Laurentian Great Lakes Basin Research Articles

Sucralose and caffeine as chemical indicators of domestic wastewater contamination in the Laurentian Great Lakes Basin.

Surface waters within the basin of the Laurentian Great Lakes are impacted by microbial contamination from municipal wastewater and agricultural runoff, as well as from other sources. In particular, microbial contamination of drinking water is an ongoing problem within many Indigenous communities located in the basin. However, it is difficult to identify the sources of microbial contamination using the traditional monitoring approaches with fecal indicator bacteria, such as total coliforms and Escherichia coli (E. coli). In this study, we evaluated whether surface waters in the basin are contaminated with fecal bacteria of human origin using chemical indicators of domestic wastewater (i.e., caffeine and sucralose) and with Bacteroidales 16S rRNA markers. Study areas included the Grand River watershed within the Lake Erie basin and three nearshore locations within the Great Lakes basin. Two of these sites are sources of drinking water for Indigenous communities. We assessed whether there were relationships between the concentrations of fecal indicator microorganisms and chemical indicators of domestic wastewater at selected study locations. Analysis of genetic markers indicated that about 30% of the Bacteroidales bacteria present at a site in the Grand River were of human fecal origin and the balance were of bovine or general animal origin. The presence of caffeine and sucralose in surface waters indicated that there was upstream contamination by domestic wastewater. However, in the drinking water treatment plant operated by Six Nations of the Grand River, the levels of these chemical indicators and fecal bacteria were reduced by the advanced water treatment technologies. The concentrations of sucralose and caffeine collectively were strongly correlated with the levels of total coliforms in samples from the Grand River (R2 = 0.75) and with levels of E. coli in samples from the Great Lakes basin (R2 = 0.97), but there appeared to be an upper threshold for this relationship. These data indicate that analysis of caffeine and sucralose and genetic markers for strains of Bacteroidales fecal bacteria may be useful tools for identifying the sources of microbiological contamination of surface waters and drinking water.

A regional examination of the footprint of agriculture and urban cover on stream water quality

Freshwater systems in cold regions, including the Laurentian Great Lakes, are threatened by both eutrophication and salinization, due to excess nitrogen (N), phosphorus (P) and chloride (Cl−) delivered in agricultural and urban runoff. However, identifying the relative contribution of urban vs. agricultural development to water quality impairment is challenging in watersheds with mixed land cover, which typify most developed regions. In this study, a self-organizing map (SOM) analysis was used to evaluate the contributions of various forms of land cover to water quality impairment in southern Ontario, a population-dense, yet highly agricultural region in the Laurentian Great Lakes basin where urban expansion and agricultural intensification have been associated with continued water quality impairment. Watersheds were classified into eight spatial clusters, representing four categories of agriculture, one urban, one natural, and two mixed land use clusters. All four agricultural clusters had high nitrate-N concentrations, but levels were especially high in watersheds with extensive corn and soybean cultivation, where exceedances of the 3 mg L−1 water quality objective dramatically increased above a threshold of ‍∼30 % watershed row crop cover. Maximum P concentrations also occurred in the most heavily tile-drained cash crop watersheds, but associations between P and land use were not as clear as for N. The most urbanized watersheds had the highest Cl− concentrations and expansions in urban area were mostly at the expense of surrounding agricultural land cover, which may drive intensification of remaining agricultural lands. Expansions in tile-drained corn and soybean area, often at the expense of mixed, lower intensity agriculture are not unique to this area and suggest that river nitrate-N levels will continue to increase in the future. The SOM approach provides a powerful means of simplifying heterogeneous land cover characteristics that can be associated with water quality patterns and identify problem areas to target management.

Winter/Spring Runoff Is Earlier, More Protracted, and Increasing in Volume in the Laurentian Great Lakes Basin

