A Comparison of Ecological Memory of Lake Ice‐Off in Eight North‐Temperate Lakes

Abstract

Lake ice is slowly disappearing around the world. This loss of winter is a clear sign of climate change, but how does a loss of lake ice affect lakes? Decades of monitoring data is required to answer this question. In this paper, Dugan leverages 274 years of lake records collected by the North Temperate Lakes Long Term Ecological Research site (NTL-LTER) from eight lakes in Wisconsin to investigate whether lakes have ecological memory of ice-off. The response of lake temperature, oxygen concentrations, and water clarity to ice-off date were variable across latitude and lake size and type. It was found that when the period of time between ice-off and spring stratification is short, bottom water conditions have ecological memory of the timing of ice-off. However, in lakes with a short duration of lake ice, the memory effect fades. The implication of this finding is that as ice-off date trends earlier in many parts of the world, the lakes that will likely experience the largest changes in spring and summer lake ecosystem properties are the lakes that currently have the longest duration of lake ice, which has implications for lake habitat and spring fish spawning conditions.