Goals,beneficiaries, and indicators of waterfront revitalization in Great Lakes Areas of Concern and coastal communities

Cleanup of Great Lakes Areas of Concern (AOCs) restores environmental benefits to waterfront communities and is an essential condition for revitalization. We define waterfront revitalization as policies or actions in terrestrial waterfront or adjacent aquatic areas that promote improvements in human socioeconomic well-being while protecting or improving the natural capital (the stocks of natural assets, biodiversity) that underlies all environmental, social, and economic benefits. Except for economic measures such as development investments, visitation rates, or commercial activity, evidence of waterfront revitalization in the Great Lakes is mostly anecdotal. We offer a perspective on waterfront revitalization that links indicators and metrics of sustainable revitalization to community goals and human beneficiaries. We compiled environmental, social, economic, and governance indicators and metrics of revitalization, many of which are based on or inspired by Great Lakes AOC case studies and community revitilization or sustainability plans. We highlight the role of indicators in avoiding unintended consequences of revitalization including environmental degradation and social inequity. Revitalization indicators can be used in planning for comparing alternative designs, and to track restoration progress. The relevancy of specific indicators and metrics will always depend on the local context.     

Defining community revitalization in Great Lakes Areas of Concern and investigating how revitalization can be catalyzed through remediation and restoration

An international effort to restore contaminated areas across the Great Lakes has been underway for over 50 years. Although experts have increasingly recognized the inherent connections between ecological conditions and community level benefits, Great Lakes community revitalization continues to be a broad and complex topic, lacking a comprehensive definition. The purpose of this study was to generate a testable “AOC-Revitalization Framework” for linking remediation and restoration success, represented by Beneficial Use Impairment (BUI) removal in U.S. Great Lakes Areas of Concern (AOC), to community revitalization. Using directed content analysis, we conducted a literature review and identified 433 potential revitalization metrics and indicators and grouped them into 15 broader community revitalization attributes to develop the following definition of Great Lakes community revitalization: “locally driven community resurgence resulting in resilient and equitable enhancements to social, economic, and environmental community structures.” We surveyed experts within the Great Lakes AOC program on the likelihood remediation and restoration success, would positively impact revitalization attributes. Focus groups triangulated survey results. Results identified BUI removal was expected to positively affect revitalization, but the type of revitalization outcome was based on the BUI being removed. The AOC-Revitalization Framework is the first to empirically outline these possible linkages, providing a clear testable structure for future research; it can be used to better understand how environmental improvements are or are not leading to community revitalization and more accurately identify components of revitalization impacted, thus supporting more equitable representation, communication, and measurement of the relationship.     

Tweeting the Laurentian Great Lakes: A community opinion analysis about Great Lakes areas as assessed through mentions on Twitter

Accounting for community opinions of environmental restoration is critical both for planning and evaluating these initiatives. While considerable research assesses the value of restoration through economic metrics focusing on expenditures or preferences for ecosystem services, these metrics may not adequately account for the sociocultural services that ecosystems provide communities, such as mental and physical health or recreational opportunities. To address this challenge, we explored the use of social media data to assess online discourse communities’ opinions about ecosystem services through a case study of Twitter mentions of sites targeted for restoration through the Great Lakes Restoration Initiative (GLRI). While there is evidence of the economic and ecological benefits of GLRI, little is known about how these benefits at sites targeted for funding are perceived by the public. From April through October 2019, we collected 40,000 tweets that mentioned an Area of Concern or a Great Lakes National Park that received GLRI funding. We used a mixed-methodological approach combining tweet content and sentiment analysis to determine themes of discussion and characterize online discourse communities’ opinions around these topics. Half of all tweets were about one of three Areas of Concern, and recreation was the most discussed theme with an overall positive sentiment. A metric accounting for the number of tweets and the sentiment of tweets was derived to understand community opinions of restoration at these areas. Our findings demonstrate the potential of social media data mining as a tool for examining online conversations about and engagement with the Great Lakes.     

