Ontario Ministry of the Environment
Recent publications
Understanding controls on primary productivity is essential for describing ecosystems and their responses to environmental change. In lakes, pelagic gross primary productivity (GPP) is strongly controlled by inputs of nutrients and dissolved organic matter. Although past studies have developed process models of this nutrient‐color paradigm (NCP), broad empirical tests of these models are scarce. We used data from 58 globally distributed, mostly temperate lakes to test such a model and improve understanding and prediction of the controls on lake primary production. The model includes three state variables–dissolved phosphorus, terrestrial dissolved organic carbon (DOC), and phytoplankton biomass–and generates realistic predictions for equilibrium rates of pelagic GPP. We calibrated our model using a Bayesian data assimilation technique on a subset of lakes where DOC and total phosphorus (TP) loads were known. We then asked how well the calibrated model performed with a larger set of lakes. Revised parameter estimates from the updated model aligned well with existing literature values. Observed GPP varied nonlinearly with both inflow DOC and TP concentrations in a manner consistent with increasing light limitation as DOC inputs increased and decreasing nutrient limitation as TP inputs increased. Furthermore, across these diverse lake ecosystems, model predictions of GPP were highly correlated with observed values derived from high‐frequency sensor data. The GPP predictions using the updated parameters improved upon previous estimates, expanding the utility of a process model with simplified assumptions for water column mixing. Our analysis provides a model structure that may be broadly useful for understanding current and future patterns in lake primary production.
Microplastic pollution constitutes a pressing global environmental issue impacting nearly every facet of human activity. This specific environmental challenge exerts profound yet still poorly understood influences on health, social dynamics, and industrial practices. A major obstacle for further investigation and mitigation of microplastics lies in their heterogeneity in size and composition. Additionally, the multitude of sources contributing to microplastic emissions further complicates their study. To enhance current detection and analytical methodologies for microplastics, this study exploits a novel approach for the easy and specific identification of microplastics within diverse environmental samples (including air, soil, lake water, rain, snow, and marine sediment) collected from various geographical locations across Canada. This method relies on fluorescent conjugated polymer nanoparticles that can be used to identify microplastics after minimal preparation. In all examined samples, originating from diverse sources and environments, microplastics were consistently present in the form of fragments and/or fibers, with polyethylene terephthalate (PET) emerging as the most abundant type, as confirmed via Raman spectroscopy either before or after labeling. This approach significantly streamlines the microplastic identification process, reducing the time needed for extraction and isolation. Our findings corroborate the efficacy of nanoparticle labeling for microplastic detection, offering promising avenues for their facile, specific, and reliable identification. Ultimately, this novel procedure holds potential to enhance remediation efforts targeting microplastics in the environment, thereby advancing our understanding of their global impact.
Pesticide pollution can present high ecological risks to aquatic ecosystems. Small streams are particularly susceptible. There is a need for reproducible and readily available methods to identify aquatic regions at risk of pesticide contamination. There is currently a limited understanding of the relationship between upstream catchment land use and the presence of pesticides in multiple aquatic matrices. The aim of this study was to develop empirical relationships between different land uses and the levels of pesticides detected in multiple aquatic matrices. The inclusion of biofilm and suspended sediment as monitoring matrices has recently been proven effective for the characterization of pesticide exposure in stream ecosystems. Ten streams in Ontario, Canada with a variety of upstream catchment land uses were sampled in 2021 and 2022. Water, suspended sediment and biofilm were collected and analyzed from each site for the presence of approximately 500 different pesticides. Each of the three matrices exhibited distinctive pesticide exposure profiles. We found a significant relationship between the percentage of agriculture and urban land use and the detection of multiple pesticides in water, sediment and biofilm (logistic regressions, P<0.05). Statistically significant probabilistic models capable of predicting pesticide detections based on upstream catchment land use were developed. High-resolution cover crop maps identified soybeans, corn and other agriculture (e.g., vegetables, berries, canola) as the key variables associated with individual pesticide detection frequencies in each of the three matrices (linear regressions, P<0.05). Soybean land use was also the strongest predictor of site-wide pesticide pollution. This modelling approach using upstream catchment land use variables has the potential to be a powerful tool to identify streams at risk of pesticide pollution.