AbstractWinter/spring runoff has changed in streams worldwide due to climate change, particularly in temperate areas where winter/spring streamflow depends on snowmelt. Such changes potentially affect receiving waters through altered nutrient loading and mixing patterns. The Laurentian Great Lakes are an important freshwater resource and have experienced a myriad of impacts due to climate change. We analyzed 70 years of stream gauge data in the Great Lakes Basin to test for changes in timing, duration, and amount of winter/spring runoff during the period 1950–2019. We found strong evidence for earlier runoff in each of the Great Lakes except Lake Erie, protracted winter/spring runoff throughout the Great Lakes Basin, and a higher runoff depth during the winter‐spring period over time for all watersheds except Lake Superior. Lake Ontario had the greatest change in the date by which 50% of the Jan–May runoff had been discharged (6 days earlier from 1950 to 2019). For winter/spring runoff duration, the most extreme change was observed in Lake Erie (increase of 19 days), and for runoff depth, the greatest change was in the Lake Huron Basin (increase of 3.3 cm). Results were similar for natural and impacted streams. Our results demonstrate dramatic changes in runoff patterns over the last seven decades in the Great Lakes Basin concomitant with previously published changes in precipitation and snowpack. Shifts toward earlier, more protracted, and more voluminous runoff likely change nutrient loading and mixing patterns that influence primary producers, particularly in the nearshore areas of the Great Lakes.

Invasive Round goby Neogobius melanostomus distribution, relative abundance, and establishment in pools of the Illinois Waterway following 30 years of invasion

Round goby Neogobius melanostomus – a small, benthic fish native to Eurasia – was first introduced to North America in the 1980s through ballast water of cargo ships. In 1990, the Round goby was first discovered in the Laurentian Great Lakes Basin and rapidly spread through all Great Lakes from 1993 to 1998. The Round goby is an aggressive, prolific, and efficient egg predator that subsequently displaced native fishes from their preferred habitats and resources in the Great Lakes, where they are well established and abundant. From Lake Michigan, Round goby moved south into the Chicago Area Waterway System in 1993 and slowly progressed down the Illinois Waterway to the Mississippi River from 2004 to 2019, where less is known about their abundance, establishment, and impact. The goal of this study was to gain a comprehensive understanding of the first large river invasion by Round goby in the Mississippi River Basin by leveraging Round goby capture data from 2019 to 2022 on all pools of the Illinois Waterway. We describe their current distribution, relative abundance (i.e., catch-per-unit-effort), frequency of occurrence, and establishment (i.e., presence of young-of-year and adults) status throughout the Illinois Waterway. Results show that catch-per-unit-effort, frequency of occurrence, and the proportion of sites where multiple life stages are present are considerably higher in the upstream pools relative to more downstream pools of the Illinois Waterway. Our data support that the Round goby has established self-sustaining populations in the Chicago Area Waterway System, the upper Illinois River (i.e. Dresden Island Pool downstream through Starved Rock Pool), and a portion of the lower Illinois River (i.e. Peoria Pool downstream through Alton Pool) of the Illinois Waterway. In the lower Illinois River, Round gobies appear to only be established in Peoria Pool, with captures occurring infrequently in La Grange Pool, and no Round gobies being captured in Alton Pool.

Towards a management strategy for microplastic pollution in the Laurentian Great Lakes—ecological risk assessment and management (part 2)

Over the past decade, plastic pollution has been documented throughout the Laurentian Great Lakes basin. Here, we demonstrate the application of published ecological risk assessment and management frameworks for microplastics in aquatic environments by comparing proposed risk thresholds derived using toxicity data from both freshwater and marine species to local monitoring data. Our results suggest that there may be measurable risks from microplastics to aquatic communities in parts of the Great Lakes where current concentrations are relatively high. For example, concentrations in 89% of surface water samples collected across the region exceed the proposed risk thresholds for food dilution toxicity. However, concentrations in all sediment samples remain below the proposed risk thresholds. Accordingly, we suggest that an appropriate and necessary next step for management may include convening a working group of local experts to develop an ecological risk assessment and management framework for the region comprising risk thresholds for microplastics in surface water and sediment. Ultimately, microplastic pollution should be addressed in the Great Lakes Water Quality Agreement to ensure coordinated and sustained efforts are taken by the governments of Canada and the United States to reduce their release and impact.

