Decadal-scale variability and warming affect spring timing and forest growth across the western Great Lakes region.

The Great Lakes region of North America has warmed by 1-2 °C on average since pre-industrial times, with the most pronounced changes observable during winter and spring. Interannual variability in temperatures remains high, however, due to the influence of ocean-atmosphere circulation patterns that modulate the warming trend across years. Variations in spring temperatures determine growing season length and plant phenology, with implications for whole ecosystem function. Studying how both internal climate variability and the "secular" warming trend interact to produce trends in temperature is necessary to estimate potential ecological responses to future warming scenarios. This study examines how external anthropogenic forcing and decadal-scale variability influence spring temperatures across the western Great Lakes region and estimates the sensitivity of regional forests to temperature using long-term growth records from tree-rings and satellite data. Using a modeling approach designed to test for regime shifts in dynamic time series, this work shows that mid-continent spring climatology was strongly influenced by the 1976/1977 phase change in North Pacific atmospheric circulation, and that regional forests show a strengthening response to spring temperatures during the last half-century.

Temporal Trends of Great Lakes Legacy Contaminants: Ecological and Biological Considerations Applying the Age-Trend Model.

The USEPA Great Lakes Fish Monitoring and Surveillance Program (GLFMSP) has been monitoring top predator lake trout and walleye contaminant concentrations since the early 1970s. Our research revealed that select legacy contaminant groups (∑PCBs, ∑DDTs, ∑chlordanes, and ∑5PBDEs) have similar t1/2 and k2 values across the Great Lakes, with the exception of both Lake Erie sites and the Lake Superior─Keweenaw Point site. The slower halving times determined at both Lake Erie sites are consistent with legacy contaminant remobilization due to extreme weather climate effects and past remedial actions on the Detroit River, whereas the Lake Superior─Keweenaw Point site demonstrates contaminant halving times approaching the exponential minimum. Overall, Great Lakes select contaminant groupings have decreased between 25.8 and 97.9% since 2004. An age-normalized Great Lakes Contaminant Index (GLCI) was devised, indicating both Lake Michigan sites as the most highly impacted. The mean absolute deviation statistic was applied, documenting the need to age-correct contaminant trends due to highly variable age profiles. With the noted exceptions, the uniformity of age-corrected trend modeling suggests that a combination of the fundamental biological and physicochemical mechanisms of natural contaminant sequestration, declining dissolved water concentrations, accumulation/metabolism/depuration, and the overall reduction of legacy contaminant loading are driving the generally consistent rates of declines in the Great Lakes. Many of the biological and ecological stressors currently associated with climate change appear to be accounted for by the age-trend model.

Legacy contaminant trends in the Great Lakes uncovered by the wildlife environmental quality index.

Since the 1970s, wildlife managers have prioritized the recovery of Great Lakes ecosystems from contamination by Persistent Organic Pollutants (POPs). Monitoring and quantifying the region's recovery is challenged by the diversity of legacy contaminants in the environment and the lack of benchmarks for their potential biological effects. We address this gap by introducing the Wildlife Environmental Quality Index (WEQI) based on prior water and sediment quality indices. The tool summarizes, in a single score, the exposure of wildlife to harmful levels of multiple contaminants - with harmful levels set by published guidelines for protecting piscivorous wildlife from biological impacts. We applied the new index to a combined Canadian and American dataset of Herring Gull (Larus argentatus) egg data to elucidate trends in wildlife for eight legacy industrial pollutants and insecticides in the Great Lakes. Environmental quality of the Great Lakes region (as indexed by WEQI) improved by 18% between 2002 and 2017. Improvement came from reductions in both the scope of contamination (the number of guideline-exceeding contaminants) and its amplitude (the average size of guideline exceedances) at bird colonies. But recovery was unequal among lakes, with Lake Erie showing no improvement at one extreme. Weakly- or non-recovering lakes (Erie, Ontario, Huron) were marked by inconsistent improvement in scope and amplitude, likely due to ongoing loading, sediment resuspension and other stressors reported elsewhere. Fast-recovering lakes (Superior and Michigan), meanwhile, improved in both scope and amplitude. Contrasting trends and contaminant profiles (e.g., exceedances of PCBs versus DDTs) highlight the importance of lake-specific management for equalizing recoveries. Lower environmental quality at American than Canadian colonies, particularly in Lake Huron, further suggest uneven success in - and opportunities for - the binational management of wildlife exposure to legacy contaminants.

Habitat selection of resident and non-resident gray wolves: implications for habitat connectivity.

Habitat selection studies facilitate assessing and predicting species distributions and habitat connectivity, but habitat selection can vary temporally and among individuals, which is often ignored. We used GPS telemetry data from 96 Gray wolves (Canis lupus) in the western Great Lakes region of the USA to assess differences in habitat selection while wolves exhibited resident (territorial) or non-resident (dispersing or floating) movements and discuss implications for habitat connectivity. We used a step-selection function (SSF) to assess habitat selection by wolves exhibiting resident or non-resident movements, and modeled circuit connectivity throughout the western Great Lakes region. Wolves selected for natural land cover and against areas with high road densities, with no differences in selection among wolves when resident, dispersing, or floating. Similar habitat selection between resident and non-resident wolves may be due to similarity in environmental conditions, when non-resident movements occur largely within established wolf range rather than near the periphery or beyond the species range. Alternatively, non-resident wolves may travel through occupied territories because higher food availability or lower human disturbance outweighs risks posed by conspecifics. Finally, an absence of differences in habitat selection between resident and non-resident wolf movements may be due to other unknown reasons. We recommend considering context-dependency when evaluating differences in movements and habitat use between resident and non-resident individuals. Our results also provide independent validation of a previous species distribution model and connectivity analysis suggesting most potential wolf habitat in the western Great Lakes region is occupied, with limited connectivity to unoccupied habitat.

Evaluating the trophic transfer of PCBs from fish to humans: Insights from a synergism of environmental monitoring and physiologically-based pharmacokinetic modeling.

Accumulation of polychlorinated biphenyls (PCBs) within fish tissues has prompted many states to issue consumption advisories. In Pennsylvania such advisories suggest one meal per month for most game species harvested from Lake Erie; however, these advisories do not account for the emergent properties of regional PCB mixtures, and the downstream accumulation of PCB congeners into human tissues is poorly documented. This study aimed to demonstrate the utility of pairing environmental monitoring with pharmacokinetic modeling for the purpose of estimating dietary PCB exposure in humans. We qualified and quantified the PCB congeners present in the filets of five Lake Erie fish species and used these data to estimate exposure under consumption scenarios that matched or exceeded the advisories. Physiologically-based pharmacokinetic (PBPK) modeling was then employed to predict PCB accumulation within seven tissue compartments of a hypothetical man and woman over 10 years. Twenty-one congeners were detected between the five fish species at concentrations ranging from 56.0 to 411.7 ng/g. Predicted accumulation in human tissues varied based on tissue type, the species consumed, biological sex, and fish-consumption rate. Notably, steady-state concentrations were higher in fatty tissue compartments ("Fat" and "Liver") and across all tissues in women compared to men. This study serves as a preliminary blueprint for generating predictions of site-specific and tissue-specific exposure through the integration of environmental monitoring and pharmacokinetic modeling. Although the details may vary across applications, this simple approach could complement traditional exposure assessments for vulnerable communities in the Great Lakes region that continue to suffer from legacy contamination.

Assessing Contaminants of Emerging Concern in the Great Lakes Ecosystem: A Decade of Method Development and Practical Application.

