Winterkill in the Washington Park Lagoon

Written by Michaela Rosenthal
    Thursday, 25 March 2021
Winterkill in the Washington Park Lagoon

Many of you venturing outside through the Milwaukee parks this spring may see various aquatic life- fish and frogs –floating rather than swimming at the surface of the park ponds.  This is known as “winterkill”. 

"Winterkill" is a natural process that happens when snow and ice cover a pond limiting the sunlight from reaching aquatic plants. When the plants die from lack of sunlight, they start to decompose, a process that uses oxygen in the water. lagoonkilltableIf the decomposing plants use too much oxygen, fish and other aquatic wildlife can die. For fish growth and activity, 5-6 ppm of dissolved oxygen within the water is required.  Levels below 3 ppm are stressful for most fish.  Levels below 2 ppm will not support fish and most other aquatic wildlife.  No worries, nothing in nature is wasted.  These dead fish will eventually decompose or be eaten by local wildlife.

Land Stewards with Urban Ecology Center work in partnership with the MKE County Parks to increase the habitat quality as well as the recreational and aesthetic aspects of the waters within Washington Park.  In late winter through early spring, we host volunteer opportunities to clean out the litter.  Late spring through summer we focus on invasive species removal such as hybrid cattail growing within the emergent waters.  By fall and early winter, we transition to the removal of woody plant species encroaching the lagoon shoreline.  Come join us and help restore our outdoors together (ROOT) during one of the public, walk-in volunteer sessions.

Washington Park ROOT Volunteering- Thursdays 3:00pm – 5:00pm & Friday 9:00am – 11:00am



Michaela Rosenthal

Michaela Rosenthal

Michaela began her days at the UEC as a volunteer, assisting the Land Stewardship team with buckthorn removal, tree and shrub planting as well as seed collecting and cleaning.  In 2013, she joined the Stewardship team as the UEC Washington Park Branch Land Steward.  Aside from her passion for land management, Michaela enjoys cooking, vegetable gardening and traveling around the United States as well as internationally.  She takes any and all opportunities to explore the outdoors.  When possible, she volunteers with local triathlon clubs with event/race set up, aid station dispenser or simply as the ultimate cheerleader.


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