In conservation strategies, getting precise and repeatable information on the species’ diet and health without relying on invasive or laborious methods is challenging. Here, we developed an efficient and non-invasive workflow for the sequencing and analysis of four taxonomic markers from fecal DNA to characterize the gut microbiota, parasites, and plants and lichens composing the winter diet of caribou (Rangifer tarandus), Canada’s most iconic endangered species. Sequencing of the 18S rRNA gene of eukaryotes from seven locations in Manitoba and Saskatchewan, Canada, allowed for the detection of five genera of parasites in caribou feces (including Nematodirella and Parelaphostrongylus) with variable frequency of occurrence depending on sampling location and sex. Our workflow also revealed a rich winter plant and lichen diet in caribou, with respectively 29 and 18 genera identified across all samples through plant and fungal ITS2 sequencing. Relationships between the gut microbiota and both the diet and parasite richness were also identified. Of note, the Central Saskatchewan sampling location was characterized by a clearly distinct gut microbiota which could be linked to an epiphytic lichen-rich diet. Overall, our results showed the potential of this multi-marker DNA metabarcoding workflow as an efficient tool to provide insights into the species biology and ecology.
Morphological abnormalities in amphibians are commonly associated with anthropogenic activity, although little baseline information on the prevalence of abnormalities in uncontaminated environments exist. Here, we leverage a 12-year study of spotted salamanders (Ambystoma maculatum (Shaw, 1802)) in an uncontaminated ecosystem in Algonquin Provincial Park, Canada, to estimate abnormality rates and explore how abnormalities affect fitness-related traits. Annual abnormality rates estimated from drift fence data ranged from 4.3% to 5.8% of individuals sampled. Abnormality rates from aquatic trapping between 2008 and 2019 varied from 1.2% to 16.7%, where temporal increases in abnormality rates were observed. We also performed a targeted, systematic literature survey and found that Caudata exhibited a slightly higher abnormality prevalence than Anura, and that the baseline frequency of abnormalities described at our drift fence site is slightly lower than rates reported in the literature (8.1%, 95% CI, 4.76%–13.3%). Salamanders with abnormalities exhibited a slightly, but not significantly, higher body condition and a significantly earlier arrival date at the breeding site, both of which are traits typically associated with high-fitness individuals. Our study suggests that abnormalities have detectable phenotypic consequences, and underlines the need for temporal sampling efforts to provide ranges of baseline abnormality rates, rather than a point estimate.
Documented plastic pollution throughout the Laurentian Great Lakes system prompted investigation of microplastics (MPs) in sediment cores. We examined offshore sediment cores from Lake Huron (LH43) and Lake Ontario (403A) to understand temporal trends and changes in microplastic (MP) pollution in the size range 53 µm to 2 mm. MP abundances varied from 18.1 to 280.1 particles per g of dry weight sediment (N g⁻¹ dw) in LH43, and 8.2–488.4 g⁻¹ dw in core 403A. The 15 cm cores are equivalent to 56 years of accumulation in Lake Huron and 72 years of accumulation in Lake Ontario. Analysis of the two cores shows an increasing trend in MP accumulation from 1964 to 1989, which mirrors the global plastic production rate. Subsequent peaks and troughs in the MP abundance profiles reflect macroeconomic changes and regional controls. These results show how changing abundances of MPs in lake sediment cores can act as proxies for global perturbations in oil supply as well as national economic shifts.