Assessing the ecological risk of contaminants in the field typically involves consideration of a complex mixture of compounds which may or may not be detected via instrumental analyses. Further, there are insufficient data to predict the potential biological effects of many detected compounds, leading to their being characterized as contaminants of emerging concern (CECs). Over the past several years, advances in chemistry, toxicology, and bioinformatics have resulted in a variety of concepts and tools that can enhance the pragmatic assessment of the ecological risk of CECs. The present Focus article describes a 10+- year multiagency effort supported through the U.S. Great Lakes Restoration Initiative to assess the occurrence and implications of CECs in the North American Great Lakes. State-of-the-science methods and models were used to evaluate more than 700 sites in about approximately 200 tributaries across lakes Ontario, Erie, Huron, Michigan, and Superior, sometimes on multiple occasions. Studies featured measurement of up to 500 different target analytes in different environmental matrices, coupled with evaluation of biological effects in resident species, animals from in situ and laboratory exposures, and in vitro systems. Experimental taxa included birds, fish, and a variety of invertebrates, and measured endpoints ranged from molecular to apical responses. Data were integrated and evaluated using a diversity of curated knowledgebases and models with the goal of producing actionable insights for risk assessors and managers charged with evaluating and mitigating the effects of CECs in the Great Lakes. This overview is based on research and data captured in approximately about 90 peer-reviewed journal articles and reports, including approximately about 30 appearing in a virtual issue comprised of highlighted papers published in Environmental Toxicology and Chemistry or Integrated Environmental Assessment and Management. Environ Toxicol Chem 2023;42:2506-2518. © 2023 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Anglers as potential vectors of aquatic invasive species: Linking inland water bodies in the Great Lakes region of the US.

Unimpeded transfer and spread of invasive species throughout freshwater systems is of global concern, altering species compositions, disrupting ecosystem processes, and diverting economic resources. The magnitude and complexity of the problem is amplified by the global connectedness of human movements and the multiple modes of inter-basin transport of aquatic invasive species. Our objective was to trace the fishing behavior of anglers delineating potential pathways of transfer of invasive species throughout the vast inland waters of the Great Lakes of North America, which contain more than 21% of the world's surface freshwater and are among the most highly invaded aquatic ecosystems in the world. Combining a comprehensive survey and a spatial analysis of the movements of thousands of anglers in 12 states within the US portion of the Great Lakes Basin and the Upper Mississippi and Ohio River Basins, we estimated that 6.5 million licensed anglers in the study area embarked on an average of 30 fishing trips over the course of the year, and 70% of the individuals fished in more than one county. Geospatial linkages showed direct connections made by individuals traveling between 99% of the 894 counties where fishing occurred, and between 61 of the 66 sub-watersheds in a year. Estimated numbers of fishing trips to individual counties ranged from 1199-1.95 million; generally highest in counties bordering the Great Lakes. Of these, 79 had more than 10,000 estimated fishing trips originating from anglers living in other counties. Although angler movements are one mechanism of invasive species transfer, there likely is a high cumulative probability of invasive species transport by several million people fishing each year throughout this extensive freshwater network. A comprehensive georeferenced survey, coupled with a spatial analysis of fishing destinations, provides a potentially powerful tool to track, predict, curtail and control the transfer and proliferation of invasive species in freshwater.

A thirty-year contaminant trend analysis in great lakes Native American fish harvests 1991-2021.