An assessment of water quality in two Great Lakes connecting channels

Compared to the Great Lakes, their connecting channels are relatively understudied and infrequently assessed. To address this gap, we conducted a spatially-explicit water quality assessment of two connecting channels, the St. Marys River and the Lake Huron-Lake Erie Corridor (HEC) in 2014–2016. We compared the condition of the channels to each other and to the up- and downriver Great Lakes with data from an assessment of the Great Lakes nearshore. In the absence of channel-specific thresholds, we assessed the condition of the area of each channel as good, fair, or poor by applying the most protective water quality thresholds for the downriver lake. Condition of the St. Marys River was rated mostly fair for total phosphorus (TP, 56% of the area) and mostly good (61% of the area) for chlorophyll a. Area-weighted mean concentrations of these parameters were intermediate to Lake Superior and Lake Huron. Unlike Lake Superior and Lake Huron, a large proportion (97%) of the area of the St. Marys River was in poor condition for water clarity based on Secchi depth. Area-weighted mean concentrations of TP and chlorophyll a in the HEC were more like Lake Huron than Lake Erie. For these indicators, most of the area of the HEC was rated good (81% and 86%, respectively). Interpretation of assessment results is complicated by variation in thresholds among and within lakes. Appropriate thresholds should align with assessment objectives and in the case of connecting channels be at least as protective as thresholds for the downriver lake.     

U.S. EPA Great Lakes National Program Office monitoring of the Laurentian Great Lakes: Insights from 40 years of data collection

The U.S. EPA Great Lakes National Program Office (GLNPO) implements long-term monitoring programs to assess Great Lakes ecosystem status and trends for many interrelated ecosystem components, including offshore water quality as well as offshore phytoplankton, zooplankton and benthos; chemical contaminants in air, sediments, and predator fish; hypoxia in Lake Erie's central basin; and coastal wetland health. These programs are conducted in fulfillment of Clean Water Act mandates and Great Lakes Water Quality Agreement commitments. This special issue presents findings from GLNPO's Great Lakes Biology Monitoring Program, Great Lakes Water Quality Monitoring Program, Lake Erie Dissolved Oxygen Monitoring Program, Integrated Atmospheric Deposition Network, Great Lakes Fish Monitoring and Surveillance Program, and Great Lakes Sediment Surveillance Program. These GLNPO programs have generated temporal and spatial datasets for all five Great Lakes that form the basis for assessment of the state of these lakes, including trends in nutrients, key biological indicators, and contaminants in air, sediments and fish. These datasets are used by researchers and managers across the Great Lakes basin for investigating physical, chemical and biological drivers of ongoing ecosystem changes; some of these analyses are presented in this special issue, along with discussion of new methods and approaches for monitoring.     

Researcher disciplines and the assessment techniques used to evaluate Laurentian Great Lakes coastal ecosystems

The Laurentian Great Lakes of North America have been a focus of environmental and ecosystem research since the Great Lakes Water Quality Agreement in 1972. This study provides a review of scientific literature directed at the assessment of Laurentian Great Lakes coastal ecosystems. Our aim was to understand the methods employed to quantify disturbance and ecosystem quality within Laurentian Great Lakes coastal ecosystems within the last 20 years. We focused specifically on evidence of multidisciplinary articles, in authorship or types of assessment parameters used. We sought to uncover: 1) where Laurentian Great Lakes coastal ecosystems are investigated, 2) how patterns in the disciplines of researchers have shifted over time, 3) how measured parameters differed among disciplines, and 4) which parameters were used most often. Results indicate research was conducted almost evenly across the five Laurentian Great Lakes and that publication of coastal ecosystems studies increased dramatically ten years after the first State of the Great Lakes Ecosystem Conference in 1994. Research authored by environmental scientists and by multiple disciplines (multidisciplinary) have become more prevalent since 2003. This study supports the likelihood that communication and knowledge-sharing is happening between disciplines on some level. Multidisciplinary or environmental science articles were the most inclusive of parameters from different disciplines, but every discipline seemed to include chemical parameters less often than biota, physical, and spatial parameters. There is a need for an increased understanding of minor nutrient, toxin, and heavy metal impacts and use of spatial metrics in Laurentian Great Lakes coastal ecosystems.     

