Twin Cities Metro Lake Histories

Students work with Dr. Kevin Theissen to investigate past and present impacts on metro area lakes in partnership with local watershed districts. Theissen and the students collect sediment cores from the lake and then analyze the sediments to determine the past ecology of the area over the past several hundred years or more. Here are some pictures of the students and Dr. Theissen collecting core samples at Lake Wabasso, in Roseville, MN.  Check out another collaborative project with the Comfort Lake Forest Lake Watershed District and the St. Croix Watershed Research Station here


 Kim Hughes is collecting data on the water chemistry, such as pH and dissolved oxygen concentration.

Dr. Theissen and Anders Noren with the first freeze core sample.

Nora Kennedy, Jake Friedrichs, Dr. Theissen, and Anders Noren preparing to make a core sample using the corer.

The result of the coring: a 3-meter core sample of Lake Wabasso.

This core sample contains lake sediment that has been accumulating for hundreds, or even, thousands of years. Different minerals and fossils present in the layers of sediment can tell scientists about the past climate conditions surrounding Lake Wabasso.

Nora and another student are getting ready to add dry ice to the freeze core. This will cause the sediment to freeze, minimizing any disruption of the sediment layers that might occur during the removal of the core from the water.

Anders Noren holds the freeze core rope in place for 10 minutes to allow for the sediment around the core to freeze and set properly before pulling the sediment core up to the surface.

Freeze core sample #2 is complete. These cores will then be brought to the Limnology Research Center at the University of Minnesota where they will later be polished and sampled by the students to further understand the past climatic conditions.