Xinyu Sun PhD Student, Arnott Lab Interactive effects of elevated salinity & heatwaves on freshwater zooplankton: From community ecology to individual physiology Freshwater ecosystems are being disturbed by multiple new and ongoing stressors that often occur simultaneously or asynchronously. Among those stressors, fluctuations in salinity levels and heatwaves that are becoming more frequent and intensified can individually and interactively impact freshwater organisms. However, we lack a good understanding of their joint impacts and how the temporal fluctuation of these stressors affects the impacts. To help fill this gap, I conducted experiments using freshwater zooplankton to investigate their interactive effects at community, population, and physiological levels. My results show that the joint effects of elevated salinity and heatwaves vary at different scales: antagonism (i.e., the joint effect is less than the sum of each individual effect) at the community level, mainly driven by species compositional changes; no interaction at the population level, caused by evolutionary changes; and synergism (i.e., the joint effect is greater than the sum of each individual effect) at the individual level, due to physiological responses. My results also suggest that the interactions between stressors change with different time intervals between them, because of the carry-over effect of the prior stressor or population and community recovery processes. My work contributes to the knowledge gap in the area of multiple-stressor interaction by showing the joint effects of elevated salinity and heatwave conditions at different levels of biological organization. The findings demonstrate that ecosystem management and restoration efforts that commonly just address the effect of a single stressor should consider prior stressor exposure, and the combined effects of two asynchronously occurring stressors can be more accurately predicted when accounting for the time intervals between the exposures. Moreover, the upscaling of lower-level (physiological and individual) results to the community or ecosystem level, which is sometimes used in the management of ecosystems, should be done with caution since there can be inconsistency in responses across ecological scales.
Gut microbes help mitigate a major challenge of hibernation Hibernation’s hallmark trait is a profound depression of metabolism that enables animals to survive long periods without eating. This makes hibernation an effective solution to winter’s food scarcity problem; however, it deprives the animal of dietary nitrogen, which is an essential building block for protein. In theory, this should threaten the structure and function of important tissues within the animal, but it has long been known that hibernating mammals avoid this fate and maintain tissue function (e.g., muscle performance) even after many months of fasting hibernation. In this talk, I will discuss our recent work that has revealed how the hibernator’s gut microbes facilitate this tissue preservation and our current work that is investigating how this process may benefit human spaceflight and human health generally.
Aaron Dain MSc, Yakimowski Lab Phenotypic variation of a moderately salt tolerant sunflower (Helianthus annuus) and a halophytic sunflower (Helianthus paradoxus) under extreme environmental salinity Environmental salinity is a global phenomenon that is increasing with anthropogenic change. Salt is toxic to most plants, but less than 1% of plant species are considered highly salt tolerant. Helianthus annuus is considered a moderately salt tolerant glycophyte, although populations occur in the saline Great Salt Lake region of Utah. This raises the question: can populations of glycophytes in saline habitats locally adapt to more extreme salinity? Furthermore, is the range and upper limit of H. annuus within the range associated with its homoploid hybrid descendent, the halophyte H. paradoxus? To investigate variation in the relation between environmental salinity and phenotypic variation, we conducted a common-garden experiment using H. annuus seeds collected from 20 populations of the species’ range with varying concentrations of environmental salinity, and seeds collected from 5 populations of H. paradoxus. Seedlings were treated with control, moderate (field), and high (field x2) salinity treatment solutions mimicking the ionic composition of H. paradoxus habitat. Phenotypic traits related to salt tolerance (above- and below-ground biomass, plant height, and growth rate) of juvenile plants were measured and compared among populations and treatment groups. Quantitative soil salinity data was collected for ten of these populations, and used to investigate the relation between environmental salinity and salt tolerance. In the Great Salt Lake region soil salinity (% sodium) ranged from 1.3 to 37.9 (n = 26 populations); thus, high-saline sites exhibit salinity in the range associated with its halophytic relative H. paradoxus. Under non-saline conditions, H. annuus plants originating from non-saline habitats are larger than those originating from saline habitats. However, under field-like salinity, saline-originating H. annuus plants retain more biomass than non-saline originating plants. H. paradoxus plants are smaller than H. annuus under non-saline conditions but are larger under field-like salinity. This suggests biomass is shaped by environmental salinity. In comparison, growth rate and plant height do not significantly differ between saline- and non-saline H. annuus populations, and those from populations with the highest salinity grow more slowly than those from populations with lower salinity. Additionally, H. paradoxus plants grow more slowly than H. annuus plants. This suggests that plant height and growth rate are not shaped by environmental salinity in the same way, and that growth rate may not be selected for in saline habitats.
