EPA’s Research Vessel Lake Guardian Begins Summer Sampling of Great Lakes

EPA's Research Vessel Lake Guardian Begins Summer Sampling of Great Lakes

August 3, 2026

CHICAGO (August 3, 2026) - Today, U.S. Environmental Protection Agency's (EPA) largest research vessel, the Lake Guardian, began its month-long summer survey of water quality and food-web conditions in all five Great Lakes. Data collected will help protect human health and the environment by safeguarding water quality for drinking and recreation, assessing ecosystem stressors, and managing fisheries.

The summer survey offers a critical assessment of lake conditions when warmer surface water overlays colder bottom water-conditions which influence nutrient and oxygen levels, algal growth, organism distribution, and fish habitat.

Joining EPA's scientists during the survey will be scientists from Oak Ridge Institute for Science and Education, Natural Resources Research Institute, Buffalo State University, Cornell University, Michigan Technological Research Institute, Michigan Technological University, University of Minnesota-Duluth, University of Chicago, Cleveland State University, Michigan State University, and University of Michigan.

The Lake Guardian has been busy with several Great Lakes monitoring efforts this year:

• April: the Lake Guardian conducted a spring survey of water quality and food-web conditions when lake temperatures were at their coldest.
• May - July: EPA scientists aboard the ship sampled Lake Michigan for water quality, zooplankton and fish larvae through six separate surveys. This collaboration with U.S. Geological Survey and other partners allowed scientists to evaluate food resources for larval fish and track populations and growth rates.
• May - September: the research vessel monitors oxygen and temperature profiles in the central basin of Lake Erie to assess water quality trends and measure progress made to achieve improvements. This snapshot determines how much oxygen is available for fish and invertebrates to breathe.
• July: Fifteen educators from across the Great Lakes basin participated in a Lake Superior sampling exercise as part of the annual Shipboard Science Immersion partnership between EPA and NOAA Sea Grant. Educators are encouraged to learn from the experience to build Great Lakes literacy in their classrooms.

EPA has conducted biannual sampling surveys since 1983, maintaining the longest-running and most extensive monitoring dataset for water quality and aquatic biota in the Great Lakes. The Lake Guardian is funded by the Great Lakes Restoration Initiative, which was launched in 2010 to protect and restore the world's largest surface freshwater ecosystem.

Read more about EPA's Great Lakes monitoring programs.

###

Follow EPA Region 5 on Instagram, XExit EPA's website and visit our FacebookExit EPA's website page. For more information about EPA Region 5, visit our website.