Interactions between sediment processes and ecosystem responses in the Green Bay of Lake Michigan

AbstractEstuaries, in particular freshwater estuaries, provide valuable economic, social, and ecological services, but their ecosystems are often heavily stressed. Located in the Laurentian Great Lakes basin, Green Bay is a large freshwater estuary and a prominent example of a degraded ecosystem due to intensive human interventions and rapid development. Excessive amounts of contaminants and nutrients were discharged to the bay by inflowing tributaries for almost half a century, while in contrast Green Bay's seasonal‐, morphological‐, and physically‐restricted mixing is unable to export a significant portion of those materials out of the bay, that is, Green Bay behaves as an efficient retention basin for the Lake Michigan. Consequently, several environmental and public health‐related issues have risen in Green Bay and turned the lower bay into an area of environmental concern since the 1980s. To address these challenges, restoration programs were developed, including the development of monitoring programs, scientific research, and remedial action plans. There is a consensus that accelerated loading rates of contaminated and nutrient‐rich sediments are a major driver of the environmental crisis in the bay, yet the fate and transport patterns of Green Bay sediments are not clearly understood. While field observations in Green Bay are season‐limited and costly, advanced computing techniques provided opportunities to refine our understanding of sediment dynamics in this estuarine system. This review of existing knowledge on Green Bay sediment processes can help to better understand the interplay between sediments, and physical/biogeochemical activities in estuarine systems and contributes conceptually to the restoration of degraded aquatic ecosystems.This article is categorized under: Science of Water > Hydrological Processes Science of Water > Water Quality Water and Life > Stresses and Pressures on Ecosystems

Conservation Genetics of Lake Sturgeon (Acipenser fulvescens): Nuclear Phylogeography Drives Contemporary Patterns of Genetic Structure and Diversity

Sustainable management of exploited and endangered species is facilitated by knowledge of their geographic genetic structure. Lake sturgeon (Acipenser fulvescens) epitomizes both categories, but genetic information has largely been limited to the Laurentian Great Lakes basin. We assessed the hierarchical geographic genetic structure of lake sturgeon across their Canadian range using a variation at 14 microsatellite loci. Observed patterns showed evidence of two ancestral groups which originated from Mississippian and Missourian glacial refugia. Coalescent analysis indicates the two lineages most recently shared common ancestry during the late Pleistocene and were likely isolated by the late Wisconsinan ice advance, with subsequent interpopulation divergences within each lineage reflecting their reciprocal isolation as glacial meltwaters receded. Hierarchical patterns of genetic relationships among contemporary populations largely reflect colonization histories and connections within primary and secondary watersheds. Populations in western Canada showed strong similarities based on their shared Missourian origins and colonization from glacial Lake Agassiz. By contrast, populations in the Great Lakes–St. Lawrence River drainage were largely founded from a Mississippian source. Sturgeon populations in northern parts of Ontario and Quebec showed evidence of mixed ancestry from secondary contact between the two refugial groups through Holocene meltwater lakes. Within major watersheds, the strong similarity among geographically separate populations reflects their shared ancestry during postglacial colonization. The general lack of structure within major river systems highlights historically continuous habitat (connectivity) and gene flow rather than contemporary barriers (dams). These data highlight the importance of Quaternary and prehistoric events on patterns of genetic diversity and divergence within and among contemporary populations, as well as the importance of these populations for conserving the species’ evolutionary legacy.

One informs the other: Unionid species at risk and benthic macroinvertebrate community monitoring data are complementary

Benthic macroinvertebrate communities, which include unionid freshwater mussels, enhance the health of river ecosystems. Human impacts have driven declines within freshwater mussel communities and due to their complex life cycles, mussel recovery efforts are complex. In Canada, conservation of imperiled species has focused on biodiversity hotspots such as the Sydenham River in the Laurentian Great Lakes Basin. In practice, species conservation and habitat monitoring are siloed between federal agencies and local conservation authorities, limiting the potential for alignment of conservation policy and practice. Here we bring together federal, local, and our own survey data to explore patterns of co-occurrences between mussel species and other macroinvertebrate taxa to explore the extent to which knowledge of one benthic community informs the other. Mussel communities (species richness, community composition) differed between sites where imperiled mussel species were present and/or absent. Benthic macroinvertebrate metrics (e.g., family richness, percent Ephemeroptera, Plecoptera, and Trichoptera taxa) and specific indicator taxa were correlated with mussel species richness and the presence of imperiled mussel species. We show that benthic macroinvertebrate diversity indicators provided insight into imperiled species occurrences that warrant further investigation. These findings underscore support for coordinated watershed monitoring efforts and could be crucial for more successful freshwater mussel conservation.

Which Traits Predict Invasive Success in Lake and Stream Environments in the Laurentian Great Lakes Basin?