Damian Bourne MSc Student, Colautti Lab Morphometric variation in Ixodid ticks at an expanding range edge Ixodid ticks (Acari: Ixodidae) are important vectors of zoonotic disease that have devastating impacts on human health and well-being. Therefore, it is essential that effective monitoring protocols be put into place to map tick abundance and richness within certain areas. Although research into the most important tick species across Eastern, Ontario is abundant, up-to-date studies looking into the morphological features that contribute to observed diversity are lacking. Geometric morphometrics is a powerful tool that allows researchers to compare shape variation between groups. This study utilizes geometric morphometrics to survey important tick species within Eastern Ontario and explore the morphological diversity that defines them. A total of 518 ticks were sampled over a 6-year period representing two medically important species known to harbour harmful pathogens: D. variabilis and I. scapularis. Morphometrics utilizing principal component analyses of these two species found that the chosen common dorsal and ventral landmarks accurately categorized individuals by their respective species and sex. Furthermore, I. scapularis females showed significantly different morphologies across locations possibly representing diverse environmental pressures that need to be considered in management protocols. Supervised machine learning algorithms were also utilized and found that the selected landmarks accurately assigned individuals to their respective groups. Additionally, this analysis identified individuals with abnormal morphologies that may represent novel or cryptic species. Future research should combine both morphometric and genetic approaches to increase the robustness of species identification and provide additional evidence for tick diversity that may lead to better mitigation and management solutions for these critical vectors of zoonotic disease.
Accelerating freshwater restoration science & practice through community-engaged research The UN Decade of Ecosystem Restoration (2021-2030) calls for an accelerated need to cooperate at local and global scales to heal our degraded planet, and that the best examples of restoration success have been community-led. Through research situated in watersheds impacted by settler-dominated agricultural intensification and urbanization, Dr. Febria will describe how farm-focused and Indigenous-led partnerships have led to richer outcomes in addition to Western-science outcomes, all of which are crucial for freshwater restoration science and its’ translation into practice and decision-making. Research on molecular and microbial properties of headwater stream ecology and community ecology of Unionid species-at-risk will be discussed as examples of how projects in the Healthy Headwatesrs lab centre human dimensions to inform the science pursued across watersheds in the Laurentian Great Lakes and our shared home known as Turtle Island/North America. Drawing on additional examples globally, this talk will demonstrate how ethical and equitable research partnerships can support a more effective and actionable science, in support of a just and sustainable freshwater future.
Non-Academic Guest Speaker Exploring the art of delivering science in the Canadian Artic: mistakes made and lessons learned When visiting university departments over the years, I’ve had the pleasure of meeting with many graduate students and Post-Doctoral researchers. At an early career stage in their career, discussions were narrowly focused on science approaches, new findings, and graduate thesis completion. This seminar intends to get people thinking beyond that, and to consider what it takes to build and lead a successful science team of your own. Drawing on my own experience conducting research in the Arctic, I will discuss topics such as how to recruit and retain the best people, establish collaborations, and identify the ‘performance measures’ of science (including, but not limited to, publication). Importantly, I will provide examples of where I made mistakes and the consequence of those, and how I spotted research and collaborative opportunities.