The Chippewa Ottawa Resource Authority (CORA) in Sault Ste. Marie, Michigan has been monitoring contaminant concentrations of mercury (Hg) and polychorinated biphenyls (PCBs) in the fillet portions of lake trout (Salvelinus namaycush) and lake whitefish (Coregonus clupeaformus) from waters of lakes Superior, Huron, and Michigan since 1991. This contaminant monitoring program is essential to supporting the fisheries interests and consumption advice for five Ojibwa and Ottawa tribes (collectively called Anishinaabe) whose ancestors ceded lands through the 1836 Treaty of Washingtonbut retained the rights to hunt and fish on those lands and waters. This manuscript presents an updated contaminant trend analysis covering the past three decades in which we observed a significant decreasing trend of median PCBs in both whitefish and lake trout harvested by tribal fishermen across all lakes. Median Hg tissue burdens significantly increased in whitefish harvests across all lakes and lake trout harvested from lake Michigan relative to earlier decades. Linear regression of fish fillets, adjusted for length, also conform to these trends. In 2021, per- and polyfluoroalkyl substances (PFAS) were detected in all Lake Michigan samples of lake trout (median 6.81pbb total PFAS) and in white fish (median 7.18 ppb total PFAS). Both decreasing and increasing trends of these key contaminants can alter fish consumption advice and risk calculations relative to advice presented in earlier decades.

Declining life expectancy in the Great Lakes region: contributors to Black and white longevity change across educational attainment.

BACKGROUND: The East North Central Census division (aka the Great Lakes region) experienced a decrease in life expectancy of 0.3 years from 2014 to 2016 - one of the largest declines across the nine Census divisions. Disadvantaged groups that typically have below-average life expectancy, including Black individuals and those without a college education, may have been disproportionately affected by this longevity shift. This investigation examines life expectancy changes among different sex, race, and education groups in the Great Lakes region, and how specific causes of death contributed to within-group longevity changes over time and across age. METHODS: We used 2008 to 2017 death counts from the National Center for Health Statistics and American Community Survey population estimates to measure within-group change in life expectancy at age 25 among non-Hispanic Black and white males and females by educational attainment. We decomposed life expectancy change over time for each subgroup by 24 causes of death and measured their contribution to longevity change across 13 age groups. RESULTS: Among persons with ≤ 12 years of education, white males and females experienced 1.3- and 1.7-year longevity declines respectively, compared to a 0.6-year decline among Black males and a 0.3-year decline among Black females. Life expectancy declined among all groups with 13-15 years of education, but especially Black females, who experienced a 2.2-year loss. With the exception of Black males, all groups with 16 + years of education experienced longevity gains. Homicide contributed 0.34 years to longevity decline among Black males with ≤ 12 years of education. Drug poisoning made large contributions to longevity losses among Black females with ≤ 12 years of education (0.31 years), white males and females with 13-15 years of education (0.35 and 0.21 years, respectively), and white males and females with ≤ 12 years of education (0.92 and 0.65 years, respectively). CONCLUSIONS: Public health efforts to reduce the risks of homicide among Black males without a college education and drug poisoning among all groups could improve life expectancy and reduce racial and educational longevity disparities in the Great Lakes region.

On the probability of ecological risks from microplastics in the Laurentian Great lakes.

The Laurentian Great Lakes represent important and iconic ecosystems. Microplastic pollution has become a major problem among other anthropogenic stressors in these lakes. There is a need for policy development, however, assessing the risks of microplastics is complicated due to the uncertainty and poor quality of the data and incompatibility of exposure and effect data for microplastics with different properties. Here we provide a prospective probabilistic risk assessment for Great Lakes sediments and surface waters that corrects for the misalignment between exposure and effect data, accounts for variability due to sample volume when using trawl samples, for the random spatiotemporal variability of exposure data, for uncertainty in data quality (QA/QC), in the slope of the power law used to rescale the data, and in the HC5 threshold effect concentration obtained from Species Sensitivity Distributions (SSDs). We rank the lakes in order of the increasing likelihood of risks from microplastics, for pelagic and benthic exposures. A lake-wide risk, i.e. where each location exceeds the risk limit, is not found for any of the lakes. However, the probability of a risk from food dilution occurring in parts of the lakes is 13-15% of the benthic exposures in Lakes Erie and Huron, and 8.3-10.3% of the pelagic exposures in Lake Michigan, Lake Huron, Lake Superior, and Lake Erie, and 24% of the pelagic exposures in Lake Ontario. To reduce the identified uncertainties, we recommend that future research focuses on characterizing and quantifying environmentally relevant microplastic (ERMP) over a wider size range (ideally 1-5000 µm) so that probability density functions (PDFs) can be better calibrated for different habitats. Toxicity effect testing should use a similarly wide range of sizes and other ERMP characteristics so that complex data alignments can be minimized and assumptions regarding ecologically relevant dose metrics (ERMs) can be validated.

