Thursday, November 14
3:30 pm – 5:00 pm

Agenda subject to change.
Updated 3 November 2019

★ Denotes that the lead author is a student.


K1: Monitoring IV – Topics

Moderator: Lisa Borre
Cary Institute of Ecosystem Studies, Millbrook, New York

3:35 Using Advanced Forensic Pollutant Source Identification to Cost-Effectively Protect Our Water Resources
Adam Questad1, Andrea Braga1, Jared Ervin2, and Brandon Steets2
1Geosyntec Consultants, Brookline, Massachusetts; 2Geosyntec Consultants, Santa Barbara, California

Surface waters in urban areas are frequently contaminated with elevated concentrations of fecal indicator bacteria and nutrients, signaling potential human and aquatic health risks. Surface waters may be impacted by a variety of anthropogenic and non-anthropogenic sources, with differing risks to receiving water beneficial uses. The tools used in most illicit discharge detection and elimination (IDDE) programs are not capable of identifying sources (human vs non-human) or locating inputs so that management actions can be taken. Geosyntec Consultants is using advanced forensic tools to identify contamination sources in surface and groundwater in projects nationwide. DNA-based markers and advanced chemical sewage indicators are being used to identify human sewage sources. Stable isotope analysis is being used to distinguish nutrients sources. The use of these advanced tools in combination with traditional IDDE tools allows for sources to be more efficiently tracked and controlled. This presentation will highlight results from two studies investigating the impacts of septics systems on impaired streams in dry weather. In the Atlanta region, DNA markers were used to show that fecal bacteria in streams were not related to septic density. In Southern California, nitrate isotopes and advanced chemical indicators were used to show that nitrate in groundwater was impacted by septics throughout the watershed, but surface waters were only impacted where there were septic systems near the stream. By efficiently identifying and locating sources, greater public and aquatic health benefit and significant cost savings may be achieved compared to structural stormwater implementation.

3:55 Why Is Vermont Losing Its Oligotrophic Lakes?
Leslie J. Matthews

Vermont Department of Environmental Conservation, Montpelier, Vermont

Results from EPA’s National Lake Assessments (NLA) suggest that phosphorus is increasing in lakes and ponds in the United States on a continental scale. Particularly troubling is the suggestion that the number of oligotrophic lakes decreased dramatically during the study period 2007–2012. Inspired by the NLA results, we used linear mixed effects models to examine change in phosphorus concentrations in 153 Vermont lakes over the past 40 years. The results suggest that while eutrophic lakes as a group have declined in total phosphorus, one-third of mesotrophic and almost all oligotrophic lakes have increased in total phosphorus. At the same time, chlorophyll-a and Secchi transparency have remained stable or declined in most lakes. Hypotheses for the drivers of these observations will be discussed.

4:15 Sediment Porewater Collection for Chemical Analyses From Locations With Variable Depth, Water Velocity, and Substrate Type in a Western Watershed
Kate McPeek1, Robert Santore1, Bart Chadwick2, and Chris Smith2
1Windward Environmental, Seattle, Washington; 2Coastal Monitoring Associates, San Diego, California

Sediment porewater chemistry is an important line of evidence for evaluating chemical risk to benthic organisms, particularly from metals. Collecting adequate porewater volume for chemical analyses (e.g., parameters to run the biotic ligand model) and maintaining anoxic conditions in the field can be challenging, particularly when sampling in deep water, fast flows, and areas with rocky substrate. We conducted a pilot study in a Western US watershed to determine if a CMA-patented Trident probe could be used to collect sufficient volumes of porewater (over 600 mL) from sand and cobble substrates at water depths of nearly 12 m and current speeds approaching 2 m/s. Real-time porewater and surface water data (e.g., temperature, pH, ORP, and conductivity) were collected throughout sampling and monitored for fluctuations that could indicate drawdown of porewater due to differences in conductivity and temperature between shallow porewater and overlying river water or deeper porewater (or groundwater). The stability of these parameters throughout sampling confirmed the porewater samples as representative of the target 0–15-cm depth (i.e., biologically active zone). Samples were successfully collected from locations with variable depths, water velocities, and bottom types using different configurations of the Trident probe. Sample bottles were filled in an oxygen-free glovebox on a boat. Adequate volumes allowed for laboratory analysis of all target analytes. Results were compared to aquatic life water quality criteria. The success of the pilot study informed the design of a subsequent large-scale porewater sampling effort and sediment toxicity study in the same watershed.

4:35 A Collaborative Approach to Upgrading the NALMS Secchi Dip-In Database and Improving Data Flows Using AWQMS and the Lake Observer App
Chris Adams1, Alyssa Anderson2, Lisa Borre3, Julie Chambers1, Kenneth Chiu4, Michael Forcella3, Philip Forsberg5, Alex Heppner6, Mark LeBaron6, Steve Lundt7, Sara Peel8, and Kathleen C. Weathers3
1Oklahoma Water Resources Board, Oklahoma City, Oklahoma; 2North American Lake Management Society, Madison, Wisconsin; 3Cary Institute of Ecosystem Studies, Millbrook, New York; 4Binghamton University, Binghamton, New York; 5North American Lake Management Society, Boulder, Colorado; 6AWQMS/Gold Systems, Salt Lake City, Utah; 7Denver Metro Wastewater Reclamation District, Denver, Colorado; 8Arion Consultants, Indianapolis, Indiana

The Oklahoma Water Resources Board (OWRB) was awarded a USEPA Exchange Network grant that included funding to work in partnership with the North American Lake Management Society (NALMS) to provide a long-term solution for Secchi Dip-In data management using the Ambient Water Quality Monitoring System (AWQMS) while simultaneously providing the Global Lake Ecological Observatory (GLEON) Lake Observer mobile app for project partners and the AWQMS community. The overall goal is to provide a long-term solution for Secchi Dip-In data management, validation, sharing, and flow to the US government’s Water Quality Exchange (WQX), and ultimately the Water Quality Portal (WQP). The project is now underway and already producing new tools for data submission and management via AWQMS and the Lake Observer app, including spreadsheet templates for formatting data for submission and a bulk data upload feature via Lake Observer’s web app. The full transition to a new system for Dip-In project participants, including citizen scientists and monitoring program staff and volunteers, to submit data directly to the new database at AWQMS will not be ready until later this year. In the meantime, project participants will have multiple ways to send in data, including spreadsheets with historical data. Project partners will present the results of the collaboration to date and preview the new data submission and database management tools to support an expanded Secchi Dip-In and increase the amount of water quality monitoring data that are publicly available via WQX and WQP.


K2: Fisheries

Moderator: Eric Howe
Lake Champlain Basin Program, Grand Isle, Vermont

3:35 Lake Trout Population Changes and Effects in Contaminant Modeling in the Great Lakes
Andrew J. Garner and James J. Pagano

SUNY Oswego Environmental Research Center, Oswego, New York

The Great Lakes Fish Monitoring and Surveillance Program (GLFMSP) has been collecting top predator fish in the Great Lakes since 1978. Each year the program collects 50 lake trout or walleye at alternating year sites in each of the Great Lakes between 600 and 700 mm in length. The GLFMSP has collected nearly 3200 lake trout from the Great Lakes and 550 walleyes from Lake Erie since 2004. Lake trout and walleye collected are measured, aged, and composited for contaminant analysis. However due to modifications in food web dynamics the average lake trout age has changed precipitating a confounding effect on contaminant trend analyses. Lake trout are growing larger, living longer, and accumulating a larger contaminant body burden prior to collection. Since 2004, the average age across the Great Lakes has increased by an average of 4 years, with a mean range of 1.7–7 years. The average weight of lake trout collected from Lakes Erie, Huron and Michigan has nearly doubled over the same period. The exception is Lake Ontario which has demonstrated an effective age increase of only 1.7 years, with no significant increase in weight or length. Lake trout weight, length, and age characteristics between the alternating year collection sites have also become more apparent. If these general trends continue, modifications to current GLFMSP collection protocols or contaminant modeling methods will be necessary to counteract the changing dynamics of the lake trout populations.

