Search

Abstract The evolutionary histories of adaptive radiations can be marked by dramatic demographic fluctuations. However, the demographic histories of ecologically-linked co-diversifying lineages remain understudied. The Laurentian Great Lakes provide a unique system of two such radiations that are dispersed across depth gradients with a predator-prey relationship. We show that the North American Coregonus species complex (“ciscoes”) radiated rapidly prior to the Last Glacial Maximum (80–90 kya), a globally warm period, followed by rapid expansion in population size. Similar patterns of demographic expansion were observed in the predator species, Lake Charr (Salvelinus namaycush), following a brief time lag, which we hypothesize was driven by predator-prey dynamics. Diversification of prey into deep water created ecological opportunities for the predators, facilitating their demographic expansion, which is consistent with an upward adaptive radiation cascade. This study provides a new timeline and environmental context for the origin of the Laurentian Great Lakes fish fauna, and firmly establishes this system as drivers of ecological diversification and rapid speciation through cyclical glaciation.

This study aims to examine the moderating role of individual (sex, symptom severity, and comorbid disorders) and familial (parental stress and parental depressive symptoms) factors on the improvement of organization, time management, and planning (OTMP) skills of youths with attention-deficit hyperactivity disorder (ADHD) following participation of families in a multimodal intervention targeting academic organizational skills. ADHD youths (M = 12.04 years, SD = 0.44; first language: 85.7% French, 11.4% English) under optimized psychostimulant treatment and their parents were randomly assigned to either an intervention group (n = 32; 21 boys and 11 girls) or a control group (n = 38; 28 boys and 10 girls). A two-dimensional questionnaire was used to measure improvement of OTMP skills: "Time Management and Planning and Memorization and Material Management (MMM)". Severity of inattention symptoms (p < 0.01) moderates MMM skills' improvement. The intervention was more efficacious in improving MMM skills of youths with more severe inattention symptoms under optimized psychostimulant treatment. No other moderating factors were observed. The intervention was effective in supporting ADHD youths improve their OTMP skills. The intervention appears to buffer the negative impact of inattention symptoms severity on MMM skills improvement.

ABSTRACT Long‐term biological monitoring and management depend on efficient protocols and methodology to characterize and precisely describe species distributions and diversity. In recent years, environmental DNA has progressively become a tool of choice in survey programs. However, the effect of variables such as sampling effort and sampling design still requires consideration. Simple random, grid, and transect‐based sampling methods are widely used in ecological surveys to obtain an unbiased estimation of species richness and community structure. However, under certain conditions where spatial information is available, sampling design and sequencing depth can be optimized to reduce effort and cost. Here, we evaluate different subsampling approaches to identify sampling strategies that are both easily implemented in the field and provide optimal recovery of species diversity for a given sampling effort. With a homogeneous grid‐based sampling (25–50 samples by lake) of 12 freshwater lakes in southeastern Québec, and using the 12S MiFish metabarcoding primer set, we demonstrate that random and stratified designs perform similarly to detect 90% and 95% of species. However, we found that, under certain circumstances, stratified sampling outperformed random sampling, requiring lower numbers of samples to detect the same species diversity. We also demonstrate that for the minimum sequence threshold and sample replication used in our study, a sequencing depth of 50K reads per sample is adequate to obtain a reliable portrayal of species richness. In this study, we contribute to the effort of eDNA sampling standardization by providing data for selecting the best sampling design, sequence depth, and sample size to detect 90%–95% of fish species found in temperate lakes.

Abstract Reconstructing the depositional history of Baffin Bay allows insights into the deglacial retreat of the Laurentide, Innuitian, and Greenland ice sheets from their maximum extent during the Last Glacial Maximum. Here, we present radiocarbon-controlled sedimentation rates from Baffin Bay based on 79 sediment cores to assess spatio-temporal variabilities in sediment deposition since the Last Glacial Maximum. This comprehensive dataset reveals that until ~15,000 years ago the deep basin and slopes were the dominant active sediment depocenters along most margins of Baffin Bay, suggesting prolonged ice-margin stability near the shelf edge, much longer than previously suggested. Between 13,000-11,000 years ago, most depocenters shifted quickly from the slope to the inner shelf, evidencing a very rapid landward ice-sheet retreat. The sedimentation rate-based mean erosion rates (0.17 and 0.08 millimeters/year) derived from the West Greenland Shelf underscore the high erosion capacity of the western Greenland Ice Sheet draining into Baffin Bay.

The path to publication is often long, emotional, and bewildering. We share key insights from our experience as authors, educators, and members of the editorial board with The Canadian Journal for the Scholarship of Teaching and Learning that we hope will help authors better understand and navigate the path to publication. In writing a compelling story, we suggest that it is necessary to join a conversation with self, the scholarly community, and the journal. We unpack each of these dimensions and offer considerations on how to craft a powerful manuscript that could ultimately get published.

IntroductionArctic marine ecosystems are changing rapidly, largely due to the observed accelerated warming that is associated with ongoing climate change. Environmental DNA (eDNA) combined with metabarcoding has great potential for large-scale biomonitoring of Arctic marine communities. However, important limitations remain, such as understanding the complexity and drivers of spatio-temporal variation in eDNA distribution.MethodsIn this study, we investigated the effect of tidal dynamics on aquatic metazoan (vertebrates and invertebrates) on eDNA metabarcoding results from nearshore estuarine and marine Arctic ports of Churchill (Manitoba) and Milne Inlet (Nunavut), respectively. We collected and sequenced 54 water samples per port at low, middle and high tide across three days, as well as two depths (surface, bottom), using four universal primer pairs (two primers in the COI gene and two in the 18S rRNA gene).ResultsWe observed a significant transition in the estuarine community structure from low to high tide, whereas the marine community structure was more stable across tides. The eDNA community structure differed between the surface and bottom waters in both the estuarine and marine ecosystems. However, the biodiversity pattern within the water column was significantly different between estuarine and marine ecosystems. Finally, we observed short-term temporal variation of the communities in both systems.DiscussionAltogether, our results highlight the short-term temporal dynamic nature of eDNA derived from coastal communities. This variability should be accounted for in eDNA sampling design to ensure robust characterization of coastal communities and long-term time series, particularly for estuarine environments where the effects of tide and depth are more important.

The primary focus of medicinal cannabis research is to ensure the stability of cannabis lines for consistent administration of chemically uniform products to patients. In recent years, tissue culture has emerged as a valuable technique for genetic preservation and rapid multiplication of cannabis clones. However, there is concern that the physical and chemical conditions of the growing media can induce somaclonal variation, potentially impacting the viability and uniformity of clones. To address this concern, we developed Comparative Restriction Enzyme Analysis of Methylation (CREAM), a novel method to assess DNA methylation patterns and used it to study a population of 78 cannabis clones maintained in tissue culture. Through bioinformatics analysis of the methylome, we successfully detected 2,272 polymorphic methylated regions among the clones. Remarkably, our results demonstrated that DNA methylation patterns were preserved across subcultures within the clonal population, allowing us to distinguish between two subsets of clonal lines used in this study. These findings significantly contribute to our understanding of the epigenetic variability within clonal lines in medicinal cannabis produced through tissue culture techniques. This knowledge is crucial for understanding the effects of tissue culture on DNA methylation and ensuring the consistency and reliability of medicinal cannabis products with therapeutic properties. Additionally, the CREAM method is a fast and affordable technology to get a first glimpse at methylation in a biological system. It offers a valuable tool for studying epigenetic variation in other plant species, thereby facilitating broader applications in plant biotechnology and crop improvement.

