Calcium Carbonate Precipitation and Transparency in Lakes: A Case Study

The major role the whiting phenomenon (precipitation of calcium carbonate) played in regulating transparency in hard water Owasco Lake, New York, during the summer of 1985 is documented. Two whiting events occurred that could have been easily mistaken by the public as phytoplankton blooms. Whiting explained more of the variability observed in Secchi disc transparency (SD) than phytoplankton pigments. SD would have been approximately 65% greater during the summer of 1985 in the absence of whiting. The failure of SD to increase since the early 1970s, despite a major reduction in the concentration of phytoplankton is probably due to a reoccurring prominent role of whiting in attenuating light in the lake. These characteristics are considered potentially widely occurring in hard‐water lakes, as the whiting phenomenon is common in these systems. Management programs for hard‐water lakes focusing on improved transparency should be aware of the potential for interference from whiting.