Background: Microplastics are a pervasive contaminant cycling through food webs-leading to concerns regarding exposure and risk to humans. Objectives: We aimed to quantify and characterize anthropogenic particle contamination (including microplastics) in fish caught for human consumption from the Humber Bay region of Lake Ontario. We related quantities of anthropogenic particles to other factors (e.g., fish size) that may help in understanding accumulation of microplastics in fish. Methods: A total of 45 samples of six fish species collected from Humber Bay in Lake Ontario near Toronto, Ontario, Canada, were examined for anthropogenic particles in their gastrointestinal (GI) tracts and fillets. Using microscopy and spectroscopy, suspected anthropogenic particles were identified and characterized. Results: We observed anthropogenic particles in the GI tracts and fillets of all species. Individual fish had a mean±standard deviation of 138±231 anthropogenic particles, with a single fish containing up to 1,508 particles. GI tracts had 93±226 particles/fish (9.8±32.6 particles/gram), and fillets had 56±61 particles/fish (0.5±0.8 particles/gram). Based on a consumption rate of 2 servings/week, the average yearly human exposure through the consumption of these fish fillets would be 12,800±18,300 particles. Discussion: Our findings suggest that consumption of recreationally caught freshwater fish can be a pathway for human exposure to microplastics. The elevated number of particles observed in fish from Humber Bay highlights the need for large-scale geographic monitoring, especially near sources of microplastics. Currently, it is unclear what the effects of ingesting microplastics are for humans, but given that recreationally caught freshwater fish are one pathway for human exposure, these data can be incorporated into future human health risk assessment frameworks for microplastics. https://doi.org/10.1289/EHP13540.
Following the detection of novel highly pathogenic avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b in Newfoundland, Canada, in late 2021, avian influenza virus (AIV) surveillance in wild birds was scaled up across Canada. Herein, we present the results of Canada’s Interagency Surveillance Program for Avian Influenza in Wild Birds during the first year (November 2021–November 2022) following the incursions of HPAIV from Eurasia. The key objectives of the surveillance program were to (i) identify the presence, distribution, and spread of HPAIV and other AIVs; (ii) identify wild bird morbidity and mortality associated with HPAIV; (iii) identify the range of wild bird species infected by HPAIV; and (iv) genetically characterize detected AIV. A total of 6,246 sick and dead wild birds were tested, of which 27.4% were HPAIV positive across 12 taxonomic orders and 80 species. Geographically, HPAIV detections occurred in all Canadian provinces and territories, with the highest numbers in the Atlantic and Central Flyways. Temporally, peak detections differed across flyways, though the national peak occurred in April 2022. In an additional 11,295 asymptomatic harvested or live-captured wild birds, 5.2% were HPAIV positive across 3 taxonomic orders and 19 species. Whole-genome sequencing identified HPAIV of Eurasian origin as most prevalent in the Atlantic Flyway, along with multiple reassortants of mixed Eurasian and North American origins distributed across Canada, with moderate structuring at the flyway scale. Wild birds were victims and reservoirs of HPAIV H5N1 2.3.4.4b, underscoring the importance of surveillance encompassing samples from sick and dead, as well as live and harvested birds, to provide insights into the dynamics and potential impacts of the HPAIV H5N1 outbreak. This dramatic shift in the presence and distribution of HPAIV in wild birds in Canada highlights a need for sustained investment in wild bird surveillance and collaboration across interagency partners. IMPORTANCE We present the results of Canada’s Interagency Surveillance Program for Avian Influenza in Wild Birds in the year following the first detection of highly pathogenic avian influenza virus (HPAIV) H5N1 on the continent. The surveillance program tested over 17,000 wild birds, both sick and apparently healthy, which revealed spatiotemporal and taxonomic patterns in HPAIV prevalence and mortality across Canada. The significant shift in the presence and distribution of HPAIV in Canada’s wild birds underscores the need for sustained investment in wild bird surveillance and collaboration across One Health partners.