Identifying sources and year classes contributing to invasive grass carp in the Laurentian Great Lakes

Relative contributions of aquaculture-origin and naturally-reproduced grass carp (Ctenopharyngodon idella) in the Laurentian Great Lakes have been unknown. We assessed occurrence and distribution of aquaculture-origin and wild grass carp in the Great Lakes using ploidy and otolith stable oxygen isotope (δ¹⁸O) data. We inferred natal river and dispersal from natal location for wild grass carp using otolith microchemistry and estimated ages of wild and aquaculture-origin fish to infer years in which natural reproduction and introductions occurred. Otolith δ¹⁸O indicated that the Great Lakes contain a mixture of wild grass carp and both diploid and triploid, aquaculture-origin grass carp. Eighty-eight percent of wild fish (n = 49 of 56) were caught in the Lake Erie basin. Otolith microchemistry indicated that most wild grass carp likely originated in the Sandusky or Maumee rivers where spawning has previously been confirmed, but results suggested recruitment from at least one other Great Lakes tributary may have occurred. Three fish showed evidence of movement between their inferred natal river in western Lake Erie and capture locations in other lakes in the Great Lakes basin. Age estimates indicated that multiple year classes of wild grass carp are present in the Lake Erie basin, recruitment to adulthood has occurred, and introductions of aquaculture-origin fish have happened over multiple years. Knowledge of sources contributing to grass carp in the Great Lakes basin will be useful for informing efforts to prevent further introductions and spread and to develop strategies to contain and control natural recruitment.     

Assessing the health of lake whitefish populations in the Laurentian Great Lakes: Lessons learned and research recommendations

Although lake whitefish Coregonus clupeaformis populations in the Laurentian Great Lakes have rebounded remarkably from the low abundance levels of the 1960s and 1970s, recent declines in fish growth rates and body condition have raised concerns about the future sustainability of these populations. Because of the ecological, economic, and cultural importance of lake whitefish, a variety of research projects in the Great Lakes have recently been conducted to better understand how populations may be affected by reductions in growth and condition. Based upon our participation in projects intended to establish linkages between reductions in growth and condition and important population demographic attributes (natural mortality and recruitment potential), we offer the following recommendations for future studies meant to assess the health of Laurentian Great Lakes lake whitefish populations: (1) broaden the spatial coverage of comparative studies of demographic rates and fish health; (2) combine large-scale field studies with direct experimentation; (3) conduct multi-disciplinary evaluation of stocks; (4) conduct analyses at finer spatial and temporal scales; (5) quantify stock intermixing and examine how intermixing affects harvest policy performance on individual stocks; (6) examine the role of movement in explaining seasonal fluctuations of disease and pathogen infection and transmission; (7) evaluate sampling protocols for collecting individuals for pathological and compositional examination; (8) quantify sea lamprey-induced mortality; and (9) enact long-term monitoring programs of stock health.     

Re-assessing the degradation of benthos beneficial use impairment in the Toronto and Region Area of Concern

Sediment quality of the Toronto and Region Area of Concern (AOC) waterfront was assessed using a weight of evidence approach following the Sediment Quality Triad, with the addition of contaminant bioaccumulation data, to determine current status following the 2013 re-designation of the “degradation of benthos” Beneficial Use Impairment as “no longer impaired.” Five stations within the AOC were sampled in 2015 and compared to lower Great Lakes nearshore reference areas (n = 22) selected based on similarity of sediment physicochemical properties. Sediment chemistry was comparable except for a localized instance of elevated perfluorinated compounds at one AOC site. Laboratory sediment toxicity bioassays indicated chronic toxicity associated with point sources to the AOC, corresponding to increased invertebrate body burdens measured in laboratory exposures. Diversity metrics and multivariate analysis showed that benthic invertebrate community composition present at the AOC sites was not significantly different from reference conditions of the lower Great Lakes. The weight of evidence from this study indicates benthic invertebrate communities continue to show effects of degraded sediment conditions at sites impacted by point sources. While the 2013 RAP decision was to re-designate the “degradation of benthos” BUI to “no longer impaired,” our results support the notion that life after AOC delisting must continue to prioritize monitoring efforts.     