3:55 Effects of Reservoir Operations on the Physical and Biogeochemical Characteristics of Deadwood Reservoir, USA
Clelia Luisa Marti1, Andrew Tranmer2, and Dana Weigel3
1Department of Civil and Environmental Engineering, University of Vermont, Burlington, Vermont; 2Center for Ecohydraulics Research, University of Idaho, Moscow, Idaho; 3Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho

The Pacific-Northwest of the United States has a large number of highly regulated river systems, which have resulted in severe impacts on numerous aquatic species such as salmon, bull trout and a number of snail species. In the Deadwood River Basin (Idaho), a 10-year investigation program (2006–2015) was conducted with the objective to improve conditions for bull trout by altering the operational regime of the Deadwood Reservoir. As part of the program, a holistic watershed assessment, coupled with adaptive management that included the collection of physical and biogeochemical data from the reservoir and its tributaries, was implemented. One of the important management tools developed by the investigation was a coupled three-dimensional hydrodynamic-ecological model of Deadwood Reservoir. The model was used to describe the current physical and biogeochemical characteristics of the reservoir and predict how reservoir conditions change with several reservoir operational scenarios that combined climate driven hydrologic regimes and water operations. The results show how reservoir operations altered reservoir water temperature and dissolved oxygen that can potentially affect habitat conditions and energy sources for bull trout. Results also provide crucial information for changing the downstream river conditions, of relevance for managing the ecosystem downstream of Deadwood Reservoir.

4:15 Toxic Cyanobacterial Blooms in a Eutrophic Lake: Evaluating Accumulation of Toxins in Select Fish Species
Natalie Flores1, Todd Miller2, and Jason Stockwell1
1The University of Vermont, Burlington, Vermont; 2University of Wisconsin-Milwaukee, Milwaukee, Wisconsin

Cyanobacteria occur in aquatic habitats throughout the world and frequently grow to high densities, a phenomenon known as a “bloom.” Cyanobacteria can produce bioactive molecules, some of which are known to be toxic to eukaryotic organisms, however the long-term effects of exposure to cyanobacteria toxins (cyanotoxins) range from tumor promotion to unknown effects. One of the primary concerns with the presence of cyanotoxins in aquatic ecosystems is their accumulation in fish, and subsequent consumption by humans. Relatively limited information is known about how cyanotoxins accumulate in wild fish, if certain species are more prone to accumulation, and whether detectable patterns exist that would help limit human exposure. We hypothesized that cyanotoxin concentrations in water are positively correlated to concentrations in fish. We conducted a field study to measure concentrations of cyanotoxins in water and two species of fish from a shallow lake in Vermont during the summer-fall seasons (2016–2017) and found numerous cyanotoxins in the water samples throughout the study period. We concurrently detected a subset of some of these toxins in the brain, liver, and muscle tissues of the fish. The detection of multiple toxins distributed among the tissues of wild fish is one of the first reported for lakes. We conclude that fish from water bodies affected by toxic cyanobacterial blooms may contain cyanotoxins and highlight the need to conduct surveys of cyanotoxins in water and natural resources used for human consumption or recreation.

4:35 Extended Discussion


K3: None


K4: Paleolimnoloy IV – Biological Response

Moderator: Tom Whitmore
University of South Florida St. Petersburg, St. Petersburg, Florida

3:35 Historical Productivity in the Great Lakes: Consistency Across Geochemical Indicators
Euan D. Reavie1, Meijun Cai1, Carsten Meyer-Jacob2, John P. Smol2, and Joseph P. Werne3
1Natural Resources Research Institute, University of Minnesota Duluth, Duluth, Minnesota; 2Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen’s University, Kingston, Ontario, Canada; 3Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, Pennsylvania

Several geochemical proxies are used to reconstruct long-term productivity from lake sediment records. Here we consider several proxies from the Laurentian Great Lakes: chlorophyll, organic carbon and nitrogen content, carbonates, sediment accumulation, δ13C, δ15N and the ratio of carbon to nitrogen. Overall, a history of cultural eutrophication is apparent in profiles of these proxies, and more recently water quality improvements and the effects of invasive mussels have been manifested as lower phytoplankton productivity. However, some proxy conflicts are apparent in some lakes, indicating that multiple environmental factors drive these proxies, and so a single proxy may be a poor indicator of lake productivity. For instance, higher values of δ13C and δ15N traditionally indicate higher productivity, but in some Great Lakes cores these analytes were not correlated, and in the case of Lake Superior they were inversely related. It is clear that paleoproductivity inferences require a multi-indicator approach that can provide a weight of evidence of long-term trends.