Dr. Edel Pérez-López Département de Phytologie, Université Laval Strawberry-leafhopper-phytoplasma, a pathosystem under siege by climate change Food security is threatened by climate change, directly through the response of crop productivity, and indirectly through the relationship of crops with plant pathogens and pests. In Quebec, strawberry growers have been noticing how in the last few years the number of insect pests have been increasing every summer, especially leafhoppers, members of the family Cicadellidae known vectors of virus and bacterial diseases. To understand these observations, we have been investigating for two years the diversity and abundance of leafhoppers in strawberry fields in the main producer areas of the province. In parallel, we have been also investigating the presence and distribution of strawberry green petal disease, a disease caused by bacterial pathogens transmitted by leafhoppers, and the role of those insects as vectors of the disease. In this seminar I will present the results of these two years of work finding an unexpected diversity of leafhoppers including eleven new reports for East Canada, an increase spread of strawberry green petal disease in Quebec fields, and evidence that new pathogens might be affecting soon strawberry fields in Canada, all this probably orchestrated by global warming.
Christina Steinecke MSc Student, Friedman Lab Selection and genetic constraints on clonal investment in a perennial plant Many plant species can reproduce both clonally (for example, via stolons or corms) and sexually via flowers and seed. The question, then, is why some plants invest resources into both, and whether phenotypic and genetic correlations exist when investing in traits associated with one mode or the other. The relative importance of the two modes of reproduction likely vary in different ecological conditions, but to what extent can selection drive different investment strategies? A population’s ability to respond to selection on clonal investment might impact its capacity to respond to environmental change. Furthermore, genetic correlations between traits can either facilitate or constrain evolutionary responses depending on the direction and strength of selection. Here, we investigate the capacity for clonal investment to respond to high or low truncation selection in a perennial population of Mimulus guttatus. The aims of our research are to first quantify the magnitude of phenotypic responses to artificial selection on clonal growth, and then to identify traits that respond in concert due to underlying genetic correlations. To address these aims, we first established an outbred population from field collected seed in a greenhouse, and then imposed four generations of divergent, truncation selection on clonal growth for two replicate high lines, two low lines, and a control line. We used quantitative genetics and pedigree analyses to investigate additive genetic variance, heritability, and the response of clonal growth through time. We then investigated genetic correlations among life history traits measured throughout the life cycle to identify whether genetic constraints might constrain evolutionary trajectories. Our results showed that selection elicited the predicted divergent response in clonal growth; however, low-clonal lines respond more strongly to selection compared to high-clonal lines. Decreased clonal growth was also negatively correlated with a suite of traits including overall size, flower number, and flowering time. These findings suggest unequal additive genetic variance in the low-clonal and high-clonal lines, and indicate that populations have greater capacity to reduce clonality in the face of selection, and that increases in clonal investment might be more difficult. This study tests a classic, yet unresolved, evolutionary question and suggests populations harbour sufficient standing genetic variation to respond rapidly to selection but that the underlying genetic architecture and trait covariation could constrain evolutionary trajectories and adaptive divergence
Jeffrey Dason, Department of Biomedical Sciences, University of Windsor Activity-dependent cholesterol redistribution is required for synaptic growth Synaptic plasticity is a fundamental property of neurons that allows their ability to transmit information to change with experience. Numerous studies have examined how synaptic plasticity is regulated by protein–protein interactions and changes in the expression and activation of various proteins. In contrast, the roles of lipids in synaptic plasticity have been less studied. Increasing evidence suggests that the lipid content of neuronal membranes does not remain constant and is altered by synaptic activity. The Drosophila larval neuromuscular junction is a well-established model system for studying synaptic growth and shares the basic molecular components found at most synapses. We generated transgenic flies that express the cholesterol binding D4H domain of Perfringolysin O toxin fused to GFP and found increased levels of cholesterol in presynaptic terminals of glutamatergic Drosophila neuromuscular junctions following periods of increased synaptic activity. We found that cholesterol is required for both synaptic growth and activity-dependent synaptic growth. Examination of several mutant and transgenic larvae reveal that cholesterol is likely regulating synaptic growth through the cAMP-PKA kinase signaling pathway. Collectively, our data demonstrates that cholesterol redistribution occurs in response to synaptic activity and that it plays a key role in development and activity-dependent synaptic plasticity.