Submarine canyons enhance shelf–slope sediment exchange and influence hydrodynamic processes, with consequences for biogeochemical cycles. This work documents variations in the vertical export of biogenic matter on the northern shore of the lower St. Lawrence Estuary (LSLE, Quebec, eastern Canada), which is characterized by the presence of an active submarine canyon system. A total of three moorings were deployed from November 2020 to September 2021. One nearshore mooring (PDMc) was deployed in the main axis of the Pointe-des-Monts (PDM) canyon system and was equipped with an acoustic Doppler current profiler (ADCP), and two moorings equipped with sediment traps were deployed in the distal PDM canyon system (PDM-154, PDM-224) and offshore Baie-Comeau (BC-133). The ADCP data revealed the occurrence of a minor sediment remobilization event (December 2020) and a small turbidity current (February 2021) in the canyon. Concurrent elevated fluxes of total particulate matter, particulate organic carbon, particulate nitrogen, and chloropigments showed that these events left a signature in sediment traps PDM-154 and PDM-224 located > 2.6 km further offshore by enhancing lateral dispersion of resuspended sediments. The composition of diatom and dinoflagellate assemblages was similar in the canyon system and offshore BC, but the diatom bloom occurred 2 weeks earlier (in mid-April) at the PDM site. A bloom of the potentially toxic diatom Pseudo-nitzschia seriata was also observed during the second half of September 2021 at the BC site. Annual diatom and dinoflagellate fluxes were almost 2 times lower at the PDM site than at the BC site, possibly due to differences in riverine input and the structure of the water column, as well as increased sediment input and resuspension at the PDM site, leading to limited light availability. This study notably helps identify the relationship between near-bed canyon processes and biogenic matter export in the water column, thereby directly influencing the ecosystem offshore PDM. The study period further covered an anomalously nearly ice-free winter, and thus, in the context of climate change, it provides valuable insight into future trends of biogenic matter export in the LSLE.

Abstract The American eel (Anguilla rostrata) has long been regarded as a panmictic fish and has been confirmed as such in the northern part of its range. In this paper, we tested for the first time whether panmixia extends to the tropical range of the species. To do so, we first assembled a reference genome (975 Mbp, 19 chromosomes) combining long (PacBio and Nanopore and short (Illumina paired‐end) reads technologies to support both this study and future research. To test for population structure, we estimated genotype likelihoods from low‐coverage whole‐genome sequencing of 460 American eels, collected at 21 sampling sites (in seven geographic regions) ranging from Canada to Trinidad and Tobago. We estimated genetic distance between regions, performed ADMIXTURE‐like clustering analysis and multivariate analysis, and found no evidence of population structure, thus confirming that panmixia extends to the tropical range of the species. In addition, two genomic regions with putative inversions were observed, both geographically widespread and present at similar frequencies in all regions. We discuss the implications of lack of genetic population structure for the species. Our results are key for the future genomic research in the American eel and the implementation of conservation measures throughout its geographic range. Additionally, our results can be applied to fisheries management and aquaculture of the species.

Abstract While Atlantic salmon (Salmo salar) of the northernmost American populations is alimentary, economically, and culturally important for Ungava Inuit communities (Nunavik, Canada) and might play a key role in the persistence of the species in a global warming context, many mysteries remain about those remote and atypical populations. Thus, our first aim was to document the genomic structure of the Nunavik populations. The second objective was to determine whether salmon only migrating to the estuary without reaching the sea, apparently unique to those populations, represent distinct populations from the typical anadromous salmons and subsequently explore the genetic basis of migratory life‐history tactics in the species. Finally, the third goal was to quantify the contribution of each genetically distinct population and life‐history tactic in the mixed‐stock subsistence fishery of the Koksoak R. estuary. We used Genotyping‐by‐Sequencing to genotype 14,061 single nucleotide polymorphisms in the genome of 248 individuals from 8 source populations and 280 individuals from the Koksoak estuary mixed‐stock fishery. Life‐history tactics were identified by a visual assessment of scales. Results show a hierarchical structure mainly influenced by isolation‐by‐distance with 7 populations out of the 8 studied rivers. While no obvious structure was detected between marine and estuarine salmon within the population, we have identified genomic regions putatively associated with those migration tactics. Finally, all salmon captured in the Koksoak estuary originated from the Koksoak drainage and mostly from 2 tributaries, but no inter‐annual variation in the contribution of these tributaries was found. Our results indicate, however, that both marine and estuarine salmon contribute substantially to estuarine fisheries and that there is inter‐annual variation in this contribution. These findings provide crucial information for the conservation of salmon populations in a rapidly changing ecosystem, as well as for fishery management to improve the food security of Inuit communities.