Which Traits Predict Invasive Success in Lake and Stream Environments in the Laurentian Great Lakes Basin?

The Impacts of Climate Change on Land Hydroclimatology of the Laurentian Great Lakes Basin

The freshwater resources of the Laurentian Great Lakes basin contribute significantly to the environment and economy of the region. With the impacts of climate change becoming more evident, sustainable management of the freshwater resources of the Laurentian Great Lakes basin is important. This study uses 36 simulations from 6 regional climate models to quantify trends and changes in land-area precipitation and temperature in two future periods (mid-century, 2035–2064 and end-century, 2065–2094) with reference to a baseline period (1951–2005) for two emission scenarios (RCP4.5 and RCP 8.5). Climatic forcings from these 36 simulations are used as input to a calibrated and validated hydrological model to assess changes in land snowpack and actual evapotranspiration, and runoff to lake. Ensemble results show wetter (7 to 15% increase in annual precipitation) and warmer (2.4–5.0°C increase in annual mean temperature) future conditions on GL land areas. Seasonal and monthly changes in precipitation and mean temperature are more sporadic, for instance although precipitation is projected to increase overall, in some scenarios, summer precipitation is expected to decrease. Projected increases in highest one-day precipitation and decreases in number of wet days indicate possible increases in extreme precipitation in future. Minimum temperature is expected to increase in a higher rate than maximum temperature. Ensemble results from the hydrological model show projected decrease in snowpack (29–58%). Similarly, actual evapotranspiration is projected to increase, especially during summer months (up to 0.4 mm/day). Annually, runoff is expected to increase (up to 48% in Superior, 40% in Michigan-Huron, 25% Erie and 28% in Ontario). Seasonal and monthly changes in runoff are more sporadic (e.g., projected decrease up to 17% in Erie subdomain in October). Such contrasting patterns of changes in land hydroclimatology of the GL basin will pose challenges to sustainable management of the water resources of the basin in future.

What can we learn from 28 years of monitoring of fish tissue polychlorinated biphenyls in Michigan's rivers?

Polychlorinated biphenyls (PCBs) are an important part of chemical legacies in the Laurentian Great Lakes basin. Used in industrial products worldwide, PCBs are now extensively monitored because of their potential toxicity to humans. Fish consumption is a major pathway for exposure. Edible portion (i.e., fish fillet) data from Michigan's fish tissue PCB monitoring program were evaluated using regression statistics, principal component analysis, and t-tests to answer three questions: (1) How do fish tissue total PCB concentrations vary across Michigan's rivers? (2) Are the PCB congener patterns uniformly distributed among tested sites and species? (3) Do monitoring methods limit our ability to discern trends in fish tissue PCB concentrations? Our results indicate that although contaminated sites have been successfully identified, based on higher PCB concentrations in samples from Areas of Concern (AOCs) compared to non-AOC sites, 77% of fish samples from 2010 to 2015 exceeded the safe fish tissue PCB concentration for unrestricted consumption (97 g/day) by sensitive populations. The PCB congener profiles vary among species and locations. Results demonstrate that these data are not useful for supplementing ongoing spatial and temporal trend analysis. Only 15 of the 83 species + waterbody pairs had adequate data for evaluating temporal trends with more than three data points. In general, the trends at each location varied based on the analytical method. Conclusions from this work can inform revisions to existing monitoring programs and improve our ability to protect human health. Integr Environ Assess Manag 2023;19:152-162. © 2022 SETAC.

Representation of Lake–Atmosphere Interactions and Lake-Effect Snowfall in the Laurentian Great Lakes Basin among HighResMIP Global Climate Models