Ruoqi Dou PhD, Monaghan Lab Investigating the role of subgroup IV calcium-dependent protein kinases (CDPKs) across the plant lineage Calcium-dependent protein kinases (CDPKs) are a unique family of integrated Ca2+-sense/response proteins with diverse functions in plants. In model plant Arabidopsis thaliana, there are 34 CDPK genes which can be clustered into four subgroups (I, II, III & IV). There are only 3 members in subgroup IV, with CPK28 being the most highly expressed among them. CPK28 is a major regulator of immune homeostasis and growth in multiple angiosperm plants including tomato, rice, cotton, and Arabidopsis. This project aims to investigate the conserved and/or diverged functions of subgroup IV CDPKs from extant lineages that represent crucial points over the evolutionary history of plants. Our results suggest that the function of subgroup IV CDPKs are well conserved across over 450 M years of evolution. By experimentally assessing whether functions of the subgroup IV CDPKs are conserved in plants with varying life history traits, I will be able to determine if these proteins play core roles in plants immune system, which holds promise for biotechnological applications by generating CDPK alleles that enhance plant microbial pathogens resistance without consequences to yield.
Dr. Ben Freeman University of British Columbia, Biodiversity Research Centre Why do tropical species live in narrow slices of mountainsides, and why does this matter in the climate change era? Why do tropical species live in narrow slices of mountainsides? Climate is the prevailing explanation for this pattern, but competition can also restrict species’ elevational ranges. In this talk I will share my research investigating the biogeography of climate change and the relative role of climate and species interactions in shaping species’ ranges in tropical mountains, Earth’s hottest biodiversity hotspots.
Visit Dr. Freeman's website here Dr. Michael Downey University of Ottawa, Faculty of Medicine New functions and regulation for inorganic polyphosphates across evolution Polyphosphates (polyP) are long chains of inorganic phosphates that are found in virtually all cells on earth. Ranging from 3 to thousands of residues in length, these chains have been implicated in diverse functions, ranging from protein folding and virulence in bacteria to cell signalling and blood clotting in higher eukaryotes. How does such a simple molecule participate is such varied functions? I will present our work suggesting that polyP functions, at least in part, via lysine polyphosphorylation. This appears to be a non-enzymatic modification wherein long chains of polyP are thought to be covalently attached to lysine residues of target proteins in bacteria, yeast, and human cells. I will also present evidence that eukaryotic cells tightly regulate polyP subcellular localization, which has important implications for the control of polyphosphorylation and other aspects of polyP biology.
Dr. Downey's CV is viewable here CRISPR-Cas9 based gene editing strategies for the correction of genetic disorders Congenital genetic defects are the leading cause of morbidity and mortality. Despite advances in our understanding of the etiology and pathophysiology of genetic diseases, treatments are lacking. Advances in precision medicine, specifically gene therapy and editing approaches, have provided hope for a cure for these diseases at their molecular roots and can help in improving pathological outcomes. Based on the route of administration, time of delivery (prenatal or postnatal) and type of vectors (viral vectors and nanoparticles), different cell types and tissues can be targeted. In this talk, I will discuss nanoparticle-mediated gene editing (including base editing) strategies for the treatment of diseases such as type 1 tyrosinemia.
Connect with Dr. Sign on Twitter, LinkedIn, or view his publication on Google Scholar Nell Libera PhD, Smol Lab Lake ecosystem impacts from the fur farming industry in Nova Scotia, Canada Residents and environmental managers in Nova Scotia (NS), Canada, have attributed mink fur farms as a possible source of nutrient pollution that is causing algal blooms in regional lakes. However, water quality monitoring was only initiated in 2008, decades after the advent (ca. 1930s) and expansion (ca. 1970s) of the fur industry in NS. Further, multiple anthropogenic stressors, including climate change, acidification, brownification, and other land-use changes are likely contributing to ecosystem change. We analyzed the sediment archives of regional lakes to document the impacts of multiple stressors, and to better understand the environmental impacts of fur farming in NS. Our analyses included a detailed water chemistry survey, bioindicator analyses (diatoms and Cladocera), stable isotopes, and spectroscopic inferences of whole-lake primary production and organic carbon. Our data clearly implicate fur farms as a source of nutrient pollution. The most severe eutrophication impacts occurred in lakes where farms were closest to the shoreline. Some lakes were more resilient to eutrophication due to high colour and trace metal concentrations. This information can be used to inform management efforts in this region and in other lake ecosystems impacted by multiple stressors.
