Under-Ice Water Quality Assessment in Perch Lake, Mud Lake, and Kimballs Bay

Abstract

Previous studies have found lower-than-expected dissolved oxygen (DO) concentrations in a number of bays of the St. Louis River estuary. These hypoxic conditions, which can negatively impact fish and other organisms, are a concern for natural resource managers and anglers. In the current study, water quality was investigated under the ice in March 2020 at Perch Lake, Mud Lake, and Kimballs Bay. DO concentrations varied among sites but were consistent with previous findings, with higher DO near connections to the estuary than farther away, and higher at middle than at lower depths. This research indicates the importance of water exchange in maintaining higher DO concentrations, and the need for future research on mechanisms responsible for low DO in these bays