Abstract Credible modeling, tools, and guidance, regarding the changing Laurentian Great Lakes and the climatic impacts, are needed by local decision-makers to inform their management and planning. The present study addresses this need through a model evaluation study of the representation of lake–atmosphere interactions and resulting lake-effect snowfall in the Great Lakes region. Analysis focuses on an extensive ensemble of 74 historical simulations generated by 23 high-resolution global climate models (GCMs) from the High-Resolution Model Intercomparison Project (HighResMIP). The model assessment addresses the modeling treatment of the Great Lakes, the spatial distribution and seasonality of climatological snowfall, the seasonal cycle of lake-surface temperatures and overlake turbulent fluxes, and the lake-effect ratio between upwind and downwind precipitation. A deeper understanding of model performance and biases is achieved by partitioning results between HighResMIP GCMs that are 1) coupled to 1D lake models versus GCMs that exclude lake models, 2) between prescribed-ocean model configurations versus fully coupled configurations, and 3) between deep Lake Superior versus relatively shallow Lake Erie. While the HighResMIP GCMs represent the Great Lakes by a spectrum of approaches that include land grid cells, ocean grid cells (with lake surface temperature and ice cover boundary conditions provided by the Met Office Hadley Center Sea Ice and Sea Surface Temperature Dataset), and 1D lake models, the current investigation demonstrates that none of these rudimentary approaches adequately represent the complex nature of seasonal lake temperature and ice cover evolution and its impact on lake–atmosphere interactions and lake-effect precipitation in the Great Lakes region. Significance Statement The purpose of this study is to evaluate the capability of high-resolution global climate models to simulate lake–atmosphere interactions and lake-effect snowfall in the Great Lakes region, given the critical influence of the lakes on regional climate and vast societal and environmental impacts of lake-effect snowfall. It is determined that the models inadequately represent lake temperatures and ice cover, often leading to insufficient annual snowfall in the lake-effect zones. More advanced, three-dimensional lake models need to be coupled to climate models to support greater credibility in regional lake and climate simulations and future climate projections.

Contaminants of emerging concern may pose prezygotic barriers to freshwater mussel recruitment

Increased detection of contaminants of emerging concern (CECs) throughout the Laurentian Great Lakes Basin has raised concern about the impact CECs may have on aquatic life. In particular, the impacts of CECs on the highly imperiled freshwater mussels (family: Unionidae) have not yet been assessed. Contaminants may alter reproductive success during either the pre- or postzygotic stages of reproduction and lead to population declines. This study sought to address possible disruption of prezygotic processes while acknowledging the complexity of CEC mixtures in nature. River waters from sites with dominant urban and agricultural land use in the Milwaukee River Basin and Lower Maumee River Basin respectively were used as treatments during 21-day exposures of adult Lampsilis cardium, Lampsilis siliquoidea, and Eurynia dilatata. At the conclusion of exposures, the development of gonad tissue was histologically examined to address deviations from expected seasonal development as a barrier to recruitment. No abnormalities in development were found compared to control waters. Sperm densities were also examined; and, though no significant differences were found among treatments, lampsiline species sperm density tended to increase along the gradient of CEC mixture complexity while E. dilatata sperm density correlated positively with a lower concentration of pharmaceuticals, especially antibiotics, despite increased pesticide detection. Given the complexity of natural occurring CEC mixtures and variable unionid response, future work may utilize these data to elucidate combinations of CECs most likely to create impacts on gametogenesis which could lead to further population declines.

Hydrological performance of ERA5 and MERRA-2 precipitation products over the Great Lakes Basin

Study regionThe Laurentian Great Lakes Basin (GLB) of North America. Study focusPrecipitation is often the paramount driver in hydrological systems and dynamics. Gridded precipitation data from the fifth generation of European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis (ERA5) and the second Modern-Era Retrospective analysis for Research and Applications (MERRA-2) are playing a key role in hydrological modelling and hydro-climatological analysis activities. This study explores the discrepancies between ERA5 total precipitation (TP) and MERRA-2 bias-corrected total precipitation (PRECTOTCORR) products and their impacts on streamflow simulation over the GLB. New hydrological insights for the regionERA5 TP and MERRA-2 PRECTOTCORR perform differently, with substantial discrepancies in the eastern and mid-southern regions of the GLB. MERRA-2 PRECTOTCORR severely underestimates precipitation along the eastern shores of the Great Lakes within the eastern GLB, where lake-effect snowfall is common. Accordingly, the MERRA-2 PRECTOTCORR-driven hydrological modelling typically significantly underpredicts streamflow in those areas. In contrast, MERRA-2 PRECTOTCORR performs very well for precipitation estimation and stream discharge simulations in the mid-southern portion of the basin (i.e., the southern portion of the U.S. State of Michigan). However, the northernmost region of the GLB exhibits streamflow overprediction from the PRECTOTCORR-driven hydrological modelling. On average, ERA5 TP overestimates precipitation, especially in winter and spring. Accordingly, ERA5 TP typically results in higher simulated streamflow when compared to PRECTOTCORR. The quantified hydrological performance for the two state-of-the art precipitation products provides critical guidance for hydrological modelling applications in the GLB or other similar regions.