Dr. Thomas A. DeFalco Western University Deciphering and engineering kinase-mediated responses to stress in plants Plants must constantly survey their environment to respond to environmental perturbations. Toward this end, plants deploy receptor kinases (RKs) at the cell surface, which allow them to sense and respond to external cues while coordinating growth and development. Many RKs have been characterized as pattern recognition receptors (PRRs), which activate pattern-triggered immunity (PTI) upon perception of non- or altered-self elicitor molecules. Intensive study of model PRRs and PTI has led to an emerging paradigm wherein activated RK complexes trigger downstream signalling via activation of cytosolic kinases. These kinases in turn function to execute downstream signalling through the direct phosphorylation and regulation of diverse substrate proteins. I will discuss our work using a key immune-regulating kinase as a molecular probe to resolve the PTI signalling pathway, as well as how such knowledge can be applied to engineer immune responses. I will also discuss how such approaches may be applied to other, non-immune pathways, and how this relates to specificity in cell signalling.
Dr. Ivan Oresnik Department of Microbiology, University of Manitoba Relationship between central carbon metabolism and nitrogen fixation in Sinorhizobium meliloti Carbon metabolism is generally well understood in Sinorhizobium meliloti. The literature is consistent with the role of dicarboxylic acid metabolism while the bacteroid is actively fixing nitrogen. However, the literature contains many nitrogen fixation phenotypes ascribed to mutants that encode enzymes in central carbon metabolism that make little sense, or are even paradoxical. For example, a mutation in pckA, which is necessary for gluconeogenesis and encodes phosphoenolpyruvate carboxy kinase, consistently gives nitrogen fixation rates that are approximately 50% of wild-type, yet no measurable enzyme activity can be detected in bacteroids. Similarly, our work has shown strains that do not have triose phosphate isomerase activity also yield plants with 50% dry matter accumulation when grown under nitrogen deficient conditions. To date there is no clear explanation why these lesions affect nitrogen fixation based on our current knowledge. Based on our observations, we are hypothesizing that carbon metabolism may be correlated with endoreplication during bacteroid development and that rates of nitrogen fixation may be linked to the copy number of genes directly involved in nitrogen fixation. Although this may explain what occurs in indeterminate nodules, it probably does not apply to determinate nodules, suggesting that what limits nitrogen fixation between these nodule types may be different. Lisa Han MSc, Yakimowski Lab Estimating the stability and heritability of resistance fueling copy number variation in glyphosate-resistant Amaranthus palmeri Copy number variation (CNV), especially when present in extrachromosomal fashion, provides unparalleled opportunity for speciation and adaptation. As observed in agricultural weed species, Amaranthus palmeri, CNV of the herbicide glyphosate’s target gene, EPSPS, has resulted in emergence of glyphosate-tolerant and resistant populations across the globe. The amplification of EPSPS copies in forms of extrachromosomal circular DNA (eccDNA) poses unique challenges when assessing the heritability of EPSPS CNV as its origin and the tethering mechanisms are still mostly unknown. I used 30 F0 pairs and 900 F1 individuals from glyphosate-resistant populations to examine the heritability of EPSPS CNV in relation to parental EPSPS CNV. The results display a shifting pattern in progeny CNV with increasing parental mean EPSPS copy number. Over 70% of progeny resulting from parental crosses of low-med CNV displayed an increase in EPSPS CNV in a single generation while the opposite pattern was observed in progeny resulting from high EPSPS CNV mean parental crosses. This result indicates a substantial decline in heritability after a threshold point of 48.8 mean parental EPSPS CNV. The weaker heritability of eccDNA gene copy number variation at high CNV suggests weak evolutionary potential of highly glyphosate resistant CNV individuals and may constrain the evolution of population EPSPS CNV mean.