3:55 Evaluating the Biological Response of Drinking Water Reservoirs to Lake Recovery Using Invertebrate Abundance and Environmental DNA
Heather E. McGuire1, Dewey W. Dunnington1, Joshua Kurek2, Wendy H. Krkosek3, Ian S. Spooner4, and Graham A. Gagnon1
1Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; 2Department of Geography and Environment, Mount Allison University, Sackville, New Brunswick, Canada; 3Halifax Water, Halifax, Nova Scotia, Canada; 4Department of Earth & Environmental Science, Acadia University, Wolfville, Nova Scotia, Canada

Many drinking water reservoirs in eastern Canada are experiencing recovery from acid deposition, resulting in increased water-column biological activity. Pockwock Lake, the primary drinking water supply for the City of Halifax, Nova Scotia, has experienced increased pH and NOM resulting in treatment challenges and increased operating costs. Halifax Water has been collecting chemical water quality data throughout the lake and tributaries since 2008, however water-column biological activity in Pockwock Lake is not well-characterized. We analyzed a dated lake sediment core for historical zooplankton (Cladocera) abundance in combination with previously obtained sedimentary diatom abundance data to evaluate historical water-column biological activity. A significant change in Cladocera assemblages throughout the Pockwock core is present, corresponding with acidification and lake recovery trends. Environmental DNA (eDNA) is used to complement bio-proxies and expand the range of organisms detectable in lake sediments. The combined use of the subfossil morphological identification and sequenced genes can provide powerful results which can inform long-term planning, monitoring and management of drinking water reservoirs.

4:15 Zooplankton Biogeography in Eastern Canada: Influence of Space, Human Activities and Environment
Cindy Paquette1,2, Irene Gregory-Eaves2,3, and Beatrix E. Beisner1,2
1Department of Biological Sciences, University of Quebec at Montreal, Montreal, Quebec, Canada; 2Group for Interuniversity Research in Limnology and Aquatic Environments (GRIL); 3Department of Biological Sciences, McGill University, Montreal, Quebec, Canada

Canada is home to more than a million lakes. While it is now generally accepted that human activities have a pronounced effect on lakes through land use and climate changes, the rate and magnitude of these impacts at landscape levels is unclear. Moreover, there is a fragmented and limited understanding of the ecological integrity of most Canadian lakes. Given their central food web position and their preservation in sediment records, zooplankton are likely excellent indicators of the ecological integrity of lakes. As part of the NSERC Canadian LakePulse Network project, 199 lakes in eastern Canada lakes were selected along a gradient of human impact. All lakes were sampled for water-column pelagic zooplankton, and sediment cores were collected from a subset of 54 lakes to analyze subfossil cladoceran assemblages. We compared pelagic zooplankton communities with subfossil assemblages from recent and pre-industrial sediment core sections to determine how and where communities have changed over the course of the Anthropocene. We also considered the influence of Canadian ecozone classification, planktivory pressure, land-use intensity and environmental variables on contemporary and past zooplankton functional and taxonomic biogeography. Results show assemblage shifts among eastern Canadian ecozones and among human impact classes. Overall, this research furthers our understanding of the health status of eastern Canadian lakes and the consequences of human activities on lake plankton.

4:35 Assessing Algal Changes in Lake Sediments Across Four Canadian Ecozones as Part of the LakePulse Network
Katherine Griffiths1, John P. Smol2, Dermot Antoniades3, Adam Jeziorski2, Paul Hamilton4, and Irene Gregory-Eaves1
1Department of Biology, McGill University, Group for Interuniversity Research in Limnology and aquatic environment (GRIL), Montréal, Quebec, Canada; 2Department of Biology, Queen’s University, Kingston, Ontario, Canada; 3Department of Geography, University of Laval, Québec City, Québec, Canada; 4Canadian Museum of Nature, Gatineau, Québec, Canada

The LakePulse Network ( is an ambitious, multi-year survey aiming to sample 680 lakes across Canada over 3 years, spanning 13 ecozones with the objective of creating the first nationwide database of Canadian lake health. One of the primary objectives of the network is to assess where, by how much, and why lakes have changed in response to human activities. To address this objective, we are conducting analyses of diatoms and other algal indicators (sedimentary chlorophyll a) from modern vs. pre-industrial sediment intervals for a subset (n ~ 50) of the 2017 sampled lakes, spanning four ecozones, a range of surface area, and degrees of anthropogenic impacts. Primary production, as assessed from spectrally-inferred chlorophyll a, increased in most of the sampled lakes. The diatom assemblages showed a consistent trend where the highly impacted lakes from within each ecozone experienced substantially greater assemblage turnover (measured as Bray Curtis dissimilarity) than low- or medium-impacted lakes from within the same ecozone. Diatom assemblage shifts from the pre-industrial (bottom) to contemporary period (top) showed an increase in diatoms associated with higher conductivity and nutrients, particularly in the more densely populated Mixedwood Plains and Atlantic Highlands ecozones, consistent with changes in land use. This landscape-level survey of diatom assemblage changes from pre-industrial to modern sediments across a suite of Canadian lakes highlights the power of paleolimnology in providing historical context for lake conditions and for understanding how anthropogenic drivers may be altering lake ecosystems from their pre-impact conditions.


K5: Modeling II

Moderator: Carl Nielsen
ESS Group, Inc., East Providence, Rhode Island

3:35 Managing Multiple Stressors for Climate Change Mitigation in European Lakes
Bryan M. Spears1, Dan Chapman1, Konstantinos Stefanidis2, Katri Rankinen3, Stephen Ives1, Laurence Carvalho1, Marko Jarvinen3, Yiannis Panagopoulos2, Jessica Richardson1, and Sebastian Birk4
1Centre for Ecology & Hydrology, Edinburgh, UK; 2National Technical University of Athens, Greece; 3Finnish Environment Institute, Finland; 4Universitat Duisberg-Essen, Germany

We demonstrate a novel and transferable risk-based approach to support climate change mitigation assessment in lakes through the manipulation of multiple and interacting stressors. Our understanding of interactions between climate and nutrient stressors in lakes is limited; despite the availability of an impressive data resource with which cross-scale comparisons can be made. To address this, we developed a common and transferable statistical approach for the determination of multiple stressor interactions on ecological response indicators. We demonstrate this approach using field data from Loch Leven, UK; the Pinions Catchment, Greece and the Lepsämänjoki Catchment, Finland, and wider data from across Europe. Statistical models were developed to predict ecological responses as a function of two main stressor effects and their interactions (e.g., synergistic, antagonistic, additive) for each case study, within the framework of linear mixed effects models (LMEs). In all cases, nutrient enrichment was identified as the primary stressor with climate change related stressors acting as secondary weaker stressors. The relative effects of the secondary stressors varied along the primary stressor gradients in most case studies; climate stressors becoming having greater relative effect at higher nutrient concentrations in the Lepsämänjoki Catchment but at lower nutrient concentrations in Loch Leven. From the best fitted models, risk of the response variable exceeding site-specific water quality thresholds were evaluated across both stressor gradients. Climate change scenarios and effects were constructed based on published literature for each case study and the capacity for these effects to be mitigated through nutrient controls confirmed.

3:55 Relative Impacts of Single and Simultaneous Stressors in Freshwater Food Webs
Jonathan J. Borrelli and Rick Relyea

Rensselaer Polytechnic Institute, Troy, New York

Global climate change (warming), eutrophication, and increasing salinization are among the major anthropogenic impacts on freshwater communities today. Most research tends to focus on the effect of a single stressor on the community. However, when multiple stressors impact a food web, we expect that nonlinear responses in population dynamics combined with interactions among species will result in effects that may be either dampened or magnified. We used a bioenergetic food web model to assess how an aquatic community may respond to multiple simultaneous stressors, and how that response differs from the impact of a single stressor. To measure the response of the community to these stressors both individually and combined we computed persistence (as fraction of species with positive biomass), and the change in biomass. Communities were less persistent following salinization than climate change. Salinization’s impact was reduced in simulations with both stressors when warming caused increased growth of basal taxa. Results were qualitatively similar under both high and low nutrient scenarios, although overall persistence was reduced in low nutrients. Total biomass decreased in salinization scenarios and increased in warming scenarios. Under both stressors, total biomass typically decreased, although the effect was not as great as salinization only. Our results underscore the importance of integrating multiple stressors into models to better understand how communities will respond to increasing anthropogenic impacts.