Phylogeography and genetic variation in Western Jacob's ladder (Polemonium occidentale) provide insights into the origin and conservation of rare species in the Great Lakes region.

The perennial herb Western Jacob's Ladder (Polemonium occidentale, Polemoniaceae) is widespread in the mountains of western North America but reappears as a disjunct in the Great Lakes Region in Minnesota and Wisconsin, USA as the narrow endemic P. occidentale subsp. lacustre. This distribution is shown by a diverse assemblage of angiosperms. It has been hypothesized that these species became isolated just after the Last Glacial Maximum, but this has not been tested. Additionally, the genetic diversity and population connectivity of the endemic Great Lakes flora has been understudied, with important conservation implications. Using genotyping-by-sequencing, we examined the relationship of P. occidentale subsp. lacustre to its closest relatives, relationships among all known populations, and genetic diversity within these populations. Polemonium occidentale subsp. lacustre represents an isolated, unique lineage that diverged from its closest relatives 1.3 Ma and arrived in the Great Lakes Region by at least 38 ka. Nearly all extant populations diverged prior to the Last Glacial Maximum, are genetically distinct, and show little within-population genetic diversity. Clonality may mitigate reduction in diversity due to drift. Mixed population signal between Wisconsin and some Minnesota populations may be due to gene flow during the Late Pleistocene. While populations of P. occidentale subsp. lacustre may be relictual from a now extinct western relative, it is best treated as a distinct species. Conservation efforts should focus more on ensuring that current populations remain rather than maintaining large populations sizes across a few populations. However, encouraging habitat heterogeneity may accomplish both simultaneously.

Tracing toxic chemical releases embodied in U.S. interstate trade and their unequal distribution.

Toxic chemicals have severe impacts on ecosystem, climate change and human health, and the current toxic releases are inequitably distributed across regions. Investigating the toxic release embodied in final demand by states and income groups can reveal the responsibility transfer of different entities. In this paper, we extended the U.S. multi-regional input-output (MRIO) model with toxic chemical release data in 2017 to conduct the production- and consumption-based accounting of toxic release by each state, and the inter-regional transfer of embodied toxic release between states. In addition, this paper analyzed how the toxic releases and inter-state transfer of embodied toxic release have been driven by income groups across states. The results showed that the toxic release from production was highly concentrated on the central states and the Great Lakes Region, while the consumption-based accounting of toxic release was more equally distributed across regions in the US. The non-metallic and metallic products manufacturing sectors were the most important sectors for most states from both production and consumption-based perspectives and were also the most essential sectors for interregional flows of embodied toxic release from Great Lake Region to Southeast, Mid-Atlantic and Northeast. Our results also showed that the largest portion (41.88%) of embodied toxic releases were triggered by households' final demand, and that the consumption of the richest 35% of households contributed to more than 50% of the total toxic chemical releases triggered by total final demand of all households.

Quantifying long-term phenological patterns of aerial insectivores roosting in the Great Lakes region using weather surveillance radar.