Abstract Amazonian blackwaters are extremely biodiverse systems containing some of Earth’s most naturally acidic, dissolved organic carbon -rich and ion‐poor waters. Physiological adaptations of fish facing these ionoregulatory challenges are unresolved but could involve microbially-mediated processes. Here, we characterize the physiological response of 964 fish-microbe systems from four blackwater Teleost species along a natural hydrochemical gradient, using dual RNA-Seq and 16 S rRNA of gill samples. We find that host transcriptional responses to blackwaters are species-specific, but occasionally include the overexpression of Toll-receptors and integrins associated to interkingdom communication. Blackwater gill microbiomes are characterized by a transcriptionally-active betaproteobacterial cluster potentially interfering with epithelial permeability. We explore further blackwater fish-microbe interactions by analyzing transcriptomes of axenic zebrafish larvae exposed to sterile, non-sterile and inverted (non-native bacterioplankton) blackwater. We find that axenic zebrafish survive poorly when exposed to sterile/inverted blackwater. Overall, our results suggest a critical role for endogenous symbionts in blackwater fish physiology.

AbstractIn Lar National Park (Caspian Sea basin, Iran), the Caspian trout (Salmo caspius) population faces different threats, including introduced fish species. Due to the harsh environmental conditions and limited accessibility, monitoring of fish species via conventional approaches proves difficult. Hence, environmental DNA metabarcoding may prove an appropriate tool for monitoring fishes within the park. Environmental DNA samples from eight stream sites in the National Park were sequenced via metabarcoding of the 12S rRNA gene, and the species identified via eDNA metabarcoding were compared to the results of electrofishing performed at the same localities on the same day. No significant difference in the number of Caspian Sea trout DNA sequence reads was detected among the collection sites (p > 0.05). The highest number of reads was detected in Dalichay Stream, but the highest population density determined via electrofishing was in Siahpalas Stream. The discrepancy between the eDNA read count and trout population density, as well as the limited sampling scheme within this study, limit our ability to provide a robust conclusion about the application of environmental DNA metabarcoding for assessment of fish density in Lar National Park. Environmental DNA metabarcoding detected more species than electrofishing, but no significant differences in the composition of the local fish community were observed. Introduced fish species were all observed or detected in Siahpalas Stream, which is characterized by high water temperature, muddy substrate, and lower flow rate. A significant effect of flow rate and total dissolved solids on the presence of introduced fish species (p = 0.02) and of flow rate alone on relative abundance of introduced fish species (p = 0.03) was detected. To standardize the application of eDNA metabarcoding as a biodiversity assessment tool in Lar National Park, future studies should characterize the parameters that affect eDNA persistence and detectability in the system.

Multiple proxies in three sediment cores from Northwestern Baffin Bay document the timing of Lancaster Sound Ice Stream (LSIS) retreat that led to Arctic–Atlantic throughflow in Parry Channel, an important source of freshwater that can impact the Atlantic Meridional Overturning Circulation. The Late Glacial to Holocene timing of ice retreat and channel opening and the responses of the regional ocean environment to these events are presented. We use quantitative mineral composition, foraminiferal assemblages, biogenic silica, ice-rafted debris (IRD), and 14C-based age models to document and date the events and environmental changes occurring during deglaciation of this major marine channel. Findings show that retreat of the LSIS into Lancaster Sound occurred before ~15.3 cal ka BP, about 800 years before the onset of major iceberg calving events from the LSIS, named the Baffin Bay Detrital Carbonate events (BBDC 1 and BBDC 0). The end of BBDC 0 occurred at ~10.6 cal ka BP, which coincides with the opening of Parry Channel. A marine environment productive of calcareous benthic and planktic foraminifera, with diminished meltwater, seasonal sea ice, warmer summer temperatures, and inflowing, nutrient-rich Arctic surface water characterizes the interval between the opening of Parry Channel and the opening of Nares Strait. Paired planktic and benthic 14C ages over this 2,200-year interval show diminishing age offsets suggesting progressive mixing of the upper ~850–900 m of the water column. The opening of Nares Strait by ~8.2 cal ka BP coincides with increased biogenic silica in the form of abundant, large centric diatoms and dissolution of CaCO3. The paucity of calcareous organisms after 8.2 cal ka BP resulted in poor chronological control in the cores to interpret changing environments after 8.2 cal ka BP.