Characterizing the cultural ecosystem services of coastal sand dunes

Coastal sand dunes provide an array of important benefits that are supported by coastal geomorphic processes and location-specific ecosystems, including direct and indirect economic benefits to humans. Coastal sand dune ecosystems are ecologically important, but their specific values and uses are little studied, poorly understood, and underappreciated. Michigan, USA, is home to the largest land area of freshwater coastal sand dunes in the world. This study used an online survey that allowed participants to record the types of activities in which they engaged during visits and respond to questions about the importance of the cultural ecosystem services of coastal sand dunes. The survey captured the responses of 3610 individuals, a majority of whom rated scenic beauty, protection for future generations, protection of a unique ecosystem, and outdoor recreation as extremely important or very important. The survey results provide some preliminary insights into the role of cultural ecosystem services of coastal sand dunes in providing and sustaining benefits for humans and how these benefits and values are perceived by the public. These insights have important implications for policy makers responsible for coastal zone management in the Great Lakes region and in other areas characterized by coastal sand dunes ecosystems.     

Great Lakes coastal fish habitat classification and assessment

Basin-scale assessment of fish habitat in Great Lakes coastal ecosystems would increase our ability to prioritize fish habitat management and restoration actions. As a first step in this direction, we identified key habitat factors associated with highest probability of occurrence for several societally and ecologically important coastal fish species as well as community metrics, using data from the Great Lakes Aquatic Habitat Framework (GLAHF), Great Lakes Environmental Indicators (GLEI) and Coastal Wetland Monitoring Program (CWMP). Secondly, we assessed whether species-specific habitat was threatened by watershed-level anthropogenic stressors. In the southern Great Lakes, key habitat factors for determining presence/absence of several species of coastal fish were chlorophyll concentrations, turbidity, and wave height, whereas in the northern ecoprovince temperature was the major habitat driver for most of the species modeled. Habitat factors best explaining fish richness and diversity were bottom slope and chlorophyll a. These models could likely be further improved with addition of high-resolution submerged macrophyte complexity data which are currently unavailable at the basin-wide scale. Proportion of invasive species was correlated primarily with increasing maximum observed inorganic turbidity and chlorophyll a. We also demonstrate that preferred habitat for several coastal species and high-diversity areas overlap with areas of high watershed stress. Great Lakes coastal wetland fish are a large contributor to ecosystem services as well as commercial and recreational fishery harvest, and scalable basin-wide habitat models developed in this study may be useful for informing management actions targeting specific species or overall coastal fish biodiversity.     

Factors governing the distribution and fish-community associations of the round goby in Michigan tributaries of the Laurentian Great Lakes

The round goby (Neogobius melanostomus) is increasingly being reported in tributaries of the Laurentian Great Lakes where these fish have been shown to adversely impact native stream biota. Determining the characteristics and distribution of invaded streams are the first steps toward effective round goby management. We sampled 30 tributaries in the Great Lakes basin and characterized each in terms of nine physical reach-scale attributes. Round goby were detected in 14 streams where abundances ranged from 4% to 53% of the fish sampled in each stream. Round goby was the single most abundant fish species sampled, constituting 14% of all fish encountered across all sites, and 30% of individuals in round goby-present sites. Round goby-present sites were larger, had lower channel slopes, less large wood, and less canopy cover than round goby-absent sites, suggesting that these attributes may promote round goby establishment. Mottled sculpin, cyprinids, brook stickleback, white sucker and rainbow trout were associated with goby absence while centrarchids, percids, yellow bullhead, and mud minnow were associated round goby presence. Collectively these results demonstrate that round goby are widespread in eastern Michigan tributaries to the Great Lakes, present in streams with a range of physical habitat characteristics, and that round goby presence is associated with certain fish species.     

