Effect of Freeze-Up on Major Ion and Nutrient Content of a Prairie Winterkill Lake

Abstract

The reduction of lake volume due to ice formation in a shallow, moderately saline eutrophic prairie lake lacking a permanent surface inflow or outflow accounts for observed increases in specific conductance and concentration of predominant major ions (Mg, Ca, Na, and SO4). Dissolved inorganic carbon, total ammonia nitrogen, and soluble reactive phosphorus concentrations follow a different pattern; their increase under the ice cover is proportional to the decrease in dissolved oxygen and chlorophyll a content. Key words: winter fish kill, freeze-up, major ions, nutrients, prairie lakes, oxygen depletion, eutrophication