Aquatic Food Webs

Understanding the effects of invasive mussels on freshwater bacterial communities in the Great Lakes

2022-2024

Graduate student fellow: Nikesh Dahal, University of Michigan

In the Great Lakes, invasive dreissenid mussels – commonly known as zebra and quagga mussels – are threatening the health of coastal ecosystems. These invasive mussels alter food webs and have been linked to occurrences of harmful cyanobacterial blooms and avian botulism outbreaks. Nikesh Dahal, PhD candidate at the University of Michigan, will investigate how predation by invasive mussels alters the structure and function of freshwater bacterial communities in Lake Erie and Lake Huron. Dahal will use genomic sequencing to analyze distribution of traits that allow species to survive and thrive under changing ecosystem conditions. Results from this work can build a deeper understanding of how invasive species affect these crucial freshwater ecosystems and inform future management strategies.

Project overview (PDF)

Measuring the role of invasive mussel larvae in lower trophic levels of Lake Huron’s food web

2022-2024

Lead principal investigator: Gordon Paterson, Michigan Technological University

Invasive zebra and quagga mussels have massively altered the flow of energy and nutrients through Great Lakes food webs. Gordon Paterson, an assistant professor at Michigan Technological University, will lead a project to investigate the role of juvenile zebra and quagga mussels (called veligers) in Lake Huron’s food web. Paterson and his team will analyze veliger samples from Saginaw Bay to determine their nutritional value and how much energy they make available to predators. Results will provide important insights into invasive species’ roles in shifting food webs around the Great Lakes.

Project overview (PDF)

Effects of nearshore nutrient cycling on Lake Michigan’s benthic invasive species

2016-2018
Kevin Pangle, Central Michigan University

Nutrient cycling in Lake Michigan has shifted in recent years, with an increased proportion of incoming nutrients being claimed by benthic, or bottom-dwelling, organisms living near shore. In places where the benthic near-shore habitat is dominated by invasive species, this diversion of energy may have wide-ranging impacts on Lake Michigan’s food web. The project team surveyed populations of bottom-dwelling invasive species in nearshore habitats and set up artificial habitats to test how well these invasive species performed under different nutrient conditions. Finally, they sampled and analyzed various Lake Michigan invertebrates, algae, plankton, and fish to determine how nutrients are cycling through nearshore and offshore habitats.

Journal article (PDF)

Understanding changes in fish populations in Saginaw Bay

2003-2006
Sara Adlerstein, University of Michigan
Edward Rutherford, University of Michigan

Full title: Impact of Exotic Species and Nutrient Decline on Fish Community Structure and Food Web Linkages in Saginaw Bay, Lake Huron

Walleye and yellow perch are two key sport fish in Saginaw Bay. Over the past decade, less available nutrients, competition with invasive species, and changes in the way the fisheries are managed has led to dramatic changes within the fisheries. Investigators used state-of-the-art statistical modeling techniques to quantify the impacts of these changes on fish community structure and distribution, particularly on walleye and yellow perch populations. Methods included an analysis of existing fisheries data and the creation of an ecosystem view of Saginaw Bay.

Project: R/ME-3

The impact of the Diporeia decline on the competitive interactions and distributions of slimy and deepwater sculpins in Lake Michigan

2003-2006
David Jude, University of Michigan

Project: R/ME-4

Complex interactions between zebra mussels and phytoplankton: Variation in grazing effects across the trophic gradient

2003-2006
Orlando Sarnelle, Michigan State University

Project: M/PD-16

Nutrient enrichment and food web changes in Lakes Michigan and Superior

2000-2003
Peggy Ostrom and Nathaniel Ostrom, Michigan State University

Full title: Evaluation of the Trophic State of Lakes Michigan and Superior

Researchers applied a new approach for evaluating the water quality of Lakes Michigan and Superior and developed a detailed database of water quality changes in the two lakes. They used oxygen isotopes to compare the rate of photosynthesis by algae to the rate of respiration by aquatic organisms, providing an indicator of the level of nutrients and algae in the waters. With funding from the U.S. Environmental Protection Agency Great Lakes National Program Office, the research has been extended to Lake Erie. The work is part of the Lake Erie Trophic Status project to understand the ecosystem’s response to recent, dramatic changes in food web structure and composition. The combined data sets from Lake Erie, Lake Superior, and Lake Michigan’s Grand Traverse Bay offer a unique perspective on the factors controlling the development of algal blooms and hypoxia. This information should allow us to better predict how climate change and biological invasions will affect algae growth and aquatic food webs of the Great Lakes.

Project: R/ES-18