Fatty acids in Great Lakes lake trout and whitefish

Fish are an excellent source of lean protein and omega-3 polyunsaturated fatty acids (PUFAs) but there is inadequate information on the levels of PUFAs in freshwater fish and specifically Great Lakes fish. Knowledge of PUFAs is necessary to make informed decisions regarding the balance between the benefits of fish consumption due to these factors versus risks of adverse health effects associated with elevated levels of contaminants known to be present in some Great Lakes fish and linked to increased risk of cancer and adverse neurological effects to both infants and adults. Our goal was to determine the lipid profiles in two species of Great Lakes fish, lake trout and whitefish. Total fat and the percentage of total and omega-3 PUFAs were with one exception significantly higher in lake trout than whitefish. Average concentrations of EPA + DHA were 11.2 and 9.7 g/100 g lipid in lake trout and whitefish, respectively. The concentrations of EPA + DHA in fatty marine fish (22.7, 23.9 and 30.2 g/100 g lipid, respectively) are about double those found in Great Lakes lake trout and whitefish. Nevertheless a 100 g serving of Great Lakes lake trout provides more than 500 mg of EPA + DHA, which is the daily intake level recommended by the American Dietetics Association for the prevention of coronary heart disease.     

Risk-benefit modeling to guide health research in collaboration with Great Lakes fish consuming Native American communities

It is well documented that fish consumption imparts both health risks and benefits. Furthermore, fish harvest and consumption are an essential part of Great Lakes Native American cultures. Quantitative models that compare risk and benefits to potential consumption scenarios can help guide future health research as well as consumption advice for potentially sensitive populations. This article presents fish consumption scenarios based on self-reported meal plans constructed by tribal members in eastern upper peninsula and northern lower Michigan Anishinaabe. Two risk–benefit models were applied to these scenarios to estimate the potential neurodevelopmental and cardiovascular risks (either increased or reduced risk) from dioxin-like polychlorinated biphenyls (DL-PCBs), methylmercury (MeHg), and omega-3 polyunsaturated fatty acids (n3-PUFA). All scenarios except maximum exposure estimates (i.e. 25th–75th percentile MeHg, DL-PCB, and n3-PUFA intakes) predicted reduced cardiovascular risk and improved neurodevelopmental outcomes. The greatest predicted benefits (adjusted for risks) occurred at the 75th percentile intake of MeHg, DL-PCB, and n3-PUFA scenarios: 5.0 visual recall memory (VRM) and 4.41 Intelligence Quotient (IQ) benefits, and 28% reduced risk of cardio-vascular disease. Scenarios based on maximum self-reported intake, however, predicted health detriments. These results suggest that most fish consumption scenarios as constructed in collaboration with Native American communities could impart health benefits despite the presence of contaminants. However, high-end consumption estimates warrant caution as well as the need for well-crafted advice. Potential benefits further underscore the value of reducing contamination burdens in Great Lakes fisheries. Future priorities of ongoing contamination monitoring and health research are discussed.     

Coalescent methods reconstruct contributions of natural colonization and stocking to origins of Michigan inland Cisco (Coregonus artedi)