Dr. Megan Bontrager Department of Ecology & Evolutionary Biology at University of Toronto Local adaptation at range edges and under anomalous climates Species’ geographic ranges are limited on the landscape. A major focus of work in the Bontrager lab is identifying which evolutionary and ecological forces interact to shape species’ geographic distributions and limit adaptation. In addition, populations are frequently adapted to their local environments, and my lab works to identify which components of the environment are the most important factors driving local adaptation. I will talk about how gene flow affects range edge populations and how these effects may be especially important under climate change. I will also present results from two quantitative syntheses of transplant experiments to 1) examine how climate change is altering patterns of local adaptation, 2) evaluate the relative importance of temperature and precipitation to local adaptation and 3) examine how the magnitude of local adaptation changes from range centres to range edges. This work explores critical drivers of plant population performance and characterizes patterns of adaptation across species' ranges.
Regan Cross PhD, Eckert Lab Long-term experimental analysis of ecological and evolutionary processes at a species’ range limit Why do species have stable range limits – and what happens if they break free? Many species’ geographic ranges have historically been stable in space, but they may shift as climate change alters habitats. My thesis first looks at why species have stable range limits; what prevents them from dispersing beyond their ranges and adapting to the new habitat? I briefly review the current state of the field of range limits and provide a novel long-term test of whether a species’ range is limited by its niche. Next, I examine a few things that might happen if species shift their ranges using a beyond-range transplant experiment with the best coastal dune plant, Camissoniopsis cheiranthifolia. First, I ask: are populations from the range center or edge better suited to establish in beyond-range habitat? And second: did populations adapt to beyond-range conditions over ten generations? Finally, I test whether local or genetically mixed populations perform best within the range, to inform conservation efforts to re-establish populations and restore habitats. Come to my talk to learn about the mechanisms stopping species from expanding their ranges, some of the ecological and evolutionary processes going on during range shifts, and which populations are best used for conservation efforts like assisted migration and habitat restoration! (The photo is me with my first flowering transplant in 2018.)
Bryan Hau MSc, Snedden Lab Investigating the interaction of Arabidopsis calmodulin-like (CML) proteins with calmodulin-binding transcription activators (CAMTAs) Understanding the how organisms detect and interpret information from their environment is an ongoing goal in cell biology. A common theme among eukaryotic cells is the use of calcium ions (Ca2+) as second messengers during information processing. In plants, Ca2+ signals are evoked during responses to abiotic and biotic stresses and during development. These signals are detected by Ca2+-binding proteins (sensors), such as the evolutionarily-conserved protein calmodulin (CaM), which regulates various downstream target proteins to organize signal transduction pathways. In addition to CaM, plants have evolved a remarkable array of CaM-like proteins (CMLs) that are not found in animals. The genetic model, Arabidopsis, has seven CaMs and 50 CMLs, most of which remain unstudied. Why do plants need so many of these Ca2+ sensors? What are their downstream targets? How do they contribute to Ca2+ signaling during stimulus response? Research on CML structure/function is needed to develop a broader understanding of how plants respond to environmental cues. Recently, our lab has been exploring the roles of two paralogs, CML13,14, which possess unique biochemical properties among CaMs and CMLs. To help uncover CML13,14 function, we screened a yeast 2-hybrid library for putative target proteins and discovered 3 families of functionally unrelated proteins that share a common structural feature; tandem IQ domains. IQs are unique CaM binding domains that have been mainly studied in the myosin motor proteins of animals. In addition to myosins, we identified several CaM-binding transcription activators (CAMTAs) as putative CML13,14 targets. CAMTAs possess multiple IQ domains and are important transcription factors in plants that regulate gene expression during abiotic and biotic stresses such as cold, drought, salt stress, pathogen attack, and herbivory. I will present data from my MSc project where I explored the question; are Arabidopsis CAMTAs targets of CML13,14? My project focused mainly on assessing the properties of CML13/14-CAMTA binding, using both in planta and in vitro methods. Using a genetic approach, I also discovered a key role in salinity stress response for CML13. Collectively, my data supports the hypothesis that CAMTAs and CMLs interact in plants and suggests a novel mechanism through which Ca2+ signals regulate gene expression during stress response.