This study explores the potential benefits of transitioning from livestock farming to high-value alternative crops as a strategy for mitigating agricultural greenhouse gas (GHG) emissions in New Zealand. The government has set ambitious targets for reducing methane (CH4) emissions. However, since animal product exports play a crucial role in New Zealand’s economy, any shift in land use will have significant impacts on both the regional and national economy. We developed a GIS framework that integrated (i) growing requirements, (ii) GHG emissions and (iii) profitability for crops. Analysis of export market opportunities identified twelve high-value “alternative crops”. Availability of suitable land for crop expansion was not a limiting factor. Working with the Ministry for Primary Industries, we explored how land use change scenarios contributed to Government 2050 biogenic CH4 emission reduction targets. Doubling the area of alternative crops (a 195,000-ha increase) by reallocating land from livestock farming resulted in reducing biogenic CH4 emissions by 1.2 to 5.4% (0.35 to 1.57 Mt CO2-e) compared to 2017 baseline values, contributing to between 2.6 and 22.5% of the 2050 CH4 reduction targets, simultaneously increasing profitability by $NZ1.25 to 1.32 billion annually. While this approach demonstrates potential benefits of land use change, a deeper understanding of the complexity of land use decision-making is required to enable successful transitions. Addressing barriers to change requires collaborative efforts from land users, researchers and policy makers.
Landuse change affects the hydrologic regime. Both agricultural intensification (tile drainage) and urban expansion result in flashier flow regimes in southern Ontario watersheds. Tile drainage effects on stream flow are most evident during wet periods of the year.
Introduction Cyanobacterial blooms are increasingly common in freshwater sources used for swimming and other recreational water contact activities in Canada. Many species of cyanobacteria can produce toxins that affect human and animal health, but there are limited data on the risk of illness associated with water contact at impacted beaches. Methods and analysis This study will investigate the incidence of recreational water illness due to exposure to cyanobacterial blooms and their toxins in four targeted and popular freshwater beaches in Ontario, Manitoba and Nova Scotia, Canada. A prospective cohort design and One Health approach will be used. On-site recruitment of recreational water users will be conducted at two beaches per year during the summers of 2024 and 2025. The population of interest includes recreational water users of any age and their pet dogs. After enrolment, an in-person survey will determine beach exposures and confounding factors, and a 3-day follow-up survey will ascertain any acute illness outcomes experienced by participants or their dogs. The target sample size is 2500 recreational water users. Water samples will be taken each recruitment day and analysed for cyanobacterial indicators (pigments), cell counts and toxin levels. Bayesian regression analysis will be conducted to estimate the association with water contact, cyanobacterial levels and risks of different acute illness outcomes. Ethics and dissemination This study has been approved by the Toronto Metropolitan University Research Ethics Board (REB 2023-461). Study results will be published in a peer-reviewed journal and as infographics on a project website.
The specific objective of this study is to explore the long-term trend of total phosphorus (TP) and total suspended sediment (TSS) concentrations and loads (C/L)s in various streams/rivers in the Great Lakes Basin. This includes related statistical analyses, such as confidence intervals, to assess variability and identify cases where measures should be taken to reduce TSS and TP. Trend analysis of TSS and TP (C/L)s are performed, combining bootstrapping with the Weighted Regressions on Time, Discharge, and Season, i.e., WRTDS_BT technique. The technique is used at ten selected monitoring stations of Northern Lake Erie, Eastern Lake Huron, and Lake Ontario and Niagara Peninsula in Ontario, Canada. Trend analysis over selected tributaries using flow-normalized (FN) TSS and TP (C/L)s reveals that trends in [FN-TSS] and [FN-TP] (C/L)s were highly variable, with significant decrease in a few stations. However, in most tributaries, TSS concentration levels are significantly higher than Canadian Water Quality Guidelines (CWQG) limit of 30 mg/L (following Toronto Region Conservation Authority (TRCA), Ontario) and TP concentration levels are significantly higher than the Ontario’s provincial water quality objectives (PWQO) limit of 0.03 mg/L. Measures to reduce TSS and TP is effective at five tributaries (Humber River, Don River, Saugeen River, Big Creek, Nottawasaga River). Although the drivers are not explicitly identified, potential attributions are discussed for policymakers in the study area.