Fish population structure in previously glaciated regions is often influenced by natural colonization processes and human-mediated dispersal, including fish stocking. Endemic populations are of conservation interest because they may contain rare and unique genetic variation. While coregonines are native to certain Michigan inland lakes, some were stocked with fish from Great Lakes sources, calling into question the origin of extant populations. While most stocking targeted lake whitefish (Coregonus clupeaformis), cisco (C. artedi) were also stocked from the Great Lakes to inland waterbodies. We used population genetic data (microsatellite genotypes and mitochondrial (mt)DNA sequences), coalescent modeling, and approximate Bayesian computation to investigate the origins of 12 inland Michigan cisco populations. The spatial distribution of mtDNA haplotypes suggests Michigan is an introgression zone for two ancestral cisco lineages associated with separate glacial refugia. Low levels of genetic diversity and high levels of genetic divergence were observed for populations located well inland of the Great Lakes relative to populations occupying waterbodies near the Great Lakes. Estimates of recent Great Lakes gene flow ranged from 27 to 48% for populations near the Great Lakes shoreline but were substantially lower (under 8%) for populations further inland. Inland lakes with elevated recent gene flow estimates may have been recipients of stocked coregonine fry, including cisco. Low levels of genetic diversity paired with a high likelihood of endemism as indicated by strong genetic divergence and low Great Lakes population inputs suggest the analyzed cisco populations occupying southern Michigan kettle lakes are of elevated conservation interest.     

Warmer and Drier Climates that Make Terminal Great Lakes

A recent empirical model of glacial-isostatic uplift showed that the Huron and Michigan lake level fell tens of meters below the lowest possible outlet about 7,900 ¹⁴C years BP when the upper Great Lakes became dependent for water supply on precipitation alone, as at present. The upper Great Lakes thus appear to have been impacted by severe dry climate that may have also affected the lower Great Lakes. While continuing paleoclimate studies are corroborating and quantifying this impacting climate and other evidence of terminal lakes, the Great Lakes Environmental Research Laboratory applied their Advanced Hydrologic Prediction System, modified to use dynamic lake areas, to explore the deviations from present temperatures and precipitation that would force the Great Lakes to become terminal (closed), i.e., for water levels to fall below outlet sills. We modeled the present lakes with pre-development natural outlet and water flow conditions, but considered the upper and lower Great Lakes separately with no river connection, as in the early Holocene basin configuration. By using systematic shifts in precipitation, temperature, and humidity relative to the present base climate, we identified candidate climates that result in terminal lakes. The lakes would close in the order: Erie, Superior, Michigan-Huron, and Ontario for increasingly drier and warmer climates. For a temperature rise of T°C and a precipitation drop of P% relative to the present base climate, conditions for complete lake closure range from 4.7T + P > 51 for Erie to 3.5T + P > 71 for Ontario.     

Land Use Land Cover Change in the U.S. Great Lakes Basin 1992 to 2001

The pace of Land Use/Land Cover (LULC) change in the Great Lakes, particularly in urban and suburban areas, far exceeds that predicted by population growth alone. Thus, quantification of LULC and change through time may be a key factor in understanding the near-shore ecology of this system. The work described in this paper is part of a larger effort called the Great Lakes Environmental Indicators Project (GLEI), whose goal was to develop and refine environmental state indicators for the U.S. near-shore zone of the Great Lakes. Here we describe methodologies for using existing Landsatbased LULC maps to assemble consistent LULC data for the U.S. portion of the Great Lakes basin for 1992 and 2001, as well as summarizing salient LULC results. Between 1992 and 2001, 2.5% (798,755 ha) of the U.S. portion of the Great Lakes watershed experienced change. Transitions due to new construction included a 33.5% (158,858 ha) increase in low-intensity development and a 7.5% (140,240 ha) increase in road area. Agricultural and forest land each experienced ∼2.3% (259,244 ha and 322,463 ha, respectively) decrease in area. Despite the large and enduring agricultural losses observed (2.23% of 1992 agricultural area), the rate of agricultural land decrease between 1992 and 2001 was less than that reported by the EPA (−9.8%) for the previous ∼10-year period. Areas of new development were largely concentrated near coastal areas of the Great Lakes. Over 38% (6,014 ha) of wetland losses to development between 1992 and 2001 occurred within 10 km of a coastal area, and most of that area was within the nearest 1 kilometer. Clearly, these land use change data will be especially useful as quantifiable indicators of landscape change over time and aid in future land use planning decisions for protection of the integrity of the Great Lakes ecosystem.     