Abstract Conservation units (CUs) are important tools for supporting the implementation of standardized management practices for exploited species. Following the adoption of the Wild Salmon Policy in Canada, CUs were defined for Pacific salmon based on characteristics related to ecotype, life history and genetic variation using microsatellite markers as indirect measures of local adaptation. Genomic data sets have the potential to improve the definition of CUs by reducing variance around estimates of population genetic parameters, thereby increasing the power to detect more subtle patterns of population genetic structure and by providing an opportunity to incorporate adaptive information more directly with the identification of variants putatively under selection. We used one of the largest genomic data sets recently published for a nonmodel species, comprising 5662 individual Coho salmon (Oncorhynchus kisutch) from 149 sampling locations and a total of 24,542 high‐quality SNPs obtained using genotyping‐by‐sequencing and mapped to the Coho salmon reference genome to (1) evaluate the current delineation of CUs for Coho in Canada and (2) compare patterns of population structure observed using neutral and outlier loci from genotype–environment association analyses to determine whether separate CUs that capture adaptive diversity are needed. Our results reflected CU boundaries on the whole, with the majority of sampling locations managed in the same CU clustering together within genetic groups. However, additional groups that are not currently represented by CUs were also uncovered. We observed considerable overlap in the genetic clusters identified using neutral or candidate loci, indicating a general congruence in patterns of genetic variation driven by local adaptation and gene flow in this species. Consequently, we suggest that the current CU boundaries for Coho salmon are largely well‐suited for meeting the Canadian Wild Salmon Policy's objective of defining biologically distinct groups, but we highlight specific areas where CU boundaries may be refined.

Concept inventories (CI) are validated, research-based, multiple-choice tests, which are widely used to assess the effectiveness of pedagogical practices in bringing about conceptual change. In order to be a useful diagnostic tool, a CI must reflect only the student understanding of the conceptual material. The Force Concept Inventory (FCI) is arguably the standard for testing conceptual understanding of Newtonian mechanics. Studies in the United States and United Kingdom have shown the existence of a gender gap in FCI scores and gains between male and female students. This study aimed to examine whether such a gap exists for Canadian students at a mid-sized university. Four-hundred and thirty-four men and 379 women taking first-term introductory physics courses from the past nine years were assessed with the FCI prior to and after receiving instruction. A gender gap in the pre-instruction and post instruction scores was revealed in favour of male students (p < 0.01). There also existed a gender disparity in the learning gains between the two tests, where males had significantly higher gains (p < 0.01), although the effect size was small. Further analysis found that both male and female students who studied in classes that included interactive engagement methods had somewhat higher gains than students in traditional lecture courses, but that the interactive engagement methods did not eliminate the gender gap between male and female students (p < 0.01). Our results sound a cross-disciplinary note of caution for anyone using concept inventories as research or self-assessment tools.

Background: Enhancing the interactions between study participants, clinicians, and investigators is imperative for advancing Parkinson's disease (PD) research. The Canadian Open Parkinson Network (C-OPN) stands as a nationwide endeavor, connecting the PD community with ten accredited universities and movement disorders research centers spanning, at the time of this analysis, British Columbia, Alberta, Ontario, and Quebec. Objective: Our aim is to showcase C-OPN as a paradigm for bolstering national collaboration to accelerate PD research and to provide an initial overview of already collected data sets. Methods: The C-OPN database comprises de-identified data concerning demographics, symptoms and signs, treatment approaches, and standardized assessments. Additionally, it collects venous blood-derived biomaterials, such as for analyses of DNA, peripheral blood mononuclear cells (PBMC), and serum. Accessible to researchers, C-OPN resources are available through web-based data management systems for multi-center studies, including REDCap. Results: As of November 2023, the C-OPN had enrolled 1,505 PD participants. The male-to-female ratio was 1.77:1, with 83% (n = 1098) residing in urban areas and 82% (n = 1084) having pursued post-secondary education. The average age at diagnosis was 60.2±10.3 years. Herein, our analysis of the C-OPN PD cohort encompasses environmental factors, motor and non-motor symptoms, disease management, and regional differences among provinces. As of April 2024, 32 research projects have utilized C-OPN resources. Conclusions: C-OPN represents a national platform promoting multidisciplinary and multisite research that focuses on PD to promote innovation, exploration of care models, and collaboration among Canadian scientists. Plain Language Summary: Teamwork and communication between people living with Parkinson's disease (PD), physicians, health professionals, and research scientists is important for improving the lives of those living with this condition. The Canadian Open Parkinson Network (C-OPN) is a Canada-wide initiative, connecting the PD community with ten accredited universities and movement disorders research centers located in – at the time of this analysis–British Columbia, Alberta, Ontario, and Quebec. The aim of this paper is to showcase C-OPN as a useful resource for physician and research scientists studying PD in Canada and around the world, and to provide snapshot of already collected data. The C-OPN database comprises de-identified (meaning removal of any identifying information, such as name or date of birth) data concerning lifestyle, disease symptoms, treatments, and results from standardized tests. It also collects blood samples for further analysis. As of November 2023, C-OPN had enrolled 1,505 PD participants across Canada. Most of the participants were male (64%), living in urban areas (83%), and completed post-secondary education (82%). The average age at diagnosis was 60.2±10.3 years. In this paper, we look at environmental factors, motor and non-motor symptoms, different disease management strategies, and regional differences between provinces. In conclusion, C-OPN represents a national platform that encourages multidisciplinary and multisite research focusing on PD to promote innovation and collaboration among Canadian scientists. [ABSTRACT FROM AUTHOR]