Organisms have been shifting their timing of life history events (phenology) in response to changes in the emergence of resources induced by climate change. Yet understanding these patterns at large scales and across long time series is often challenging. Here we used the US weather surveillance radar network to collect data on the timing of communal swallow and martin roosts and evaluate the scale of phenological shifts and its potential association with temperature. The discrete morning departures of these aggregated aerial insectivores from ground-based roosting locations are detected by radars around sunrise. For the first time, we applied a machine learning algorithm to automatically detect and track these large-scale behaviors. We used 21 years of data from 12 weather surveillance radar stations in the Great Lakes region to quantify the phenology in roosting behavior of aerial insectivores at three spatial levels: local roost cluster, radar station, and across the Great Lakes region. We show that their peak roosting activity timing has advanced by 2.26 days per decade at the regional scale. Similar signals of advancement were found at the station scale, but not at the local roost cluster scale. Air temperature trends in the Great Lakes region during the active roosting period were predictive of later stages of roosting phenology trends (75% and 90% passage dates). Our study represents one of the longest-term broad-scale phenology examinations of avian aerial insectivore species responding to environmental change and provides a stepping stone for examining potential phenological mismatches across trophic levels at broad spatial scales.

Distributions of Cisco (Coregonus artedi) in the upper Great Lakes in the mid-twentieth century, when populations were in decline.

The restoration of the once abundant Cisco (Coregonus artedi) is a management interest across the Laurentian Great Lakes. To inform the restoration, we (1) described historical distributions of Cisco and (2) explored whether non-indigenous Rainbow Smelt (Osmerus mordax) and Alewife (Alosa pseudoharengus) played a role in the decline of Cisco populations across the upper Great Lakes (i.e., Lakes Superior, Michigan, and Huron). Our source data were collected from fishery-independent surveys conducted by the U.S. Fish and Wildlife Service's research vessel R/V Cisco in 1952-1962. By analyzing data collected by gill-net surveys, we confirmed the importance of embayment and shallow-water habitats to Cisco. We found that Cisco was abundant in Whitefish Bay and Keweenaw Bay, Lake Superior, and in Green Bay, Lake Michigan, but we also found a sign of Cisco extirpation in Saginaw Bay, Lake Huron. Our results also showed that Ciscoes generally stayed in waters <80 m in bottom depth throughout the year. However, a substantial number of Ciscoes stayed in very deep waters (>150 m in bottom depth) in summer and fall in Lake Michigan, although we cannot exclude the possibility that these Ciscoes had hybridized with the other Coregonus species. By comparing complementary data collected from bottom-trawl surveys, we concluded that the spatiotemporal overlap between Rainbow Smelt and Cisco likely occurred across the upper Great Lakes throughout 1952-1962. These data were consistent with the hypothesis that Rainbow Smelt played a role in the decline of Cisco populations across the upper Great Lakes in the period. We also found that the spatiotemporal overlap between Alewife and Cisco likely occurred only in Saginaw Bay in fall 1956 and in Lake Michigan after 1960. Thus, any potential recovery of Cisco after the 1950s could have been inhibited by Alewife in Lakes Michigan and Huron.

Variation in Susceptibility to Permethrin in Culex pipiens and Culex restuans Populations in the Great Lakes Region of the United States.

Two Culex pipiens form Pipiens colony strains and a field population of Cx. restuans from Michigan were susceptible and a Cx. pipiens form Molestus colony strain was comparatively less susceptible to a dose of 43 µg/ml of permethrin in Centers for Disease Control and Prevention (CDC) bottle bioassays. Using this diagnostic dose and these populations as controls, adult female Cx. pipiens and Cx. restuans were reared from egg rafts from 28 sites in Illinois, Ohio, Michigan, Iowa, Indiana, Wisconsin, and Minnesota. Tested mosquitoes showed high mortality in populations from 12 sites, less mortality (90-96%) at 9 sites, and less than 90% mortality from 7 sites during 30-min exposures. However, all tested populations showed 97-100% mortality at 60 min, indicating low phenotypic penetrance of resistance factors. These results indicate variation in susceptibility to permethrin in populations of West Nile virus vectors in the Great Lakes region of the United States, with evidence of modest resistance at 7 of 28 (25%) of the sampled populations.

Fish consumption and advisory awareness in the Great Lakes basin.