Significance of toxaphene in Great Lakes fish consumption advisories

Fish consumption advisories have been issued for the Great Lakes generally based on the most restrictive contaminant. For the Canadian waters of the Great Lakes, toxaphene causes minor restrictions only in Lake Superior, i.e., 3% of the total (restrictive + unrestrictive) advisories issued. However, the significance of the hazard posed by toxaphene in fish is not clear since more restrictive advisories due to other priority contaminants may be masking the less restrictive advisories. We simulated fish consumption advisories for the Toxaphene-only scenario by neglecting the presence of contaminants other than toxaphene, and compared with the issued advisories as well as with the published simulated Mercury-only scenario. Restrictive advisories under the Toxaphene-only scenario compared to the issued toxaphene related advisories would increase from 3% to 14%, < 1% to 4%, and 0% to 2% for Lakes Superior, Huron and Ontario, respectively, and remain at 0% for Lake Erie. For Lake Superior, most of the restrictive Toxaphene-only advisories would be for fatty fish. Overall, the Toxaphene-only advisories would be significantly less restrictive compared to the issued advisories, and also generally less restrictive compared to the Mercury-only scenario. These results suggest that toxaphene is less of a concern than PCBs (including dioxin-like PCBs), dioxins–furans and mercury from the perspective of health risk to humans consuming Great Lakes fish; elevated toxaphene is mainly a concern for human consumers of Lake Superior fatty fish. Our results suggest that the routine monitoring of toxaphene in other Canadian waters of the Great Lakes and Lake Superior lean/pan fish could be discontinued.     

Relative abundance,age structure,and body size in mudpuppy populations in southwestern Ontario

Little is known of mudpuppy (Necturus maculosus) population structure and ecology; some populations in the Great Lakes are thought to be in decline. Mudpuppies are the obligate hosts for the mudpuppy mussel (Simpsonaias ambigua), a species that is endangered in Canada and in many Great Lakes states. We surveyed mudpuppies from the Sydenham River, the only known Canadian locality of the mudpuppy mussel, in order to generate information on relative density, deformity rates and population age/size structure and used this information to compare them to known mudpuppy populations from Great Lakes sites in the Detroit River, Lake St. Clair and Long Point in Lake Erie. Deformity rates were elevated at some sites in the Sydenham River. The relative density of mudpuppies in the Sydenham River was lower than that of other Great Lakes sites and their age was skewed towards younger individuals. Although at lower densities than at other Great Lakes sites, the mudpuppy population in the Sydenham River appears stable and is showing signs of recruitment which bodes well for the future of the mudpuppy mussel population of the river.     

Molecular characterization of bacterial communities associated with sediments in the Laurentian Great Lakes

The Laurentian Great Lakes freshwater ecosystem comprises a series of interconnected lakes exhibiting wide spatial differences in hydrogeochemistry, productivity, and allochthonous inputs of nutrients and xenobiotics. Bacterial communities associated with offshore sediments in this ecosystem have been rarely studied. We evaluated bacterial communities associated with sediments from 10 locations in four of the five Great Lakes (Lakes Superior, Michigan, Huron, and Ontario) by generating16S rRNA pyrosequence libraries. Pyrosequencing analysis revealed the presence of 26 bacterial phyla and proteobacterial classes among Great Lakes sediment samples. Actinobacteria, Acidobacteria, Betaproteobacteria, and Gammaproteobacteria were the most abundant groups of bacteria. Redundancy analysis was used to examine the role of sediment properties, including depth and chemical composition, in shaping bacterial community structure. One sample from Lake Huron was distinctly different from all other samples. Phylogenetic analysis revealed that the sample contained greater abundances of groups of bacteria associated with polluted environments. This study constitutes the most extensive examination of bacteria associated with Laurentian Great Lakes sediments and sheds useful insight into the microbial ecology of the Great Lakes.