Dr. Anusha Shankar Lab of Ornithology at Cornell University Hot and cold hummingbirds: The ecology, physiology and genes of cold endotherms Information about Dr. Anusha Shankar here
Hummingbirds live fast. They have among the highest metabolic rates of all vertebrates, and must eat constantly to stay alive. I will talk about some of what I have learned about how they manage their energy budgets during the day, and how they allocate time and energy to different activities based on changes in their environment. At night, they save energy by entering the fascinating hibernation-like state of torpor. How do they manage to get so cold (~50°F/10°C) and slow their metabolism down as much as they do, and stay alive? This is what I am currently working on finding out. My work integrates methods and approaches from ecology, physiology and transcriptomics to understand how these tiny endotherms manage to survive in a variety of environmental conditions. Kapillesh Balasubramaniam MSc, Smol Lab Assessing the impacts of emerging anthropogenic stressors on lakes within the Rideau Canal system: A paleolimnological re-assessment Earlier diatom-based paleolimnological studies were conducted on a suite of diverse lakes (i.e., Lower Rideau L., Big Rideau L., Otter L., Upper Rideau L., Indian L., L. Opinicon) within the Rideau Canal system ~25-30 years ago and provided important information regarding the ecological impacts of canal construction (1827-1832). Following these early paleolimnological studies, the same lakes are now facing the potential impacts of newly emerging environmental stressors, particularly accelerated climate warming. Here, I revisited the same suite of lakes by conducting a series of paleolimnological analyses, focusing on recent changes in diatom assemblage composition, to assess the potential ecological impacts of newly emerging environmental stressors. Despite the substantial environmental impacts associated with canal construction, the highest rate of diatom compositional change across the suite of lakes only took place in the past ~25-30 years, which coincided mainly with an increase in planktonic diatom taxa. This recent shift in assemblage composition could not be explained by nutrient enrichment, as total phosphorus (TP) concentrations, measured since the 1980s, have significantly declined across the study lakes. The continued increase of planktonic taxa across the study lakes suggests the impact invasive zebra (ca. 1990) mussels in the Rideau Canal region appeared to have only been modest. Rather, these recent changes in diatom assemblage composition were strongly related to increasing regional air temperatures, as the conditions associated with warmer temperatures (i.e., longer, and stronger periods of thermal stratification, alterations to water-column mixing regimes, reduced ice cover duration) provide favorable conditions for extensive planktonic diatom growth. Lakes within the Rideau Canal system are changing rapidly in ecologically significant ways and will likely continue to do so as temperatures continue to rise.
Zoe Lai MSc Candidate, Regan Lab Exploring the cellular basis of environmental stress and plant development: Bioremediation potential of Senna and gene function in Populus As of 2021, the earth holds about 3.04 trillion trees. Plants account for 80% of the world’s total biomass. Trees, and plants in general, inherently play very important roles in our daily lives. My thesis examines the potential of a plant, Senna occidentalis, to phytoremediate arsenic- and cadmium-contaminated soils. Additionally, my thesis advances our understanding of leaf and stem development though the analysis of a mutant line of Populus tremula x Populus alba called shriveled leaf.
Mabel Fuentes MSc Candidate, Colautti Lab Genetic exploration of two invasive species to study rapid evolution and invasion genetics Classical genetics entails the study of spontaneous or introduced genomic mutations, analyzing the corresponding phenotypes, and then identifying the affected genes. Today's research is based on reverse genetics, which starts with the gene sequence and then explores its functions by analyzing the phenotype of an induced mutation. But how do we move from that specific phenotype to analyze fitness in a population?