BACKGROUND: Fish is a dietary staple in the United States. Risk of exposure to persistent contaminants through fish consumption is a significant health concern. Great Lakes basin states, along with the US Environmental Protection Agency and the Great Lakes Consortium for Fish Consumption Advisories, have developed and continuously updated fish consumption advisories specifically for the Great Lakes basin residents. OBJECTIVES: To characterize Great Lakes basin residents' fish consumption and advisory awareness, we conducted a point-in-time survey to describe fish consumption habits and awareness of state and EPA/FDA fish advisories. METHODS: We used a randomized, address-based sampling approach to recruit respondents from the eight Great Lakes basin states. Weighted survey analysis procedures were used to estimate population prevalence of fish consumption habits, state and EPA/FDA advisory awareness, and demographic and background characteristics. Logistic regression models were used to assess the associations between demographic and background factors and fish consumption and awareness of advisories, respectively. RESULTS: About 92% of respondents, representing an estimated 61 million adults, reported eating fish in the last 12 months. About 64% of respondents only consumed commercial fish, and an estimated 5 million fish consumers exceeded the EPA/FDA recommended limit for fish meals. Minorities were more likely to exceed the EPA/FDA recommended limit. About half of the respondents were aware of state or EPA/FDA advisories; however, minorities and women were less aware of the EPA/FDA advisory. After adjusting for demographic characteristics, sportfish consumption was significantly associated with state advisory awareness; commercial fish consumption was significantly associated with EPA/FDA awareness. DISCUSSION: Most respondents only consumed commercial fish, but an estimated 18.6 million adults consumed sportfish. While half of the fish consumers were aware of state or EPA/FDA advisories, minorities and women continue to be less aware of fish advisories. Improved outreach strategies are needed to inform them about safe fish-consumption guidelines.

SARS-CoV-2 exposure in wild white-tailed deer (Odocoileus virginianus).

Widespread human SARS-CoV-2 infections combined with human-wildlife interactions create the potential for reverse zoonosis from humans to wildlife. We targeted white-tailed deer (Odocoileus virginianus) for serosurveillance based on evidence these deer have angiotensin-converting enzyme 2 receptors with high affinity for SARS-CoV-2, are permissive to infection, exhibit sustained viral shedding, can transmit to conspecifics, exhibit social behavior, and can be abundant near urban centers. We evaluated 624 prepandemic and postpandemic serum samples from wild deer from four US states for SARS-CoV-2 exposure. Antibodies were detected in 152 samples (40%) from 2021 using a surrogate virus neutralization test. A subset of samples tested with a SARS-CoV-2 virus neutralization test showed high concordance between tests. These data suggest white-tailed deer in the populations assessed have been exposed to SARS-CoV-2.

Weather Conditions Conducive for the Early-Season Production and Dispersal of Cercospora beticola Spores in the Great Lakes Region of North America.

In many parts of the world including the Great Lakes region of North America, Cercospora leaf spot (CLS), caused by the fungal pathogen Cercospora beticola, is a major foliar disease of sugar beet (Beta vulgaris). Management of CLS involves an integrated approach which includes the application of fungicides. To guide fungicide application timings, disease prediction models are widely used by sugar beet growers in North America. While these models have generally worked well, they have not included information about pathogen presence. Thus, incorporating spore production and dispersal could make them more effective. The current study used sentinel beets to assess the presence of C. beticola spores in the environment early in the 2017 and 2018 growing seasons. Weather variables including air temperature, relative humidity, rainfall, leaf wetness, wind speed, and solar radiation were collected. These data were used to identify environmental variables that correlated with spore levels during a time when CLS is not generally observed in commercial fields. C. beticola spores were detected during mid-April both years, which is much earlier than previously reported. A correlation was found between spore data and all the weather variables examined during at least one of the two years, except for air temperature. In both years, spore presence was significantly correlated with rainfall (P < 0.0001) as well as relative humidity (P < 0.0090). Rainfall was particularly intriguing, with an adjusted R2 of 0.3135 in 2017 and 0.1652 in 2018. Efforts are ongoing to investigate information on spore presence to improve prediction models and CLS management.

