure to zebrafish (Danio rerio): uptake, metabolism and photo-activation. 1Department of Biology, University of Saskatchewan, Saskatoon, SK; 2Department of Veterinary Medical Sciences, University of Saskatchewan, Saskatoon, SK. 

Cadmium (Cd), a trace metal, and benzo-a-pyrene (BaP), a polycyclic aromatic hydrocarbon, are pollutants commonly found in water bodies in Canada. Cd is released as a by-product of mining, while BaP is found in petroleum products and released during incomplete combustion of organic matter. Both pollutants are toxic to aquatic organisms and can induce a variety of harmful effects at sublethal doses, primarily through the decimation of the anti-oxidant defences. Excessive reactive oxygen species (ROS), highly reactive molecules capable of damaging DNA and proteins within the cell, cause cell death, organ damage and physiological dysfunctions. Organs highly affected by ROS include the cardiovascular system, liver and gills. Recently, BaP toxicity has been shown to increase after ultra-violet (UV) light exposure, due to formation of more reactive UV-activated products. How UV affects toxicity thresholds and whether environmental regulations are still protective is unclear and a growing concern. Questions also remain about how co-exposure to Cd and BaP affect toxicity. Furthermore, most research to date examined early life stage toxicity. This has left a knowledge gap regarding sublethal effects in adult fish which my address hopes to address.     



#32.  2:00 pm CLARA SUPERBIE, KATHRINE M. STEWART & PHILIP D. MCLOUGHLIN. Understanding how threatened woodland caribou select and interact with their habitat; a multi-step modelling approach. Department of Biology, University of Saskatchewan, Saskatoon, SK. 

Conserving species at risk requires a deep understanding of their habitat requirements. Resource selection functions (RSF) model the probabilities of resource units to be used by an animal, proportional to their availability. They have been used for many years as a means to both quantify how animals select their habitat and predict species’ probability of occurrence in a given landscape. I will present RSF results modelling seasonal habitat selection at different spatial scales by boreal woodland caribou (Rangifer tarandus caribou) in Saskatchewan’s Boreal Shield. Boreal caribou are threatened and well-studied across Canada in areas where human activities prevail. However, the Saskatchewan’s boreal population has been understudied while experiencing in a unique, naturally regulated environment characterized by low anthropogenic pressure and extremely high rates of wildfire. Therefore, this population is ideal to improve our knowledge about caribou-habitat interactions in an environment close to the one they historically evolved in and estimate how natural disturbances affect their population dynamics. I also wish to discuss the limits of the applicability of RSF methods in conservation strategies while emphasizing that they still provide a solid starting point for the development of individual-based models to empirically link habitat use to individual fitness and population dynamics.



#33.  2:15 pm PATRICIA A. TOMCHUK & PHILIP D. MCLOUGHLIN.  Habitat selection of black bears, gray wolves, and boreal woodland caribou in Saskatchewan’s Boreal Shield.  Department of Biology, University of Saskatchewan, Saskatoon, SK. 

Boreal woodland caribou (Rangifer tarandus caribou) are listed as Threatened on Canada’s Species at Risk Act. In Saskatchewan’s Boreal Shield, woodland caribou exist in relatively pristine conditions with low anthropogenic impacts, high fire, and few invasive species.  Wolves (Canis lupus) are key predators of adult caribou but black bears (Ursus americanus) may be effective predators of caribou calves. I intend to use resource selection functions (RSFs) to model habitat selection of collared black bears, wolves, and caribou in Saskatchewan's Boreal Shield. I will test the predator facilitation hypothesis in relation to caribou: If predator facilitation plays a role in caribou habitat selection during calving season, then selection patterns of black bears and caribou should show greater overlap as caribou choose calving sites away from wolves. My objectives are to (i) provide novel information on black bear and wolf ecology in Saskatchewan’s Boreal Shield; (ii) provide a baseline of data to which black bear-caribou interactions in more disturbed areas can be compared; and (iii) determine the extent to which black bears may play a role in limiting caribou populations through predation. Overall, these results will uncover potentially important factors relevant to the conservation of woodland caribou in Saskatchewan and Canada.



#34.  2:45 pm   CARMEN MARQUEZ-MELLIDEZ, EWA MISKIEWICZ & KENNETH WILSON. The Light Green Phenotype 1 protein is required for Photosystem II-Light Harvesting Complexes’ assembly in Chlamydomonas reinhardtii. Department of Biology, University of Saskatchewan, Saskatoon, SK.