The role of propagule pressure and environmental factors on the establishment of a large invasive cyprinid: black carp in the Laurentian Great Lakes basin

Understanding the factors underlying species establishment is critical for the management of invasive fishes, yet the roles of propagule pressure and environmental factors are infrequently quantified in joint models. We estimated the establishment likelihood of the invasive black carp (Mylopharyngodon piceus) by examining the relative influence of propagule pressure (introduction size and age structure) and environmental factors (temperature-driven young-of-year [YOY] overwinter survival, adult survival, age at maturity, and longevity). Simulations demonstrated that both propagule pressure and environmental factors can act as non-linear bottlenecks to establishment. When the model was applied to 12 Great Lakes tributaries and nearshore areas, black carp establishment was probable with sufficient propagules and under most environmental conditions (median p = 0.21–0.73, 0.70–1.00, and 0.46–0.97 for 100 pairs of age 4, age 9, and age 16 fish, respectively), except for YOY (p < 0.01). Our analysis is one of the few studies to examine the relative role of propagule pressure and environmental conditions on establishment, indicating that both factors can lead to establishment failure independently or concurrently within an ecosystem.

An adaptive management implementation framework for evaluating supplemental sea lamprey (Petromyzon marinus) controls in the Laurentian Great Lakes

Invasive sea lamprey (Petromyzon marinus) populations in the Laurentian Great Lakes Basin have been suppressed for over 60 years primarily by migration barriers and lamprey-specific pesticides. Improving control outcomes by supplementing barriers and pesticides with additional control strategies has been a long-standing objective of managers and stakeholders, but progress towards this objective has been limited. We developed an adaptive management implementation framework and applied it to this objective. The framework consists of a set of adaptive management implementation goals (develop effective monitoring practices, develop effective participatory process, and conduct management experiments), a set of aspirational targets hypothesized to be related to Sea Lamprey Control Program adaptive capacity (multi-level political and social organization, creation of safe-to-fail decision making arenas, and effective use of multi-criteria decision analysis), and a feedback loop linking adaptive capacity and progress towards adaptive management implementation goals. Progress towards improving sea lamprey control outcomes by integrating supplemental control strategy into the Sea Lamprey Control Program may be possible through adaptive management implementation.

Towards improving an Area of Concern: Main-channel habitat rehabilitation priorities for the Maumee River

The Maumee River watershed in the Laurentian Great Lakes Basin has been impacted by decades of pollution and habitat modification due to human settlement and development. As such, the lower 35 km of the Maumee River and several smaller adjacent watersheds comprising over 2000 km2 were designated the Maumee Area of Concern (AOC) under the revised Great Lakes Water Quality Agreement in 1987. As part of pre-rehabilitation assessments in the Maumee AOC, we assessed fish and invertebrate communities in river km 24–11 of the Maumee River to identify: 1) areas that exhibit the highest biodiversity, 2) habitat characteristics associated with high biodiversity areas, 3) areas in need of protection from further degradation, and 4) areas that could feasibly be rehabilitated to increase biodiversity. Based on benthic trawl data, shallow water habitats surrounding large island complexes had the highest fish diversity and catch per unit effort (CPUE). Electrofishing displayed similar fish diversity and CPUE patterns across habitat types early in the study but yielded no discernable fish diversity or CPUE patterns towards the end of our study. Although highly variable among study sites, macroinvertebrate density was greatest in shallow water habitats <2.5 m and around large island complexes. Our results provide valuable baseline data that could act as a foundation for developing rehabilitation strategies in the lower Maumee River and for assessing the effectiveness of future aquatic habitat rehabilitation projects. In addition to increasing in-channel habitat, watershed-scale improvements of water quality might be necessary to ensure rehabilitation strategies are successful.

