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, 2026

CHICAGO (April 7, 2026) - On April 4, U.S. Environmental Protection Agency's (EPA's) largest research vessel, the R/VLake Guardian, began its annual water quality monitoring of the Great Lakes. The data collected help EPA and partner agencies assess ecosystem stressors, including invasive species and harmful algal blooms. The information EPA collects will also help support management of fisheries and water quality to better protect the Great Lakes so they can be used for drinking water, fishing, and recreation.

During the month-long spring survey, scientists will visit each of the five Great Lakes to collect water samples and small aquatic organisms such as phytoplankton (microscopic algae) and zooplankton (small crustacean animals). The spring survey enables scientists to capture vital information because water temperatures are uniformly cold from top to bottom and nutrient concentrations are generally at their highest for the season. Because seasonal conditions affect the parameters studied, samples are collected in both the spring and summer to give a more complete picture of the conditions of the lakes.

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

Background

Since 1983, EPA has conducted sampling surveys in the spring and summer to provide a comprehensive assessment of the lakes' conditions, part of the longest-running and most extensive monitoring dataset for water quality and aquatic biota in the Great Lakes. Data from surveys conducted aboard the R/V Lake Guardian were recently incorporated into the 2025 State of the Great Lakes reportExit EPA's website, an overview of the status and trends of the Great Lakes ecosystem.

The R/V 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.

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