In the green alga Chlamydomonas reinhardtii, the light harvesting (LHC) proteins form a dynamic complex that regulates the amount of light energy absorbed. Studies suggest that LHC organization requires the assistance of chaperone factors, but to date none have been identified. In our study, we are using a secondary mutated strain obtained from a PsaF mutant, which could survive under high-light conditions. In addition to this, our light-green phenotype 1 mutant (lgp1) is resistant to paromomycin and capable of growing on minimal media at light levels above 750 µmol m-2 s-1, which defines the aim of our project: to characterize and define the lgp1 mutant through mapping and cloning the paromomycin resistant gene. The cells accumulate approximately 66% of wild-type Chlorophyll levels, with an elevated Chlorophyll a to b ratio, suggesting LHC abundance. Our introductory analysis suggests that the LGP1 protein is involved in connecting specific LHC proteins to PSII. This will be confirmed by examining protein-protein interactions between LGP1, PSII, and the diminished LHC proteins. If confirmed, LGP1 would be the first LHC assembly-factor identified in C. reinhardtii. Ultimately, our project will shed a light on explaining how plants are able to survive under light stress conditions.



#35.  3:00 pm OGHENEMISE ABIRHIRE & JEFF HUDSON. Modeling turbidity in Lake Diefenbaker using Landsat-8 OLI imagery. Department of Biology, University of Saskatchewan, Saskatoon, SK. 

High turbidity influences a variety of physical conditions in reservoirs (e.g., stratification, light penetration), which in turn can affect phytoplankton growth. There is evidence that high turbidity may be limiting phytoplankton productivity in Lake Diefenbaker (LD) as reported in other reservoirs. However, long term records of turbidity in LD are not available. Therefore, we examined the possibility of using a remote sensing based model to acquire historical turbidity. First, 12 Landsat-8 OLI images were acquired within 8 days of field measurements of turbidity in LD (n= 80). Our field turbidity observations was related to the reflectance of single band combinations (red, blue, green and near-infrared) of Landsat-8 OLI using multiple linear regression analysis (n= 39). We then validated our model using a separate field observations (n = 41). Reflectance from red and near-infrared bands were strongly related to field observations (R2 = 0.89). Our estimated turbidity was strongly related to our separate field observations (R2 = 0.79, RMSE 0.19 NTU). Therefore, we now have a model that can predict historical turbidity accurately in LD. Consequently, we will be able to quantify the light environment and characterize the degree of light limitation of phytoplankton for the past 33 years in LD.



#36.  3:15 pm   ANOOSHA ATTARAN, SOM NIYOGI & DOUGLAS P. CHIVERS. Effects of chronic exposure to selenium on social and antipredator behaviours of zebrafish (Danio Rerio).  Department of Biology, University of Saskatchewan, Saskatoon  SK  S7N 5E2. 

Social behaviours are critical for many species for finding food or mates, defending territories, and avoiding predators. For example, fishes that live in groups often shoal together, which increases their probability to detect and escape predation. In some cases, however, pollution can disrupt these important social behaviours and thus reduce fitness. There are growing concerns about some elements, such as selenium (Se), that are essential to animals but can become toxic at high concentrations. Here, we investigated the effects of chronic dietary exposure to Se (as selenomethionine) on social and antipredator behaviours of zebrafish. High concentrations of Se altered group preferences and antipredator behaviour. While control fish preferred larger groups, those exposed to the highest dose (34.5 µg/g) showed no preference. Moreover, this dosage caused a failure to respond correctly to injured conspecific cues (i.e., alarm cues) that indicated an attacking predator. These negative outcomes were not observed at lower Se doses. Our results may suggest that Se disrupts an important underlying neurological pathway that causes abnormal social behaviour resulting in impaired group preferences and antipredator reactions.



#37.  3:30 pm  JOSEPH STAR ABRAMS & JAMES BENSON. Agent-Based Modeling of CPA Equilibration.  Department of Biology, University of Saskatchewan, Saskatoon, SK. 