Ecological genetics approach goes the other direction, observing the impact of a phenomenon in an ecosystem and analyzing community interactions, population dynamics, fitness, and observing a particular phenotype that may be of interest. There are not many studies that analyze the genes associated with a phenotype in the context of a natural community. In other words, how do we go from studying ecosystem diversity to genetic diversity? Invasive species provide the opportunity to study the expression of genes in populations subject to a changing environment. Since invasive species are known to adapt quickly and spread rapidly thus posing a threat to native ecosystems, more information on the genetic mechanisms of invasion can give us clues to how natural species can adapt to rapid changes, including under future climate change scenarios. My research provides evidence for the functional annotation of the draft genomes of Alliaria petiolata (garlic mustard) and Lythrum salicaria (purple loosestrife). These two plant species of Eurasian origin have successfully invaded and spread across North America. Each species has characteristics that make them valuable as a model for invasion. Alliaria petiolata belongs to the family Brassicaceae and dominates forest understories in absence of disturbance and produces glucosinolates and flavonoids as defensive chemicals that affect the growth of competitors. In contrast, L. salicaria belongs to the family Lythraceae, invades wetlands and has rapidly evolved differences in flowering time to adapt to differences in season length. Both species are highly prolific with the difference that L. salicaria is an obligate outcrossed, so populations maintain a higher level of genetic variation in comparison with A. petiolata which is known to have a comparatively higher rate of self fertilization. Using the draft genomes of both species as a reference, my research has focused on the assembly and analysis of the transcriptome (RNA) of samples from different conditions. For A. petiolata, RNA was extracted from leaf and root samples from individual plants subjected to mechanical injury and exposed to jasmonic acid to mimic herbivory. From these data candidate genes could be identified as potentially having a role in defense metabolic pathways. For L. salicaria, RNA was extracted from floral tissue of early and late flowering plants to predict candidate genes associated with flowering time. Using this new information, the draft genome annotations assemblies can be further improved, which will enable future molecular and functional genomic studies to investigate the genetic mechanisms of invasion and rapid adaptation in novel environments. Denis Bourguet Thomas Guillemaud French National Research Institute of Agronomy and Environment (INRAE) Peer Community In: A free alternative to evaluate, validate (and publish?) preprint :The Peer Community in (PCI, https://peercommunityin.org) project offers an alternative to the current system of publication - which is particularly expensive and not transparent. PCI is a non-profit scientific organization that aims to create specific communities of researchers reviewing and recommending, for free, unpublished preprints in their field (i.e. unpublished articles deposited on open online archives like arXiv.org and bioRxiv.org). Each PCI is a group of several hundred recommenders playing the role of editors who recommend such preprints based on peer-reviews to make them complete, reliable and citable articles, without the need for publication in ‘traditional’ journals (although the authors can submit their recommended preprints afterwards). Evaluations and recommendations by a PCI are free of charge. When a recommender decides to recommend a preprint, they write a recommendation text that is published along with all the editorial correspondence (reviews, recommender's decisions, authors’ replies) by PCI. The preprint itself is not published by PCI: it remains in the preprint server where it has been posted by the authors and can therefore be submitted to a journal and publish in Peer Community Journal, an open access diamond journal that PCI will launch, this fall. The first Peer Community in has been launched in 2017: Peer Community in Evolutionary Biology (PCI Evol Biol). PCI genomics was created two years ago. More than 1200 recommenders have already joined PCI Evol Biol, PCI Genomics, PCI Paleontology, PCI Ecology, PCI Animal Science, PCI Zoology, PCI Mathematical and Computational Biology, PCI Archaeology, etc. PCI won the 2020 LIBER award for library innovation of the European League of Research Libraries.
BIO: Thomas Guillemaud is a senior scientist at the French National Institute for Research in Agronomy and environment (INRAE). He works in Sophia Antipolis, France, on the evolutionary biology aspects of biological invasions. He obtained his phD a long time ago in the Institute for Evolutionary Biology of the university of Montpellier, France. He co-founded PCI in late 2016 and co-manages PCI since then. Denis Bourguet is a senior scientist at the French National Institute for Research in Agronomy and environment (INRAE). He works in Montpellier, France, in evolutionary biology on pesticide resistance evolution. He obtained his phD a long time ago in the Institute for Evolutionary Biology of the university of Montpellier, France. He co-founded PCI in late 2016 and co-manages PCI since then. |
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