In conservation strategies, getting precise and repeatable information on the species’ diet and health without relying on invasive or laborious methods is challenging. Here, we developed an efficient and non-invasive workflow for the sequencing and analysis of four taxonomic markers from fecal DNA to characterize the gut microbiota, parasites, and plants and lichens composing the winter diet of caribou ( Rangifer tarandus ), Canada's most iconic endangered species. Sequencing of the 18S rRNA gene of eukaryotes from seven locations in Manitoba and Saskatchewan, Canada, allowed for the detection of several parasites in caribou feces but provided limited information about plants and lichens - only algal symbionts were detected. An improved sensitivity and higher taxonomic resolution for plants and lichens was achieved through the sequencing of the ITS2 region, which revealed a rich winter diet in caribou as well as differences among sampling locations. Sequencing of the 16S rRNA gene of prokaryotes highlighted the relationships between the gut microbiota and both the diet and parasites. Overall, our results showed the potential of this multi-marker DNA metabarcoding workflow as an efficient tool to generate relevant information on the diet and health of caribou populations and provide insights into the species biology and ecology.
In conservation strategies, getting precise and repeatable information on the species’ diet and health without relying on invasive or laborious methods is challenging. Here, we developed an efficient and non-invasive workflow for the sequencing and analysis of four taxonomic markers from fecal DNA to characterize the gut microbiota, parasites, and plants and lichens composing the winter diet of caribou ( Rangifer tarandus ), Canada's most iconic endangered species. Sequencing of the 18S rRNA gene of eukaryotes from seven locations in Manitoba and Saskatchewan, Canada, allowed for the detection of several parasites in caribou feces but provided limited information about plants and lichens - only algal symbionts were detected. An improved sensitivity and higher taxonomic resolution for plants and lichens was achieved through the sequencing of the ITS2 region, which revealed a rich winter diet in caribou as well as differences among sampling locations. Sequencing of the 16S rRNA gene of prokaryotes highlighted the relationships between the gut microbiota and both the diet and parasites. Overall, our results showed the potential of this multi-marker DNA metabarcoding workflow as an efficient tool to generate relevant information on the diet and health of caribou populations and provide insights into the species biology and ecology.
Large lakes, such as Lake Simcoe, Ontario, Canada, are undergoing significant change due to local and global stressors. Uni- and multivariate analyses of Lake Simcoe's zooplankton community from 1986 to 2012 indicated multiple events of ecosystem change that were synchronous across three lake stations. In the mid-1990s, shifts in zooplankton species abundance and richness, and total cladoceran body size were strongly correlated with the invasion of the zooplanktivore, Bythotrephes cederstroemii. In the early 2000s, additional shifts in zooplankton abundance, as well as copepod body size, coincided with increased water clarity (linked to filter feeding by the invader Dreissena polymorpha) and hypolimnetic water temperature. Further community changes occurred in the 2000s when Bythotrephes declined and many vulnerable cladoceran species recovered. However, the Lake Simcoe community did not fully return to its pre-invasion state as the cold-water herbivores, Daphnia longiremis and Daphnia pulicaria, remained absent. The Lake Simcoe zooplankton community illustrates ongoing ecosystem change that propagated throughout the lake food web and may be reflected in other lakes experiencing global stressors of climate change and species invasions.
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38 members
Vince Pileggi
  • Standards Development Branch
James A Rusak
  • Dorset Environmental Science Centre
Hamdi Jarjanazi
  • Environmental Monitoring and Reporting Branch
Pradeep Goel
  • Environmental Monitoring and Reporting Branch
Brie Edwards
  • Inland Waters Unit
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