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EPA Deploys Autonomous Underwater Vehicle to Assess Lake Erie’s Dissolved Oxygen Levels

Nokomis monitoring device
While gliding autonomously through Lake Erie’s central basin, Nokomis records continuous high-resolution measurements of dissolved oxygen along with other parameters that monitor the health of the lake.

(Sept. 18, 2019) - The U.S. EPA glider Nokomis, an Autonomous Underwater Vehicle, was deployed by EPA’s Office of Research and Development in Lake Erie near Cleveland from the US EPA Research Vessel Lake Guardian on September 5, 2019. Since then, it’s been cruising transects in the central basin assessing low dissolved oxygen levels, or hypoxia, as part of a larger Cooperative Science and Monitoring Initiative project in Lake Erie also examining late-summer harmful algal blooms. 

The glider is “flown” with coding and sensors to keep it safe and on course. Along its route, it changes buoyancy to ascend, descend and move forward in a sawtooth pattern.

U.S. EPA scientist Tom Hollenhorst recalibrates the glider Nokomis before a three-week deployment in Lake Erie.

As it travels, the glider records continuous high-resolution data on:

  • dissolved oxygen
  • temperature
  • conductivity (water's ability to conduct electricity)
  • chlorophyll-a
  • colored dissolved organic matter, which consists of molecules from decaying animals and plants
  • optical backscatter (the redirection of light molecules hitting the water)

Nokomis is deployed in Lake Erie near Cleveland from U.S. EPA's Research Vessel Lake Guardian.

After a 22-day deployment in Lake Erie, Nokomis will be retrieved by the Lake Guardian on September 27, 2019.

EPA’s Great Lakes National Program Office and its activities, such as Lake Guardian surveys and the glider, are funded under the Great Lakes Restoration Initiative.

Learn more on EPA’s website: