SFS Annual Meeting

5/21/2018  |   09:00 - 09:15   |  430 B

OF SMALL STREAMS AND GREAT LAKES: INTEGRATING TRIBUTARIES TO UNDERSTAND THE ECOLOGY AND BIOGEOCHEMISTRY OF LAKE SUPERIOR Lake Superior receives inputs from approximately 2800 tributaries that provide limiting nutrients and dissolved organic matter (DOM) to the nearshore zone of this oligotrophic lake. Instream uptake of nitrogen, phosphorus, and dissolved organic carbon (DOC) can be rapid but varies seasonally in magnitude. Peak tributary export occurs during snowmelt-driven spring runoff, with additional pulses during rain-driven storm events. Tributary plumes with elevated DOC concentration, higher turbidity, and distinct DOM character can be detected in the near-shore during times of high runoff, but plumes can be quickly transported and diluted by in-lake currents and mixing. Understanding the variability in size and load of these tributary plumes, how they are transported within the lake, and how long they persist may be best addressed with environmental sensors and remote sensing using autonomous and unmanned vehicles. The biogeochemical connections between Lake Superior and its tributaries are vulnerable to climate change, and understanding and predicting future changes to these valuable freshwater resources will require a nuanced and detailed consideration of tributary inputs and interactions in time and space.

Amy Marcarelli (Primary Presenter/Author), Michigan Technological University, ammarcar@mtu.edu;


Ashley Coble (Co-Presenter/Co-Author), National Council for Air and Stream Improvement, Inc., acoble@ncasi.org;


Karl Meingast (Co-Presenter/Co-Author), Michigan Technological University, kmmeinga@mtu.edu ;


Evan Kane (Co-Presenter/Co-Author), Michigan Technological University, eskane@mtu.edu;


Colin Brooks (Co-Presenter/Co-Author), Michigan Tech Research Institute, cnbrooks@mtu.edu;


Ishi Buffam (Co-Presenter/Co-Author), University of Cincinnati, buffamii@ucmail.uc.edu;


Sarah Green (Co-Presenter/Co-Author), Michigan Technological University, sgreen@mtu.edu;


Casey Huckins (Co-Presenter/Co-Author), Michigan Technological University, cjhuckin@mtu.edu;


David Toczydlowski (Co-Presenter/Co-Author), Michigan Technological University, t-11@mtu.edu;


Robert Stottlemyer (Co-Presenter/Co-Author), Michigan Technological University, rstottle@earthlink.net;


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5/21/2018  |   09:15 - 09:30   |  430 B

MODELED WEEKLY TOTAL PHOSPHORUS LOADS FOR ALL UNITED STATES RIVERS FEEDING THE GREAT LAKES High phosphorus loads from rivers have been identified as an important driver of excessive algal growth in the Great Lakes, and are therefore a major concern for regional management efforts. High-quality estimates of nutrient loading are needed at a large spatial extent but fine temporal resolution to support regional decision making about nutrient load targets, algal responses to nutrients, and watershed prioritization. Landscape factors like urban and agricultural land uses interact with climatic factors and weather to drive nutrient concentrations in streams and rivers. Such landscape controls on nutrient loading (and their proxies) have been used successfully in the past to estimate nutrient loading to the Great Lakes, but at coarse time steps or for subsets of watersheds only. Here, we describe a simple but accurate approach to estimate total phosphorus loads, and predictions of weekly total phosphorus loading to the Great Lakes from all major tributaries (N = 1,532) over a 14 year time span. Performance of the approach for spatial and temporal load prediction are presented, and model applications for management decision support explored.

Peter Esselman (Primary Presenter/Author), U.S. Geological Survey, Great Lakes Science Center, pesselman@usgs.gov;


Anthony Kendall (Co-Presenter/Co-Author), Michigan State University Department of Geology, kendal30@msu.edu ;


David Hyndman (Co-Presenter/Co-Author), Michigan State University Department of Geology, hyndman@msu.edu;


Sherry Martin (Co-Presenter/Co-Author), Michigan State University Department of Geology, marti686@msu.edu;


Jan Stevenson (Co-Presenter/Co-Author), Michigan State University, rjstev@cns.msu.edu;


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5/21/2018  |   09:30 - 09:45   |  430 B

NITROGEN LIMITATION OF LAKE SUPERIOR COASTAL WETLANDS Nitrate concentrations are relatively high and rising in the offshore waters of Lake Superior. Coastal habitats, on the other hand, appear to exhibit closer stoichiometric balance between N and P with primary productivity potentially limited by N availability. We conducted biofilm nutrient amendments in coastal wetlands along the south shore of Lake Superior. We predicted that N limitation was related to surrounding watershed land cover and coastal geomorphology, and that N limitation would vary within wetlands. Our results suggest that algal biofilms in Lake Superior coastal wetlands are N limited in general and that both coastal geomorphology and surrounding land cover influence N limitation. The strongest N limitation occurred in wetlands protected from wave energy and pelagic mixing and surrounded by forested land. Tributary sediment deposition reduced biofilm productivity and influenced within-wetland nutrient limitation patterns. Coastal wetlands represent important nutrient gateways that link tributaries to the Lake Superior nearshore. As climate and land use patterns change throughout the Great Lakes basin, N cycling within the coastal margin is likely to change as well, which could have broad implications that are not currently understood.

Aletha Hefko (Co-Presenter/Co-Author), Northland College, hefkoa821@myemail.northland.edu;


Michele Wheeler (Co-Presenter/Co-Author), Wisconsin Department of Natural Resources, Michele.Wheeler@wisconsin.gov;


Matthew Cooper (Primary Presenter/Author), Burke Center for Freshwater Innovation, Northland College, mcooper@northland.edu;


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5/21/2018  |   09:45 - 10:00   |  430 B

FISH USE OF LAKE MICHIGAN DROWNED RIVER MOUTHS: A CONCEPTUAL MODEL OF LIFE HISTORY TYPES Freshwater river mouths in large lakes are centers for biological activity, yet there has been relatively little ecological research on these ecosystems relative to upstream rivers and downstream large lakes. Drowned river mouths (DRMs) are protected, lake-like ecosystems that connect tributaries to large lakes and are a common feature along Lake Michigan’s eastern shoreline. DRMs have diverse fish assemblages and are more eutrophic than Lake Michigan with greater biomasses of phytoplankton, zooplankton, and benthic macroinvertebrates. Using a conceptual model of the three main habitats (lake, DRM, and river), I identify nine possible life history types: three resident (i.e., fish primarily use one habitat) and six migratory types. For each migratory type, fish can be classified as stragglers that “accidentally” use another habitat type, opportunists that enter another habitat at some point in their life cycle, or habitat-dependent that require another habitat for critical stages in their life cycle. Based on literature and field studies, I provide examples of fishes for each life history type. I hypothesize that most fishes in DRMs are residents; however, complex migratory behaviors emphasize many cases where fishes provide direct links among the three habitats.

Carl R. Ruetz III (Primary Presenter/Author), Grand Valley State University, ruetzc@gvsu.edu;


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5/21/2018  |   10:00 - 10:15   |  430 B

POTENTIAL IMPACTS OF TRIBUTARY LOADS ON COASTAL ECOSYSTEM SERVICES IN LAKE MICHIGAN Tributary nutrient loads degrade Great Lakes coastal ecosystems and services they provide, including drinking water, fisheries, and recreation. In Lake Michigan, open-lake phosphorus (P) concentrations are below mandated targets, but coastal concentrations are generally elevated due in part to agricultural and urban runoff. Here we use a three-dimensional hydrodynamic model of Lake Michigan to explicitly simulate the redistribution of tributary P loads within the lake from 2007-2010, and then assess their potential impacts on ecosystem services. Time-varying river inputs are based on observed flows and concentrations in 11 major tributaries, which collectively represent 70% of the total load. Elevated P loads during spring high-flows is trapped along the shoreline. In summer, lake stratification allows tributary plumes to spread offshore. By comparing maps of aggregate tributary loads and ecosystem services, we find that use of coastal waters for fishing and swimming may be particularly compromised along the southeastern shore. Our analyses illustrates the insights into coastal ecosystem health arising from simultaneously quantifying nutrient loads, in-lake physics, and ecosystem services. The framework developed here is applicable to a wide range of pollutants and waterbodies, and can help to guide coastal management efforts.

Lucas Gloege (Primary Presenter/Author), Columbia University, gloege@ldeo.columbia.edu;


Galen McKinley (Co-Presenter/Co-Author), Columbia University, mckinley@ldeo.columbia.edu;


Robert J. Mooney (Co-Presenter/Co-Author), Center for Limnology, University of Wisconsin - Madison, rjmooney@wisc.edu;


David Allan (Co-Presenter/Co-Author), University of Michigan, dallan@umich.edu;


Matthew Diebel (Co-Presenter/Co-Author), Wisconsin Department of Natural Resources, matthew.diebel@wisconsin.gov;


Peter B. McIntyre (Co-Presenter/Co-Author), Cornell University, pbm3@cornell.ecu;


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