Examining historical mercury sources in the Saint Louis River estuary: How legacy contamination influences biological mercury levels in Great Lakes coastal regions.

Industrial chemical contamination within coastal regions of the Great Lakes can pose serious risks to wetland habitat and offshore fisheries, often resulting in fish consumption advisories that directly affect human and wildlife health. Mercury (Hg) is a contaminant of concern in many of these highly urbanized and industrialized coastal regions, one of which is the Saint Louis River estuary (SLRE), the second largest tributary to Lake Superior. The SLRE has legacy Hg contamination that drives high Hg concentrations within sediments, but it is unclear whether legacy-derived Hg actively cycles within the food web. To understand the relative contributions of legacy versus contemporary Hg sources in coastal zones, Hg, carbon, and nitrogen stable isotope ratios were measured in sediments and food webs of SLRE and the Bad River, an estuarine reference site. Hg stable isotope values revealed that legacy contamination of Hg was widespread and heterogeneously distributed in sediments of SLRE, even in areas lacking industrial Hg sources. Similar isotope values were found in benthic invertebrates, riparian spiders, and prey fish from SLRE, confirming legacy Hg reaches the SLRE food web. Direct comparison of prey fish from SLRE and the Bad River confirmed that Hg isotope differences between the sites were not attributable to fractionation associated with rapid Hg bioaccumulation at estuarine mouths, but due to the presence of industrial Hg within SLRE. The Hg stable isotope values of game fish in both estuaries were dependent on fish migration and diet within the estuaries and extending into Lake Superior. These results indicate that Hg from legacy contamination is actively cycling within the SLRE food web and, through migration, this Hg also extends into Lake Superior via game fish. Understanding sources and the movement of Hg within the estuarine food web better informs restoration strategies for other impaired Great Lakes coastal zones.

Phylogeographic Genetic Diversity in the White Sucker Hepatitis B Virus across the Great Lakes Region and Alberta, Canada.

Hepatitis B viruses belong to a family of circular, double-stranded DNA viruses that infect a range of organisms, with host responses that vary from mild infection to chronic infection and cancer. The white sucker hepatitis B virus (WSHBV) was first described in the white sucker (Catostomus commersonii), a freshwater teleost, and belongs to the genus Parahepadnavirus. At present, the host range of WSHBV and its impact on fish health are unknown, and neither genetic diversity nor association with fish health have been studied in any parahepadnavirus. Given the relevance of genomic diversity to disease outcome for the orthohepadnaviruses, we sought to characterize genomic variation in WSHBV and determine how it is structured among watersheds. We identified WSHBV-positive white sucker inhabiting tributaries of Lake Michigan, Lake Superior, Lake Erie (USA), and Lake Athabasca (Canada). Copy number in plasma and in liver tissue was estimated via qPCR. Templates from 27 virus-positive fish were amplified and sequenced using a primer-specific, circular long-range amplification method coupled with amplicon sequencing on the Illumina MiSeq. Phylogenetic analysis of the WSHBV genome identified phylogeographical clustering reminiscent of that observed with human hepatitis B virus genotypes. Notably, most non-synonymous substitutions were found to cluster in the pre-S/spacer overlap region, which is relevant for both viral entry and replication. The observed predominance of p1/s3 mutations in this region is indicative of adaptive change in the polymerase open reading frame (ORF), while, at the same time, the surface ORF is under purifying selection. Although the levels of variation we observed do not meet the criteria used to define sub/genotypes of human and avian hepadnaviruses, we identified geographically associated genome variation in the pre-S and spacer domain sufficient to define five WSHBV haplotypes. This study of WSHBV genetic diversity should facilitate the development of molecular markers for future identification of genotypes and provide evidence in future investigations of possible differential disease outcomes.