International commitments to preserve global biodiversity target the protection of 30% of marine habitats by 2030. The lack of even basic knowledge of many marine areas (e.g., deep oceans) combined with short timelines require integrative knowledge and multidisciplinary techniques to be used to efficiently identify areas worthy of protection. Here we outline a case study of the discovery of the Makkovik Hanging Gardens found in a deep-water trough in coastal Labrador, Canada. The area is of ecological significance because it supports high densities of vulnerable marine ecosystem indicator taxa, including the gorgonian coral Primnoa resedaeformis on portions of its vertical submarine walls. This study illustrates the exploratory process initiated by Nunatsiavut, which integrated local knowledge, scientific models, and a variety of technologies (such as remotely operated vehicles and multibeam sonar) to discover deep-water hidden biodiversity toward the advancement of both local Indigenous and global conservation goals.

Abstract One of the most important steps in conservation of the subterranean life forms is to decipher their distribution and ecology, which is challenging using traditional approaches. Development of an environmental DNA (eDNA) assay provides an efficient means for discovering and monitoring subterranean life forms. In this study, the distribution of three Iranian blind cave fish species (blind Iran cave barb Garra typhlops, blind Lorestan cave barb Garra lorestanensis, and blind cave loach Eidinemacheilus smithi) was assessed using 12S rRNA eDNA metabarcoding performed using MiFish‐U PCR primers and preliminary species distribution modeling (SDM) using bioclimatic data. The majority of sampling localities with positive detection of cave barb eDNA fall within suitable habitats in the Zagros Mountains of Iran. Our results revealed that Lorestan and Iran cave barbs have differential distribution patterns, with some extent of habitat overlap in the vicinity of the originally discovered cave barb locality. According to the observed distribution patterns, the blind Lorestan cave barb and cave loach are mostly distributed in habitats close to the Sezar River (Dez River drainage, Iran), and the blind Iran cave barb is distributed towards the west and probably in a few springs in the Karkheh River drainage. Our data support the previously proposed distribution pattern for the cave barbs, in which the species show partial niche separation and reproductive isolation, with the Lorestan cave barb being a water flow‐dependent species and the Iran cave barb being a generalist species preferring variable flow rates. We showed eDNA metabarcoding to be a useful approach for ecological surveys of subterranean fish biodiversity with implications for conservation.

Here, the authors show that enhanced tropical cyclone activity was synchronized with increased Asian dust emissions during the Little Ice Age, implying a mechanism linking tropical cyclone climatology to Asian dust levels, at 100 to 1000 year scales.

AbstractDense single nucleotide polymorphism (SNP) arrays are essential tools for rapid high-throughput genotyping for many genetic analyses, including genomic selection and high-resolution population genomic assessments. We present a high-density (200 K) SNP array developed for the Eastern oyster (Crassostrea virginicar2C. virginica

AbstractCoho salmon (Oncorhynchus kisutch