Journal of Great Lakes Research最新文献

Contaminated sediments continue to limit ecological recovery of the Detroit and Rouge River Areas of Concern. Co-production of knowledge and co-innovation of solutions for contaminated sediments have been underway since the remedial action plan program began in 1985 and are accelerating with increased investment in remediation. In the Detroit River, up to 5.1 million m³ of contaminated sediments on the U.S. side require remediation. On the Canadian side, no further sediment remediation is required beyond one completed project in Turkey Creek. An estimated 350,000 m³ of contaminated sediment require remediation in the Rouge River (Michigan). Co-innovation of solutions, including collaborative funding, has estimated a $100 million shortfall in non-federal match funding necessary to secure Great Lakes Legacy Act funds. All stakeholders and rightsholders must have a sense of urgency to address this shortfall because, as of 2023, only three years remain of Legacy Act funding. If this window of opportunity is missed, there is no guarantee that comparable federal money will be available in the future. We recommend: ensuring environmental justice is a priority; completing all necessary sediment remediation in the U.S. portion of the Detroit River and lower Rouge River; recruiting partners, including the State of Michigan, to help meet necessary non-federal match requirements; exploring creative financing like environmental, social, and governance and sustainability-linked investment opportunities; and developing a compelling ecosystem vision that is carried in the hearts and minds of all watershed denizens, coupled with a complementary investment thesis to help make these watersheds more investable.

Grass carp (Ctenopharyngodon idella, Val.) is an invasive species in the Laurentian Great Lakes region with the potential for damaging the lake ecosystem and harming the region's economy. Grass carp spawning was documented in the Sandusky River, Ohio, in 2015 through targeted egg sampling. Continued egg sampling in the Sandusky River suggested that grass carp spawning is related to discharge and water temperature. We used egg sampling data from 2014 to 2021 to develop a Bayesian model to understand the likely conditions related to grass carp spawning in the Lake Erie watershed. The resulting model estimates the likelihood of spawning as a function of discharge and water temperature. The results suggest that spawning is most likely to occur when discharge is above 10 m³/s and water temperature is below 25 ℃. The model provides a tool for setting research and management priorities to develop management strategies to reduce the grass carp population in Lake Erie. Furthermore, the Bayesian nature of the model makes the model updatable when new data are available, whether from the same river or from another river, to incorporate river-specific features to identify likely spawning rivers.

Lake trout (Salvelinus namaycush) is an ecologically and economically important fall-spawning species that inhabits northern lakes at a wide range of latitudes and with widely varying temperature dynamics. However, fall spawning also means that adult behavior is largely divorced from the conditions at hatching. Embryonic development must therefore be responsive to external stimuli in a way that consistently results in hatch occurring during a viable period despite considerable variability in phenology. Despite extensive work on lake trout development and culture, hatch timing remains difficult to predict precisely by either days-to-hatch or thermal units (TU)-to-hatch without experience with a particular system and strain. We hypothesized that this problem may be due in part to a non-linear response to temperature variability during development, coupled with the potential for poorly controlled variability in past studies due to differences in hysteresis and thermal inertia among experimental setups. To test this hypothesis, we reared individually identified embryos from controlled parental crosses in temperature-controlled incubators set to maintain a range of constant or variable temperatures and measured both the timing and size of all individuals at hatch. Our results show that temperature variation has a pronounced effect on the timing of hatching, with embryos reared in a system with a 3 °C daily swing hatching an average of six days earlier than those raised in a constant environment with the same mean temperature. These findings raise questions about the utility of TU as a predictor of hatch timing, especially in natural systems that are often inherently variable.

In a previous study, we identified several novel contaminants of emerging concern (CECs) using non-targeted screening of extracts prepared from passive samplers deployed in wastewater and surface waters in Hamilton Harbour. In the present study, we investigated whether several of these novel compounds are widely distributed in tributaries and coastal waters in other areas of the Great Lakes Basin. Extracts prepared from archived Polar Organic Chemical Integrated Samplers (POCIS) were analyzed for targeted CECs, which included four tire-derived compounds, two prescription pharmaceuticals (i.e., lamotrigine, formycin), a metabolite of a cough suppressant (i.e., dextrorphan) and a component of coal tar (i.e., lepidine). Five of these analytes were widely distributed in the basin. Concentrations in surface waters were estimated using sampling rates (R_s) predicted from physical-chemical properties. The estimated maximum time-weighted average concentrations for three compounds derived from tire-wear, hexamethoxymethylmelamine (HMMM), diphenylguanidine and 6PPD-quinone were 680, 48 and 17 ng/L, respectively. The distribution of these tire-wear compounds and lepidine indicated that they are transported into surface waters from urban runoff. Dextrorphan and lamotrigine were detected at the highest estimated concentrations near discharges of domestic wastewater. This study demonstrates an approach to identify and assess the sources of novel CECs as part of the development of an “Early Warning System” for potential threats to the Laurentian Great Lakes and their tributaries.