Weaving Indigenous and Western Science Knowledges Through a Land-Based Field Course at Bkejwanong Territory (Laurentian Great Lakes)

In response to a growing interest in building Indigenous-led educational experiences, we codeveloped a land-based field course that wove Indigenous ways of knowing together with Western ecological concepts. The spirit of the course was the one rooted in varied ways of knowing nature, on the land, the water, and the culture—to see the Great Lakes from an Anishinaabe perspective. Situated in the heart of the Laurentian Great Lakes Basin at Bkejwanong Territory (Walpole Island First Nation), in the Traditional Territory of the Three Fires Confederacy of First Nations (Ojibwe, Odawa, and Potawatomi) on Turtle Island (North America), this inaugural undergraduate university course was led by an Indigenous instructor with contributions from non-Indigenous science faculty from the university and local community knowledge keepers. Here, we describe our journey in cocreating land-based teaching modules with Indigenous scholars and scholars at the University of Windsor, Ontario, Canada. We focused on experiences that exposed students to traditional ways of knowing nature, and reflections were used as the main teaching pedagogy. The course offered daily perspectives and activities across land and water and examined dimensions of biodiversity as sacred beings and medicine. Outcomes and indicators of success were driven by the individual’s reflection and evaluation on their own growth, as expressed through a final project aimed at bridging knowledges, supporting community initiatives or both. This case is designed to offer an example that has potential for application to many other contexts where community-faculty partnerships and land-based learning opportunities are available.

Twenty-First Century Science Calls for Twenty-First Century Groundwater Use Law: A Retrospective Analysis of Transboundary Governance Weaknesses and Future Implications in the Laurentian Great Lakes Basin

How has groundwater use been historically governed by the binational to municipal government levels across the Laurentian Great Lakes Basin (GLB)? To what extent have they contemplated the physical–environmental requirements to maintain aquifer storage in devising policies and making decisions governing groundwater use? Although it is amongst the largest freshwater stores in the globe, cases of groundwater shortages are increasingly being reported across GLB communities, raising questions on the fitness of governance approaches to maintain groundwater storage (GWS) with growing climate and human pressures. Applying retrospective analytical methods to assess the century-old collaboration of the United States and Canada to maintain GLB water quantities, we characterize long-term trends and undertake systematic diagnosis to gain insight into causal mechanisms that have persisted over the years resulting in current GWS governance gaps. We reveal the surprising prominence of policies originally intended to safeguard surface water quantities being used to govern groundwater use and thereby maintain GWS. We also connect these, based on sustainable aquifer yield theory, to growing groundwater insecurity in the Basin’s drought-prone and/or groundwater-dependent communities. Based on deep understanding of long-standing policy pathologies, findings inform transboundary GWS governance reform proposals that can be highly useful to multiple levels of government policymakers.

Influence of perfluoroalkyl acids and other parameters on circulating thyroid hormones and immune-related microRNA expression in free-ranging nestling peregrine falcons

Exposure to certain perfluoroalkyl acids (PFAAs) can have considerable effects on the endocrine and immune systems, although such effects remain largely uncharacterized in wildlife. Using an apex avian predator, we investigated possible relationships of thyroid hormones (THs), specifically free (F) and total (T) thyroxine (FT4; TT4) and triiodothyronine (FT3; TT3), and the expression of an immune-related microRNA biomarker (i.e., miR-155), with the concentrations of 11 PFAAs in nestling peregrine falcons (Falco peregrinus). Nestling peregrines (n = 56; usually two chicks of each sex per nest) were blood sampled when 23 ± 4 days old in urban and rural regions of the Laurentian Great Lakes Basin (Ontario, Canada) in 2016 and 2018. The circulating concentrations of several PFAAs were significantly associated with THs and estimated thyroid gland activity (TT3:TT4; FT3:FT4), including PFHxS (FT3; FT3:FT4), PFDS (TT3; TT3:TT4), PFOA (TT4; FT3:FT4), PFTeDA (TT4; FT3:FT4), PFHxDA (TT4; TT3:TT4) and ΣPFCAs (TT4). Our novel evaluation of miR-155 in peregrine nestlings identified significantly negative relationships of plasma miR-155 counts with PFHxS and PFOA concentrations, indicating potential down-regulation of miR-155 expression and impaired immunity. Several PFAA homologues significantly predicted the variation in THs and miR-155 in conjunction with year (e.g., inter-annual differences in weather, ambient temperature, rainfall), region (urban/rural), nestling age, and/or diet (trophic position; δ15N), which suggests that multiple environmental and biological stressors, including PFAA exposure, influenced thyroid activity and immune function in these nestlings. Further research is warranted to identify the mechanisms and additional impacts of PFAA-related thyroid and immune disruption on the growth, development, and health risks in developing birds.