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

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

April 7, 2025

CHICAGO (April 7, 2025) - U.S. Environmental Protection Agency's largest research vessel, the R/VLake GuardianExit EPA's website, has begun its annual spring water quality survey. During the month-long mission, scientists will collect samples of water and organisms such as plankton and zooplankton in each of the five Great Lakes. The data gathered by R/VLake Guardian enables EPA and partner agencies to assess the impact of invasive species and algal blooms, manage fisheries, and protect the quality of Great Lakes water so it can be used for drinking water, fishing, and recreation.

Since 1983, EPA has conducted biannual sampling surveys, which together provide a comprehensive assessment of the lakes' health. The spring survey samples the lakes when temperatures are uniformly cold from top to bottom and nutrient concentrations are generally at their highest for the season. The summer water quality survey will sample the lakes when warmer surface water overlays colder bottom water, since these conditions influence nutrient and oxygen levels, algal growth, organism distribution, and fish habitat. These two surveys will add to EPA's Great Lakes water quality dataset, the longest-running and most extensive monitoring program for water quality and aquatic biota for all five Great Lakes.

Scientists from the Oak Ridge Institute for Science and Education, University of Minnesota Duluth - Natural Resources Research Institute, Cornell University, Michigan Tech Research Institute, Michigan Technological University, Case Western Reserve University, and the University of Chicago will join scientists from EPA's Great Lakes National Program Office to conduct the survey.

These surveys support EPA Administrator Lee Zeldin's Powering the Great American Comeback initiative, specifically the pillars of Clean Air, Land, and Water for Every American and Cooperative Federalism and Cross-Agency Partnerships. They also fulfill EPA's statutory requirements in the Clean Water Act to monitor the water quality of the Great Lakes.

Read more about EPA's Great Lakes monitoring programsExit EPA's website.

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