4:15 Effects of Pumped Storage on Two San Diego Reservoirs
Imad Hannoun1, Jeffery Pasek2, Goldamer Herbon3, Sarah Brower2, and Ira Rackley1
1Water Quality Solution, McGaheysville, Virginia; 2City of San Diego Public Utilities Department, San Diego, California; 3San Diego County Water Authority, San Diego, California

Hodges and Olivenhain Reservoirs, located in San Diego County, California, are owned and operated by the City of San Diego and the San Diego County Water Authority. Hodges Reservoir (capacity 30,250 acre-feet) historically only received nutrient-rich inflows from its local 303 square mile watershed and is highly eutrophic. Olivenhain Reservoir (capacity 24,000 acre-feet) is located adjacent to but 765 feet above Hodges Reservoir. Olivenhain Reservoir historically received only imported water inflows from the Colorado River and northern California and had low productivity. In 2012, the Hodges/Olivenhain Pumped Storage Project, with a capacity of 1,200 acre-feet per day, enabled water to be exchanged between the two reservoirs. Ten years of water quality data (2008 to 2017) reveals significant changes in both reservoirs after implementing the pumped storage project. Chlorophyll a at Olivenhain Reservoir increased twenty-fold since 2013, coupled with a significant decrease in Secchi depth. These changes directly correspond to the introduction of nutrient-rich water from Hodges Reservoir via pumped storage operations. In Hodges Reservoir chlorophyll a values nearly doubled, while Secchi depths declined by 38%. Other water quality effects were investigated using a three-dimensional model (AEM3D) of the two-reservoir system. Modeling results show that changes in nutrient loading, algal productivity, dissolved oxygen, and other water quality characteristics in Hodges Reservoir are related to the entrainment of nutrient-rich hypolimnetic water into the surface layer when the pumped storage system is in operation. A hypolimnetic oxygenation system will be implemented in Hodges Reservoir in 2019 to address water quality impairments.

4:35 Hydrodynamic Modeling Results Showing the Effects of the Luce Bayou Interbasin Transfer on Salinity in Lake Houston, Texas
Erik Smith1 and Sachin Shah2
1US Geological Survey, Ann Arbor, Michigan; 2US Geological Survey, Seattle, Washington

Historically, groundwater over-reliance for water supply in the Houston (Texas) metropolitan area led to aquifer drawdowns and land subsidence that were widely recognized by the 1970s. Over the past several decades, regional water suppliers have been switching over to primarily surface water resources to meet water demand. One of the primary surface water sources for the City of Houston, Lake Houston, will require further supplemental inflows to meet demand over the coming decades. The Luce Bayou Interbasin Transfer Project, set to be completed later in 2019, will divert up to 500 million gallons per day of Trinity River water into Lake Houston. As the Trinity River water has significantly different water quality than the current Lake Houston tributaries, it is necessary to evaluate how that could change water quality. With a focus on salinity as a surrogate for changes in water quality, the US Geological Survey used a three-dimensional Lake Houston hydrodynamic model (Environmental Fluid Dynamics Code) to simulate Lake Houston from 2009–2017. The calibrated baseline model was able to successfully simulate a wide range of events, with Nash-Sutcliffe index of efficiencies greater than 0.85 and 0.80 for water elevations and salinity, respectively. Additional scenarios run to simulate the Luce Bayou Interbasin Transfer found that the Luce Bayou Interbasin Transfer would cause salinities to rise over most of the modeled time (2009–2017), except for the 2011 drought when the Luce Bayou Interbasin Transfer buffered high salinities and low water-surface elevations.