In this thesis, we will attempt to determine the effectiveness of agent-based cell modeling on cryoprotectant equilibration. The focus of our modeling will be on the equilibration of permeating cryoprotectants; permeating cryoprotectants called permeating CPA’s are a component of both slow and rapid freezing and vital to maintain cellular viability through the entire process of cryopreservation. In this manuscript, a 3d tissue model of Islets of Langerhans and secondary stage ovarian follicles is prepared, explored numerically and experimentally validated. Statistical analysis of the model is done by comparing the adhesion/repulsion force constants and cellular volumes in the tissue model to in vitro whole islets of Langerhans from Mesocricetus auratus (Golden Hamsters) and secondary ovarian follicles from non-human primates. The spring constant value, k, in the model is fit to the experimentally determined value followed by comparison of mean model cell volume to mean experimental cell volume. In this model, we assume the intercellular forces will be a linear  from hookes law where F is force, k is the spring constant and x is displacement. Cell volume is modeled using a 2-parameter volume model; this is solved as a system of ordinary differential equations solved numerically using an Adams-Bashforth method. Additionally, the implementation of a CPA toxicity cost function shows the potential future benefit of agent-based modeling in cryobiology the research.



#38.  3:45 pm  MD NOIM IMTIAZY1, ANDREW PATERSON2, HUAXIA YAO2, SUZANNE COUTURE3, SCOTT HIGGINS4 & JEFF J. HUDSON1. Recent changes in the long-term patterns of dissolved organic carbon in eastern Canadian lakes as related to regional and global factors. 1Department of Biology, University of Saskatchewan, Saskatoon, SK; 2Dorset Environmental Science Centre, Ontario Ministry of the Environment and Climate Change, Dorset, ON; 3Environment Canada, Water Science and Technology, Montreal, QC; 4IISD Experimental Lakes Area, Winnipeg, MB.  

Dissolved organic carbon (DOC) is an important water quality parameter that affects major biological and chemical processes. We re-examined the ice-free DOC patterns reported in Zhang et al. (2010) with an additional 15 years (~2000-2015) of measurements. DOC trends in 49 eastern Canadian lakes from four sites were analyzed (Dorset, Kejimkujik, Yarmouth and Experimental Lakes Area, IISD-ELA). Patterns were synchronous in lakes within a site but not across sites, except in Kejimkujik and Yarmouth which were pooled into a single Nova Scotia (NS) site. Increases in DOC concentration in Dorset were evident between 1997 and 2015 (0.12 mg L-1 year-1 increase, r2= 0.68, p< 0.001). Similar patterns were also apparent in NS between 2000 and 2015 (0.11 mg L-1 year-1 increase; r2= 0.34, p= 0.02). Although DOC in ELA lakes increased initially (0.10 mg L-1 year-1 increase; r2= 0.39, p= 0.005), such increases were not evident in last two decades (r2= 0.02, p= 0.59). Sulfate deposition was found to be the most important explanatory variable across all regions whereas summer precipitation explained a significant amount of variation in DOC in Dorset and NS. Interestingly, some global factors (e.g. North Atlantic Oscillation) were also found to be important explanatory variables.

Previous Years Symposium Awards


  • Best Poster Presentation:  Kyla Bass (Clark Group) 
  • Best Oral Presentation, Field-based Research:  Stephen Srayko (Chivers Lab) 
  • Best Oral Presentation, Lab-based Research:  Yen Le  (Ambrose Lab)


  • Best Oral Presentation, Lab-based Research:  Jessica Popp (Ferrari Lab)
    • Runner up: Maryam Nourimand (Todd Lab)
  • Best Oral Presentation, Field-based Research:  Amelia Raquel (Clark Lab)
    • Runner up: Rachel Parkinson (Alisauskas)
  • Best Poster Presentation, Lab-based Research:  Stephen Srayko (Chivers Lab)
    • Runner up: Rachel Parkinson (Gray Lab)
  • Best Poster Presentation, Field-based Research:  Clara Superbie (McLoughlin Lab)
    • Runner up: Oghenemise Abirhire (Hudson Lab)


  • Best Oral Presentation, Lab-based Research: Cody Manchester (Gray Lab)
  • Best Oral Presentation, Field-based Research: Melanie Jean (Johnstone Lab)
  • Best Poster Presentation: Daniel Andres (McLoughlin Lab)


  • Best Oral Presentation, Lab-based Research: Irani Solmaz (Todd Lab)
  • Best Oral Presentation, Field-based Research: Adam Crane (Ferrari Lab)
  • Best Poster Presentation: Maryam Nourimand (Todd Lab)