The objective of this study was to integrate passive sampling with targeted analysis to quantify known contaminants of emerging concern (CECs) and, with non-targeted analysis. to identify previously unknown water-soluble compounds. Polar Organic Chemical Integrative Samplers (POCIS) were deployed in the treated effluent of a wastewater treatment plant serving the City of Hamilton, ON, Canada, as well as at three stations in Hamilton Harbour and at nearshore locations in Lake Ontario. Targeted analysis indicated that there was a gradient of pharmaceuticals, caffeine, and artificial sweeteners from highest levels in wastewater to lowest levels in the harbour furthest from the wastewater discharge. The estimated concentrations of current use pesticides were highest in the central part of the harbour. Pooled POCIS extracts were also analyzed using high-resolution quadrupole-time-of-flight mass spectrometry and the exact mass data generated were screened using a pattern recognition application. The greatest number of features were detected in positive ion mode from POCIS deployed in the central part of the harbour, and so exact mass data from this station were further evaluated using the Global Natural Products Social Molecular Networking data base. Novel CECs tentatively identified included pharmaceuticals from the angiotensin receptor blocker class. Follow-up targeted analysis confirmed that a tire wear compound, hexamethoxymethylmelamine (HMMM), the coal-tar derived compound, lepidine, the anticonvulsant, lamotrigine and a metabolite of a cough suppressant, dextrorphan, were present in POCIS. We propose that this approach be part of a Great Lakes Early Warning System to identify emerging threats from chemical contaminants.

Lake Michigan’s water level recently rose by >1.5 m, from its historical low (in 2013) to a near-historical high (in 2020). This study evaluates the lake-level rise-associated physiographic and sand volumetric changes at four of Chicago’s engineered urban lakefront embayments. Insights from lowstand and highstand topobathymetric measurements are compared to shoreline morphodynamic trends. The recent low–high phase transition is also compared to that of the mid-1960s through mid-1970s period of lake-level rise, the most similar in terms of magnitude and rate. While embayed beaches of Chicago’s urban lakefront (n>20) responded predictably to lake-level rise, with shoreline recession and overwash into backshore regions a common dynamic, spatial patterns and magnitudes of change were beach-specific and influenced by aspect, infrastructure design, littoral sand availability/supply, and type of beach-management activities. Patterns of shoreline rotation during lake-level rise reflect embayment orientation, groin placement and design, and/or antecedent backshore topographic conditions. Sedimentary dynamics within the enclosed nearshore are predictable along strike and often decoupled from subaerial morphodynamics. This relates, in part, to different sand-supply conditions along the highly fragmented urban littoral system. Sediment interconnectivity between coastal embayments is likely to vary with changes in water level. This topic requires further study. Beach managers should consider local (beach-specific) and regional (sand supply-related) impacts on morphodynamics across subaerial and subaqueous parts of lakefront embayments for climate-change mitigation planning.

Over the past 20 years, Lake Huron’s ecosystem has undergone an unprecedented amount of change, including a reduction in offshore productivity, prey fish collapse, and transformation of the benthic food web. Yet, little is known about how these changes affected the diet of key fish species. In this study, we used 18,543 stomach samples collected between 2004 and 2019 to characterize the diet of five key species: lake trout (Salvelinus namaycush), lake whitefish (Coregonus clupeaformis), chinook salmon (Oncorhynchus tshawytscha), rainbow trout (Oncorhynchus mykiss), and walleye (Sander vitreus), from the Ontario waters of Lake Huron including the North Channel, Georgian Bay and the main basin. Specifically, we described regional diets using an index of relative importance and diet biomass proportions, and we determined the Schoener diet overlap index between the five predators. We found that invasive species dominated the diets of the predators. Lake whitefish diets were dominated by dreissenid mussels in the southern main basin and by round goby (Neogobius melanostomus) in the central main basin. Chinook salmon had a very uniform diet of rainbow smelt (Osmerus mordax) and coregonines, contributing to the high levels of diet overlap with lake trout, especially in the North Channel. Our study demonstrates that while invasive species are pervasive in the diets of predatory fish lake-wide, there remains a significant degree of regional variation that needs to be taken into account when considering food web effects of the recent ecosystem changes and when devising management strategies aimed at balancing predator and prey populations.

Invasive sea lamprey (Petromyzon marinus) are controlled in the Great Lakes with 4-nitro-3-(trifluoromethyl)phenol (commonly 3-trifluoromethyl-4-nitrophenol or TFM). The proper amount of TFM must be applied during treatments to effectively kill larval sea lamprey while minimizing impacts to non-target species. In this study, bioassay tests were conducted in May, July, and September in a portable test trailer at six larval sea lamprey infested rivers in Michigan to determine potential seasonal changes in sensitivity of larval sea lamprey to TFM. Larvae greater than 60 mm were collected from each stream and exposed for 12 h in TFM-treated stream water using two independent continuous-flow diluter systems. A suite of water chemistries and larval physiological parameters were collected during the tests and modeled as potential predictors of seasonal changes in the sensitivity of larval sea lamprey to TFM. The observed minimum lethal concentrations to larval sea lamprey were 0–40% lower (May), 8% lower–59% higher (July), and 49–117% higher (September) than sea lamprey control personnel treatment prediction charts. Water temperature, liver glycogen content, and time of year were strongly associated with seasonal differences in TFM sensitivity, offering sea lamprey control personnel more exact predictions to limit potential residual lamprey surviving future treatments.

A widespread Typha (cattail) hybrid zone in southeastern Canada and northeastern USA comprises T. latifolia, T. angustifolia, and their hybrid T. × glauca. In this region the hybrid is considered invasive because of its detrimental impacts on wetlands and biodiversity. Researchers and managers are increasingly interested in tracking and controlling the spread of the invasive hybrid, but this can be hampered by challenges in differentiating taxa: while the parent species and F1 hybrids can often be identified from morphological characteristics, advanced-generation and backcrossed hybrids can be common, and these have obscured morphological distinctions among taxa. Here we present five species-specific genetic markers that differentiate T. latifolia, T. angustifolia, F₁ hybrids, and advanced-generation/backcrossed hybrids. Unlike the pre-existing species-specific microsatellite markers, these markers require only PCR or PCR followed by a restriction enzyme digest, and can be visualized on an agarose gel. As a result, they require less specialized equipment than existing species-specific markers, and should therefore be useful for a larger group of practitioners. Future use of these markers could include monitoring range expansions, assessing the outcomes of restoration programs, and avoiding the unnecessary elimination of native Typha.

Most studies of Lake Michigan lake trout (Salvelinus namaycush) have focused on adults, with scant attention to juveniles (<400 mm). We explored the spatial distribution and diet of juvenile lake trout using U.S. Geological Survey September bottom trawl data (2015–2022) and stomach content information opportunistically collected since 2012 by various agencies using multiple gear types. Most juvenile lake trout in the September bottom trawl survey were caught at 37–64 m bottom depths. Length frequency data from the bottom trawl survey identified three size classes likely associated with wild juvenile lake trout age: < 85 mm (∼age-0), 85–170 mm (∼age-1) and > 170 mm (∼age-2+). Largest catches of wild lake trout < 170 mm occurred along a northeastern transect (near Frankfort, Michigan), whereas most > 170 mm were collected along southern transects. Mysis diluviana was the dominant prey for juvenile lake trout < 170 mm, and > 250 mm were primarily piscivorous, while 170–250 mm appeared to be a transitional period of switching from Mysis to fish. Species composition of prey fishes consumed by lake trout varied spatially and we found evidence of seasonal and annual diet variation within Grand Traverse Bay. Diporeia, once an important component of juvenile lake trout diet, appears to no longer be consumed by juvenile lake trout in Lake Michigan to any measurable degree. Continued research on the ecology of juvenile lake trout may provide insight into the effects of a changing ecosystem on juvenile lake trout diet and growth, thereby contributing to the effort to rehabilitate the Lake Michigan lake trout population.